Add DB9 CAD reference data

Reposition the ESP32 and RS-232 reference within the notched outline,
preserve the A0 snapshot, and add second-pass two-layer routing
evidence.
Refresh validation reports and draft previews while keeping fabrication
status provisional.

docs/agent/architecture.md

@@ -187,6 +187,14 @@ Admin SSH `exit`, remote reboot, SSH stop/disconnect, and host-key rotate/reset
 
 Browser stop/reboot uses this same owner-adapter control path. Exact forced certificate rotation instead uses the typed queue union and immutable `dispatcher_actions` mask to hand off after drain/200 ms to the existing 12 KiB dispatcher, not the 4 KiB control stack. Pending input is discarded through execution and an executing slot remains reserved across self-detach. Canonical shared service/identity replacement preserves commit/stop/start failure semantics. Parsed other-account interactive add/password and forced role/delete are allowed. Canonical Wi-Fi commands are also allowed, including hidden secret prompts and disruptive changes; these use the ordinary owner queue and may cut off the browser before output arrives, without a deferred acknowledgement guarantee. Browser self/generated/key/recovery, mDNS mutations and restricted SSH shell actions remain denied; typed Settings has separate permissions. Post-prompt currentness is operation admission, not an atomic session-liveness/NVS guarantee. [Browser policy and recovery](../web_administration.md#browser-shell-policy).
 
+### Shared IPv4/IPv6 diagnostics
+
+`network_console` owns root and `wifi`-alias ping/traceroute/nslookup for UART0, admin SSH and browser Admin. Family flags are parsed once; explicit IPv6 never silently falls back to IPv4. Hostname probes use IPv4-first resolution fallback only; nslookup queries A and AAAA separately and shows unscoped link-local answers. Probes require a device-local link-local zone (`%sta`, `%ap`, valid index/name). Resolver policy/DNS provisioning and serial transport ownership are unchanged.
+
+Traceroute owns one raw socket and a 1280-byte transient receive buffer on the shared dispatcher stack, one eight-byte probe per hop (max30), and one-second absolute receive deadlines. It rejects incomplete/corrupt/unrelated packets and unsupported IPv6 extension headers/fragments. IDF5.5.0-specific framing, automatic ICMPv6 checksum, common `IP_TTL` hop-limit behavior and millisecond timeout flooring are pinned/retested; <1ms remaining returns timeout rather than configuring an infinite wait. DNS and send/scheduler latency are not covered by the receive deadline.
+
+Ping keeps the 4200-byte PSRAM-only lazy queue payload and SDK transient task. Permanent callback context plus a pending reservation survives the count-based console deadline; later pings cannot reset a live producer's queue. SDK receive can outlast its timeout under unrelated ICMP, so a timed-out session stays reserved until END. END means callback production ended, not synchronous task/socket destruction; retiring resources can briefly overlap a new session. These diagnostics serialize administration but never execute on HTTPD or enter the serial hot path. Tests and exact limits: `tests/network_diagnostics/README.md`.
+
 ## Wi-Fi and persistence
 
 `wifi_config` owns a fixed-width versioned NVS schema with four prioritized station profiles and AP policy `off`, `fallback`, or `always`. Missing configuration generates per-device defaults including a random AP password. Invalid stored data is generally left untouched while RAM defaults are used.

docs/agent/code-map.md

@@ -150,6 +150,7 @@ Shared UI regression: `tests/web_ui_session/run.py` and its domain `.cjs` fixtur
 - Ownership: dispatcher is sole `esp_console_run()` caller; the SSH owner exclusively performs post-initialization wolfSSH runtime calls.
 - Lifecycle: remote session tokens include slot generation; fixed output/history/prompt state is wiped immediately on idle close or after an executing handler returns. Admin SSH `exit` and Ctrl+D on an empty command line request bounded deferred self-disconnect after best-effort output draining.
 - Constraint: one slow command or prompt serializes all administration. Admin SSH is unavailable until command registration and UART frontend creation complete; supported deferred actions wait only for a bounded application-buffer drain heuristic.
+- Dual-stack diagnostics: `network_console.*` is the shared root/`wifi` handler on all three admin surfaces. `-4`/`-6`, device-local `%sta`/`%ap`/index/name; default probes IPv4-first resolution fallback only, nslookup explicit A+AAAA and unscoped link-local display. One-second/hop raw IPv4/IPv6 traceroute validates full outer packet/quoted echo and rejects IPv6 extensions/fragments. IDF5.5.0 raw framing/hoplimit/checksum/timeout contract is version-guarded. Ping uses existing PSRAM queue and SDK transient task with permanent callback context/deadline/pending reservation; END does not imply completed SDK teardown. Tests: `tests/network_diagnostics` (actual handlers/packet and SDK contracts), `tests/network_diagnostics_surfaces` (routing/policy/completion). No serial hot-path changes.
 
 ## Wi-Fi
 

docs/agent/current-state.md

@@ -2,6 +2,20 @@
 
 Working memory, not an implementation timeline. Source is authoritative; begin with [code map](code-map.md), [architecture](architecture.md) and [decisions](design-decisions.md).
 
+## Carrier PCB A1 — revised placement and CAD integration
+
+- `hardware/PCB/serial-carrier.kicad_pcb`: routed 82 × 80 mm two-layer draft; 36 × 19 mm top-left notch, ESP32 shifted down for bottom USB access, RS-232 bare PCB front flush with carrier top. Exact ESP32 body/USB/antenna envelope remains pending user measurements; RF reserve is provisional.
+- Adafruit STEP metal geometry extracted and validated; provenance/dimensions in `hardware/PCB/db9-mechanical-notes.md`. Flange front sits 1.930 mm inside carrier edge, screw-lock mouths 2.870 mm outside, shell nose 3.870 mm outside. Case wall plane is not yet fixed. Seven board-local Dwgs.User projections added; rerun `add_db9_envelope.py` and `add_device_silkscreen.py` after moving modules.
+- Placement PDF and SVG/PNG/3D previews refreshed. Fresh PCB, independent routing, preservation and CAD validators pass: 38/38 connections, 565 segments, 22 vias, 0 physical DRC violations/unrouted, one expected provisional U2 footprint parity warning. Not fabrication-ready; no hardware qualification or Gerbers. Existing project/schematic/library work preserved; board saves must use `SaveBoard(..., True)` and require checking editor lock. Prior A0 preserved in validation backup.
+
+## Dual-stack diagnostics follow-up — implemented, device validation pending
+
+- User explicitly requested IPv6 ping/traceroute/nslookup on all surfaces after accepting Phase12. Shared `network_console.*` now supports one `-4`/`-6` anywhere after command, preserves count/hop bounds, root and `wifi` aliases. Default probes try IPv4 then IPv6 on resolution failure only; nslookup performs A+AAAA queries separately (one selected address/family), displays unscoped link-local records. Link-local probes require ESP-local `%sta`/`%ap`/index/name; no client-interface guess or IPv4-mapped fallback. Help/completion updated; permissions unchanged.
+- Actual IDF5.5.0 audit: raw ICMPv6 includes outer IPv6 header, automatic TX checksum, common `IPPROTO_IP/IP_TTL` hoplimit; replies validate checksums/target/id/seq and reject extensions/fragments. Traceroute one socket/max30 probes/1s receive deadline, 1280B receive buffer. Review caught sub-ms timeout flooring to infinite SDK wait; <1000us now returns timeout, actual SDK conversion/mailbox tests verify. No dependency/config/partition/serial path change.
+- Ping retains4200B PSRAM queue, max20 probes and SDK transient task; permanent callback context plus pending reservation protects delayed END after count*2+2 second console deadline. SDK unrelated-ICMP receive loop may outlive timeout; later pings fail busy until END, which does not prove synchronous resource destruction. Read exact limits in command reference/tests README. IPv6-only unicast DNS still requires a configured resolver; no RDNSS/DHCPv6 provisioning added.
+- `pio run` PASS **94,452 B linked RAM / 1,857,673 B flash**, +8/+3,188 versus accepted prior build. Traceroute receive-wait object frame measured240→1408B (not runtime stack high-water). No new permanent task/socket/queue capacity. Hardware/ changes in working tree belong to other agent and were not read/edited.
+- Parent PASS: production diagnostics8027 checks+10k malformed packet inputs, seven installedSDK hashes+actualtimeout fixtures, 432 SSH/WEB root+alias routing cases/UART parity/ordinary-role and revocation guards/completion, existing admin policy and browser Wi-Fi secret fixture. Independent review fixes verified no remaining actionable findings in scoped paths. ASan/UBSan host runtimes absent. Broader console-boundary pre-existing missing rebootfake remains (not changed). No upload/device/network test; Phase12 acceptance remains valid only for its recorded baseline, not this follow-up.
+
 ## Phase 12 COMPLETE — explicit user validation
 
 - User states: “I just validated Phase 12 successfully.” Record acceptance, not a pending phase. Canonical device evidence and reusable regression guidance: [Phase 12](../roadmap.md#phase-12--advanced-network-integration). No unreported DHCP capture, DNS-zone update, exhaustive address/service transition, fault/soak or byte-integrity pass is implied.

docs/command_reference.md

@@ -108,12 +108,38 @@ Opening `/dev/ttyACM*` with DTR asserted creates the `usb-cdc` broker client, st
 | `wifi ap secret` / `wifi ap show-secret` | Set or reveal the AP password. |
 | `wifi save|load|defaults|reset` | Persist, restore, reset in RAM, or reset and persist configuration. |
 | `wifi counters|clear-counters` | Show or clear Wi-Fi counters. |
-| `wifi ping <host> [count]` | Send 1–20 IPv4 or IPv6 ICMP probes. |
+| `wifi ping [-4\|-6] <host> [count]` | IPv4/IPv6 ICMP echo; 1–20 probes, default 4. |
-| `wifi nslookup <host>` | Resolve and display unique IPv4/IPv6 addresses. |
+| `wifi nslookup [-4\|-6] <host>` | Explicit A/AAAA lookup; default queries both families. |
-| `wifi traceroute <host> [max-hops]` | Run IPv4 ICMP traceroute with up to 30 hops. |
+| `wifi traceroute [-4\|-6] <host> [max-hops]` | IPv4/IPv6 ICMP echo traceroute; 1–30 hops, default 16. |
 
 `ping`, `nslookup`, and `traceroute` are root aliases. The four station-profile slots use lower priority values first. Edits to a disabled profile's SSID, priority, security mode, or secret are staged in RAM and do not interrupt the current Wi-Fi connection. Enabling or disabling a profile, changing an enabled profile, or changing AP policy/configuration applies the new radio policy and may reconnect Wi-Fi. Use `wifi save` to persist working changes. Passwords are not displayed by ordinary status output.
 
+### Dual-stack network diagnostics
+
+Root `ping`, `traceroute` and `nslookup`, and their `wifi` aliases, share one implementation on **UART0, admin SSH and the browser Admin console**. They execute on the ESP32, not the client computer or the attached UART1 equipment. Ordinary serial-role users do not gain administration access. `-4` and `-6` completion is available for all six command prefixes.
+
+```text
+ping -6 example.com 4
+ping example.com 4 -4
+wifi ping -6 fe80::1%sta 3
+traceroute -6 example.com 16
+wifi traceroute -4 example.com 16
+nslookup example.com
+nslookup -6 peer.local
+```
+
+One optional family selector can appear before or after the host/count; duplicate/conflicting selectors and unknown options are rejected. Probe counts/hop limits are positional, not Linux `-c`/`-m` options. Without a selector, numeric addresses retain their family and probe hostnames try IPv4 resolution, then IPv6 if no address was obtained. A failed probe does **not** retry the other family; this is not Happy Eyeballs. Explicit `-6` never silently uses IPv4.
+
+Link-local **probe destinations** require a scope on the ESP32: `%sta`, `%ap`, an existing numeric lwIP interface index, or an existing lwIP interface name. These are not the browser/SSH computer's interface names. If name resolution returns an unscoped link-local address, `nslookup` displays it, but ping/traceroute request an explicit scoped literal rather than guessing an interface. Numeric `nslookup` input is displayed without DNS/reverse lookup.
+
+`nslookup` without a selector performs separate A and AAAA queries. The installed resolver returns one selected address per family (`CONFIG_LWIP_DNS_MAX_HOST_IP=1`), not a complete DNS RRset. Missing records, DNS timeouts and server failures can share the same SDK error; partial success is displayed rather than hidden. Unicast names require a usable configured DNS server; SLAAC alone does not provision one in this firmware. `.local` uses the existing lwIP mDNS query support. No DNS server or RA/DHCP policy is changed by these commands.
+
+Traceroute sends one eight-byte echo probe per hop with a one-second absolute receive deadline; it can stop up to 999 microseconds early to avoid the SDK's zero-millisecond/infinite-wait conversion. Hop addresses are numeric. ICMPv6 replies are checked against the actual IDF raw framing/checksum, destination and probe identity; IPv6 extension headers/fragments in replies or quotes are unsupported and ignored. Filtering/rate limiting can produce `*` even when ordinary connectivity works. DNS, scheduler and send latency are outside the receive deadline.
+
+Ping retains the SDK's bounded-count transient task and existing PSRAM event queue. Its console wait is bounded to `count * 2 + 2` seconds after start, but unrelated ICMP can extend the SDK receive loop: after a console timeout, further pings are refused until the old END event arrives. END finishes callback production; SDK resource teardown may briefly overlap a subsequent session. No IPv6 TTL is printed because the installed SDK does not provide a valid received IPv6 hop-limit profile. These commands serialize the administration dispatcher while executing; they do not run on HTTPD or change the broker/serial path.
+
+Focused host/SDK and surface tests: `tests/network_diagnostics/` and `tests/network_diagnostics_surfaces/`. Real IPv4/IPv6/scoped ping, DNS and multi-hop traceroute remain device-validation tasks for this follow-up.
+
 ## mDNS
 
 | Command | Description |
@@ -125,7 +151,7 @@ Opening `/dev/ttyACM*` with DTR asserted creates the `usb-cdc` broker client, st
 
 When the Wi-Fi station has IPv4 or a preferred IPv6 address, the Wi-Fi manager announces `sak-<suffix>.local` and advertises available HTTPS/SSH services through DNS-SD. This is STA-only, local-link discovery, not certificate or host-key trust. The default suffix is the lower-case hexadecimal STA MAC address. Suffixes may contain lowercase ASCII letters, digits, and internal hyphens only. Changing a suffix queues a best-effort reannouncement and updates the DHCPv4 hostname (`sak-<suffix>`, without `.local`) for subsequent DHCP exchanges; it does not force a lease restart. A configured DHCP/DNS server may publish that name in its own zone.
 
-`wifi status` and browser Network status distinguish IPv4 absence and IPv6 link-local/ULA/GUA availability. `wifi` / `wifi status` and the web Network settings dialog additionally list up to three actual preferred IPv6 addresses, labelled link-local, ULA or GUA; these are copied with the flags, not inferred from enabled IPv6 support. A link-local destination needs the client's interface as its zone. To separate client address preference from IPv6 reachability, run `ping -6 -c 3 sak-1024.local` on an IPv6-capable client; choosing IPv4 with plain `ping` does not mean the device lacks IPv6. If lookup fails, inspect AAAA resolution (for example `avahi-resolve-host-name -6 sak-1024.local` where Avahi is installed), then test the numeric address from `wifi status` directly. Link-local-only connectivity counts as `ONLINE` and can retire the fallback AP after the existing stability interval; it does not establish Internet access. HTTPS/WebSocket and SSH support both families; browser IPv6 literals require brackets and cannot contain interface zones. Use the `.local` hostname for link-local browser access where supported by the client. Existing ping selects the first usable resolver result without family racing, and traceroute remains IPv4-only. mDNS failures do not stop Wi-Fi, UART0, UART1, or native USB access. See [Phase 12](roadmap.md#phase-12--advanced-network-integration) for discovery convergence limits and pending device validation.
+`wifi status` and browser Network status distinguish IPv4 absence and IPv6 link-local/ULA/GUA availability. `wifi` / `wifi status` and the web Network settings dialog additionally list up to three actual preferred IPv6 addresses, labelled link-local, ULA or GUA; these are copied with the flags, not inferred from enabled IPv6 support. A link-local destination needs the client's interface as its zone. To separate client address preference from IPv6 reachability, run `ping -6 -c 3 sak-1024.local` on an IPv6-capable client; choosing IPv4 with plain `ping` does not mean the device lacks IPv6. If lookup fails, inspect AAAA resolution (for example `avahi-resolve-host-name -6 sak-1024.local` where Avahi is installed), then test the numeric address from `wifi status` directly. Link-local-only connectivity counts as `ONLINE` and can retire the fallback AP after the existing stability interval; it does not establish Internet access. HTTPS/WebSocket and SSH support both families; browser IPv6 literals require brackets and cannot contain interface zones. Use the `.local` hostname for link-local browser access where supported by the client. On-device diagnostics support explicit family selection and scoped IPv6 as described above; Linux client syntax and interface scope are separate. mDNS failures do not stop Wi-Fi, UART0, UART1, or native USB access. See [Phase 12](roadmap.md#phase-12--advanced-network-integration) for discovery convergence limits and recorded user acceptance.
 
 ## HTTPS web terminal
 

docs/roadmap.md

@@ -314,7 +314,7 @@ The device is not intended to become a general-purpose router. Captive-portal in
 - mDNS 1.12.0 exposes no readiness acknowledgement and can silently drop queued family actions. Absent families are disabled on each one-second owner pass; available families are re-enabled/reprobed on a 30-second repair cadence. Upstream synchronous calls can delay this cadence. There can be a transient stale/zero-A response window after IPv4 loss before disable is processed. AAAA records follow upstream **valid-address** semantics, including deprecated-but-still-valid addresses, not preferred-only filtering. Client caches expire independently.
 - `cmake/mdns_membership.*` applies one version/hash-guarded, build-local source overlay to mDNS 1.12.0: balance per-family multicast leaves and unwind joins after PCB creation failure. Managed sources and dependency versions remain unchanged. An upstream mismatch fails configuration for deliberate review; see `tests/mdns_membership/README.md` for maintenance/removal and regression evidence. This is not the abandoned Phase 9 patch set.
 - `sdkconfig.defaults` explicitly enables IPv4/IPv6 and increases mDNS service capacity from one to two. Existing saved configurations override defaults: verify `CONFIG_LWIP_IPV4=y`, `CONFIG_LWIP_IPV6=y`, `CONFIG_MDNS_MAX_SERVICES=2` and STA-only predefined mDNS interfaces before building. The local N16R8 saved configuration was updated accordingly. No new task, transport socket, broker slot, serial buffer, partition, filesystem or generated web asset was added.
-- Existing diagnostic limits remain: hostname ping selects the resolver's first usable result (not Happy Eyeballs), scoped link-local ping is not newly supported, and traceroute remains IPv4-only. DHCPv6, infrastructure DNS registration of SLAAC addresses, and new IPv6 resolver provisioning are outside this baseline.
+- The accepted baseline initially retained IPv4-only traceroute and limited family/scope selection. The later requested [dual-stack diagnostics follow-up](command_reference.md#dual-stack-network-diagnostics) adds `-4`/`-6` to ping/traceroute/nslookup across UART0, admin SSH and browser Admin, scoped IPv6 probes and explicit A+AAAA lookup. This follow-up is built/host-tested, not covered retroactively by the acceptance capture below. DHCPv6, infrastructure DNS registration of SLAAC addresses, and new IPv6 resolver provisioning remain outside scope.
 
 #### Validation evidence and acceptance
 

docs/web_administration.md

@@ -28,7 +28,7 @@ HTTPD alone owns browser-admin socket IO and its 1,552-byte PSRAM-only payload.
 Typed Settings permissions do not expand shell permissions. Parsed canonical arguments, not raw prefixes or completion suggestions, control admission:
 
 - Browser `web` permits only `web status`, `web stop`, and exact `web certificate rotate --force`; certificate info/reset, diagnostics/performance and other web forms are denied.
-- Browser `wifi` uses the canonical command handler, including bare `wifi` (status), profile/AP settings, persistence, lifecycle and network diagnostics. Profile/AP secret entry uses the shared hidden prompt: no input echo, history or completion of secret bytes; cancellation, disconnect and failed currentness discard the input. Explicit `wifi ap show-secret` reveals the AP password only in the invoking admin terminal; routine status and completion do not reveal credentials. Browser `mdns` still permits only exact `mdns status`.
+- Browser `wifi` uses the canonical command handler, including bare `wifi` (status), profile/AP settings, persistence, lifecycle and network diagnostics. Profile/AP secret entry uses the shared hidden prompt: no input echo, history or completion of secret bytes; cancellation, disconnect and failed currentness discard the input. Explicit `wifi ap show-secret` reveals the AP password only in the invoking admin terminal; routine status and completion do not reveal credentials. Browser `mdns` still permits only exact `mdns status`. Root and `wifi`-prefixed ping/traceroute/nslookup support the same `-4`/`-6` and device-local IPv6 scope syntax as UART0/admin SSH; see [dual-stack diagnostics](command_reference.md#dual-stack-network-diagnostics). They run on the shared dispatcher, not HTTPD or the client browser; no extra endpoint or permission expansion is involved.
 - Browser `user` permits status/list/show and interactive add/password plus forced role/delete for **other accounts only**. Self changes, generated passwords, key commands and recovery are denied there; typed Accounts supports the separately bounded self/generated/key workflows.
 - Browser SSH stop/disconnect/reset and host-key mutation are denied; typed SSH Settings has its own safe owner path. Do not claim full browser-shell parity.
 - Browser `reboot` and owner-relative `exit` are supported. First-admin provisioning uses normal `user add` on UART0; unavailable-database recovery is UART0-only. The legacy `user bootstrap` and web credential commands no longer exist.

hardware/PCB/.gitignore

@@ -0,0 +1,7 @@
+# KiCad per-user state, locks and automatic backups
+*.kicad_prl
+*.lck
+~*.lck
+*-backups/
+*.bak
+__pycache__/

hardware/PCB/Carrier.kicad_sym

@@ -0,0 +1,116 @@
+(kicad_symbol_lib (version 20231120) (generator "kicad_symbol_editor")
+(symbol "HW678_N16R8" (pin_names (offset 0.762)) (in_bom yes) (on_board yes)
+(property "Reference" "U" (at 0 34.29 0) (effects (font (size 1.27 1.27)) ))
+(property "Value" "HW678_N16R8" (at 0 31.75 0) (effects (font (size 1.27 1.27)) ))
+(property "Footprint" "Carrier:HW678_2x22_Provisional" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Datasheet" "" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Description" "HW-678 V0.0.0 / N16R8 carrier interface; project numbering; onboard USB/regulator retained" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(symbol "HW678_N16R8_0_1" (rectangle (start -17.78 29.21) (end 17.78 -29.21) (stroke (width 0.254) (type default)) (fill (type background))))
+(symbol "HW678_N16R8_1_1"
+(pin power_out line (at -22.86 26.67 0) (length 5.08) (name "3V3" (effects (font (size 1.016 1.016)) )) (number "1" (effects (font (size 1.016 1.016)) )))
+(pin passive line (at -22.86 24.13 0) (length 5.08) (name "3V3" (effects (font (size 1.016 1.016)) )) (number "2" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 21.59 0) (length 5.08) (name "EN" (effects (font (size 1.016 1.016)) )) (number "3" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 19.05 0) (length 5.08) (name "GPIO4" (effects (font (size 1.016 1.016)) )) (number "4" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 16.51 0) (length 5.08) (name "GPIO5" (effects (font (size 1.016 1.016)) )) (number "5" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 13.97 0) (length 5.08) (name "GPIO6" (effects (font (size 1.016 1.016)) )) (number "6" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -22.86 11.43 0) (length 5.08) (name "GPIO7" (effects (font (size 1.016 1.016)) )) (number "7" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -22.86 8.89 0) (length 5.08) (name "GPIO15" (effects (font (size 1.016 1.016)) )) (number "8" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 6.35 0) (length 5.08) (name "GPIO16" (effects (font (size 1.016 1.016)) )) (number "9" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -22.86 3.81 0) (length 5.08) (name "GPIO17" (effects (font (size 1.016 1.016)) )) (number "10" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 1.27 0) (length 5.08) (name "GPIO18" (effects (font (size 1.016 1.016)) )) (number "11" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 -1.27 0) (length 5.08) (name "GPIO8" (effects (font (size 1.016 1.016)) )) (number "12" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at -22.86 -3.81 0) (length 5.08) (name "GPIO3" (effects (font (size 1.016 1.016)) )) (number "13" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at -22.86 -6.35 0) (length 5.08) (name "GPIO46" (effects (font (size 1.016 1.016)) )) (number "14" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at -22.86 -8.89 0) (length 5.08) (name "GPIO9" (effects (font (size 1.016 1.016)) )) (number "15" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 -11.43 0) (length 5.08) (name "GPIO10" (effects (font (size 1.016 1.016)) )) (number "16" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at -22.86 -13.97 0) (length 5.08) (name "GPIO11" (effects (font (size 1.016 1.016)) )) (number "17" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -22.86 -16.51 0) (length 5.08) (name "GPIO12" (effects (font (size 1.016 1.016)) )) (number "18" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 -19.05 0) (length 5.08) (name "GPIO13" (effects (font (size 1.016 1.016)) )) (number "19" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 -21.59 0) (length 5.08) (name "GPIO14" (effects (font (size 1.016 1.016)) )) (number "20" (effects (font (size 1.016 1.016)) )))
+(pin passive line (at -22.86 -24.13 0) (length 5.08) (name "5V" (effects (font (size 1.016 1.016)) )) (number "21" (effects (font (size 1.016 1.016)) )))
+(pin power_out line (at -22.86 -26.67 0) (length 5.08) (name "GND" (effects (font (size 1.016 1.016)) )) (number "22" (effects (font (size 1.016 1.016)) )))
+(pin passive line (at 22.86 26.67 180) (length 5.08) (name "GND" (effects (font (size 1.016 1.016)) )) (number "23" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 24.13 180) (length 5.08) (name "GPIO43" (effects (font (size 1.016 1.016)) )) (number "24" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 21.59 180) (length 5.08) (name "GPIO44" (effects (font (size 1.016 1.016)) )) (number "25" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 19.05 180) (length 5.08) (name "GPIO1" (effects (font (size 1.016 1.016)) )) (number "26" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 16.51 180) (length 5.08) (name "GPIO2" (effects (font (size 1.016 1.016)) )) (number "27" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 13.97 180) (length 5.08) (name "GPIO42" (effects (font (size 1.016 1.016)) )) (number "28" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 11.43 180) (length 5.08) (name "GPIO41" (effects (font (size 1.016 1.016)) )) (number "29" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 8.89 180) (length 5.08) (name "GPIO40" (effects (font (size 1.016 1.016)) )) (number "30" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 6.35 180) (length 5.08) (name "GPIO39" (effects (font (size 1.016 1.016)) )) (number "31" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 3.81 180) (length 5.08) (name "GPIO38" (effects (font (size 1.016 1.016)) )) (number "32" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 1.27 180) (length 5.08) (name "GPIO37" (effects (font (size 1.016 1.016)) )) (number "33" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 -1.27 180) (length 5.08) (name "GPIO36" (effects (font (size 1.016 1.016)) )) (number "34" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 -3.81 180) (length 5.08) (name "GPIO35" (effects (font (size 1.016 1.016)) )) (number "35" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 -6.35 180) (length 5.08) (name "GPIO0" (effects (font (size 1.016 1.016)) )) (number "36" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 -8.89 180) (length 5.08) (name "GPIO45" (effects (font (size 1.016 1.016)) )) (number "37" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 -11.43 180) (length 5.08) (name "GPIO48" (effects (font (size 1.016 1.016)) )) (number "38" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 -13.97 180) (length 5.08) (name "GPIO47" (effects (font (size 1.016 1.016)) )) (number "39" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 -16.51 180) (length 5.08) (name "GPIO21" (effects (font (size 1.016 1.016)) )) (number "40" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 -19.05 180) (length 5.08) (name "GPIO20" (effects (font (size 1.016 1.016)) )) (number "41" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 -21.59 180) (length 5.08) (name "GPIO19" (effects (font (size 1.016 1.016)) )) (number "42" (effects (font (size 1.016 1.016)) )))
+(pin passive line (at 22.86 -24.13 180) (length 5.08) (name "GND" (effects (font (size 1.016 1.016)) )) (number "43" (effects (font (size 1.016 1.016)) )))
+(pin passive line (at 22.86 -26.67 180) (length 5.08) (name "GND" (effects (font (size 1.016 1.016)) )) (number "44" (effects (font (size 1.016 1.016)) )))
+)
+)
+(symbol "MAX3243_Module_Reference" (pin_names (offset 0.762)) (in_bom yes) (on_board yes)
+(property "Reference" "U" (at 0 22.86 0) (effects (font (size 1.27 1.27)) ))
+(property "Value" "MAX3243_Module_Reference" (at 0 20.32 0) (effects (font (size 1.27 1.27)) ))
+(property "Footprint" "" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Datasheet" "" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Description" "Adafruit male 6253 intended; physical numbering from published female 5988 CAD, VERIFY MALE" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(symbol "MAX3243_Module_Reference_0_1" (rectangle (start -15.24 17.78) (end 15.24 -17.78) (stroke (width 0.254) (type default)) (fill (type background))))
+(symbol "MAX3243_Module_Reference_1_1"
+(pin power_in line (at -20.32 13.97 0) (length 5.08) (name "Vin" (effects (font (size 1.016 1.016)) )) (number "1" (effects (font (size 1.016 1.016)) )))
+(pin power_in line (at -20.32 11.43 0) (length 5.08) (name "GND" (effects (font (size 1.016 1.016)) )) (number "2" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -20.32 8.89 0) (length 5.08) (name "DCD" (effects (font (size 1.016 1.016)) )) (number "3" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -20.32 6.35 0) (length 5.08) (name "RX" (effects (font (size 1.016 1.016)) )) (number "4" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -20.32 3.81 0) (length 5.08) (name "TX" (effects (font (size 1.016 1.016)) )) (number "5" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -20.32 1.27 0) (length 5.08) (name "DTR" (effects (font (size 1.016 1.016)) )) (number "6" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -20.32 -1.27 0) (length 5.08) (name "DSR" (effects (font (size 1.016 1.016)) )) (number "7" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -20.32 -3.81 0) (length 5.08) (name "RTS" (effects (font (size 1.016 1.016)) )) (number "8" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -20.32 -6.35 0) (length 5.08) (name "CTS" (effects (font (size 1.016 1.016)) )) (number "9" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -20.32 -8.89 0) (length 5.08) (name "RI" (effects (font (size 1.016 1.016)) )) (number "10" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -20.32 -11.43 0) (length 5.08) (name "VLD" (effects (font (size 1.016 1.016)) )) (number "11" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -20.32 -13.97 0) (length 5.08) (name "OFF_N" (effects (font (size 1.016 1.016)) )) (number "12" (effects (font (size 1.016 1.016)) )))
+)
+)
+(symbol "OLED_I2C_26mm" (pin_names (offset 0.762)) (in_bom yes) (on_board yes)
+(property "Reference" "DS" (at 0 12.7 0) (effects (font (size 1.27 1.27)) ))
+(property "Value" "OLED_I2C_26mm" (at 0 10.16 0) (effects (font (size 1.27 1.27)) ))
+(property "Footprint" "Carrier:OLED_26mm_I2C_Provisional" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Datasheet" "" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Description" "User fit-verified 26 mm OLED; front/top header GND VCC SCL SDA" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(symbol "OLED_I2C_26mm_0_1" (rectangle (start -10.16 7.62) (end 10.16 -7.62) (stroke (width 0.254) (type default)) (fill (type background))))
+(symbol "OLED_I2C_26mm_1_1"
+(pin power_in line (at -15.24 3.81 0) (length 5.08) (name "GND" (effects (font (size 1.016 1.016)) )) (number "1" (effects (font (size 1.016 1.016)) )))
+(pin power_in line (at -15.24 1.27 0) (length 5.08) (name "VCC" (effects (font (size 1.016 1.016)) )) (number "2" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -15.24 -1.27 0) (length 5.08) (name "SCL" (effects (font (size 1.016 1.016)) )) (number "3" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at -15.24 -3.81 0) (length 5.08) (name "SDA" (effects (font (size 1.016 1.016)) )) (number "4" (effects (font (size 1.016 1.016)) )))
+)
+)
+(symbol "SW_NO" (pin_names (offset 0.762)) (in_bom yes) (on_board yes)
+(property "Reference" "SW" (at 0 7.62 0) (effects (font (size 1.27 1.27)) ))
+(property "Value" "SW_NO" (at 0 5.08 0) (effects (font (size 1.27 1.27)) ))
+(property "Footprint" "Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Datasheet" "" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Description" "Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(symbol "SW_NO_0_1" (polyline (pts (xy -2.54 0) (xy 2.54 1.524)) (stroke (width 0.254) (type default)) (fill (type none)))(circle (center -2.54 0) (radius 0.35) (stroke (width 0.1524) (type default)) (fill (type none)))(circle (center 2.54 0) (radius 0.35) (stroke (width 0.1524) (type default)) (fill (type none))))
+(symbol "SW_NO_1_1"
+(pin passive line (at -5.08 0 0) (length 2.54) (name "~" (effects (font (size 1.016 1.016)) )) (number "1" (effects (font (size 1.016 1.016)) )))
+(pin passive line (at 5.08 0 180) (length 2.54) (name "~" (effects (font (size 1.016 1.016)) )) (number "2" (effects (font (size 1.016 1.016)) )))
+)
+)
+(symbol "R" (pin_names (offset 0.762)) (in_bom yes) (on_board yes)
+(property "Reference" "R" (at 0 6.096 0) (effects (font (size 1.27 1.27)) ))
+(property "Value" "R" (at 0 3.556 0) (effects (font (size 1.27 1.27)) ))
+(property "Footprint" "Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Datasheet" "" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Description" "Resistor, axial DIN0207 footprint; exact MPN pending" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(symbol "R_0_1" (rectangle (start -2.54 1.016) (end 2.54 -1.016) (stroke (width 0.254) (type default)) (fill (type background))))
+(symbol "R_1_1"
+(pin passive line (at -5.08 0 0) (length 2.54) (name "~" (effects (font (size 1.016 1.016)) )) (number "1" (effects (font (size 1.016 1.016)) )))
+(pin passive line (at 5.08 0 180) (length 2.54) (name "~" (effects (font (size 1.016 1.016)) )) (number "2" (effects (font (size 1.016 1.016)) )))
+)
+)
+)

hardware/PCB/Carrier.pretty/HW678_2x22_Provisional.kicad_mod

@@ -0,0 +1,56 @@
+(footprint "HW678_2x22_Provisional"
+  (version 20260206)
+  (generator "pcbnew")
+  (layer "F.Cu")
+  (descr "HW-678, component/top view antenna up USB down; origin pad 1; left top-bottom 1..22, right top-bottom 23..44; only header centres verified; no GPIO mapping, outline, courtyard or antenna keepout; PROVISIONAL connector fit: 1.70 mm pads / 1.00 mm drills from installed KiCad PinHeader_1x04_P2.54mm_Vertical, awaiting selected actual pin/socket datasheet")
+  (tags "module provisional THT")
+  (attr through_hole)
+  (property "Reference" "REF**" (at 12.7 -3) (layer "F.SilkS") (effects (font (size 1 1) (thickness 0.15))))
+  (property "Value" "HW678_2x22_Provisional" (at 12.7 57) (layer "F.Fab") (effects (font (size 1 1) (thickness 0.15))))
+  (fp_text user "PROVISIONAL CONNECTOR FIT" (at 12.7 25) (layer "F.Fab") (effects (font (size 1 1) (thickness 0.15))))
+  (fp_text user "ANTENNA UP / USB DOWN" (at 12.7 28) (layer "F.Fab") (effects (font (size 1 1) (thickness 0.15))))
+  (pad "1" thru_hole rect (at 0.00 0.00) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "2" thru_hole circle (at 0.00 2.54) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "3" thru_hole circle (at 0.00 5.08) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "4" thru_hole circle (at 0.00 7.62) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "5" thru_hole circle (at 0.00 10.16) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "6" thru_hole circle (at 0.00 12.70) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "7" thru_hole circle (at 0.00 15.24) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "8" thru_hole circle (at 0.00 17.78) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "9" thru_hole circle (at 0.00 20.32) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "10" thru_hole circle (at 0.00 22.86) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "11" thru_hole circle (at 0.00 25.40) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "12" thru_hole circle (at 0.00 27.94) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "13" thru_hole circle (at 0.00 30.48) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "14" thru_hole circle (at 0.00 33.02) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "15" thru_hole circle (at 0.00 35.56) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "16" thru_hole circle (at 0.00 38.10) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "17" thru_hole circle (at 0.00 40.64) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "18" thru_hole circle (at 0.00 43.18) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "19" thru_hole circle (at 0.00 45.72) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "20" thru_hole circle (at 0.00 48.26) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "21" thru_hole circle (at 0.00 50.80) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "22" thru_hole circle (at 0.00 53.34) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "23" thru_hole circle (at 25.40 0.00) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "24" thru_hole circle (at 25.40 2.54) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "25" thru_hole circle (at 25.40 5.08) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "26" thru_hole circle (at 25.40 7.62) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "27" thru_hole circle (at 25.40 10.16) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "28" thru_hole circle (at 25.40 12.70) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "29" thru_hole circle (at 25.40 15.24) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "30" thru_hole circle (at 25.40 17.78) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "31" thru_hole circle (at 25.40 20.32) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "32" thru_hole circle (at 25.40 22.86) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "33" thru_hole circle (at 25.40 25.40) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "34" thru_hole circle (at 25.40 27.94) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "35" thru_hole circle (at 25.40 30.48) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "36" thru_hole circle (at 25.40 33.02) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "37" thru_hole circle (at 25.40 35.56) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "38" thru_hole circle (at 25.40 38.10) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "39" thru_hole circle (at 25.40 40.64) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "40" thru_hole circle (at 25.40 43.18) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "41" thru_hole circle (at 25.40 45.72) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "42" thru_hole circle (at 25.40 48.26) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "43" thru_hole circle (at 25.40 50.80) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "44" thru_hole circle (at 25.40 53.34) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+)

hardware/PCB/Carrier.pretty/MAX3243_Reference_Provisional.kicad_mod

@@ -0,0 +1,34 @@
+(footprint "MAX3243_Reference_Provisional"
+  (version 20260206)
+  (generator "pcbnew")
+  (layer "F.Cu")
+  (descr "PROVISIONAL female 5988 CAD reference / VERIFY MALE 6253 geometry and pad map. Top view DE9 toward -Y; origin JP2 pin 1. Female reference: 1 Vin, 2 GND, 3 DCD, 4 RX, 5 TX, 6 DTR, 7 DSR, 8 RTS, 9 CTS, 10 RI, 11 VLD, 12 OFF. PROVISIONAL connector fit: carrier pads 1.70 mm / drill 1.00 mm. No verified DE9 envelope or courtyard. CAD-derived outline: Limor Fried/Ladyada for Adafruit Industries, CC BY-SA 3.0; see rs232-footprint-notes.md")
+  (tags "MAX3243 module female5988 reference male6253 provisional THT")
+  (attr through_hole)
+  (property "Reference" "REF**" (at 13.97 -23) (layer "F.SilkS") (effects (font (size 1 1) (thickness 0.15))))
+  (property "Value" "MAX3243_Reference_Provisional" (at 13.97 -20.5) (layer "F.Fab") (effects (font (size 0.8 0.8) (thickness 0.12))))
+  (fp_text user "PROVISIONAL" (at 13.97 -16) (layer "F.SilkS") (effects (font (size 1 1) (thickness 0.15))))
+  (fp_text user "FEMALE CAD REF" (at 13.97 -14) (layer "F.SilkS") (effects (font (size 0.8 0.8) (thickness 0.12))))
+  (fp_text user "VERIFY MALE" (at 13.97 -12.3) (layer "F.SilkS") (effects (font (size 0.8 0.8) (thickness 0.12))))
+  (fp_text user "1" (at 0 1.7) (layer "F.SilkS") (effects (font (size 0.8 0.8) (thickness 0.12))))
+  (fp_line (start 29.845 0.127) (end 29.845 -26.67) (stroke (width 0.1) (type solid)) (layer "F.Fab"))
+  (fp_line (start 29.845 -26.67) (end -1.905 -26.67) (stroke (width 0.1) (type solid)) (layer "F.Fab"))
+  (fp_line (start -1.905 -26.67) (end -1.905 0.127) (stroke (width 0.1) (type solid)) (layer "F.Fab"))
+  (fp_arc (start -1.905 0.127) (mid -1.161051224 1.923051224) (end 0.635 2.667) (stroke (width 0.1) (type solid)) (layer "F.Fab"))
+  (fp_line (start 0.635 2.667) (end 27.305 2.667) (stroke (width 0.1) (type solid)) (layer "F.Fab"))
+  (fp_arc (start 27.305 2.667) (mid 29.101051224 1.923051224) (end 29.845 0.127) (stroke (width 0.1) (type solid)) (layer "F.Fab"))
+  (pad "1" thru_hole rect (at 0 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "2" thru_hole circle (at 2.54 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "3" thru_hole circle (at 5.08 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "4" thru_hole circle (at 7.62 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "5" thru_hole circle (at 10.16 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "6" thru_hole circle (at 12.7 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "7" thru_hole circle (at 15.24 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "8" thru_hole circle (at 17.78 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "9" thru_hole circle (at 20.32 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "10" thru_hole circle (at 22.86 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "11" thru_hole circle (at 25.4 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "12" thru_hole circle (at 27.94 0) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "" np_thru_hole circle (at 1.905 -8.763) (size 3 3) (drill 3) (layers "*.Cu" "*.Mask"))
+  (pad "" np_thru_hole circle (at 26.035 -8.763) (size 3 3) (drill 3) (layers "*.Cu" "*.Mask"))
+)

hardware/PCB/Carrier.pretty/OLED_26mm_I2C_Provisional.kicad_mod

@@ -0,0 +1,21 @@
+(footprint "OLED_26mm_I2C_Provisional"
+  (version 20260206)
+  (generator "pcbnew")
+  (layer "F.Cu")
+  (descr "User-verified front/display view, header at top; origin top-left PCB corner; 1 GND, 2 VCC, 3 SCL, 4 SDA; PROVISIONAL connector fit: 1.70 mm pads / 1.00 mm drills from installed KiCad PinHeader_1x04_P2.54mm_Vertical, awaiting selected actual pin/socket datasheet")
+  (tags "module provisional THT")
+  (attr through_hole)
+  (property "Reference" "REF**" (at 13 -2) (layer "F.SilkS") (effects (font (size 1 1) (thickness 0.15))))
+  (property "Value" "OLED_26mm_I2C_Provisional" (at 13 28) (layer "F.Fab") (effects (font (size 1 1) (thickness 0.15))))
+  (fp_text user "PROVISIONAL CONNECTOR FIT" (at 13 30) (layer "F.Fab") (effects (font (size 1 1) (thickness 0.15))))
+  (fp_rect (start 0 0) (end 26 26) (stroke (width 0.1) (type solid)) (fill no) (layer "F.Fab"))
+  (fp_rect (start 1 4.5) (end 25.5 21) (stroke (width 0.1) (type dash)) (fill no) (layer "F.Fab"))
+  (pad "1" thru_hole rect (at 9.19 1.50) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "2" thru_hole circle (at 11.73 1.50) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "3" thru_hole circle (at 14.27 1.50) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "4" thru_hole circle (at 16.81 1.50) (size 1.7 1.7) (drill 1) (layers "*.Cu" "*.Mask") (remove_unused_layers no))
+  (pad "" np_thru_hole circle (at 1.75 1.75) (size 2 2) (drill 2) (layers "*.Cu" "*.Mask"))
+  (pad "" np_thru_hole circle (at 24.25 1.75) (size 2 2) (drill 2) (layers "*.Cu" "*.Mask"))
+  (pad "" np_thru_hole circle (at 1.75 24.25) (size 2 2) (drill 2) (layers "*.Cu" "*.Mask"))
+  (pad "" np_thru_hole circle (at 24.25 24.25) (size 2 2) (drill 2) (layers "*.Cu" "*.Mask"))
+)

hardware/PCB/README.md

@@ -0,0 +1,268 @@
+# KiCad 10 module carrier — schematic and routed PCB draft
+
+Open **`serial-carrier.kicad_pro`** in KiCad 10, then open
+**`serial-carrier.kicad_sch`**. A readable export is **`serial-carrier.pdf`**.
+This is a native, editable schematic with actual connected nets, not an image
+or a SKiDL-only netlist. **`serial-carrier.kicad_pcb` now contains a routed,
+82 × 80 mm two-copper-layer A1 carrier draft with a top-left antenna notch,
+USB toward the bottom and RS-232 toward the top.** It is **not fabrication-ready**.
+See **`pcb-draft-notes.md`** for placement, chosen dimensions/rules, provisional
+mechanical assumptions and validation. A review drawing is `pcb-placement-draft.pdf`.
+
+The schematic contains the complete ESP32 development-board interface, MAX3243
+breakout logic interface, I²C OLED, three Omron B3F-1000 buttons and three 2.2 kΩ
+button pull-ups. USB connectors, regulator, reset/boot circuit, DE-9 and MAX3243
+charge pump are already on their respective modules and are not duplicated on
+the carrier. All 3.3 V and ground connections are explicit named nets.
+
+## Files and use
+
+| File | Purpose |
+|---|---|
+| `serial-carrier.kicad_pro`, `serial-carrier.kicad_sch` | Native KiCad project and A3 single-sheet schematic |
+| `serial-carrier.pdf` | Schematic review/print export |
+| `serial-carrier.kicad_pcb` | Routed 82 × 80 mm stepped, two-copper-layer PCB draft |
+| `pcb-draft-notes.md`, `pcb-placement-draft.pdf` | PCB design decisions/limits and 1:1 placement review |
+| `validation/pcb-draft.png`, `validation/pcb-draft-3d.png` | Copper/fab preview and carrier-only 3D render |
+| `validate_pcb_draft.py` | Fresh schematic-to-PCB net checks, bounds/layers and DRC/parity report |
+| `generate_pcb_draft.py`, `route_pcb_draft.py` | Optional destructive-regeneration tools with explicit overwrite guards |
+| `add_device_silkscreen.py` | Refresh board-local OLED/RS-232 outlines and ESP32 header guides after placement/routing; preserves copper and project settings |
+| `db9-mechanical-notes.md`, `reference/db9-cad/` | STEP-derived metal dimensions, originals, source licenses and repeatable extraction/validation |
+| `add_db9_envelope.py` | Refresh nominal connector metal projections on Dwgs.User; not a case cutout or assembly clearance |
+| `Carrier.kicad_sym`, `sym-lib-table` | Project-local module, switch and resistor symbols |
+| `Carrier.pretty/`, `fp-lib-table` | OLED/ESP32/RS-232-reference provisional footprints; standard KiCad 10 switch/resistor/mounting-hole library references |
+| `oled-fit-check.svg` | User-fit-verified OLED mechanical template |
+| `footprint-notes.md`, `rs232-footprint-notes.md` | Footprint origins, provisional pad/drill choices, validation and RS-232 adaptation attribution |
+| `adafruit-research.md`, `button-notes.md`, `reference/` | Manufacturer evidence, pad maps and source/license records |
+| `bom-draft.csv` | Draft procurement list and unresolved selections |
+| `validate_schematic.py`, `validation/` | Repeatable netlist/firmware/ERC checks and exported evidence |
+| `validate_footprints.py` | Native KiCad footprint geometry regression checks via system Python/pcbnew |
+| `generate_schematic.py` | Optional stdlib-only initial design generator; not needed to open/edit in KiCad |
+
+Keep these files together so project-relative libraries resolve. Standard KiCad
+10 footprint libraries must be installed for the THT buttons, resistors and mounting holes.
+SKiDL 2.3.0 is installed, but no SKiDL dependency is required for this native design.
+
+**Normal validation from the repository root:**
+
+```sh
+python3 hardware/PCB/validate_schematic.py
+```
+
+This checks the current schematic without regenerating it, exports its netlist,
+runs KiCad ERC, checks all 17 connected nets and all 15 firmware GPIO assignments,
+and refreshes PDF/SVG review exports. It requires Python 3 and `kicad-cli`.
+The expected-net snapshot records the initial design contract; intentional wiring
+changes need a deliberate update to the checks and snapshot.
+
+**Do not casually rerun `generate_schematic.py`:** it overwrites the schematic,
+symbol library, library tables and expected-net snapshot, discarding subsequent
+manual edits to those files. It preserves existing project settings and does not
+modify footprints. The generated KiCad files are the editable design artifacts.
+
+## Schematic conventions and design decisions
+
+- U1 numbering is project-specific: viewed from the component side, antenna up
+  and USB down, left row is 1–22 and right row is 23–44, both top-to-bottom.
+  These numbers map directly to the local HW678 footprint, not to GPIO numbers
+  or the official DevKit header reference designators. Signal order was transcribed
+  from the user-supplied component-side board-label photos; the user confirmed
+  matching board markings. This is photo/label evidence, not a continuity test:
+  verify actual pin-to-function mapping before release, especially on clones.
+- DS1 pins 1–4 are GND, VCC, SCL, SDA, front/display view with header at top.
+- U2 pin numbering follows published Adafruit **5988 female** CAD as a provisional
+  reference for the selected **6253 male** module. Its footprint is deliberately
+  **unassigned in the schematic** until the actual male header and mechanics are
+  verified. The PCB draft assigns `Carrier:MAX3243_Reference_Provisional` on the
+  PCB only, causing one documented footprint-parity warning. Its reference nets
+  are routed for review, not male-board qualification. See `adafruit-research.md`
+  and `pcb-draft-notes.md`; this is not a generic DE-9 footprint.
+- No-connect crosses mean unused on the carrier, not disconnected internally.
+  Native USB GPIO19/20, UART0 GPIO43/44, memory-conflicting GPIO35–37 and the 5 V
+  header are not connected to carrier circuitry.
+- U1 pin 1 (3V3) and pin 22 (GND) model the onboard supply as power outputs for
+  ERC; the other duplicate rail pins are passive. This does not verify the
+  regulator's capacity or USB power isolation. GPIO9 is modeled as a programmable
+  bidirectional pad; firmware **must use open-drain mode** for OFF. ERC does not
+  enforce that configuration or model the breakout's internal OFF pull-up.
+- Selected buttons are Omron B3F-1000 with their verified KiCad THT footprint.
+  Added R1–R3, **2.2 kΩ, 1%, at least 0.125 W**, from each button input to 3.3 V.
+  They provide nominal 1.5 mA contact current / 4.95 mW dissipation while pressed,
+  rather than relying on the internal pull-up for the silver-contact rated load.
+  Firmware's internal pull-ups and debouncing remain enabled; no firmware changes
+  are required. Final supply tolerance/load budget still needs checking.
+  DIN0207 axial footprints are selected; exact resistor MPNs remain pending.
+- External I²C pull-ups are **not assigned guessed values**. Verify OLED onboard
+  pull-ups, resistance and rail before electrical sign-off and add appropriately
+  sized carrier pull-ups if needed. The OLED must be powered from 3.3 V.
+
+## Validation status
+
+KiCad CLI 10.0.6 loaded the schematic and exported PDF, SVG and XML netlist.
+ERC reported **zero errors/warnings**, with no project exclusions added. Exact
+net memberships, all 44 U1 pins and firmware GPIO assignments were checked.
+The PDF was rendered and visually inspected for layout/readability. Both local
+footprints loaded in KiCad's native footprint loader. Two retained regression tests
+passed with `/usr/bin/python3 -B hardware/PCB/validate_footprints.py`; the binding
+emits startup PROPERTY_ENUM assertions but completes the checks. See
+`footprint-notes.md` for scope and limitations.
+
+OLED PCB/header/display/mounting-hole geometry was physically fit-verified by
+the user. This does **not** validate connector drills, male RS-232 geometry,
+electrical operation, power budget, procurement or fabrication.
+
+The routed PCB draft has **0 physical DRC violations and 0 unconnected items**;
+a fresh netlist-to-PCB check passes. One deliberate U2 footprint-parity warning
+remains (PCB reference footprint versus blank schematic assignment). No added
+DRC exclusions hide this warning. Missing courtyards are ignored by default DRC
+and remain a manual release check. Run `/usr/bin/python3 -B
+hardware/PCB/validate_pcb_draft.py` from the repository root; see
+`pcb-draft-notes.md` for the complete verification scope and remaining gates.
+No firmware build or device tests were run: this PCB work did not modify firmware.
+
+## Evidence and components
+
+Repository sources: `../../docs/wiring.md`, `../../src/board_pins.h`,
+`../../docs/electrical_tests.md`, and `../../README.md`.
+
+| Assembly | Repository identification | Footprint status |
+|---|---|---|
+| ESP32 development board | User confirmed HW-678 V0.0.0 markings and S3-N16R8 shield, two USB-C ports | Two 22-pin rows; nominal 2.54 mm pitch and 25.40 mm row spacing supported by simultaneous breadboard fit. Mechanical outline registration and socket/drill selection remain pending. |
+| RS-232 module | Adafruit MAX3243 full-pinout breakout; male is product 6253, female is 5988 | Eagle pin map/PCB geometry and STEP metal dimensions extracted. User confirms identical male/female external dimensions; actual fit and male electrical map remain release checks. Reference footprint used on PCB only. |
+| Display | 128×64 yellow/blue I²C OLED, address 0x3c; Amazon ASIN B0F13SSSFB | 26 mm square board, 22.50 mm hole spacing, Ø2 mm holes and centred header 1.50 mm from top edge are user-fit-verified. Local footprint assigned; header pad/drill selection remains provisional. |
+| Three buttons | Omron B3F-1000; previous, select, next; normally open to ground, active low | Datasheet and `Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x` pad mapping verified. External 2.2 kΩ pull-ups included. Live distributor stock remains unverified. |
+
+Adafruit manufacturer CAD starting point:
+https://learn.adafruit.com/adafruit-rs-232-full-pinout-level-shifter-breakout/downloads
+
+Published female-module Eagle CAD and its header map were retrieved and verified;
+see `adafruit-research.md` for pinned revision, hashes, attribution and geometry.
+The original files and CC BY-SA 3.0 notices are retained in `reference/`; they
+remain under their upstream license. Omron reference documents retain their
+manufacturer notices. The CAD-parts repository's STEP and MIT license are separately
+retained under `reference/db9-cad/`. External metal geometry is used for the male
+module on the user's explicit equivalence confirmation; this does not validate
+its electrical map, connector threads, tolerances, assembly fit or case cutout.
+
+## Verified logical connections for the existing firmware profile
+
+This table uses signal names, **not physical connector positions**. The schematic
+and its local symbols additionally capture the project's physical pad numbering.
+The wiring guide warns that compatible ESP32 boards may have different layouts.
+
+| ESP32 connection | Peripheral connection |
+|---|---|
+| 3V3 | RS-232 Vin; existing I²C OLED VCC |
+| GND | RS-232 GND; OLED GND; one contact of each button |
+| GPIO17 | RS-232 TX |
+| GPIO18 | RS-232 RX |
+| GPIO15 | RS-232 RTS |
+| GPIO16 | RS-232 CTS |
+| GPIO7 | RS-232 DTR |
+| GPIO5 | RS-232 DSR |
+| GPIO4 | RS-232 DCD |
+| GPIO6 | RS-232 RI |
+| GPIO8 | RS-232 VLD |
+| GPIO9 | RS-232 OFF (active-low shutdown; open-drain drive) |
+| GPIO11 | Existing I²C OLED SDA |
+| GPIO12 | Existing I²C OLED SCL |
+| GPIO10 | Previous/back switch to GND |
+| GPIO13 | Select/confirm switch to GND |
+| GPIO14 | Next switch to GND |
+
+## Electrical constraints from the repository
+
+- Keep UART0 / GPIO43 and GPIO44 available through the onboard USB-UART bridge.
+- Reserve GPIO19 and GPIO20 for onboard native USB.
+- Existing firmware profile powers RS-232 Vin and OLED VCC from 3.3 V, not 5 V.
+- Confirm the exact development board's regulator capacity and USB power-path
+  behavior before finalizing the power design, especially with both USB ports attached.
+- Display pull-up presence, resistance and termination rail must be checked on
+  the actual module. Do not select external pull-up values without this information.
+- Firmware enables internal button pull-ups; this carrier additionally uses 2.2 kΩ
+  external pull-ups for the selected buttons' contact-current requirement.
+- RS-232 OFF uses the breakout's onboard pull-up; GPIO9 releases it to enable.
+- The breakout is not galvanically isolated; signal grounds are common.
+- Preserve access to both development-board USB connectors and account for the
+  antenna keepout using the exact board/module documentation.
+
+## User-confirmed design direction
+
+- ESP32 purchase: https://www.amazon.de/dp/B0F3XMYYQY
+- OLED purchase: https://www.amazon.de/dp/B0F13SSSFB — I²C, not SPI.
+- Both Amazon URLs returned an access-check page on inspection; the ASINs alone
+  do not establish a verified manufacturer drawing or footprint.
+- Use the male Adafruit breakout. User reports male/female board dimensions match;
+  verify the selected male board against its manufacturer CAD.
+- Carrier for complete modules: soldered module headers for final assembly,
+  sockets for beta testing without a case. Header pitch, row spacing, drill size
+  and socket clearance must be validated against selected hardware.
+- Power only through the ESP32 development board's USB connectors, typically a
+  powerbank or the serial peer's USB port, with common ground. Do not introduce
+  another carrier power input or assume simultaneous USB supplies are isolated.
+- Select readily available THT buttons; the existing random switches need not be reused.
+- Case will be 3D-printed after PCB finalization. Include mounting provisions in
+  the layout, but screw size, hole diameter and insert bosses are not yet selected.
+
+## User-supplied mechanical evidence
+
+- ESP32 listing pictures show HW-678 V0.0.0; user confirms matching markings and
+  actual shield S3-N16R8. Disregard the listing picture's N8R2 marking for memory
+  identification and its erroneous USB labels: native USB is GPIO19 D− / GPIO20 D+.
+- ESP32 raw measurements: header first-to-last centres initially 52.6 mm, revised
+  to 52.93 mm; row spacing measured 25.00 mm. User subsequently confirmed both
+  rows fit a standard breadboard simultaneously without forcing. Use nominal
+  2.54 mm pitch (53.34 mm over 21 intervals) and 25.40 mm row spacing based on
+  that fit check, not the raw caliper measurements. Verify with a 1:1 print before fabrication.
+- ESP32 seller drawing states 28 mm width and annotates 63 mm length; its 20 mm
+  arrow is not header row spacing. Antenna extent and header-to-outline offsets
+  are not fully dimensioned.
+- OLED actual PCB outline measured by user: 26 × 26 mm, superseding the seller's
+  28.7 × 27.8 mm dimensions. Seller's 4.1 mm height remains unverified.
+- OLED front view, connector at top: GND, VCC, SCL, SDA from left to right,
+  confirmed on actual module. Raw first-to-last span revised from 7 mm to 7.49 mm;
+  user confirms standard breadboard fit and agrees nominal pitch is 2.54 mm
+  (7.62 mm span).
+- OLED mounting-hole diameter measured as 2 mm. User approved the latest edge
+  measurements as superseding the earlier 22.16 mm hole-spacing measurement:
+  centres are 1.75 mm from adjacent edges, giving 22.50 mm spacing in both axes.
+- User verified the template's PCB outline and mounting-hole placement against
+  the actual OLED module: both fit perfectly. Header-pin centres were subsequently
+  corrected to 1.50 mm from the top PCB edge, superseding 0.75 mm. The header row
+  is therefore 0.25 mm nearer the top edge than the upper mounting-hole centres.
+- User measured the display outline margins: top 4.5 mm, bottom 5 mm, left 1 mm,
+  right 0.5 mm. On the 26 mm PCB this defines a 24.5 × 16.5 mm rectangle from
+  (1, 4.5) to (25.5, 21), shown dashed in the template. This records the supplied
+  display boundary, not an independently verified active-pixel area or case cutout.
+- User subsequently confirmed the revised template is "about a perfect fit",
+  validating the PCB outline, mounting-hole placement, corrected 1.50 mm header
+  position and display outline against the actual module. This is a user-reported
+  mechanical fit check, not electrical or fabrication validation.
+- User explicitly approved a horizontally centred header, superseding the earlier
+  approximate 7.33 mm hole-to-pin measurements.
+- Approved coordinates in mm, viewed from the display side with the header at
+  the top, origin at the top-left PCB corner, X right and Y down:
+  GND (9.19, 1.50), VCC (11.73, 1.50), SCL (14.27, 1.50), SDA (16.81, 1.50).
+  Mounting-hole centres: (1.75, 1.75), (24.25, 1.75), (1.75, 24.25),
+  (24.25, 24.25), each diameter 2 mm. Board outline: (0, 0) to (26, 26).
+- `oled-fit-check.svg` is a 1:1 mechanical template of that geometry. Print at
+  100%, without fit-to-page, and verify its 20 mm scale before checking the module.
+  Crosshairs denote header centres, not specified pad or drill diameters. This
+  template is not a KiCad footprint or a fabrication file.
+
+## Remaining mechanical/electrical checks
+
+1. OLED outline, mounting-hole placement, revised header position and display
+   outline are user fit-verified. Select carrier header/socket pads and drills
+   from the actual connector drawings.
+2. Before final module outlines/courtyards, establish their registration to header
+   centres, connector overhang and display position from drawings or measurements.
+3. Verify power-path schematic/regulator capacity and OLED pull-up implementation.
+   Photos alone do not establish those electrical properties.
+
+The native schematic, local libraries and routed two-layer PCB draft are present.
+Before fabrication, finish the above checks, qualify the male RS-232 module map
+and footprint, and confirm procurement. The carrier now proposes an 82 × 80 mm
+stepped outline and four Ø3.2 mm M3 mounting holes; case hardware is not yet fixed.
+The PCB's RF reserve is a draft design allocation, not a verified module antenna
+keepout. Module/USB/DE-9 clearances must still be established from actual hardware.

hardware/PCB/adafruit-research.md

@@ -0,0 +1,142 @@
+# Adafruit MAX3243 breakout: authoritative CAD header research
+
+Research date: 2026-09-20. Scope: source retrieval and pad/geometry extraction only; no project schematic or layout modified.
+
+## Critical product distinction
+
+**Product 5988 is the DE-9 female version. The male version is product 6253.** The product-5988 page's male variant link goes to `/product/6253`; each product description explicitly identifies its connector gender. Both link to the same Learn guide. Do not describe the downloaded CAD as verified male-specific CAD: its connector is `X2`, value `DE9-F`, package `F09HP`, and the repository README identifies product 5988.
+
+The exact header map below is proven for the published 5988 board. It is useful reference for the family, but identical male-board geometry/pad numbering has **not** been established by a male-specific CAD file or physical measurement. Confirm the actual 6253 module before releasing a male carrier footprint. No inference from connector gender or a generic DE-9 footprint is substituted for that check.
+
+## Provenance and downloaded originals
+
+Authoritative chain:
+
+1. [Adafruit Learn downloads](https://learn.adafruit.com/adafruit-rs-232-full-pinout-level-shifter-breakout/downloads) links to the Eagle repository below, a TI datasheet, fab print and 3D models.
+2. [Adafruit PCB repository](https://github.com/adafruit/Adafruit-RS-232-Level-Shifter-Breakout-PCB).
+3. Retrieved `main` commit **`63c6200bb3ef17d491089cfa6441b1810d79bb20`**, committed 2024-08-12T22:42:27Z. All four local originals were downloaded from this immutable revision, not a moving branch.
+4. [Product 5988, female](https://www.adafruit.com/product/5988), [product 6253, male](https://www.adafruit.com/product/6253), and [Learn pinouts](https://learn.adafruit.com/adafruit-rs-232-full-pinout-level-shifter-breakout/pinouts) corroborate identity and signal names.
+
+Local files in `reference/`, unchanged upstream contents:
+
+| File | SHA-256 |
+|---|---|
+| `Adafruit RS-232 Full Pinout Level-Shifter Breakout.brd` | `6a7b35ef909f5a2d243c326c34db3957aaa01275bf2aac8e0c749ff18162e870` |
+| `Adafruit RS-232 Full Pinout Level-Shifter Breakout.sch` | `4efbbe0ad14194e4e4563dd5f7dac007dfd52eba636f7390ffb822f3e81cd896` |
+| `README.md` | `2825ba741a8ce83abdaf2c7cb9170641473357630ccbee40a0016dcdb5cd80bb` |
+| `license.txt` | `075dad5e5fc96c27014fabc269f4f5732909cffd178a486f546d982b6cf86b74` |
+
+Raw URL prefix for each filename (URL-encode spaces):
+
+`https://raw.githubusercontent.com/adafruit/Adafruit-RS-232-Level-Shifter-Breakout-PCB/63c6200bb3ef17d491089cfa6441b1810d79bb20/`
+
+**License:** upstream `license.txt` is **Creative Commons Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0)**. README attribution: “Designed by Limor Fried/Ladyada for Adafruit Industries.” README explicitly requires all its preceding text in redistribution; the full original README and license are therefore retained. Preserve these notices when redistributing CAD and comply with applicable attribution/share-alike obligations for adaptations. The CAD-derived content of this report is attributed to that design and provided under CC BY-SA 3.0.
+
+The guide also links [5988 3D CAD](https://github.com/adafruit/Adafruit_CAD_Parts/tree/main/5988%20RS-232%20Level%20Shifter). Its directory listing contains `.f3d`, `.step`, `.stl`, and `.jpg`; these were **not downloaded or used for measurements**, and their licensing was not independently assessed. No male-specific 3D model was verified in this research.
+
+## Exact header numbering and net map
+
+Source: Eagle XML `drawing/board/elements/element[@name='JP2']`, embedded `microbuilder` package `1X12_ROUND_76MIL`, and `drawing/board/signals/signal/contactref`. Cross-checked against schematic `JP2`, deviceset `HEADER-1X12`, selected device `76MIL`: symbol pin N maps directly to physical pad N.
+
+**Viewing convention:** component/top view, DE-9 pointing toward the top of the page (+Y), logic header along the bottom. X increases rightward, Y upward. The origin is the lower-left bounding-box corner of the bare PCB (the corner itself is rounded). These are Eagle board coordinates in **millimetres**, not a mating-face view and not a bottom view.
+
+```text
+                  DE-9 / +Y
+           +-----------------------+
+           |                       |
+           |   o               o   |  module mounting holes
+           |                       |
+           | 1  2  3 ...       12   |  JP2, y = 2.667 mm
+           +-----------------------+
+             Vin                OFF
+                    +X ->
+```
+
+| JP2 physical pad | Label / function | CAD net | X (mm) | Y (mm) | MAX3243 IC1 pad | DE-9 X2 pad via level shifter |
+|---:|---|---|---:|---:|---:|---:|
+| 1 | Vin | VCC | 1.905 | 2.667 | 26 | — |
+| 2 | GND | GND | 4.445 | 2.667 | 25 | 5 (direct ground) |
+| 3 | DCD | DCD | 6.985 | 2.667 | 15 | 1 |
+| 4 | RX | RXD | 9.525 | 2.667 | 16 | 2 |
+| 5 | TX | TXD | 12.065 | 2.667 | 13 | 3 |
+| 6 | DTR | DTR | 14.605 | 2.667 | 14 | 4 |
+| 7 | DSR | DSR | 17.145 | 2.667 | 17 | 6 |
+| 8 | RTS | RTS | 19.685 | 2.667 | 12 | 7 |
+| 9 | CTS | CTS | 22.225 | 2.667 | 19 | 8 |
+| 10 | RI | RI | 24.765 | 2.667 | 18 | 9 |
+| 11 | VLD | !INVALID | 27.305 | 2.667 | 21 | — |
+| 12 | OFF | !FORCEOFF | 29.845 | 2.667 | 22 | — |
+
+**Left-to-right order: `Vin GND DCD RX TX DTR DSR RTS CTS RI VLD OFF`.** This is physical pad order, not the order of rows in the project's wiring table.
+
+At the logic header, TX/DTR/RTS are inputs to the MAX3243; RX/DCD/DSR/CTS/RI are outputs from it. Schematic gates explicitly map TX to T2IN, DTR to T1IN, RTS to T3IN, RX to R4OUT, DCD to R5OUT, DSR to R3OUT, CTS to R1OUT and RI to R2OUT. RS-232 and logic signal nets are separated by the chip; matching signal names do not mean direct continuity.
+
+OFF is **active low** (`!FORCEOFF`, IC1 pad 22) with 10 kΩ pull-up R1 to VCC. The Learn pinout page agrees. The upstream README and shop prose incorrectly say high shuts it down; do not propagate that prose error. VLD is `!INVALID`, high on valid input detection. Use 3.3 V Vin for this project's ESP32 interface, as already required by `docs/wiring.md`.
+
+## Exact published PCB geometry
+
+All figures below are nominal CAD dimensions, not measured tolerances.
+
+### Logic header JP2
+
+- Single row, **12 plated through-hole pads at 2.54 mm (0.100 inch) pitch**.
+- Element origin `(15.875, 2.667)`; no element rotation or mirroring (R0).
+- Package local pad centres: `x = -13.970 + 2.540 × (N - 1)`, `y = 0`, N = 1…12.
+- Board coordinates: `x = 1.905 + 2.540 × (N - 1)`, `y = 2.667`.
+- First-to-last centre span **27.940 mm (1.100 inch)**.
+- All holes: **1.000 mm drill**, explicit **1.9304 mm (76 mil) round copper diameter**. Each pad has `rot="R90"`; that does not rotate the header row or change a round pad's outline.
+- Both end pad centres are **1.905 mm** from the corresponding vertical board edge.
+- Row is **2.667 mm (0.105 inch)** above the lower bounding-box edge.
+- No square pad-1 marker is defined by this package: identify pad 1 using Vin and the stated view, not assumed square copper.
+
+### Bare-board outline and mounting holes
+
+Source: `drawing/board/plain/wire[@layer='20']` and mounting-hole element/package definitions.
+
+- Bare PCB bounding box: **31.750 mm X × 29.337 mm Y** (1.250 × 1.155 inches), X = 0…31.750, Y = 0…29.337.
+- Straight top edge `(0,29.337)` to `(31.750,29.337)`; square top corners.
+- Bottom corners: **2.540 mm radius**, defined by 90° arcs `(0,2.540)` → `(2.540,0)` and `(29.210,0)` → `(31.750,2.540)`.
+- Bottom straight edge: X = 2.540…29.210 at Y = 0.
+- Module mounting holes: `U$2` at **(3.810, 11.430)** and `U$3` at **(27.940, 11.430)**.
+- Both use `MOUNTINGHOLE_3.0_PLATEDTHIN`, pad `P$1`, **3.000 mm drill / 3.600 mm copper diameter**. They are plated pads, not anonymous NPTH holes, and neither appears in the board's signal contactrefs.
+- Hole centre spacing **24.130 mm (0.950 inch)**; hole row is **8.763 mm** above the header row.
+
+For a carrier footprint using header pad 1 as `(0,0)` with Y still upward:
+
+- Header pads: `(2.540 × (N - 1), 0)`.
+- Mounting hole centres: **(1.905, 8.763)** and **(26.035, 8.763)**.
+- Bare-board bounding box: X = **−1.905…29.845**, Y = **−2.667…26.670**; retain corner arcs described above.
+
+If the destination CAD uses screen coordinates with Y downward, transform Y deliberately; do not silently mirror physical pad numbering. The placement side and whether the module faces up or down must be fixed before generating a carrier footprint.
+
+### DE-9 on the downloaded female CAD (not male qualification)
+
+`X2` origin `(15.875,17.907)`, R0, package `F09HP`, value `DE9-F`.
+
+| X2 pad | Board X (mm) | Board Y (mm) | CAD net |
+|---|---:|---:|---|
+| 1 | 10.3886 | 16.637 | RS_DCD |
+| 2 | 13.1318 | 16.637 | RS_RXD |
+| 3 | 15.8750 | 16.637 | RS_TXD |
+| 4 | 18.6182 | 16.637 | RS_DTR |
+| 5 | 21.3614 | 16.637 | GND |
+| 6 | 11.7602 | 19.177 | RS_DSR |
+| 7 | 14.5034 | 19.177 | RS_RTS |
+| 8 | 17.2466 | 19.177 | RS_CTS |
+| 9 | 19.9898 | 19.177 | RS_RI |
+| G1 | 3.3528 | 17.907 | no signal contactref |
+| G2 | 28.3972 | 17.907 | no signal contactref |
+
+Signal holes have 1.016 mm drill and 1.778 mm octagonal copper; shell/mechanical pads G1/G2 have 3.302 mm drill and 5.080 mm copper, spaced 25.0444 mm. Shell pads are not shown tied to GND by signal contactrefs; DE-9 pin 5 is grounded. These are **PCB solder-tail coordinates**, not front-face pin coordinates.
+
+The connector package's layer-21 drawing reaches local Y = 17.907, hence board Y = 35.814, beyond the board's Y = 29.337. This is library drawing evidence, **not a validated mechanical envelope**. Do not size an enclosure from silkscreen. Product pages list assembled dimensions of 33.6 × 32.0 × 14.1 mm (5988) and 33.7 × 31.8 × 14.2 mm (6253), with no coordinate/tolerance definition; these do not replace a male-specific mechanical drawing, and differ from the female library drawing extent.
+
+## Validation and next-use boundary
+
+- Parsed the actual Eagle board and schematic XML successfully using Python's standard-library XML parser.
+- Joined package pad names to board signal contactrefs, applied JP2's unrotated element translation, and cross-checked schematic header numbering/net assignments.
+- Extracted outline arcs, mounting-hole package dimensions, and connector pad data directly; no dimensions inferred from product photos.
+- Recorded SHA-256 hashes of the downloaded originals.
+- No firmware build or hardware tests performed: this task changed research/reference files only.
+- **Ready:** exact published 5988 header map, pad centres, board outline and hole coordinates for CAD reference.
+- **Still required for a male-module carrier release:** establish that the purchased module is 6253, verify its header order and mounting geometry against male-specific CAD or the physical module, and verify connector overhang, mating clearance, module height and mounting orientation. The shared guide alone is insufficient proof of identical male geometry.

hardware/PCB/add_db9_envelope.py

@@ -0,0 +1,93 @@
+#!/usr/bin/env python3
+"""Add nominal STEP-derived metal bounding projections on Dwgs.User only.
+
+Not silkscreen, a courtyard, or a case cutout. See db9-mechanical-notes.md for
+source attribution, selected face subsets and the user-confirmed male/female
+external-geometry equivalence. No module height or case-wall thickness assumed.
+"""
+import json
+from pathlib import Path
+import uuid
+import pcbnew as p
+
+ROOT=Path(__file__).resolve().parent
+PCB=ROOT/"serial-carrier.kicad_pcb"
+NS=uuid.UUID("ba7274a8-c35d-46bc-908d-cd86708fc6c4")
+
+
+def main():
+    lock=ROOT/"~serial-carrier.kicad_pcb.lck"
+    if lock.exists():
+        raise SystemExit("Close PCB Editor before refreshing the CAD envelopes")
+    before=PCB.read_bytes()
+    project=ROOT/"serial-carrier.kicad_pro"
+    project_before=project.read_bytes()
+    board=p.LoadBoard(str(PCB))
+    u2=next(f for f in board.GetFootprints() if f.GetReference()=="U2")
+    assert u2.GetOrientationDegrees()==0, "Review transform for rotated module"
+    x0,y0=p.ToMM(u2.GetPosition().x),p.ToMM(u2.GetPosition().y)
+    data=json.loads((ROOT/"reference/db9-cad/measurements.json").read_text())
+    owned={str(uuid.uuid5(NS,str(i))) for i in range(64)}
+    for drawing in list(board.GetDrawings()):
+        if drawing.m_Uuid.AsString() in owned:
+            board.Delete(drawing)
+    count=0
+
+    def point(x,y):
+        # STEP/Eagle axes +Y toward connector; KiCad local Y is downward.
+        return p.VECTOR2I(p.FromMM(x0+x-1.905),p.FromMM(y0+2.667-y))
+
+    def add(item):
+        nonlocal count
+        assert count<64
+        item.SetLayer(p.Dwgs_User)
+        item.SetUuid(p.KIID(str(uuid.uuid5(NS,str(count)))))
+        board.Add(item)
+        count+=1
+
+    for feature in ("front_flange_exposed_faces", "shell_outer_including_root_and_lip",
+                    "left_front_hex_post", "right_front_hex_post"):
+        xmin,ymin,_,xmax,ymax,_=data[feature]["bounds"]
+        rect=p.PCB_SHAPE(board)
+        rect.SetShape(p.SHAPE_T_RECT)
+        rect.SetStart(point(xmin,ymax)); rect.SetEnd(point(xmax,ymin))
+        rect.SetWidth(p.FromMM(0.1))
+        add(rect)
+    for axis in data["front_lock_axes"]:
+        x=axis["location"][0]
+        # These mark front-facing Y axes, not holes through the carrier PCB.
+        line=p.PCB_SHAPE(board)
+        line.SetShape(p.SHAPE_T_SEGMENT)
+        line.SetStart(point(x,26.907)); line.SetEnd(point(x,32.707))
+        line.SetWidth(p.FromMM(0.08))
+        add(line)
+    label=p.PCB_TEXT(board)
+    label.SetText("CAD METAL ENVELOPES - NOT CASE CUTOUT")
+    label.SetPosition(p.VECTOR2I(p.FromMM(x0+13.97),p.FromMM(y0-17.67)))
+    label.SetTextSize(p.VECTOR2I(p.FromMM(0.65),p.FromMM(0.65)))
+    label.SetTextThickness(p.FromMM(0.1))
+    add(label)
+    for drawing in board.GetDrawings():
+        if not isinstance(drawing,p.PCB_TEXT):
+            continue
+        value=drawing.GetText()
+        if value.startswith("DE-9 OUT /"):
+            drawing.SetPosition(p.VECTOR2I(p.FromMM(x0+13.97),p.FromMM(y0-20.67)))
+        elif value=="82 x 80 mm / 2 copper layers":
+            drawing.SetPosition(p.VECTOR2I(p.FromMM(141),p.FromMM(91)))
+        elif value.startswith("Nominal RS-232 metal verified;"):
+            drawing.SetPosition(p.VECTOR2I(p.FromMM(141),p.FromMM(93.5)))
+    temp=ROOT/"serial-carrier-envelope-tmp.kicad_pcb"
+    try:
+        assert p.SaveBoard(str(temp),board,True)
+        if lock.exists() or PCB.read_bytes()!=before:
+            raise RuntimeError("PCB changed or reopened; refusing overwrite")
+        assert project.read_bytes()==project_before
+        temp.replace(PCB)
+    finally:
+        temp.unlink(missing_ok=True)
+    print(f"Added {count} nominal CAD projection graphics on Dwgs.User; no copper/project changes")
+
+
+if __name__=="__main__":
+    main()

hardware/PCB/add_device_silkscreen.py

@@ -0,0 +1,181 @@
+#!/usr/bin/env python3
+"""Refresh board-local device outlines without modifying libraries or project settings.
+
+Uses pcbnew and Shapely from system Python. Only owned F.SilkS graphics are
+replaced; source F.Fab outlines, copper, footprints and board edges are retained.
+"""
+from pathlib import Path
+import math
+import uuid
+import pcbnew as p
+from shapely.geometry import LineString, Point, box
+from shapely.ops import unary_union, polygonize
+
+ROOT = Path(__file__).resolve().parent
+PCB = ROOT / "serial-carrier.kicad_pcb"
+NS = uuid.UUID("67964aa4-c3a5-45d8-9b54-250fb68e7c41")
+WIDTH = 0.12
+GAP = 0.22  # Additional clearance from mask openings and existing silk strokes.
+
+
+def xy(point):
+    return p.ToMM(point.x), p.ToMM(point.y)
+
+
+def vec(point):
+    return p.VECTOR2I(p.FromMM(point[0]), p.FromMM(point[1]))
+
+
+def outline_lines(shape):
+    if shape.GetShape() == p.SHAPE_T_RECT:
+        x1, y1 = xy(shape.GetStart())
+        x2, y2 = xy(shape.GetEnd())
+        return [LineString([(x1,y1),(x2,y1)]), LineString([(x2,y1),(x2,y2)]),
+                LineString([(x2,y2),(x1,y2)]), LineString([(x1,y2),(x1,y1)])]
+    if shape.GetShape() == p.SHAPE_T_SEGMENT:
+        return [LineString([xy(shape.GetStart()), xy(shape.GetEnd())])]
+    return []
+
+
+def add_outlines(board):
+    owned = {str(uuid.uuid5(NS, str(i))) for i in range(4096)}
+    for drawing in list(board.GetDrawings()):
+        if drawing.m_Uuid.AsString() in owned:
+            board.Delete(drawing)
+    footprints = {f.GetReference(): f for f in board.GetFootprints()}
+    obstacles = []
+    for fp in board.GetFootprints():
+        for pad in fp.Pads():
+            if not pad.IsOnLayer(p.F_Mask):
+                continue
+            assert pad.GetOrientationDegrees() % 90 == 0
+            x,y = xy(pad.GetPosition())
+            expansion = max(0, p.ToMM(pad.GetSolderMaskExpansion(p.F_Mask)))
+            if pad.GetShape() == p.PAD_SHAPE_CIRCLE:
+                geom = Point(x,y).buffer(p.ToMM(pad.GetSize().x)/2, quad_segs=32)
+            else:
+                bb=pad.GetBoundingBox()
+                geom=box(p.ToMM(bb.GetX()),p.ToMM(bb.GetY()),p.ToMM(bb.GetRight()),p.ToMM(bb.GetBottom()))
+            obstacles.append(geom.buffer(expansion+GAP+WIDTH/2))
+        for graphic in fp.GraphicalItems():
+            if isinstance(graphic,p.PCB_SHAPE) and graphic.GetLayer()==p.F_SilkS:
+                for line in outline_lines(graphic):
+                    obstacles.append(line.buffer(p.ToMM(graphic.GetWidth())/2+GAP+WIDTH/2))
+    # Clear even tented vias for a robust visible guide, independent of mask settings.
+    for track in board.GetTracks():
+        if isinstance(track,p.PCB_VIA):
+            obstacles.append(Point(xy(track.GetPosition())).buffer(p.ToMM(track.GetWidth(p.F_Cu))/2+GAP+WIDTH/2,quad_segs=32))
+    blocked=unary_union(obstacles)
+    edges = [LineString([xy(d.GetStart()), xy(d.GetEnd())])
+             for d in board.GetDrawings() if d.GetLayer() == p.Edge_Cuts]
+    polygons = list(polygonize(edges))
+    assert len(polygons) == 1, 'Expected a single closed carrier outline'
+    # U2's bare PCB front is flush with the carrier edge; do not print across it.
+    silk_area = polygons[0].buffer(-(GAP + WIDTH / 2))
+    count=0
+
+    def add(shape):
+        nonlocal count
+        assert count < 4096
+        shape.SetLayer(p.F_SilkS)
+        shape.SetUuid(p.KIID(str(uuid.uuid5(NS,str(count)))))
+        board.Add(shape)
+        count+=1
+
+    def line(a,b):
+        clipped=LineString([a,b]).intersection(silk_area).difference(blocked)
+        pieces=list(clipped.geoms) if hasattr(clipped,"geoms") else [clipped]
+        for piece in pieces:
+            if piece.geom_type!="LineString" or piece.length < 0.25:
+                continue
+            shape=p.PCB_SHAPE(board)
+            shape.SetShape(p.SHAPE_T_SEGMENT)
+            shape.SetStart(vec(piece.coords[0])); shape.SetEnd(vec(piece.coords[-1]))
+            shape.SetWidth(p.FromMM(WIDTH))
+            add(shape)
+
+    for ref in ("DS1","U2"):
+        assert footprints[ref].GetOrientationDegrees()==0, "Review outlines for rotated modules"
+        for source in footprints[ref].GraphicalItems():
+            if not isinstance(source,p.PCB_SHAPE) or source.GetLayer()!=p.F_Fab:
+                continue
+            if source.GetShape()==p.SHAPE_T_ARC:
+                # Test small spans for clearance, but retain true circular arcs
+                # for each visible run rather than replacing corners with chords.
+                cx,cy=xy(source.GetCenter())
+                sx,sy=xy(source.GetStart()); mx,my=xy(source.GetArcMid())
+                start=math.atan2(sy-cy,sx-cx)
+                sweep=2*math.atan2((sx-cx)*(my-cy)-(sy-cy)*(mx-cx),
+                                   (sx-cx)*(mx-cx)+(sy-cy)*(my-cy))
+                radius=math.hypot(sx-cx,sy-cy)
+                steps=max(1,math.ceil(abs(math.degrees(sweep))))
+                def at(t):
+                    angle=start+sweep*t/steps
+                    return cx+radius*math.cos(angle),cy+radius*math.sin(angle)
+                run=None
+                for i in range(steps+1):
+                    span=LineString([at(i),at(i+0.5),at(i+1)])
+                    clear=i<steps and silk_area.covers(span) and not span.intersects(blocked)
+                    if clear and run is None:
+                        run=i
+                    if not clear and run is not None:
+                        if radius*abs(sweep)*(i-run)/steps>=0.25:
+                            arc=p.PCB_SHAPE(board)
+                            arc.SetShape(p.SHAPE_T_ARC)
+                            arc.SetArcGeometry(vec(at(run)),vec(at((run+i)/2)),vec(at(i)))
+                            arc.SetWidth(p.FromMM(WIDTH))
+                            add(arc)
+                        run=None
+                continue
+            for edge in outline_lines(source):
+                # Display boundary is visually distinct from the PCB perimeter.
+                dashed = ref=="DS1" and round(edge.bounds[0]-xy(footprints[ref].GetPosition())[0],2) in (1.0,25.5)
+                if dashed:
+                    distance=0.0
+                    while distance < edge.length:
+                        line(edge.interpolate(distance).coords[0],edge.interpolate(min(distance+0.8,edge.length)).coords[0])
+                        distance+=1.3
+                else:
+                    line(edge.coords[0],edge.coords[-1])
+    # These are pad-row guides, not inferred socket/body or ESP32 PCB dimensions.
+    fp=footprints["U1"]
+    assert fp.GetOrientationDegrees()==0, "Review guide construction for rotated U1"
+    pads={pad.GetNumber():xy(pad.GetPosition()) for pad in fp.Pads()}
+    for first,last in (("1","22"),("23","44")):
+        x,ytop=pads[first]; _,ybottom=pads[last]
+        corners=[(x-1.2,ytop-1.2),(x+1.2,ytop-1.2),(x+1.2,ybottom+1.2),(x-1.2,ybottom+1.2)]
+        for a,b in zip(corners,corners[1:]+corners[:1]):
+            line(a,b)
+    label=p.PCB_TEXT(board)
+    label.SetText("HEADER GUIDES")
+    a,b=pads["1"],pads["23"]
+    label.SetPosition(vec(((a[0]+b[0])/2,a[1]+28)))
+    label.SetTextSize(p.VECTOR2I(p.FromMM(0.85),p.FromMM(0.85)))
+    label.SetTextThickness(p.FromMM(0.12))
+    add(label)
+    return count
+
+
+def main():
+    lock=ROOT/"~serial-carrier.kicad_pcb.lck"
+    if lock.exists():
+        raise SystemExit("Close PCB Editor before updating silkscreen")
+    before=PCB.read_bytes()
+    project=ROOT/"serial-carrier.kicad_pro"
+    project_before=project.read_bytes()
+    board=p.LoadBoard(str(PCB))
+    count=add_outlines(board)
+    temp=ROOT/"validation/pcb-routing-silk-tmp.kicad_pcb"
+    try:
+        assert p.SaveBoard(str(temp),board,True)
+        if lock.exists() or PCB.read_bytes()!=before:
+            raise RuntimeError("PCB changed or reopened; refusing to overwrite")
+        assert project.read_bytes()==project_before,"Project settings changed"
+        temp.replace(PCB)
+    finally:
+        temp.unlink(missing_ok=True)
+    print(f"Added {count} board-local silkscreen graphics; project settings preserved.")
+
+
+if __name__=="__main__":
+    main()

hardware/PCB/bom-draft.csv

@@ -0,0 +1,8 @@
+References,Quantity,Description,Manufacturer,MPN or identification,Footprint,Status
+U1,1,ESP32-S3 N16R8 development board,User supplied,HW-678 V0.0.0 / ASIN B0F3XMYYQY,Carrier:HW678_2x22_Provisional,Header pitch/spacing confirmed; connector drill fit and module envelope pending
+U2,1,MAX3243 full-pinout RS-232 breakout male,Adafruit,6253,Carrier:MAX3243_Reference_Provisional,PCB-only reference footprint; schematic assignment blank; male header/geometry verification required
+DS1,1,128x64 yellow-blue I2C OLED 26mm PCB,User supplied,ASIN B0F13SSSFB,Carrier:OLED_26mm_I2C_Provisional,Module geometry user-fit-verified; carrier header drill fit pending
+SW1 SW2 SW3,3,Normally-open 6mm THT tactile switch,Omron,B3F-1000,Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x,Datasheet/footprint checked; stock unverified
+R1 R2 R3,3,2.2k ohm 1 percent axial resistor at least 0.125W,TBD,TBD,Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal,Design value selected; exact MPN and body/lead fit pending
+H1 H2 H3 H4,4,Proposed M3 case mounting locations with 3.2mm NPTH,TBD,TBD,MountingHole:MountingHole_3.2mm_M3,Board-only hole locations; screws and insert/standoff dimensions not selected
+Assembly hardware,TBD,Module headers and optional beta-test sockets plus mounting hardware,TBD,TBD,,Not yet selected; not included in electrical component count

hardware/PCB/button-notes.md

@@ -0,0 +1,107 @@
+# Button selection: Omron B3F-1000
+
+Verified 2026-09-20 against the Omron datasheet and installed KiCad libraries. This research covers three active-low GPIO-to-GND buttons.
+
+**Integration decision:** the A0 schematic now implements B3F-1000 switches with one **2.2 kΩ, 1%, at least 0.125 W external pull-up** per input. The lower-current/internal-pull-up-only discussion below records the selection rationale, not an unselected schematic option. Firmware is unchanged. Exact resistor MPN, supply tolerance/budget and stock remain release checks.
+
+## Schematic-ready recommendation
+
+**B3F-1000 fits the installed footprint mechanically and its normally-open contact topology matches the circuit. Low-current operation with internal pull-ups needs the qualification below.**
+
+For each of the three buttons:
+
+- Value / manufacturer part number: **B3F-1000**, Omron; standard silver-plated contacts, ivory flat plunger, no separate ground terminal.
+- Symbol: **`Switch:SW_Push`** (normally open, two passive pins).
+- Explicitly assign footprint: **`Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x`**. The installed symbol's default footprint field is empty.
+- Symbol pin **1 → GPIO**, symbol pin **2 → GND**. The switch is nonpolar; swapping these two nets is electrically equivalent.
+
+| Function | Pin 1 net | Pin 2 net |
+|---|---|---|
+| Previous/back | GPIO10 | GND |
+| Select/confirm | GPIO13 | GND |
+| Next | GPIO14 | GND |
+
+GPIO assignments verified in `src/board_pins.h`. The PCB README specifies normally-open buttons to GND with internal pull-ups. Released = high; pressed = low. No voltage source connects directly through the switch: any external pull-up goes through a resistor to 3.3 V.
+
+## Exact terminal and pad mapping
+
+The installed footprint has **four physical holes but only two distinct electrical pad numbers: `1,1,2,2`**, not four uniquely numbered pads. The installed `SW_Push` symbol has pin 1 at the left and pin 2 at the right in its default orientation; pin numbers are hidden by the symbol.
+
+Unrotated footprint, front/top view; local coordinates in mm, positive Y downward:
+
+```text
+                  6.5 mm
+KiCad pad 1 (0,0) ----------- KiCad pad 1 (6.5,0)
+Omron terminal 4             Omron terminal 3
+                       NO
+                    contact                 4.5 mm
+Omron terminal 2             Omron terminal 1
+KiCad pad 2 (0,4.5) --------- KiCad pad 2 (6.5,4.5)
+```
+
+The horizontal connections above are permanent internal connections; pressing joins the two rows. Omron datasheet **page 4**, upper-left **“Terminal Arrangement/Internal Connections (Top View)”**, explicitly shows terminals **4–3 common** and **2–1 common**. This maps to KiCad's upper pair numbered 1 and lower pair numbered 2 when aligned as shown. **Omron terminal 1 is not KiCad pad 1 in this orientation.** The manufacturer's separate bottom-view numbering sketch must not be mistaken for a top view. Omron states terminal numbers are not marked on the switches. A 180° insertion swaps the two electrical sides without affecting this nonpolar circuit.
+
+Both pads numbered 1 receive the symbol pin-1 net; both pads numbered 2 receive pin-2's net. Do not attach a four-unique-pin symbol to this footprint without an explicit remapping. Connecting GPIO and GND to two terminals within the same common pair would permanently ground the GPIO.
+
+The footprint sets `duplicate_pad_numbers_are_jumpers no`; do not assume PCB routing software will treat the internal metal as a routing jumper. Route/check the duplicate-pad nets normally.
+
+## Manufacturer dimensions and ratings
+
+Source: Omron B3F datasheet, ordering table p. 1, ratings/operating characteristics p. 3, B3F-1000 drawing p. 4. Dimensions below are mm.
+
+| Item | Datasheet specification |
+|---|---|
+| Body | 6 ±0.2 × 6 ±0.2 |
+| Overall height above seating plane | 4.3 ±0.2 |
+| Plunger diameter | 3.5 |
+| Terminal row spacing | 4.5 ±0.2 |
+| Formed terminal span at hole-entry region | 6.5 ±0.5 |
+| Maximum-width dimension shown across formed leads | 7.7 ±0.5 |
+| Lead projection below seating plane | 3.5 |
+| Lead thickness / width callouts | 0.3 / 0.7 |
+| Recommended PCB hole-centre grid | 6.5 ±0.1 × 4.5 ±0.1 |
+| Recommended PCB holes | Four, diameter 1 ±0.1; reference drawing for PCB thickness 1.6 |
+| General dimensional tolerance | ±0.4 unless otherwise specified |
+| Contact form | SPST-NO |
+| Rated resistive load, standard silver version | **1–50 mA at 3–24 VDC** |
+| Minimum applicable load | **10 µA at 1 VDC, reference value** |
+| Initial contact resistance | 100 mΩ maximum |
+| Bounce | 5 ms maximum |
+| Operating force | 0.98 ±0.29 N (100 ±30 gf) |
+| Release force | 0.2 N minimum |
+| Pretravel | 0.25 +0.2/−0.1 |
+| Durability for B3F-1000, 0.98 N | 1,000,000 operations minimum |
+| Protection / washing | IP00 / washing not possible |
+
+### Installed footprint comparison
+
+Inspected `/usr/share/kicad/footprints/Button_Switch_THT.pretty/SW_TH_Tactile_Omron_B3F-100x.kicad_mod` (file format version `20260206`, generator version `10.0`) and `/usr/share/kicad/symbols/Switch.kicad_sym`.
+
+- Hole centres: `(0,0)`, `(6.5,0)`, `(0,4.5)`, `(6.5,4.5)` — match Omron's nominal PCB grid.
+- All four plated through-hole pads: circular copper diameter **1.7**, drill **1.0**, front/back copper and mask — nominal drill matches Omron's reference hole diameter. Confirm the fabricator's finished-hole tolerance when ordering.
+- Fab body: `(0.25,-0.75)` to `(6.25,5.25)`, **6 × 6**, matching nominal body dimensions.
+- Courtyard: `(-1.1,-1.1)` to `(7.6,5.6)`, **8.7 × 6.7**. This is a library placement boundary, not an enclosure or finger-access clearance specification.
+- Footprint description specifies H4.3 mm. No physical sample fit, enclosure-height check, or independent 3D-model measurement was performed.
+
+## Low-current qualification / selection decision
+
+**Do not claim internal-pull-up operation meets the standard part's full rated-load range.** At 3.3 V, pull-up resistance greater than 3.3 kΩ gives less than 1 mA contact current. For illustration only, 45 kΩ would give about 73 µA; that is not a verified resistance specification for this board's GPIOs.
+
+Omron's 10 µA / 1 V minimum is explicitly a **reference value**, not an unconditional low-current reliability guarantee. B3F-1000 is a reasonable prototype choice, but internal-pull-up-only contact reliability should be qualified in the intended environment and over life.
+
+For a conservative silver-contact design within the stated rated load, consider **one external 2.2 kΩ pull-up to 3.3 V per button** (about 1.5 mA while pressed); verify supply/resistor tolerances and GPIO limits before adopting. This recommendation was subsequently adopted in the A0 carrier schematic; see the integration decision above. If low current is important, the datasheet also lists **B3F-1002-G** with gold contacts in the same p. 4 dimensional group, rated 100 µA–50 mA at 3–24 VDC, but with a different operating force (1.76 ±0.49 N); weak internal pull-ups are not automatically within that rated range either. It has not been selected or stock-checked here.
+
+Retain firmware debouncing; a mechanical switch is not bounce-free. The device is unsealed (IP00), and the datasheet prohibits washing.
+
+## Supply evidence
+
+**Live stock not verified; no supply assurance.** On 2026-09-20 a request to the [DigiKey B3F-1000 product URL](https://www.digikey.com/en/products/detail/omron-electronics-inc-emc-div/B3F-1000/33150) returned HTTP 403 / an anti-bot challenge. No quantity, price, lead time, or lifecycle status could be established from that response. Confirm the exact MPN and available quantity with a distributor before BOM release; datasheet availability is not stock evidence.
+
+## Evidence and remaining checks
+
+- [Authoritative Omron datasheet](https://omronfs.omron.com/en_US/ecb/products/pdf/en-b3f.pdf), retrieved 2026-09-20.
+- [Local PDF](reference/button-omron-b3f.pdf).
+- [Extracted text](reference/button-omron-b3f.txt) for searching; use the PDF for drawing interpretation.
+- [Rendered page 4](reference/button-omron-b3f-page4.png), visually checked for the internal connections and dimensions.
+
+Before manufacturing: validate the selected pull-up strategy against supply tolerances/budget; check ERC/net assignment and PCB DRC in the actual design; confirm finished holes, enclosure/actuator access and a sample's fit/continuity; confirm procurement. This review verifies datasheet-to-library compatibility, not a completed-board electrical or mechanical test.

hardware/PCB/db9-mechanical-notes.md

@@ -0,0 +1,133 @@
+# DE-9 mechanical reference — pinned Adafruit 5988 STEP
+
+Research: 2026-09-21. **Nominal CAD geometry, not a toleranced connector drawing or physical fit qualification.** No board, schematic, footprint, application dependency or main README changes.
+
+**User-confirmed assumption:** male and female modules have identical external dimensions; use the external geometry below for mechanical planning of the male module on that basis. This is not independent male-CAD verification and **does not verify the male pin map**. The source explicitly identifies `DE9-F` / `F09HP` (5988). Do not infer contact numbering from gender, the model, or the front view.
+
+## Sources, attribution and licensing
+
+- User's link: https://github.com/adafruit/Adafruit_CAD_Parts/tree/main/5988%20RS-232%20Level%20Shifter
+- Pinned repository revision: **`5b8a21fb5e2e48478faf8901077be812f5224066`**, 2024-09-05, Noe Ruiz, “Adding 5988 RS-232 Level Shifter”. GitHub path history returned this as the latest change to that directory at retrieval.
+- Immutable directory: https://github.com/adafruit/Adafruit_CAD_Parts/tree/5b8a21fb5e2e48478faf8901077be812f5224066/5988%20RS-232%20Level%20Shifter
+- Unmodified originals retained in `reference/db9-cad/`: STEP, repository-root `README.md`, repository-root `LICENSE`. `sources.json` records **full immutable raw URLs and SHA-256 hashes**.
+
+| Original | SHA-256 |
+|---|---|
+| `5988 RS-232 Level Shifter.step` | `8eab9dc591a985fc987ceec2d7534e5e259263c73bebc64c0c3cd847e135906f` |
+| `LICENSE` | `f60436644e066301d4c2e8f1f0674a157b1f60e4fd5586717b99dde255cc18cd` |
+| `README.md` | `9ed9beac7600623b7b9bd0d02e1fdcd86610ce22966723179e6c6b618e399dce` |
+
+The CAD repository root license is **MIT, Copyright (c) 2016 Adafruit Industries**; root README merely describes STEP/Fusion/STL parts. No part-specific license file is present in the four-file directory. Retain the original MIT notice and warranty disclaimer with redistribution. This assessment follows the repository's stated license, not an independent audit of any imported vendor geometry. F3D, STL and JPG were listed but not downloaded or used; no image-derived dimensions or mesh fallback were needed.
+
+The separate Eagle board reference is from `Adafruit-RS-232-Level-Shifter-Breakout-PCB`, commit `63c6200bb3ef17d491089cfa6441b1810d79bb20`; its local `.brd` hash was rechecked (`6a7b35ef909f5a2d243c326c34db3957aaa01275bf2aac8e0c749ff18162e870`). Eagle-derived registration/hole information is attributed to **Limor Fried/Ladyada for Adafruit Industries**, under **CC BY-SA 3.0 Unported**; retain `reference/README.md` and `reference/license.txt`. The Eagle-derived portions of these notes use that license. Do not silently substitute the CAD-parts repository's MIT license for the Eagle design license.
+
+## Extraction method and confidence
+
+Used Python/OpenCascade (`cadquery-ocp==7.9.3.1.1`) in the isolated project `.cache/cad-tools/venv`; no application dependencies changed. The initially attempted older OCP wheel was unavailable for this Python; the pinned installed version succeeded.
+
+- `reference/db9-cad/extract.py`: STEPControl import with assembly placements applied; `BRepBndLib.AddOptimal` with triangulation and shape-tolerance enlargement disabled; analytic planes/cylinders via `BRepAdaptor_Surface`. No tessellation used for measurement.
+- `geometry.json`: all 15 solids and their faces, bounds, validity, analytic cylinder radii/axes, plane normals. All 15 pass `BRepCheck_Analyzer`.
+- `validate.py`: checks original hashes, all 12 header centres against actual Eagle XML, board bounds, mounting holes and selected front-face geometry; writes `measurements.json` containing explicit face selections and their bounds.
+- For unique PCB/connector bodies, STEP `CLOSED_SHELL` face order is associated with import face order, checking face counts, every surface type and every cylinder radius. Appearance assignments corroborate feature identification; **colour is not a material certification**.
+- Imported solid 12 = STEP `#101` / `Body2`, the main connector. It fuses housing/insert, contacts, flange, shell and front hex posts; its whole-solid bounds are **not metal-only dimensions**. Solids 13/14 = `#102`/`#103` (`Body3`/`Body4`), separate anchor brackets.
+- Front shell/flange/hex-post faces have the shared `Opaque(245,245,246)` appearance and the expected geometric continuity. The report measures those **face subsets**, excluding plastic, contacts, PCB and ICs. There is no separate hollow metal shell solid from which to certify wall thickness.
+
+**High confidence:** numerical nominal positions/bounds/radii of identified modeled features and STEP-to-Eagle board registration. **Moderate confidence:** physical fidelity of the simplified connector model and material boundaries; the contact/tail geometry differs from Eagle. **Unverified:** manufacturing tolerances, actual purchased-part fit, threads, male electrical mapping, cable/backshell envelope and final enclosure cutout. Extra decimal places below support reproducibility, not manufacturing accuracy.
+
+## Coordinate system and orientation
+
+All dimensions are **mm**. Use `(X,Y,Z)` in the imported STEP assembly:
+
+- X rightward in component/top view; Y toward the connector/cable, Z above the PCB.
+- Bare breakout PCB: **X 0…31.750, Y 0…29.337, Z 0…1.570**. PCB front edge is **Y = 29.337**; underside is Z = 0, component-side surface Z = 1.570.
+- Logic header hole row: **Y = 2.667**, X = `1.905 + 2.540 × (N−1)`, N = 1…12. No installed header/socket body is modeled; this is the hole-axis datum, not a plastic-header edge.
+- STEP XY is already Eagle board XY: **identity transform**, no scale, rotation or translation. Verified by all 12 header holes, both mounting holes and PCB bounds. STEP connector symmetry alone would not establish this registration.
+- Existing carrier footprint coordinates (header pad 1 origin, Y downward): **`x = X − 1.905; y = 2.667 − Y`**. Height above module PCB top: **`h = Z − 1.570`**. Add the chosen module-top elevation later to get case/carrier height; socket/standoff stack is not yet selected.
+- Connector front/mating approach is along Y, **parallel to the PCB**, not down into it. A cable approaches from +Y and inserts toward −Y. A front view looks along −Y with +Z up; +X then appears to the viewer's **left**, unlike component/top view. Do not reuse top-view left/right pin numbering as front-view numbering.
+
+## Metal feature dimensions — selected subsets, not assembly bounds
+
+The Z centre of the D profile and front screw-lock axes is **7.84762024**, or **6.27762024 above the PCB top**. Connector centre X = **15.875** (carrier-local x = **13.970**).
+
+| Feature | X bounds | Y bounds | Z bounds | Nominal dimensions / evidence |
+|---|---|---|---|---|
+| Front metal flange, exposed faces | 0.475…31.275 | 27.007…27.407 | 1.572620…14.122620 | **30.800 wide × 12.550 high × 0.400 axial thickness**; solid 12 faces 8, 11–14 |
+| D-shell straight outer wall region | 8.035981…23.714019 | 28.007…32.607 | 3.897620…11.797620 | **15.678038 wide × 7.900 high**, straight axial length **4.600**; faces 18–25 |
+| D-shell outer surface including root blend and rounded front lip | 7.435981…24.314019 | 27.407…33.207 | 3.297620…12.397620 | **16.878038 wide × 9.100 high × 5.800 axial extent**; faces 18–25, 81–88, 103–110 |
+| Left front hex screw-lock post | 0.719189…6.030811 | 27.407…32.207 | 5.547620…10.147620 | **4.600 across flats**, **5.311622 across corners**, **4.800 long**; faces 53–61, 89 |
+| Right front hex screw-lock post | 25.719189…31.030811 | 27.407…32.207 | 5.547620…10.147620 | Same dimensions; faces 62–70, 90 |
+
+The flange is centred laterally on the PCB, inset **0.475** from each side. Its lower edge is only **0.002620** above the modeled PCB top, upper edge **12.552620** above it. Preserve this tiny source offset in registration; do not interpret it as a designed assembly clearance.
+
+The D-shell has sloping side planes at **10° from vertical** in the front cross-section (`|normal X| = cos 10°`, `|normal Z| = sin 10°`), corner-cylinder radii **1.700**, root/lip rounding radius **0.600**. The wider side is upper (+Z). The maximum 16.878038 × 9.100 envelope occurs at the **root blend**, not uniformly along the projecting nose. These are bounding dimensions of a D shape, not a rectangular cutout prescription. Shell wall thickness / actual hollow cavity geometry is **not verified** by this fused representation.
+
+### Front cable screw-lock holes: actual modeled cylinders, not thread specifications
+
+- Axes **parallel to Y**, at `(X,Z) = (3.375,7.84762024)` and `(28.375,7.84762024)`.
+- **Axis spacing = 25.000**, symmetric ±12.500 about X = 15.875.
+- Carrier-local axis x = **1.470 and 26.470**; post front plane y = **−29.540**.
+- Solid 12 faces **60 / 69**, raw STEP faces **#13822 / #13831**, are inward-facing cylindrical hole surfaces: **radius 1.500, diameter 3.000**, Y = **27.407…32.007** (straight cylindrical length **4.600**).
+- Mouth cones (faces **89 / 90**) run Y = **32.007…32.207**, growing to **diameter 3.400** at the front: **0.200 axial × 0.200 radial** chamfer. Front mouth plane **Y = 32.207**.
+- Flat modeled bottoms at Y = **27.407** (faces 61/70): total modeled mouth-to-bottom depth **4.800** including chamfer.
+- **No helical threads modeled. Do not call this M3, 4-40, a tap drill, minor/major thread diameter, or usable engagement depth.** Actual screw standard, pitch, engagement and tolerances require a connector drawing or physical check.
+
+## Front planes, PCB overhang and header offsets
+
+There is no single interchangeable “front plane”. The flange, hex-post mouth and shell lip differ. The shell's foremost geometric plane is a useful **mating-face reference**, but the source does not establish a manufacturer's functional fully-mated datum or panel seating specification.
+
+| Reference plane | STEP/Eagle Y | Forward of PCB front edge Y=29.337 | Forward of header row Y=2.667 | Carrier-local y |
+|---|---:|---:|---:|---:|
+| Flange rear face | 27.007 | −2.330 | 24.340 | −24.340 |
+| Flange front face / shell root | **27.407** | **−1.930** | **24.740** | **−24.740** |
+| Straight shell begins | 28.007 | −1.330 | 25.340 | −25.340 |
+| Breakout PCB front edge | **29.337** | 0 | **26.670** | **−26.670** |
+| Front hex-post mouth faces | **32.207** | **+2.870** | **29.540** | **−29.540** |
+| Straight shell ends / rounded lip begins | 32.607 | +3.270 | 29.940 | −29.940 |
+| Foremost shell lip / modeled insert face | **33.207** | **+3.870** | **30.540** | **−30.540** |
+
+Thus the modeled shell nose projects **3.870 beyond the breakout PCB**; the hex posts project **2.870**, ending **1.000 behind the shell nose**. The flange itself is **1.930 behind the PCB front edge**. Do not position a case wall at the flange while ignoring that the PCB extends 1.930 beyond it.
+
+For later unrotated, component-up carrier placement with header pad 1 at `(x0,y0)`:
+
+- Breakout front edge: `y0 − 26.670`.
+- Flange front: `y0 − 24.740`.
+- Hex mouths: `y0 − 29.540`.
+- Shell nose: `y0 − 30.540`.
+- If the **breakout PCB front edge** is aligned with carrier top edge `ytop`, choose `y0 = ytop + 26.670`; shell nose is then at `ytop − 3.870`, hex mouths at `ytop − 2.870`.
+- If instead the **shell nose** is aligned with that edge, choose `y0 = ytop + 30.540`; breakout front edge is then 3.870 inward. These are different choices, not a recommended final layout.
+
+## Three distinct mechanical systems — do not interchange
+
+| System | Axes / coordinates | Spacing | Diameter or geometry | Purpose |
+|---|---|---:|---|---|
+| Front cable screw-lock holes | Y axes; X 3.375 / 28.375, Z 7.847620 | **25.000** | Modeled bore Ø3.000, mouth Ø3.400; no thread qualification | Retain mating cable at connector front |
+| Breakout PCB mounting holes | Z axes; `(3.810,11.430)` / `(27.940,11.430)` | **24.130** | Eagle drill Ø3.000 / plated copper Ø3.600; STEP hole cylinders Ø3.000 | Mount module to carrier/standoffs |
+| Connector shell/anchor PCB holes G1/G2 | Z axes; Eagle `(3.3528,17.907)` / `(28.3972,17.907)` | **25.0444** | Eagle drill Ø3.302 / copper Ø5.080; STEP rounds X to 3.353 / 28.397 | Receive connector anchor legs, **not** carrier mounting or cable screws |
+
+### Separate metal anchor brackets and underside clearance
+
+Solids **13/14** represent the bent anchor brackets/legs, not the front hex posts. Per bracket whole-solid bounds (leg-only components, not whole assembly):
+
+- Right: **X 25.875…30.875, Y 17.907…24.307, Z −2.230…10.122620**.
+- Left: **X 0.875…5.875**, same Y and Z.
+- Each bracket envelope: **5.000 wide × 6.400 deep × 12.352620 high**. Bent sheet regions are **0.500 thick**; the lower two fingers occupy Y = **17.907…18.407**, not a circular screw shank.
+- Tips reach **2.230 below the module underside**, i.e. **3.800 below the module top**. This needs carrier/case underside clearance; do not turn these bounds into a mounting-hole drill recommendation.
+- Bracket symmetry centres X = **3.375 / 28.375**, lower sheet midplane Y = **18.157**. Relative to Eagle G1/G2, centre offsets are respectively **+0.0222 / −0.0222 in X** and **+0.250 in Y**. These are source-model differences, not a reason to move the Eagle pads.
+- Main fused body's signal tails separately reach Z = **−1.607380**. Their modeled rows are Y = **16.467 / 19.307**, versus Eagle **16.637 / 19.177**; horizontal pitch also differs (model 2.770 versus Eagle 2.7432). The 3D model is **not suitable as electrical pin/drill authority**.
+
+No complete all-metal rear housing reconstruction is claimed: only the explicitly selected front surfaces and separate anchor brackets above. Main solid 12's 30.800 × 18.200 × 15.730 bounds include plastic/contact tails and must not be relabeled as a shell-only envelope.
+
+## Validation, reproduction and release boundary
+
+From project root:
+
+```sh
+.cache/cad-tools/venv/bin/python -B hardware/PCB/reference/db9-cad/extract.py
+python3 -B hardware/PCB/reference/db9-cad/validate.py
+```
+
+Both successfully ran; validation reported PASS for original hashes, 15 valid solids, all 12 Eagle header centres, PCB bounds, mounting holes, metal-appearance subsets and front lock cylinders. Extraction artifacts retain unrounded floating-point values. No firmware build, board DRC, hardware measurement or physical mating test was performed (research-only task).
+
+**Ready for nominal placement planning:** metal flange dimensions, shell outer envelope, front hex-post dimensions and bore geometry, their distinct front planes, 25.000 front-axis spacing, PCB/header registration and overhang, anchor-leg underside extent. The A1 PCB now aligns the breakout front edge with the carrier top edge. Nominal metal bounding projections and screw-lock axes appear on Dwgs.User; companion layout/footprint notes have been updated. Neither projection nor nominal bound is an enclosure cutout or clearance qualification.
+
+**Before fabrication / final case design:** verify actual male pin map; check physical connector profile and overhang against these nominal values; select header/socket and standoff heights; establish manufacturing/assembly clearances, cable backshell/tool access, wall thickness and cutout shape; verify thread standard and retention; perform a 1:1 fit/mating check. In particular, do not use exact-fit nominal bounds as an enclosure clearance or assume the CAD's Ø3.000 lock bore specifies a real screw thread.

hardware/PCB/footprint-notes.md

@@ -0,0 +1,105 @@
+# Provisional carrier module footprints
+
+These project-local footprints are in `Carrier.pretty`. They are mechanical
+starting points, **not fabrication-ready connector selections**. Both are now
+assigned to their matching symbols in the native schematic through the project
+library tables and used in the routed PCB draft. The assembled module 3D models
+are not provided. See `pcb-draft-notes.md` for placement/routing and
+`rs232-footprint-notes.md` for the additional provisional RS-232 reference footprint.
+
+## Shared pad/drill provenance and limits
+
+Reference inspected locally: installed KiCad library footprint
+`Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical`, file
+`/usr/share/kicad/footprints/Connector_PinHeader_2.54mm.pretty/PinHeader_1x04_P2.54mm_Vertical.kicad_mod`
+(format version `20260206`; local KiCad `10.0.6-1.fc44`).
+
+Both footprints use that reference's **1.70 × 1.70 mm plated through-hole pads,
+1.00 mm drills, rectangular pad 1, and circular remaining pads**, on
+`*.Cu` and `*.Mask`, with unused copper layers retained. Nominal pitch is 2.54 mm.
+Only the reference's pad/drill convention is reused, not its connector body,
+courtyard, or 3D model. HW678 pad 23 is circular: only overall pad 1 is rectangular.
+
+**PROVISIONAL connector fit — awaiting the selected actual pin/socket datasheet.**
+Breadboard fit supports centre spacing, not drill size, finished-hole tolerance,
+annular-ring suitability, socket body clearance, mating height, or solderability.
+Validate those against the actual final headers and beta-test sockets and the PCB
+fabricator's process before release. No electrical nets or ESP32 GPIO assignments
+are inferred. No courtyards are supplied: module/connector assembly clearances
+remain incomplete, so automated courtyard checks cannot establish fit.
+
+Coordinates below are millimetres, unrotated on the carrier front side, X right
+and Y down. Views are not mirrored. Placement on the back side or viewing the
+module from its solder side requires the appropriate KiCad transform; do not
+silently reverse the numbering.
+
+## `Carrier:OLED_26mm_I2C_Provisional`
+
+Origin: top-left corner of the module PCB, viewed from the front/display side,
+header at the top. User-verified geometry from the current request and the later
+mechanical-evidence section of `README.md`:
+
+| Pad | Signal | X | Y |
+|---|---|---:|---:|
+| 1 | GND | 9.19 | 1.50 |
+| 2 | VCC | 11.73 | 1.50 |
+| 3 | SCL | 14.27 | 1.50 |
+| 4 | SDA | 16.81 | 1.50 |
+
+- PCB boundary: (0, 0) to (26, 26), solid rectangle on `F.Fab`.
+  This depicts the module, not the carrier's routed edge; no `Edge.Cuts` is used.
+- Four unnumbered, non-plated through holes, diameter 2.00 mm, at
+  (1.75, 1.75), (24.25, 1.75), (1.75, 24.25), (24.25, 24.25).
+  Hole centres are 1.75 mm from adjacent edges, with 22.50 mm spacing in both axes.
+  These transfer the verified module hole geometry to the carrier; they do not
+  select screws, inserts, bosses, or hardware clearance envelopes.
+- Display boundary: (1, 4.5) to (25.5, 21), 24.5 × 16.5 mm, dashed on `F.Fab`.
+  This is the supplied display boundary, not a verified active-pixel area or case cutout.
+- Pad-to-signal mapping is documented here and in the footprint description;
+  footprint pads themselves have numbers, not assigned nets.
+
+The approved geometry supersedes the earlier 22.16 mm hole-spacing measurement:
+22.50 mm hole spacing, Y=1.50 mm header centres, and the centred header coordinates
+above apply. See README for the user-reported successful template fit check.
+
+## `Carrier:HW678_2x22_Provisional`
+
+Component/top view: antenna up, USB connectors down. Origin is the top-left header
+centre (pad 1), **not a PCB corner**.
+
+- Left row: pads 1 through 22, top to bottom, X=0.
+- Right row: pads 23 through 44, top to bottom, X=25.40.
+- Y=0 through 53.34 in 2.54 mm increments for each row (21 intervals).
+- User breadboard fit verifies nominal 2.54 mm pitch and 25.40 mm row spacing;
+  these supersede the earlier raw caliper dimensions in README.
+- Numbering follows the project's explicit convention, not a generic dual-row
+  connector's alternating or counterclockwise numbering. Physical numbers do
+  **not** establish GPIO, supply, or ground assignments.
+- Only pads and annotation text are present. **No PCB outline, antenna keepout,
+  courtyard, USB envelope, mounting holes, or 3D model is guessed.** Text positions
+  are annotations, not dimensional evidence. Outline registration, antenna extent,
+  connector offsets/overhang, and assembly height remain unknown.
+
+## Validation and release gates
+
+Validation performed with KiCad 10.0.6 `pcbnew.FootprintLoad`: both footprints
+parsed successfully. Assertions passed for pad counts, all numbered pad positions,
+pad shapes/types/sizes/drills, OLED NPTH positions and diameters, both OLED `F.Fab`
+rectangle bounds, and absence of courtyards, `Edge.Cuts`, and keepout zones.
+HW678 was also checked to contain no graphical shapes. The local Python binding
+emitted three startup `PROPERTY_ENUM` assertions (also seen on a version-only
+import); these did not prevent loading or the checks from passing.
+
+Repeat the retained footprint regression checks from the repository root with:
+
+```sh
+/usr/bin/python3 -B hardware/PCB/validate_footprints.py
+```
+
+This requires the system Python with KiCad's `pcbnew` binding. It checks the
+native-loaded pad counts, coordinates, pad types, sizes, drills and geometry. Parsing is
+not DRC, electrical verification, connector fit verification, or fabrication approval.
+Print both footprints at 1:1 and check the real assemblies, especially HW678 row
+numbering/orientation. Before layout release, select and verify connectors, map
+HW678 pins from reliable board evidence, and establish module envelopes,
+antenna restrictions, USB access, mounting hardware, and courtyards.

hardware/PCB/fp-lib-table

@@ -0,0 +1,6 @@
+(fp_lib_table (version 7)
+ (lib (name "Carrier")(type "KiCad")(uri "${KIPRJMOD}/Carrier.pretty")(options "")(descr "Provisional module carrier footprints; see footprint-notes.md"))
+ (lib (name "Button_Switch_THT")(type "KiCad")(uri "${KICAD10_FOOTPRINT_DIR}/Button_Switch_THT.pretty")(options "")(descr "KiCad standard THT switches"))
+ (lib (name "Resistor_THT")(type "KiCad")(uri "${KICAD10_FOOTPRINT_DIR}/Resistor_THT.pretty")(options "")(descr "KiCad standard axial resistors"))
+ (lib (name "MountingHole")(type "KiCad")(uri "${KICAD10_FOOTPRINT_DIR}/MountingHole.pretty")(options "")(descr "KiCad standard mounting holes"))
+)

hardware/PCB/generate_pcb_draft.py

@@ -0,0 +1,206 @@
+#!/usr/bin/env python3
+"""Create the compact placement draft from a fresh KiCad XML netlist.
+
+Requires system Python + pcbnew. Refuses to overwrite an existing PCB unless
+--overwrite is explicit. This is a draft generator, not a manufacturing tool.
+Does not modify the schematic, footprint libraries or project settings.
+SaveBoard(..., True) deliberately preserves the user's existing project rules.
+"""
+import argparse
+
+from pathlib import Path
+import re
+import subprocess
+import xml.etree.ElementTree as ET
+import pcbnew as p
+
+ROOT = Path(__file__).resolve().parent
+PCB = ROOT / "serial-carrier.kicad_pcb"
+LIBS = Path("/usr/share/kicad/footprints")
+ORIGIN = (100, 100)
+OUTLINE = [(36,0), (82,0), (82,80), (0,80), (0,19), (36,19)]
+PLACEMENT = {
+    "U1": ("Carrier:HW678_2x22_Provisional", 8, 23),
+    "U2": ("Carrier:MAX3243_Reference_Provisional", 43, 26.670),
+    "DS1": ("Carrier:OLED_26mm_I2C_Provisional", 43, 36),
+    "R1": ("Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal", 43, 34),
+    "R2": ("Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal", 54, 34),
+    "R3": ("Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal", 65, 34),
+    "SW1": ("Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x", 43, 68),
+    "SW2": ("Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x", 55, 68),
+    "SW3": ("Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x", 67, 68),
+}
+MOUNTS = [(3.5,22.5), (3.5,75), (78,4), (78,76)]
+# Deliberate allocation, NOT a measured antenna envelope or an RF guarantee.
+RF_RESERVE = [(10,19), (31,19), (31,32), (10,32)]
+
+def mm(v):
+    return p.FromMM(v)
+
+def xy(x,y):
+    return p.VECTOR2I(mm(x+ORIGIN[0]), mm(y+ORIGIN[1]))
+
+def text(board, value, x, y, layer=p.F_SilkS, size=1):
+    item = p.PCB_TEXT(board)
+    item.SetText(value)
+    item.SetPosition(xy(x,y))
+    item.SetLayer(layer)
+    item.SetTextSize(p.VECTOR2I(mm(size),mm(size)))
+    item.SetTextThickness(mm(0.15))
+    board.Add(item)
+    return item
+
+def polygon(zone, points):
+    poly=zone.Outline()
+    poly.NewOutline()
+    for x,y in points:
+        pt=xy(x,y)
+        poly.Append(pt.x,pt.y)
+
+def load(lib_id):
+    lib,name=lib_id.split(":",1)
+    folder=ROOT / "Carrier.pretty" if lib=="Carrier" else LIBS / (lib+".pretty")
+    fp=p.FootprintLoad(str(folder),name)
+    if fp is None:
+        raise RuntimeError("Cannot load "+lib_id)
+    fp.SetFPIDAsString(lib_id)
+    return fp
+
+def quiet_footprint(fp):
+    # Retain all mechanical geometry, but replace sprawling research annotation
+    # text with concise board annotations. Libraries are never modified.
+    for graphic in list(fp.GraphicalItems()):
+        if isinstance(graphic,p.PCB_TEXT):
+            fp.Remove(graphic)
+    fp.Value().SetVisible(False)
+    fp.Reference().SetTextSize(p.VECTOR2I(mm(1),mm(1)))
+    fp.Reference().SetTextThickness(mm(0.15))
+    fp.Reference().SetLayer(p.F_SilkS)
+
+
+def copy_schematic_fields(fp, component):
+    for field in component.findall("fields/field"):
+        name=field.get("name")
+        if name in ("Reference", "Value", "Footprint"):
+            continue
+        fp.SetField(name, field.text or "")
+        fp.GetField(name).SetVisible(False)
+
+
+
+def main():
+    parser=argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--overwrite",action="store_true")
+    args=parser.parse_args()
+    if PCB.exists() and not args.overwrite:
+        parser.error("PCB exists; preserve manual edits or explicitly use --overwrite")
+    if ROOT.joinpath("~serial-carrier.kicad_pcb.lck").exists():
+        parser.error("PCB is open in KiCad; close it before regenerating")
+    netfile=ROOT / "validation/pcb-source-netlist.xml"
+    subprocess.run(["kicad-cli","sch","export","netlist","--format","kicadxml","-o",str(netfile),str(ROOT/"serial-carrier.kicad_sch")],check=True)
+    source=ET.parse(netfile).getroot()
+    components={c.get("ref"):c for c in source.findall("components/comp")}
+    assert set(components)==set(PLACEMENT), "Schematic component set changed; review layout"
+    schematic=ROOT.joinpath("serial-carrier.kicad_sch").read_text()
+    root_uuid=re.search(r'\(uuid "?([a-f0-9-]{36})"?\)',schematic).group(1)
+    board=p.BOARD()
+    board.SetCopperLayerCount(2)
+    settings=board.GetDesignSettings()
+    settings.SetBoardThickness(mm(1.6))
+    settings.m_MinClearance=mm(0.25)
+    settings.m_CopperEdgeClearance=mm(0.5)
+    settings.m_HoleClearance=mm(0.25)
+    settings.m_TrackMinWidth=mm(0.25)
+    settings.m_ViasMinSize=mm(0.7)
+    # Proposed in-memory draft rules only; never overwrite the user's project settings.
+    title=board.GetTitleBlock()
+    title.SetTitle("Serial Swiss Army Knife - 82x80 mm carrier draft")
+    title.SetRevision("A1 DRAFT")
+    title.SetComment(0,"NOT FOR FABRICATION - USB / antenna geometry pending; verify module pinout / assembly")
+    pad_nets={}
+    for source_net in source.findall("nets/net"):
+        net=p.NETINFO_ITEM(board,source_net.get("name"))
+        board.Add(net)
+        for node in source_net.findall("node"):
+            pad_nets[node.get("ref"),node.get("pin")]=(net,node)
+    for ref,(lib_id,x,y) in PLACEMENT.items():
+        comp=components[ref]
+        if ref != "U2":
+            assert comp.findtext("footprint")==lib_id,(ref,"Schematic footprint changed")
+        fp=load(lib_id)
+        fp.SetReference(ref)
+        fp.SetValue(comp.findtext("value"))
+        path=p.KIID_PATH()
+        path.push_back(p.KIID(root_uuid))
+        path.push_back(p.KIID(comp.findtext("tstamps")))
+        fp.SetPath(path)
+        fp.SetSheetfile("serial-carrier.kicad_sch")
+        fp.SetSheetname("serial-carrier")
+        fp.SetPosition(xy(x,y))
+        board.Add(fp)
+        quiet_footprint(fp)
+        copy_schematic_fields(fp,comp)
+        if ref=="U1":
+            fp.Reference().SetPosition(xy(20.7,44))
+        elif ref=="U2":
+            fp.Reference().SetPosition(xy(56.97,14.670))
+        elif ref=="DS1":
+            fp.Reference().SetPosition(xy(56,49))
+        elif ref.startswith("SW"):
+            fp.Reference().SetPosition(xy(x+3.25,y-2))
+        else:
+            fp.Reference().SetLayer(p.F_Fab)
+            fp.Reference().SetPosition(xy(x+3.81,y-1.6))
+        for pad in fp.Pads():
+            key=ref,pad.GetNumber()
+            if pad.GetNumber():
+                net,node=pad_nets[key]
+                pad.SetNet(net)
+                pad.SetPinFunction(node.get("pinfunction", ""))
+                pad.SetPinType(node.get("pintype", "passive"))
+    for i,(x,y) in enumerate(MOUNTS,1):
+        fp=load("MountingHole:MountingHole_3.2mm_M3")
+        fp.SetReference("H"+str(i))
+        fp.SetValue("M3 mounting proposal / 3.2mm")
+        fp.SetBoardOnly(True)
+        fp.SetExcludedFromBOM(True)
+        fp.SetExcludedFromPosFiles(True)
+        fp.SetPosition(xy(x,y))
+        board.Add(fp)
+        quiet_footprint(fp)
+        fp.Reference().SetVisible(False)
+    for a,b in zip(OUTLINE,OUTLINE[1:]+OUTLINE[:1]):
+        edge=p.PCB_SHAPE(board)
+        edge.SetShape(p.SHAPE_T_SEGMENT)
+        edge.SetStart(xy(*a)); edge.SetEnd(xy(*b))
+        edge.SetLayer(p.Edge_Cuts); edge.SetWidth(mm(0.05))
+        board.Add(edge)
+    reserve=p.ZONE(board)
+    reserve.SetIsRuleArea(True)
+    layers=p.LSET(); layers.AddLayer(p.F_Cu); layers.AddLayer(p.B_Cu)
+    reserve.SetLayerSet(layers)
+    reserve.SetZoneName("PROVISIONAL RF RESERVE - verify actual antenna clearance")
+    reserve.SetDoNotAllowTracks(True); reserve.SetDoNotAllowVias(True)
+    reserve.SetDoNotAllowZoneFills(True); reserve.SetDoNotAllowPads(True)
+    reserve.SetDoNotAllowFootprints(False)  # the module itself spans this region
+    polygon(reserve,RF_RESERVE)
+    board.Add(reserve)
+    text(board,"RF RESERVE",20.5,26,p.Dwgs_User,1.2)
+    text(board,"VERIFY ANTENNA",20.5,29,p.Dwgs_User,1)
+    text(board,"ESP32 HW678",20.7,48)
+    text(board,"USB ACCESS - VERIFY",18,83,p.Dwgs_User,1)
+    text(board,"DE-9 OUT / NOMINAL MALE",56.97,-1.830,p.Dwgs_User,1)
+    text(board,"MAX3243 REF",56.97,17.670)
+    text(board,"26mm OLED",56,52)
+    for label,x in zip(("BACK","SELECT","NEXT"),(46.25,58.25,70.25)):
+        text(board,label,x,75, size=0.9)
+    text(board,"DRAFT - NOT FOR FAB",56,78,size=0.9)
+    text(board,"82 x 80 mm / 2 copper layers",41,-5,p.Dwgs_User,1.5)
+    text(board,"Nominal RS-232 metal verified; ESP32 USB / antenna / assembly clearance pending",41,-2.5,p.Dwgs_User,0.9)
+    board.BuildConnectivity()
+    assert p.SaveBoard(str(PCB),board,True)
+    print("Created",PCB,"with 9 circuit footprints, 4 proposed M3 mounts, 2 copper layers.")
+    print("Placement draft only. U2 nominal male external metal dimensions user-confirmed; pin map / assembly still require qualification.")
+
+if __name__=="__main__":
+    main()

hardware/PCB/generate_schematic.py

@@ -0,0 +1,167 @@
+#!/usr/bin/env python3
+"""Generate the initial native KiCad carrier schematic (Python stdlib only).
+
+Explicit bootstrap/regeneration tool: overwrites the generated schematic, symbol
+library and library tables. Do not run over subsequent manual KiCad edits without
+reviewing/backing them up. It does not regenerate footprints or the fit template.
+"""
+import json
+from pathlib import Path
+import uuid
+
+ROOT = Path(__file__).resolve().parent
+PROJECT = "serial-carrier"
+NS = uuid.UUID("b6f75dd1-a843-42f2-9067-57c995968145")
+
+def uid(key):
+    return str(uuid.uuid5(NS, key))
+
+def q(value):
+    return json.dumps(str(value), ensure_ascii=False)
+
+def n(value):
+    return f"{value:.4f}".rstrip("0").rstrip(".") if value else "0"
+
+def effects(size=1.27, extra=""):
+    return f"(effects (font (size {size} {size})) {extra})"
+
+def prop(name, value, x=0, y=0, hidden=False):
+    return f'(property {q(name)} {q(value)} (at {n(x)} {n(y)} 0) {effects(extra="(hide yes)" if hidden else "")})'
+
+# Physical module numbering is a project convention, not ESP32 GPIO numbering:
+# component side, antenna up / USB down; left row 1..22, right row 23..44.
+left = ["3V3", "3V3", "EN", "GPIO4", "GPIO5", "GPIO6", "GPIO7", "GPIO15", "GPIO16", "GPIO17", "GPIO18", "GPIO8", "GPIO3", "GPIO46", "GPIO9", "GPIO10", "GPIO11", "GPIO12", "GPIO13", "GPIO14", "5V", "GND"]
+right = ["GND", "GPIO43", "GPIO44", "GPIO1", "GPIO2", "GPIO42", "GPIO41", "GPIO40", "GPIO39", "GPIO38", "GPIO37", "GPIO36", "GPIO35", "GPIO0", "GPIO45", "GPIO48", "GPIO47", "GPIO21", "GPIO20", "GPIO19", "GND", "GND"]
+GPIO_NET = {4:"RS_DCD",5:"RS_DSR",6:"RS_RI",7:"RS_DTR",8:"RS_VALID",9:"RS_OFF_N",10:"BTN_PREVIOUS",11:"OLED_SDA",12:"OLED_SCL",13:"BTN_SELECT",14:"BTN_NEXT",15:"RS_RTS",16:"RS_CTS",17:"RS_TX",18:"RS_RX"}
+OUTPUTS = {7, 12, 15, 17}
+INPUTS = {4, 5, 6, 8, 10, 13, 14, 16, 18}
+
+def gpio_type(name):
+    if not name.startswith("GPIO"):
+        return "input" if name == "EN" else "passive"
+    number = int(name[4:])
+    if number == 9:
+        # Model the programmable MCU pad, not a discrete open-collector device.
+        # The required firmware open-drain mode and module pull-up are noted on sheet.
+        return "bidirectional"
+    return "output" if number in OUTPUTS else "input" if number in INPUTS else "bidirectional"
+
+# Pin tuples: physical number, name, electrical type, local X, local Y, angle.
+MCU = []
+for side, names in enumerate((left, right)):
+    for index, name in enumerate(names):
+        number = index + 1 + side * 22
+        kind = "power_out" if number in (1, 22) else gpio_type(name)
+        MCU.append((str(number), name, kind, -22.86 if side == 0 else 22.86, 26.67-index*2.54, 0 if side == 0 else 180))
+
+# Published Adafruit 5988 CAD reference; male 6253 correspondence is provisional.
+RS_NAMES = ["Vin", "GND", "DCD", "RX", "TX", "DTR", "DSR", "RTS", "CTS", "RI", "VLD", "OFF_N"]
+RS = [(str(i+1), name, "power_in" if i < 2 else "input" if name in ("TX","DTR","RTS","OFF_N") else "output", -20.32, 13.97-i*2.54, 0) for i,name in enumerate(RS_NAMES)]
+OLED = [(str(i+1),name,kind,-15.24,3.81-i*2.54,0) for i,(name,kind) in enumerate((("GND","power_in"),("VCC","power_in"),("SCL","input"),("SDA","bidirectional")))]
+TWO = [("1","~","passive",-5.08,0,0),("2","~","passive",5.08,0,180)]
+
+SPECS = {
+    "HW678_N16R8": (MCU, 17.78, 29.21, "U", "Carrier:HW678_2x22_Provisional", "HW-678 V0.0.0 / N16R8 carrier interface; project numbering; onboard USB/regulator retained"),
+    "MAX3243_Module_Reference": (RS, 15.24, 17.78, "U", "", "Adafruit male 6253 intended; physical numbering from published female 5988 CAD, VERIFY MALE"),
+    "OLED_I2C_26mm": (OLED, 10.16, 7.62, "DS", "Carrier:OLED_26mm_I2C_Provisional", "User fit-verified 26 mm OLED; front/top header GND VCC SCL SDA"),
+    "SW_NO": (TWO, 2.54, 2.54, "SW", "Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x", "Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs"),
+    "R": (TWO, 2.54, 1.016, "R", "Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal", "Resistor, axial DIN0207 footprint; exact MPN pending")
+}
+
+def symbol_definition(name, embedded=False):
+    pins, halfwidth, halfheight, ref, footprint, description = SPECS[name]
+    out = [f'(symbol {q("Carrier:"+name if embedded else name)} (pin_names (offset 0.762)) (in_bom yes) (on_board yes)',
+           prop("Reference", ref, 0, halfheight+5.08), prop("Value", name, 0, halfheight+2.54),
+           prop("Footprint", footprint, hidden=True), prop("Datasheet", "", hidden=True), prop("Description",description,hidden=True)]
+    if name == "SW_NO":
+        shape = '(polyline (pts (xy -2.54 0) (xy 2.54 1.524)) (stroke (width 0.254) (type default)) (fill (type none)))'
+        shape += ''.join(f'(circle (center {x} 0) (radius 0.35) (stroke (width 0.1524) (type default)) (fill (type none)))' for x in (-2.54,2.54))
+    else:
+        shape = f'(rectangle (start {-halfwidth} {halfheight}) (end {halfwidth} {-halfheight}) (stroke (width 0.254) (type default)) (fill (type background)))'
+    out.append(f'(symbol {q(name+"_0_1")} {shape})')
+    out.append(f'(symbol {q(name+"_1_1")}')
+    for number,label,kind,x,y,angle in pins:
+        length = abs(x)-halfwidth
+        out.append(f'(pin {kind} line (at {n(x)} {n(y)} {angle}) (length {n(length)}) (name {q(label)} {effects(1.016)}) (number {q(number)} {effects(1.016)}))')
+    out.extend([')', ')'])
+    return '\n'.join(out)
+
+ROOT.joinpath("Carrier.kicad_sym").write_text('(kicad_symbol_lib (version 20231120) (generator "kicad_symbol_editor")\n'+'\n'.join(symbol_definition(name) for name in SPECS)+'\n)\n')
+ROOT.joinpath("sym-lib-table").write_text('(sym_lib_table (version 7)\n (lib (name "Carrier")(type "KiCad")(uri "${KIPRJMOD}/Carrier.kicad_sym")(options "")(descr "Project-local module interfaces"))\n)\n')
+ROOT.joinpath("fp-lib-table").write_text('(fp_lib_table (version 7)\n (lib (name "Carrier")(type "KiCad")(uri "${KIPRJMOD}/Carrier.pretty")(options "")(descr "Provisional module carrier footprints; see footprint-notes.md"))\n (lib (name "Button_Switch_THT")(type "KiCad")(uri "${KICAD10_FOOTPRINT_DIR}/Button_Switch_THT.pretty")(options "")(descr "KiCad standard THT switches"))\n (lib (name "Resistor_THT")(type "KiCad")(uri "${KICAD10_FOOTPRINT_DIR}/Resistor_THT.pretty")(options "")(descr "KiCad standard axial resistors"))\n (lib (name "MountingHole")(type "KiCad")(uri "${KICAD10_FOOTPRINT_DIR}/MountingHole.pretty")(options "")(descr "KiCad standard mounting holes"))\n)\n')
+# Preserve project settings on regeneration.
+project_file = ROOT / (PROJECT + ".kicad_pro")
+if not project_file.exists():
+    project_file.write_text(json.dumps({"meta":{"filename":project_file.name,"version":3}},indent=2)+"\n")
+
+root_uuid = uid("root")
+items = [f'(kicad_sch (version 20250114) (generator "eeschema") (uuid {q(root_uuid)}) (paper "A3")',
+         '(title_block (title "ESP32 Serial Swiss Army Knife - Module Carrier") (date "2026-09-20") (rev "A0 DRAFT") (comment 1 "Not fabrication-ready: provisional module footprints and male RS-232 mapping"))',
+         '(lib_symbols '+'\n'.join(symbol_definition(name,True) for name in SPECS)+')']
+expected = {}
+
+def wire(x1,y1,x2,y2,key):
+    items.append(f'(wire (pts (xy {n(x1)} {n(y1)}) (xy {n(x2)} {n(y2)})) (stroke (width 0) (type default)) (uuid {q(uid("wire:"+key))}))')
+
+def label(net,x,y,key):
+    items.append(f'(label {q(net)} (at {n(x)} {n(y)} 0) {effects(1.016,"(justify left bottom)")} (uuid {q(uid("label:"+key))}))')
+
+def note(text,x,y,size=1.27):
+    items.append(f'(text {q(text)} (at {n(x)} {n(y)} 0) {effects(size,"(justify left top)")} (uuid {q(uid("text:"+text))}))')
+
+def place(name,ref,value,x,y,nets,extra=None):
+    pins,hw,hh,_,footprint,description = SPECS[name]
+    instance = [f'(symbol (lib_id {q("Carrier:"+name)}) (at {n(x)} {n(y)} 0) (unit 1) (in_bom yes) (on_board yes) (dnp no) (uuid {q(uid(ref))})',
+                prop("Reference",ref,x,y-hh-5.08),prop("Value",value,x,y-hh-2.54),prop("Footprint",footprint,x,y,True),prop("Datasheet","",x,y,True)]
+    for k,v in (extra or {}).items():
+        instance.append(prop(k,v,x,y,True))
+    instance.extend(f'(pin {q(p[0])} (uuid {q(uid(ref+":"+p[0]))}))' for p in pins)
+    instance.append(f'(instances (project {q(PROJECT)} (path {q("/"+root_uuid)} (reference {q(ref)}) (unit 1)))))')
+    items.append('\n'.join(instance))
+    for number,_,_,px,py,angle in pins:
+        ax,ay=x+px,y-py
+        net=nets.get(number)
+        key=ref+":"+number
+        if net is None:
+            items.append(f'(no_connect (at {n(ax)} {n(ay)}) (uuid {q(uid("nc:"+key))}))')
+        else:
+            end=ax-12.7 if angle==0 else ax+12.7
+            wire(ax,ay,end,ay,key)
+            label(net,end,ay,key)
+            expected.setdefault(net,[]).append([ref,number])
+
+mcu_nets={}
+for number,name,*_ in MCU:
+    if name == "3V3":
+        mcu_nets[number]="+3V3"
+    elif name == "GND":
+        mcu_nets[number]="GND"
+    elif name.startswith("GPIO") and int(name[4:]) in GPIO_NET:
+        mcu_nets[number]=GPIO_NET[int(name[4:])]
+place("HW678_N16R8","U1","HW678 / S3-N16R8",95.25,109.22,mcu_nets,{"Status":"Header geometry nominal; outline/antenna clearance pending","Pin_numbering":"Left 1-22; right 23-44; both top-to-bottom, antenna up"})
+rs_nets=dict(zip(map(str,range(1,13)),["+3V3","GND","RS_DCD","RS_RX","RS_TX","RS_DTR","RS_DSR","RS_RTS","RS_CTS","RS_RI","RS_VALID","RS_OFF_N"]))
+place("MAX3243_Module_Reference","U2","Adafruit MAX3243 / male 6253",228.6,96.52,rs_nets,{"Status":"VERIFY male header numbering; footprint intentionally unassigned","Datasheet_source":"adafruit-research.md; reference female 5988 CAD"})
+place("OLED_I2C_26mm","DS1","128x64 I2C OLED / 0x3C",228.6,152.4,{"1":"GND","2":"+3V3","3":"OLED_SCL","4":"OLED_SDA"},{"Status":"Module outline/header/display user fit-verified; pad/drill fit provisional"})
+for index,(net,function) in enumerate((("BTN_PREVIOUS","Previous / back"),("BTN_SELECT","Select / confirm"),("BTN_NEXT","Next")),1):
+    y=88.9+(index-1)*35.56
+    place("R",f"R{index}","2.2k 1%",327.66,y,{"1":"+3V3","2":net},{"Rating":"At least 0.125 W; exact resistor MPN pending"})
+    place("SW_NO",f"SW{index}","B3F-1000",327.66,y+15.24,{"1":net,"2":"GND"},{"Manufacturer":"Omron","MPN":"B3F-1000","Function":function,"Procurement":"Live stock not verified"})
+    note(function,302.26,y+21.59,1.016)
+
+note("MODULE CARRIER - INITIAL SCHEMATIC",15.24,15.24,2.54)
+note("Native KiCad 10 schematic. Named wire labels join matching nets on this sheet.\nRead hardware/PCB/README.md before layout or fabrication.",15.24,24.13)
+note("U1: complete development board",53.34,57.15,1.778)
+note("Antenna up / USB down: left row 1-22, right row 23-44.\nNC marks mean unused on carrier, not unused inside module.",53.34,64.77,1.016)
+note("U2: complete RS-232 breakout",177.8,57.15,1.778)
+note("Male 6253 selected. Numbers from published 5988 female CAD.\nVERIFY male header before routing; no footprint assigned.\nDE-9 and charge pump are already on the module.",177.8,64.77,1.016)
+note("Controls: active-low, firmware-debounced",292.1,57.15,1.778)
+note("External 2.2k pull-ups: ~1.5 mA pressed at 3.3 V.\nChosen for B3F-1000 rated contact load; internal\npull-ups may remain enabled. Exact resistor MPN pending.",292.1,64.77,1.016)
+note("DS1: front view GND / VCC / SCL / SDA",177.8,128.27,1.524)
+note("Power at 3.3 V only. Verify on-module I2C pull-ups;\nexternal values intentionally not guessed.",177.8,165.1,1.016)
+note("POWER / RECOVERY\nPower only through U1's existing USB ports. No carrier 5 V input.\nU1 regulator supplies +3V3; GND pins are common on the module.\nPin 1 +3V3 and pin 22 GND model the onboard supply for ERC.\nGPIO19/20 native USB and GPIO43/44 UART0 remain onboard.\nVerify USB power isolation before attaching two powered hosts.\nKeep both USB connectors and reset/boot buttons accessible.",15.24,185.42)
+note("RS-232 / ELECTRICAL LIMITS\nTX/RX and modem labels are at the ESP32 logic side.\nOFF_N is active low; GPIO9 must remain open-drain.\nBreakout provides its OFF pull-up. No galvanic isolation.\nNo carrier connection to raw RS-232 voltages.\nCarrier GND, USB GND and RS-232 signal ground are common.\nNever power OLED or MAX3243 logic from 5 V.",152.4,185.42)
+note("BEFORE PCB RELEASE\nVerify male breakout pin order/footprint.\nConfirm header/socket finished-hole requirements.\nComplete module courtyards and antenna clearance.\nVerify 3.3 V budget, OLED pull-ups and USB power path.\nChoose mounting hardware and confirm button stock.\nERC is not hardware or fabrication approval.",292.1,185.42)
+items.append(')')
+ROOT.joinpath(PROJECT+".kicad_sch").write_text('\n'.join(items)+'\n')
+ROOT.joinpath("validation/expected-nets.json").write_text(json.dumps(expected,indent=2,sort_keys=True)+'\n')
+print("Generated native KiCad schematic, project-local symbol library and tables.")

hardware/PCB/oled-fit-check.svg

@@ -0,0 +1,37 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="100mm" height="90mm" viewBox="0 0 100 90">
+  <title>OLED module mechanical fit check — front view</title>
+  <desc>26 mm square PCB, four 2 mm mounting holes at 1.75 mm edge offsets. Centred four-pin header at 2.54 mm pitch, 1.50 mm from top edge. Display outline at (1, 4.5), measuring 24.5 × 16.5 mm. Header crosses indicate centres only, not drill sizes.</desc>
+  <g font-family="sans-serif" font-size="3" fill="black">
+    <text x="5" y="7">OLED mechanical fit check — front view</text>
+    <text x="5" y="12">Print at 100%; disable fit-to-page.</text>
+    <text x="5" y="17">Verify the scale below before use.</text>
+  </g>
+  <g transform="translate(35 27)" stroke="black" stroke-width="0.15" fill="none">
+    <rect width="26" height="26"/>
+    <rect id="display-outline" x="1" y="4.5" width="24.5" height="16.5" stroke-dasharray="0.6 0.4"/>
+    <circle cx="1.75" cy="1.75" r="1"/>
+    <circle cx="24.25" cy="1.75" r="1"/>
+    <circle cx="1.75" cy="24.25" r="1"/>
+    <circle cx="24.25" cy="24.25" r="1"/>
+    <path id="header-centres" d="M8.79 1.5h.8 M9.19 1.1v.8 M11.33 1.5h.8 M11.73 1.1v.8 M13.87 1.5h.8 M14.27 1.1v.8 M16.41 1.5h.8 M16.81 1.1v.8"/>
+    <g stroke="none" fill="black" font-family="sans-serif" font-size="1.5" text-anchor="middle">
+      <text x="9.19" y="-1">GND</text>
+      <text x="11.73" y="-1">VCC</text>
+      <text x="14.27" y="-1">SCL</text>
+      <text x="16.81" y="-1">SDA</text>
+      <text x="13" y="7">Dashed: display outline</text>
+      <text x="13" y="10">24.5 × 16.5 mm</text>
+      <text x="13" y="13">26 × 26 mm PCB</text>
+      <text x="13" y="16">Holes: Ø2 mm</text>
+      <text x="13" y="19">Hole spacing: 22.50 mm</text>
+    </g>
+  </g>
+  <g stroke="black" stroke-width="0.15" fill="none">
+    <path d="M35 65h20 M35 63v4 M55 63v4"/>
+  </g>
+  <g font-family="sans-serif" font-size="2.5" fill="black">
+    <text x="39" y="71">20 mm scale</text>
+    <text x="5" y="79">Header crosses mark pin centres, not drill sizes.</text>
+    <text x="5" y="84">Mechanical reference only — not a fabrication file.</text>
+  </g>
+</svg>

hardware/PCB/pcb-draft-notes.md

@@ -0,0 +1,243 @@
+# Compact two-layer PCB — A1 draft
+
+Open **`serial-carrier.kicad_pcb`** in KiCad 10. The routed board belongs to the
+existing `serial-carrier.kicad_pro` / `.kicad_sch` project. **Not for fabrication.**
+No Gerbers, production drills or manufacturing archive were generated.
+
+## Size and placement
+
+- **Carrier bounding dimensions: 82 × 80 mm**, within the requested 100 × 100 mm.
+- **Two copper layers**, F.Cu and B.Cu. All components mount on the front.
+- Proposed **1.6 mm** carrier thickness; fabrication stackup/process not selected.
+- Stepped outline: a **36 × 19 mm top-left antenna cutaway** fits within a simple
+  rectangular/square case. The lower edge is now straight, with ESP32 USB toward
+  the bottom and RS-232 toward the top. U1 moved down by 19 mm; its exact USB/body
+  registration remains provisional pending the user's measured ESP32 geometry.
+- Module and mating-plug overhangs are not included in the carrier dimensions.
+  The final complete assembly/enclosure envelope still needs measurement.
+
+Coordinates in the following table are local millimetres from the carrier's
+upper-left corner, X right/Y down, viewed from the component side. In the KiCad
+file add (100, 100) mm to obtain absolute board coordinates. All footprints are
+unrotated; their origins are defined in the footprint notes, not necessarily
+component body corners.
+
+| Reference | Local origin (X, Y) | Placement |
+|---|---|---|
+| U1 | (8, 23) | ESP32 left header pin 1; antenna toward top-left cutaway, USB toward bottom edge |
+| U2 | (43, 26.670) | MAX3243 header pin 1; bare module PCB front exactly flush with carrier top edge |
+| DS1 | (43, 36) | OLED module upper-left PCB corner; display faces up |
+| R1 / R2 / R3 | (43 / 54 / 65, 34) | Axial pull-ups in the gap between RS-232 and OLED |
+| SW1 / SW2 / SW3 | (43 / 55 / 67, 68) | Back, select, next below display; switch pad 1 origins |
+| H1 | (3.5, 22.5) | Proposed case mounting hole below antenna notch |
+| H2 | (3.5, 75) | Proposed case mounting hole near bottom-left edge |
+| H3 | (78, 4) | Proposed case mounting hole |
+| H4 | (78, 76) | Proposed case mounting hole |
+
+Outline vertices: (36,0), (82,0), (82,80), (0,80), (0,19), (36,19), closed.
+The previous A0 board is retained in `validation/pcb-a0-before-reposition.kicad_pcb`.
+The board area is **58.76 cm²**; its bounding rectangle is 65.6 cm².
+
+H1–H4 are proposed **Ø3.2 mm NPTH M3 clearance holes**, not a previously agreed
+case specification. They are marked board-only and excluded from the electrical
+BOM. The OLED and RS-232 module mounting holes are additional, separate holes.
+Screw heads, spacers, heat-set inserts, tool access and underside lead clearance
+must be checked against the final case and assembly heights. No insert dimensions
+or module stand-off heights are assumed.
+
+## Routing and electrical status
+
+The PCB contains actual copper, not just ratsnest placement:
+
+- All **38 required physical-pad spanning connections** across **17 connected
+  nets** routed, including both duplicated pads of each switch contact.
+- **565 segments**, signal width **0.25 mm**, 3.3 V and GND width **0.50 mm**.
+- **22 through vias**, **0.70 mm copper / 0.30 mm drill**.
+- **No copper pours**; ground is explicitly routed. This is an initial routing
+  solution, not a reviewed return-current/EMI or power-integrity design.
+- Proposed minimum different-net clearance **0.25 mm** and copper-edge clearance
+  **0.50 mm**. These are selected draft design rules, not fabrication qualification.
+- Project netclasses align interactive routing defaults with the draft: Default
+  uses 0.25 mm tracks / 0.25 mm clearance, while Power matches `/+3V3` and `/GND`
+  with 0.50 mm tracks. Both use 0.70 / 0.30 mm vias.
+- Schematic pad-net assignments, component values and UUID linkage are retained.
+  U1's intentionally unused GPIO/USB/UART0/5 V header pads remain unused.
+
+The bounded draft router prioritizes connectivity and conservative geometric
+clearance, not optimal trace topology. Do not treat DRC passage as evidence of
+current-carrying capacity, supply stability, I²C signal quality or EMC compliance.
+
+## Explicit provisional mechanical choices
+
+### ESP32 and RF
+
+A two-layer **no-tracks/no-vias/no-pads/no-zone-fill rule area** reserves local
+X=10…31 mm, Y=19…32 mm beneath the antenna-side end of U1, adjacent to the notch. This is a deliberate carrier design
+allocation, **not a measured antenna envelope or a manufacturer RF keepout**.
+The module itself may span the rule area; footprint placement is not forbidden.
+No carrier copper enters the reserve, but copper runs close to its boundary.
+
+U1's exact PCB/antenna/USB offsets are still unmeasured. The intended antenna
+overhang and USB access must be checked with the actual board and a printed
+placement template. Move U1, change the edge or enlarge the reserve if required.
+Missing RF clearance cannot be signed off from the current footprint alone.
+
+### RS-232
+
+U2 uses the new **`Carrier:MAX3243_Reference_Provisional`** footprint **on the PCB
+only**. Its bare-module outline/header/holes are adapted from published female
+5988 CAD for the intended male 6253 module. The user explicitly confirms identical
+male/female external dimensions. The linked Adafruit STEP has now been measured
+with OpenCascade; its nominal metal geometry is used on that basis. Male header
+mapping, actual fit, tolerances and the mounting stack still need qualification.
+See `rs232-footprint-notes.md` and `db9-mechanical-notes.md` for evidence/licenses.
+
+The module's **bare PCB front is flush with carrier Y=0**, as requested. The
+connector has distinct front planes, not one universal case-wall datum:
+
+| Feature | Position relative to carrier top edge | Meaning |
+|---|---:|---|
+| Flange front / shell root | 1.930 mm inside | Behind the PCB edge |
+| Breakout PCB front | 0 | Flush with the carrier edge |
+| Hex screw-lock mouth faces | 2.870 mm outside | Front cable-retention hole mouths |
+| Shell nose | 3.870 mm outside | Foremost modeled shell surface |
+
+The front screw-lock axes are **25.000 mm apart**, with centres **6.277620 mm
+above the module PCB top**. They are not the two 24.130 mm-spaced PCB mounting
+holes. The source models Ø3.000 mm bores but **no threads**; this does not establish
+M3 or 4-40 hardware. The main metal flange is 30.800 × 12.550 × 0.400 mm; the
+shell envelope including its root/lip is 16.878 × 9.100 × 5.800 mm.
+
+`add_db9_envelope.py` places the measured metal bounding projections and screw-lock
+axes on **Dwgs.User**, relative to U2. They are not silkscreen, a courtyard or a
+case cutout. Run the helper after moving U2; it preserves copper and project
+settings. The original STEP and its extraction/validation scripts are retained.
+
+**Case-wall positioning remains a design decision:** PCB-edge alignment does not
+put the flange or screw-lock mouths at that same plane. For example, making the
+hex mouths flush with the case exterior would place that exterior 2.870 mm beyond
+the carrier edge. No wall thickness, cable-backshell clearance or sealing scheme
+has been assumed. The model's anchor legs extend **2.230 mm below the module
+underside**; select a stand-off/header stack or clearance solution before assembly.
+
+The schematic footprint remains intentionally blank, preserving its caution
+and avoiding edits to the schematic that was open in KiCad. Consequently there
+is **one known schematic-parity warning**: U2 footprint differs from the empty
+schematic assignment. This is not excluded/suppressed, and is not a net mismatch.
+Once the male footprint is qualified, explicitly assign it in the schematic
+before relying on Update PCB from Schematic to manage U2's footprint.
+
+### OLED and controls
+
+OLED geometry, including its display boundary, is the user-fit-verified geometry.
+The module schematic/library files are unchanged. The new overall placement still
+needs an assembly fit check: adjacent resistor bodies, module underside parts,
+header/socket bodies, button actuation and finger/plunger clearance are not
+represented by complete assembly courtyards. In particular the axial resistors
+are tightly packed between the module outlines; confirm clearance and height.
+
+## Device outlines on front silkscreen
+
+The PCB now has **0.12 mm front-silkscreen outlines** for the OLED PCB and the
+published RS-232 reference module, plus a dashed OLED display boundary. The
+RS-232's visible rounded corners retain true arcs. Small gaps clear pad/mask
+openings, vias and adjacent resistor markings; the original full F.Fab geometry
+remains unchanged.
+
+U1 instead has **header-row guides**, labelled `HEADER GUIDES`: guide edges are
+1.20 mm outside the outer pin centres. These are graphic alignment aids, **not
+claimed socket-body dimensions or an inferred ESP32 PCB outline**. The actual
+U1 body/antenna/USB outline still requires measured offsets. Existing button and
+resistor silkscreen remains unchanged.
+
+These are board-local drawings, not edits to the footprint libraries. If the
+module placement or routing changes, close PCB Editor and refresh them with:
+
+```sh
+/usr/bin/python3 -B hardware/PCB/add_device_silkscreen.py
+```
+
+The script requires pcbnew and Shapely, replaces only its own generated graphics,
+and refuses an open PCB or concurrent board change. It leaves project settings,
+copper, pads and source F.Fab outlines unchanged. Run it **after** placement or
+routing regeneration; moving a footprint does not move these board-local drawings.
+It currently supports the draft's unrotated module placements.
+
+The original A0 silkscreen-only change left its routing unchanged. A1 deliberately
+repositions U1/U2 and reroutes all connections, then refreshes these outlines.
+Silkscreen is clipped away from the new flush U2 front board edge. Physical DRC
+remains **0 violations**, **0 unconnected**, with the same U2 footprint-parity
+warning. PDF and both previews have been refreshed.
+
+## Review outputs
+
+- `validation/pcb-draft.svg` / `pcb-draft.png`: combined copper/outline/fab review.
+- `validation/pcb-draft-3d.png`: KiCad render of the carrier and available standard
+  component models. **ESP32, OLED and RS-232 assembled module models are absent**;
+  the render is not an assembled-device or enclosure fit check.
+- `pcb-placement-draft.pdf`: **1:1** front placement/pad/outline drawing. Print at
+  100%, disable fit-to-page, and confirm the outer width is 82 mm before use.
+  It includes the known module outlines and nominal STEP-derived DE-9 metal
+  bounding projections; no guessed U1 body or case-wall geometry.
+
+## Validation and limits
+
+Run from the repository root with the system Python containing KiCad bindings:
+
+```sh
+/usr/bin/python3 -B hardware/PCB/validate_pcb_draft.py
+/usr/bin/python3 -B hardware/PCB/validation/pcb-routing-check.py
+```
+
+The first script exports a **fresh saved-schematic netlist** and checks the actual
+PCB pad assignments, component linkage, dimensions, layer count, nominal thickness,
+mounting holes, track/via sizes and KiCad DRC. It never rewrites the PCB or project.
+It reports the single expected U2 parity warning explicitly, and fails on any
+other parity issue, DRC violation or unconnected item. Reports are retained in
+`validation/pcb-parity-drc.json` and `pcb-validation-summary.json`.
+
+The second independently checks continuous copper/hole/edge geometry and original
+placement/net/UUID preservation against the initial unrouted snapshot. It needs
+locally installed NumPy and Shapely in addition to pcbnew. It is not a substitute
+for current-schematic net validation and is specific to this initial layout.
+
+Results with KiCad **10.0.6**:
+
+- **0 physical DRC errors/warnings; 0 unconnected items.**
+- All saved-schematic pad nets match the PCB; **1 expected U2 footprint parity warning**.
+- Independent minimum different-net/copper-to-NPTH gap **0.270544 mm**; minimum
+  copper/NPTH-to-board-edge gap **1.900 mm**.
+- All 9 electrical footprints and 4 board-only mounts retained; positions, outline
+  and RF area revised as documented, with electrical linkage preserved.
+- Startup `PROPERTY_ENUM` assertions from the local pcbnew binding are still
+  emitted, but the checks complete successfully.
+
+DRC uses the existing default ignored checks: `missing_courtyard`,
+`track_not_centered_on_via`, `tuning_profile_track_geometries`,
+`footprint_filters_mismatch`, `footprint_type_mismatch`. No new exclusions were
+added to hide problems. **Missing module courtyards therefore remain an explicit
+manual release gate**. The draft rules do not represent a chosen fabricator's
+complete capability set. No electrical/hardware/fabrication tests were performed.
+
+## Regeneration and project settings
+
+Normal use is to **edit the native PCB in KiCad**, not regenerate it. The optional
+`generate_pcb_draft.py` recreates the *unrouted* A1 placement and discards manual
+PCB work only with explicit `--overwrite`; it refuses an open-project lock. A1 was
+made by mutating the existing board, not running that generator. All A1 saves use
+`SaveBoard(..., True)` to preserve user project settings. The original A0 creation
+populated the minimal project with rules; this revision leaves those settings and
+the schematic unchanged. Refresh device silkscreen and CAD envelope helpers after
+any intentional regeneration or placement/routing changes.
+
+`route_pcb_draft.py` requires NumPy and pcbnew. By default it never saves; replacing
+existing tracks requires explicit `--route --overwrite --replace-routes`. Do not
+run that over manual routing without a backup. It is a bounded initial-draft
+router, **not** a general-purpose autorouter. See `validation/pcb-routing-summary.md`
+for algorithm limits and commands. These scripts do not need downloaded packages
+or services in the current environment and create no manufacturing outputs.
+
+Before fabrication: qualify all module pin maps/footprints and connectors,
+complete assembly courtyards and RF/USB/DE-9 checks, review power/return paths,
+verify the existing USB power circuit and OLED pull-ups, confirm procurement and
+case hardware, rerun ERC/DRC, and perform an independent hardware design review.

hardware/PCB/reference/README.md

@@ -0,0 +1,32 @@
+## Adafruit RS-232 Full Pinout Level-Shifter Breakout PCB
+
+<a href="http://www.adafruit.com/products/5988"><img src="assets/5988.jpg?raw=true" width="500px"><br/>
+Click here to purchase one from the Adafruit shop</a>
+
+PCB files for the Adafruit RS-232 Full Pinout Level-Shifter Breakout. 
+
+Format is EagleCAD schematic and board layout
+* https://www.adafruit.com/product/5988
+
+### Description
+
+If you want to interface with telco, retro, or industrial equipment, you'll probably run into RS-232 interfaces. The Adafruit RS232 Full-Pinout Breakout with 8 Channels of UART to RS-232 Level Shifters is your friend in such cases. It gives you 5 input and 3 output channels of level shifting and takes care of the high/negative voltage generation all in a low-cost breakout board. We use the trusty MAX3243 from TI, a classic chip part of the MAX232 lineage, so you know it will work great for all your RS-232 needs, up to 250Kbps.
+
+RS-232 is what we had before USB: a 9- or 25-pin D-Sub connector that allowed data plus flow control lines. Many folks may remember these interfaces were used for mice, modems, barcode scanners, teletypes, and more. We still find devices sold with RS-232 ports, although many folks use a USB to RS-232 adapter these days.
+
+If you want to use a microcontroller or microcomputer to chat with an RS-232, then thankfully, all you need is a serial port / UART (something just about any microcontroller has) and a level shifter. The level shifter is required because while most UARTs are 0-3.3V or 0-5V logic level, RS-232 requires +-6 to +-10V, yep the signal voltage goes negative! That means a specialized shifter is required to generate extra high and low voltages and safely convert the logic levels.
+
+Sure you could buy a raw MAX232 chip and wire up the necessary capacitors, but this board does it all for you and even comes with a DE-9 connector for plugging in directly into your 'client' device. It can run on 3.3V power and logic, which many older chips can't do. It also can do all 8 data pins, so you can use all of the flow control signals like RTS, CTS, DTR, DSR, DCD and RI.
+
+We also include two separate lines from the MAX3243: 'Valid' and 'Off'. The Valid line output will have logic level high when the chip detects signal voltages from the device its plugged into. So you can use it as a 'connection made' signal. There's also the Off pin, which when set to logic high by the microcontroller will tri-state all the pins for power reduction.
+
+This breakout comes fully assembled with a UART side for low-voltage power/logic level, and a DE-9F RS-232 side for high-voltage signals. We also include some header so you can solder to a breadboard in a few minutes.
+
+### License
+
+Adafruit invests time and resources providing this open source design, please support Adafruit and open-source hardware by purchasing products from [Adafruit](https://www.adafruit.com)!
+
+Designed by Limor Fried/Ladyada for Adafruit Industries.
+
+Creative Commons Attribution/Share-Alike, all text above must be included in any redistribution. 
+See license.txt for additional details.

hardware/PCB/reference/button-omron-b3f.txt

@@ -0,0 +1,753 @@
+  Tactile Switch                                                                                                      B3F
+Through-hole-mounting Switches
+in a Wide Range of Models:
+6 × 6 mm, 12 × 12 mm, Side-operated
+Models, Gold-plated Contacts, and
+Radial Tape
+• Extended mechanical/electrical durability: 10 x 106
+  operations for 12 x 12 mm type and 1 x 106
+  operations for the 6 x 6 mm type
+• Taped radial type, vertical type and high force
+  types are available.
+• Gold plated models available for increased
+  contact reliability, resistance to corrosive gas and
+  insulation failure prevention for ion migration in
+  harsh environments
+• B32-series Key Tops mount to models with
+  projected plungers.
+RoHS Compliant
+
+■ List of Models
+
+6 × 6 mm Models
+    Type     Contact      Plunger          Height        Operating      Plunger                             Bags
+             material                                    force (OF)      color    Without ground Minimum          With ground    Minimum
+                                                                                     terminal    packing unit      terminal     packing unit
+Standard:    Silver     Flat type        4.3 mm        0.98 N {100 gf} lvory      B3F-1000                      B3F-1100
+B3F-1000     plated                                    1.47 N {150 gf} Yellow     B3F-1002                      B3F-1102
+Series
+                                                       2.55 N {260 gf} Orange     B3F-1005                      B3F-1105
+                                                       4.9 N {500 gf}   Red       B3F-1006                      ---
+                                         5.0 mm        0.98 N {100 gf} Black      B3F-1020                      B3F-1120
+                                                       1.47 N {150 gf} Gray       B3F-1022                      B3F-1122
+                                                       2.55 N {260 gf} Pink       B3F-1025                      B3F-1125
+                                                       4.9 N {500 gf}   Blue      B3F-1026                      ---
+                                         5.0 mm         0.98 N {100 gf} Black     ---                           B3F-1110
+                                         (7.5-mm pitch)
+                                         7.0 mm        0.98 N {100 gf} Black      B3F-1060        100 pcs       ---             100 pcs
+                                                       1.47 N {150 gf} Yellow     B3F-1062                      ---
+                                         9.5 mm        0.98 N {100 gf} Black      B3F-1070                      ---
+                                                       1.47 N {150 gf} Yellow     B3F-1072                      ---
+                                                       2.55 N {260 gf} Orange     B3F-1075                      ---
+                                         7.3 mm        0.98 N {100 gf} lvory      B3F-1050                      B3F-1150
+                        Projected type
+                                                       1.47 N {150 gf} Yellow     B3F-1052                      B3F-1152
+
+                                                       2.55 N {260 gf} Orange     B3F-1055                      B3F-1155
+
+                                                       4.9 N {500 gf}   Red       B3F-1056                      ---
+
+
+
+
+                                                                                                                                           1
+B3F                                                                                                                                          B3F
+
+    Type        Contact       Plunger         Height          Operating       Plunger                               Bags
+                material                                      force (OF)       color      Without ground Minimum          With ground    Minimum
+                                                                                             terminal    packing unit      terminal     packing unit
+Side-           Silver                      3.15 mm        0.98 N {100 gf} lvory         ---                            B3F-3100
+                           Flat type
+operated:       plated                                     1.47 N {150 gf} Yellow        ---                            B3F-3102
+B3F-3000
+Series                                                     2.55 N {260 gf} Orange        ---                            B3F-3105
+                                            3.85 mm        0.98 N {100 gf} Black         ---                            B3F-3120
+                                                           1.47 N {150 gf} Gray          ---                            B3F-3122
+                                                           2.55 N {260 gf} Pink          ---                            B3F-3125
+                           Projected type 6.15 mm          0.98 N {100 gf} lvory         ---                            B3F-3150
+
+                                                           1.47 N {150 gf} Yellow        ---                            B3F-3152
+
+                                                           2.55 N {260 gf} Orange        ---                            B3F-3155
+
+High-        Gold                           4.3 mm         1.76 N {180 gf} Yellow        B3F-1002-G                     B3F-1102-G
+                           Flat type
+reliability  plated
+gold-plated:                                5.0 mm                           Gray        B3F-1022-G                     B3F-1122-G
+B3F-1000-G                                  7.0 mm                           Yellow      B3F-1062-G       100 pcs       ---             100 pcs
+Series                                                                                   (see note)
+                                            9.5 mm                           Yellow      B3F-1072-G                     ---
+                                                                                         (see note)
+Side-                      Projected type 7.3 mm                             Yellow      B3F-1052-G                     ---
+operated
+with highly
+reliable
+gold-plated:
+B3F-3000-G
+Series
+                                            3.85 mm                          Gray        ---                            B3F-3122-G
+                           Flat type
+                                                                                                                        (see note)
+
+
+
+
+Note:   Bulk Packaged, 100 Switches per bag. Order in multiples of the package quantity.
+12 × 12 mm Models
+    Type        Contact     Plunger           Height          Operating       Plunger                               Bags
+                material (or LED color)                       force (OF)       color      Without ground Minimum          With ground    Minimum
+                                                                                             terminal    packing unit      terminal     packing unit
+Standard:       Silver     Flat type        4.3 mm         1.27 N {130 gf} lvory         B3F-4000                       B3F-4100
+B3F-4000        plated                                     2.55 N {260 gf} Yellow        B3F-4005                       B3F-4105
+Series
+                           Projected type 7.3 mm           1.27 N {130 gf} lvory         B3F-4050                       B3F-4150
+                                                           2.55 N {260 gf} Yellow        B3F-4055                       B3F-4155
+Long durability: Silver    Flat type        4.3 mm         1.27 N {130 gf} Blue          B3F-5000                       B3F-5100
+                                                                                                          100 pcs                       100 pcs
+B3F-5000 Se- plated
+ries                       Projected type 7.3 mm                             Blue        B3F-5050                       B3F-5150
+High reliability Gold      Flat type        4.3 mm         1.27 N {130 gf} Blue          B3F-5001                       B3F-5101
+gold-plated: plated
+B3F-5001                   Projected type 7.3 mm                             Blue        B3F-5051                       B3F-5151
+Series
+Note:   Bulk Packaged, 100 switches per bag. Order in multiples of the package quantity.
+6 × 6 mm Radial Models (Taping Specifications)
+    Type        Contact       Plunger          Height         Operating       Plunger                         Taped Radial
+                material                                      force (OF)       color      Without ground Minimum          With ground    Minimum
+                                                                                             terminal    packing unit      terminal     packing unit
+Taped           Silver     Flat type        4.3 mm         0.98 N {100 gf} lvory         B3F-6000                       B3F-6100
+Radial:         plated                                     1.47 N {150 gf} Yellow        B3F-6002                       B3F-6102
+B3F-6000
+Series                                      5.0 mm         0.98 N {100 gf} Black         B3F-6020                       B3F-6120
+                                                                                                          1,000 pcs                     1,000 pcs
+                                                           1.47 N {150 gf} Gray          B3F-6022                       B3F-6122
+                           Projected type   7.3 mm         0.98 N {100 gf} lvory         B3F-6050                       B3F-6150
+                                                           1.47 N {150 gf} Yellow        B3F-6052                       B3F-6152
+Note:   The switches are tape packaged in units of 1,000 per package. Order in multiples of the package size. Switches are not sold individually.
+
+
+
+
+2
+B3F                                                                                                                                              B3F
+
+■ Ratings/Characteristics
+
+Rating (resistive load)                         1 to 50 mA, 3 to 24 VDC (B3F-G: 100 μA to 50 mA, 3 to 24 VDC)
+Minimum applicable load (reference value)       10 μA at 1 VDC (resistive load)
+Ambient operating temperature                   -25°C to +70°C at 60%RH max. (with no icing or condensation)
+Ambient operating humidity                      35% to 85% (at +5 to +35°C)
+Contact form                                    SPST-NO
+Contact resistance (initial value)              100 mΩ max.
+Insulation resistance                           100 MΩ min. (at 250 VDC with insulation tester)
+Dielectric strength                             500 VAC, 50/60 Hz for 1 min
+Bounce time                                     5 ms max.
+Vibration resistance                            Malfunction: 10 to 55 Hz, 1.5 mm double amplitude
+Shock resistance                                Destruction: 1,000 m/s2 {approx. 100G} max.
+                                                Malfunction: 100 m/s2 {approx. 10G} max.
+Durability                                      B3F-1000, B3F-3000, B3F-6000:
+                                                    1,000,000 operations min (OF: 0.98 N {100 gf}) (B3F-1070: 500,000 operations min)
+                                                    300,000 operations min (OF: 1.47 N {150 gf})
+                                                    100,000 operations min (OF: 2.55 N {260 gf})
+                                                    50,000 operations min (OF: 4.9 N {500 gf})
+                                                B3F-4000:
+                                                    3,000,000 operations min (OF: 1.27 N {130 gf})
+                                                    1,000,000 operations min (OF: 2.55 N {260 gf})
+                                                B3F-5000/5001:
+                                                    10,000,000 operations min.
+                                                B3F-G:
+                                                    300,000 operations min.
+Weight                                          6 × 6 mm models: approx. 0.25 g
+                                                12 × 12 mm models (standard types): approx. 0.85 g
+                                                Radial models: approx. 0.25 g
+Degree of protection                            IEC IP00
+Washing                                         Not possible
+
+
+■ Operating Characteristics
+
+6 × 6 mm Models
+                                                               B3F-1000, B3F-3000, B3F-6000                                        B3F-G
+         Operating force (OF)          0.98 N                   1.47 N                   2.55 N                4.9 N               1.76 N
+                                     B3F-1@@0                  B3F-1@@2               B3F-1@@5              B3F-10@6           B3F-1@@2-G
+Item                                 B3F-3@@0                  B3F-3@@2               B3F-3@@5                                 B3F-3@@2-G
+                                     B3F-6@@0                  B3F-6@@2
+Operating force (OF)            0.98±0.29 N             1.47±0.49 N               2.55±0.69 N          4.9±1.47 N           1.76±0.49 N
+                                 {100±30 gf}            {150±50 gf}                {260±70 gf}         {500±150 gf}         {180±50 gf}
+Releasing force (RF)            0.2 N {20 gf} min.      0.49 N {50 gf}min.        0.49 N {50 gf}min.   0.7 N {70 gf} min.   0.49 N {50 gf}min.
+Pretravel (PT)                  0.25+0.2/–0.1 mm                                                                            0.25+0.2/–0.1 mm
+
+
+12 × 12 mm Models
+                                     B3F-4000, B3F-5000, B3F-5001
+         Operating force (OF)          1.27 N                   2.55 N
+                                     B3F-4@@0                  B3F-4@@5
+Item                                 B3F-5@@0
+                                     B3F-5@@1
+Operating force (OF)            1.27±0.49 N             2.55±0.69 N
+                                {130±50 gf}              {260±70 gf}
+Releasing force (RF)            0.29 N {30 gf} min.     0.49 N {50 gf} min.
+Pretravel (PT)                  0.3+0.2/–0.1 mm
+
+
+
+
+                                                                                                                                                   3
+B3F                                                                                                                                                                                                                                                      B3F
+
+■ Dimensions (Unit: mm)
+Note:              The numbers used for terminals in the following graphics are indicated in the “Bottom View” diagram below. In this                                                                                                           2       1
+                   diagram, the Switch is rotated so that the terminals are on the right and left-hand sides, and the OMRON logo ap-                                                                                                            4       3
+                   pears the right way up. (Except Side-operated and Radial Models)                                                                                                                                                           (Bottom View)
+
+6 × 6 mm Models
+
+Standard, Flat Plunger Type                                                                                                       Standard, Flat Plunger Type
+(without Ground Terminal)                                                                                                         (with Ground Terminal)
+B3F-1000, B3F-1002, B3F-1005, B3F-1006                                                                                            B3F-1100, B3F-1102, B3F-1105
+B3F-1020 (See note.), B3F-1022 (See note.),                                                                                       B3F-1120 (See note.), B3F-1122 (See note.)
+B3F-1025 (See note.), B3F-1026 (See note.)                                                                                        B3F-1125 (See note.)
+B3F-1002-G, B3F-1022-G (See note.)                                                                                                B3F-1102-G, B3F-1122-G (See note.)
+                                                                                     PCB Processing Dimensions                                                                                                   PCB Processing Dimensions
+                                                                                     (Reference Only) (Top View)                                                                                                 (Reference Only) (Top View)
+                         6±0.2                                                       (PCB thickness, t=1.6)                                              6±0.2                                                   (PCB thickness, t=1.6)
+
+
+     6±0.2                              4.5±0.2                                                                                     6±0.2                                4.5±0.2
+                                                                                                                4.5±0.1                                                                                                                       4.5±0.1
+
+                                                                                                                                                                                                              4.1±0.1
+                                                                                                                                                                  1.5                           3.5
+                                                                                            6.5±0.1         Four, 1±0.1 dia.                                                                    dia.                                         Five, 1±0.05 dia.
+                                                              3.5
+                                                              dia.                                                                      (See note.)                                                                          6.5±0.1
+                                                                                                                                   4.3±0.2                                    3.4
+          (See note.)                                                       Terminal Arrangement/                                                                                                            Terminal Arrangement/Internal
+    4.3±0.2                              3.4                                Internal Connections (Top View)                                                                                                  Connections (Top View)
+                                                                                                                                      3.5
+                                                                                       4                    3                                                            0.3
+      3.5                                                                                                                                                                                                               4              3
+                                        0.3                                                                                                               0.7
+                                                                                                                                                                                          0.7          0.7
+                        6.5±0.5                                                                                                                         6.5±0.5
+                                                                                                                                                                                    0.3
+                        7.7±0.5                         0.7          0.7               2                    1                                           7.7±0.5                                                         2              1
+                                                                                                                                 Note: The height of B3F-1120, B3F-1122, and                                                   5
+    Note: The height of B3F-1020, B3F-1022, B3F-1025,
+          and B3F-1026 is 5±0.2 mm.                                                                                                    B3F-1125 is 5±0.2 mm.
+
+
+
+Standard, Flat Plunger Type                                                                                                       Standard, Flat Plunger Type
+(with Ground Terminal, Pitch: 7.5 mm)                                                                                             (without Ground Terminal)
+B3F-1110                                                                                                                          B3F-1060, B3F-1062, B3F-1062-G
+                                                                                     PCB Processing Dimensions                                                                                                   PCB Processing Dimensions
+                                                                                     (Reference Only) (Top View)                                                                                                 (Reference Only) (Top View)
+                                                                                     (PCB thickness, t=1.6)                                                                                                      (PCB thickness, t=1.6)
+                        6±0.2
+                                                                                                                                                      6±0.2
+
+ 6±0.2                                                                                                           4.5±0.1
+                                        4.5±0.2                                                                                                                                                                                              4.5±0.1
+                                                                                                                                6±0.2                              4.5±0.2
+                                                                           4.1±0.1
+
+                                                                                                                Four,                                                                     3.5
+                                  1.5                                                                           1.2±0.05 dia.                                                             dia.
+                                                                                              1±0.05 dia.                                                                                                                   6.5±0.1
+                                                                                                                                                                                                                                           Four,
+                                                          3.5                              7.5±0.1                                                                0.5 max.                                                                 1±0.05 dia.
+                                                          dia.
+                                                                                                                                7±0.2
+                                                                           Terminal Arrangement/Internal                                                                3.4
+ 5±0.2
+                                          3.4
+                                                                           Connections (Top View)                                                                                                               Terminal Arrangement/
+                                                                                                                                                                    (1.8)
+                                                                                                                                3.5
+                                                                                      4                 3                                                         0.3
+                                                                                                                                                                                                                Internal Connections
+    3.5                                                                                                                                                                                                         (Top View)
+                                        0.3                                                                                                       6.5±0.5
+                                                                                                                                                  7.7±0.5                           0.7          0.7
+                                                                                                                                                                                                                        4              3
+                         0.7                        0.7          0.7                  2                 1
+                        7.5±0.5
+                                                  0.3                                       5
+                         9±0.5
+                                                                                                                                                                                                                        2              1
+
+
+Note:              Unless otherwise specified, a tolerance of ±0.4 mm applies to all dimensions. No terminal numbers are indicated on the Switches.
+
+
+
+
+4
+B3F                                                                                                                                                                                                                                                                                   B3F
+
+
+Standard, Flat Plunger Type                                                                                                                             Standard, Projected Plunger Type
+(without Ground Terminal)                                                                                                                               (without Ground Terminal)
+B3F-1070, B3F-1072, B3F-1075, B3F-1072-G                                                                                                                B3F-1050, B3F-1052
+                                                                                                                                                        B3F-1055, B3F-1056
+                                                                                        PCB Processing Dimensions                                       B3F-1052-G                      PCB Processing Dimensions
+                                                                                        (Reference Only) (Top View)                                                                                                                          (Reference Only) (Top View)
+                                                                                        (PCB thickness, t=1.6)                                                                                                                               (PCB thickness, t=1.6)
+                     6±0.2                                                                                                                                                     6±0.2
+
+
+ 6±0.2                                  4.5±0.2                                                                                     4.5±0.1               6±0.2                             4.5±0.2                                                                                4.5±0.2
+
+
+                                                                 3.5
+                                                                 dia.                                                                                                                                                                                      6.5±0.1            Four,
+                                                                  3                                        6.5±0.1             Four,                                     2.4 × 2.4±0.1                              3.5 dia.                                                  1±0.05 dia.
+                                                                 dia.                                                          1±0.05 .dia
+
+                                    0.5 max.                                   Terminal Arrangement/Internal                                                                                1.8±0.1                                   Terminal Arrangement/Internal
+  9.5                                                                          Connections (Top View)                                                                                                                                 Connections (Top View)
+                                                                                                                                                 7.3±0.2
+                                         3.4                                                                                                           4.3±0.2                               3.4
+                                                                                              4                                3                                                                                                                   4                          3
+                                         (1.8)
+  3.5                                                                                                                                                         3.5
+                                    0.3                                                                                                                                                     0.3
+                     6.5±0.5                                                                  2                                1                                              6.5±0.5                                                              2                          1
+                     7.7±0.5                               0.7          0.7                                                                                                                                       0.7        0.7
+                                                                                                                                                                              7.7±0.5
+
+
+
+Standard, Projected Plunger Type                                                                                                                         Side-operated, Flat Plunger Type
+(with Ground Terminal)                                                                                                                                   B3F-3100, B3F-3102, B3F-3105
+B3F-1150, B3F-1152, B3F-1155
+
+                                                                                          PCB Processing Dimensions                                                                                                                      PCB Processing Dimensions
+                                                                                          (Reference Only) (Top View)                                                                                                                    (Reference Only) (Top View)
+                                                                                          (PCB thickness, t=1.6)                                                                   7.3                                                   (PCB thickness, t=1.6)
+                                6±0.2
+                                                                                                                                                                                                                                                                 Two, 1.5 ±0.05 dia.
+                                                                                                                                                               6.25
+             6±0.2                                4.5±0.2                                                                           4.5±0.1
+                                                                                                                                                                                                                                                                                  2.5±0.1
+                                                                                    4.1±0.1
+                                                                                                                                                                                3.5 dia.
+                                         1.5                                                                                       Five, 1 ±0.05 dia.                                                                                                  4.5±0.1
+                        2.4 × 2.4±0.1                                    3.5 dia.                                                                                                                                                                       7±0.1                Two,
+                                                                                                            6.5±0.1                                                                                                                                                          1±0.05 dia.
+                                                                                                                                                        7.4
+                                                 1.8±0.1                                  Terminal Arrangement/                                                                                                                          Terminal Arrangement/
+                                                                                                                                                                    4
+ 7.3±0.2                                                                                  Internal Connections                                                                                                                           Internal Connections
+       4.3±0.2                                       3.4                                  (Top View)                                                                                                                                     (Top View)
+                                                                                                                                                        3.5
+                                                                                                  4                            3                                                                                                                                         4
+             3.5                                                                                                                                                                                                    0.3                        3
+                                                                                                                                                                        0.7                        0.3                               1
+                                                 0.3                                                                                                                             4.5±0.5                                                           1                 2
+                                                                                                  2                            1                                                                                   2.25
+                                0.7                                 0.7        0.7                                                                                                7±0.5                                            2.5±0.5
+                               6.5±0.5                                                                       5                                                                                                    3.15±0.2
+                                                                 0.3                                                                                                              8.7
+                               7.7±0.5
+
+
+
+Side-operated, Flat Plunger Type (Height: 3.85 mm)                                                                                                        Side-operated, Projected Plunger Type
+B3F-3120, B3F-3122, B3F-3125, B3F-3122-G                                                                                                                  B3F-3150, B3F-3152, B3F-3155
+                                                                                          PCB Processing Dimensions                                                                                                                          PCB Processing Dimensions
+                             7.3                                                                                                                                                   7.3                                                       (Reference Only) (Top View)
+                                                                                          (Reference Only) (Top View)
+                                                                                          (PCB thickness, t=1.6)                                                                                                                             (PCB thickness, t=1.6)
+                                                                                                                     Two, 1.5 ±0.05 dia.                       6.25                                                                                                  Two, 1.5 ±0.05 dia.
+      6.25
+
+
+                                                                                                                                   2.5±0.1                                                                                                                                          2.5±0.1
+
+                        3.5 dia.
+                                                                                                          4.5±0.1                                                                                                                                          4.5±0.1
+                                                                                                                                                                                 3.5 dia.
+                                                                                                           7±0.1               Two,                                                                                                                         7±0.1                 Two,
+                                                                                                                               1±0.05 dia.                                                                                                                                        1±0.05 dia.
+7.4                                                                                      Terminal Arrangement/                                          7.4                                       2.4 × 2.4±0.1                                   Terminal Arrangement/
+         4                                                                               Internal Connections                                                                                                                                     Internal Connections
+                                                                                                                                                                    4
+                                                                                         (Top View)                                                                                                                                               (Top View)
+3.5
+                                                                                                                           4                            3.5                                                                                                                  4
+                                                                                              3                                                                                                                                                    3
+                                                                  0.3
+             0.7                               0.3                                  1                                                                                                                                        0.3
+                         4.5±0.5                                                                      1                2                                                0.7                       0.3                                         1        1                 2
+                                                                                                                                                                                 4.5±0.5                           1.8±0.1
+                                                                 2.25
+                          7±0.5                                               2.5±0.5                                                                                                                                     2.25
+                                                            3.85±0.2                                                                                                              7±0.5                                                  2.5±0.5
+                          8.7                                                                                                                                                                                        6.15±0.2
+                                                                                                                                                                                  8.7
+
+Note:          Unless otherwise specified, a tolerance of ±0.4 mm applies to all dimensions. No terminal numbers are indicated on the Switches.
+
+
+
+
+                                                                                                                                                                                                                                                                                                5
+B3F                                                                                                                                                                                                                              B3F
+
+12 × 12 mm Models
+ Standard, Long-durability,                                                                                      Standard, Long-durability,
+ and High-reliability Models                                                                                     and High-reliability Models
+ Flat Plunger Type                                                                                               Flat Plunger Type
+ (without Ground Terminal)                                                                                       (with Ground Terminal)
+    B3F-4000, B3F-4005,                                                                                          B3F-4100, B3F-4105,
+    B3F-5000, B3F-5001                                                                                           B3F-5100, B3F-5101
+                                                                     PCB Processing Dimensions                                                                                         PCB Processing Dimensions
+                                                                     (Reference Only) (Top View)                                                                                       (Reference Only) (Top View)
+                                                                     (PCB thickness, t=1.6)                                                                                            (PCB thickness, t=1.6)
+                                                                                                                                                                                                              Two, 1.8±0.05 dia.
+                                                                                    Two, 1.8±0.05 dia.                                                                                                        (for positioning boss)
+                   12±0.2                                                           (for positioning boss)                        12±0.2
+
+
+                                                                                                                                                                                                                        5±0.1    9±0.1
+                                                                                              5±0.1   9±0.1
+    12±0.2                        5±0.2                                                                           12±0.2                            5±0.2
+                                                                                                                                                                          6.9±0.1
+
+                                                                                                                                                                                                                       Five,
+                                                                                            Four,                                                                                                                      1.2±0.05 dia.
+                                                                         12.5±0.1           1.2±0.05 dia.
+                                                                                                                                            1.6                                                    12.5±0.1
+
+
+                                                 7.1 dia.
+                                                                        Terminal Arrangement/                                                                                                 Terminal Arrangement/
+                                                                                                                                                                   7.1 dia.
+                                                                        Internal Connections                                                                                                  Internal Connections
+ 4.3±0.2
+                                                                        (Top View)                                                                                                            (Top View)
+                                 3.5                                                                             4.3±0.2                           3.5
+       3.5                                                                 4                    3                                                                                                    4                   3
+                                                                                                                     3.5
+                   1.6 dia.                                                                                                                                                            1.6 dia.
+                                 0.3             1           1                                                                0.9                  0.3            1            1
+                   12.5±0.5                          9±0.1                 2                    1                                12.5±0.5                        6.9                                 2                   1
+                   13.8±0.5                                                                                                     13.8±0.5                               9±0.1                                  5
+
+
+
+
+Standard, Long-durability,                                                                                        Standard, Long-durability,
+and High-reliability Models                                                                                       and High-reliability Models
+Projected Plunger Type                                                                                            Projected Plunger Type
+(without Ground Terminal)                                                                                         (with Ground Terminal)
+B3F-4050, B3F-4055,                                                                                              B3F-4150, B3F-4155,
+B3F-5050, B3F-5051                                               PCB Processing Dimensions                       B3F-5150, B3F-5151                                                     PCB Processing Dimensions
+                                                                 (Reference Only) (Top View)                                                                                            (Reference Only) (Top View)
+                                                                 (PCB thickness, t=1.6)                                                                                                 (PCB thickness, t=1.6)
+                                                                                                                                    12±0.2                                                                    Two, 1.8±0.05 dia.
+                                                                                    Two, 1.8±0.05 dia.
+                                                                                    (for positioning boss)                                                                                                    (for positioning boss)
+                        12±0.2
+
+                                                                                                                    12±0.2                               5±0.2
+                                                                                                                                                                                                                        5±0.1    9±0.1
+                                                                                               5±0.1 9±0.1
+        12±0.2                           5±0.2
+                                                                                                                                                                          6.9±0.1
+
+                                                                                                                                             1.6                                                                       Five,
+                                                                                             Four,                                                                                                                     1.2±0.05 dia.
+                                                                         12.5±0.1            1.2±0.05 dia.
+                                                                                                                                  @3.8±0.1                                                         12.5±0.1
+                      @3.8±0.1
+                                                      7.1 dia.                                                                                                          7.1 dia.
+
+                                                                        Terminal Arrangement/                                                        1.8±0.2                                       Terminal Arrangement/
+                                       1.8±0.2
+                                                                        Internal Connections                  7.3±0.2                                                                              Internal Connections
+7.3±0.2
+      4.3±0.2                      3.5                                  (Top View)                                  4.3±0.2                         3.5                                            (Top View)
+             3.5                                                          4                    3                        3.5                                                                              4                   3
+
+                      1.6 dia.                                                                                                                                                          1.6 dia.
+                                   0.3               1           1                                                              0.9                 0.3              1             1
+                      12.5±0.5                           9±0.1            2                    1                                   12.5±0.5                        6.9                                   2                   1
+                      13.8±0.5                                                                                                     13.8±0.5                              9±0.1
+                                                                                                                                                                                                                  5
+
+
+
+
+Note:         Unless otherwise specified, a tolerance of ±0.4 mm applies to all dimensions.
+
+
+
+
+6
+B3F                                                                                                                                                                                                          B3F
+
+Note:   The numbers used for terminals in the following graphics are indicated in the “Bottom View” diagram below. In this                                                                                   1
+        diagram, the Switch is rotated so that the terminals are on the right and left-hand sides, and the OMRON logo appears
+        the right way up.
+                                                                                                                                                                                                           2
+6 mm × 6 mm Radial Types (Taping Specifications): Sold in Units of 1,000 Switches
+                                                                                                                                                                                                     (Bottom View)
+
+
+Flat Plunger Type                                      6±0.3           Surface B
+(without Ground Terminal)
+B3F-6000, B3F-6002                      6±0.3
+                                                                                                                                                    12.7±1
+                                                                                                                                                 6.35±1
+                                                                                                                                                                                                    2 max.
+                                                 3.5 dia.              Surface A
+
+                                                                                          0.5 max.
+                                                                                                                                       Support
+                                                                                                                               0.9     tape                                           9
+                                                                            (1)         4.3                                                                                0.5 max.           +1
+                                                                                               3.4                                                                                         180
+
+                                                                                                                                                                                6
+                                                                                                                 0.2 max.                                                           9±0.5
+                                           0.5
+                                                                                                                                                                                                      +1
+                                                       5-0.2
+                                                            +0.8                                               0.3                                                                                 18-0.5
+
+                                                                                                                                                          4 dia. ±0.2
+                                                            Terminal Arrangement
+                                PCB Processing Dimensions /Internal Connections
+                                                                                                                                                             12.7±0.3     Carrier tape
+                                (Reference Only) (Top View) (Top View)
+ Note: The tape is random
+                                (PCB thickness, t=1.6)
+       between surface A
+       and surface B.
+                                                 +0.1                                          2                       1
+                                   Two, 1          0 dia.           5±0.1
+
+
+
+
+Flat Plunger Type                                       6±0.3                                                                                       12.7±1
+                                                                                                                                                 6.35±1
+(with Ground Terminal)                                                                                                                                                                              2 max.
+B3F-6100, B3F-6102                       6±0.3                                      2
+
+
+                                                  3.5 dia.
+                                                                                                                                       Support                                        11
+                                                                                              0.5 max.                                 tape                                0.5 max.
+                                                                                                                                                                                           20±0.5
+                                                                                                                                0.9
+                                          (1)                                           4.3     3.4
+                                                                                                                                                                                6
+                                                                                                                                                                                    9±0.5
+                                                                                    3.1
+                                                                                                                                                                                                      +1
+                                                                                                                     0.2 dia.                                                                     18-0.5
+                                            0.5                    5±0.2                                 0.3
+                                                            +0.8                                                                                     4±0.2 dia.
+                                                       5-0.2                                             0.6
+
+
+                                                                                                                                                             12.7±0.3     Carrier tape
+                              PCB Processing Dimensions                                       Terminal Arrangement
+                              (Reference Only) (Top View)                                     /Internal Connections
+                              (PCB thickness, t=1.6)                                          (Top View)
+
+
+
+                                       +0.1                                                        2                       1
+                            Three, 1     0 dia.       5±0.1                                                                     3
+                                                                   5±0.1
+
+
+
+ Flat Plunger Type                                          6±0.3           Surface B
+ (without Ground Terminal)                                                                                                                          12.7±1
+ B3F-6020, B3F-6022                                                                                                                              6.35±1
+                                                                                                                                                                                                    2 max.
+                                          6±0.3
+
+
+                                                   3.5 dia.                 Surface A
+                                                                                                                                       Support                                        9
+                                                                                               0.5 max.                                tape                                0.5 max.           +1
+                                                                                                                                                                                            180
+                                                                                                                                 0.9
+                                                                              (1)         5
+                                                                                                   3.4                                                                          6
+                                                                                                                                                                                    9±0.5
+                                                                                                                                                                                                       +1
+                                                                                                                     0.2 max.                                                                       18-0.5
+                                                0.5
+                                                              +0.8
+                                                            5-0.2                                               0.3                                          4±0.2 dia.
+
+                                                           Terminal Arrangement                                                                                           Carrier tape
+ Note: The tape is random      PCB Processing Dimensions /Internal Connections
+                                                                                                                                                              12.7±0.3
+
+       between surface A       (Reference Only) (Top View) (Top View)
+       and surface B.          (PCB thickness, t=1.6)
+
+
+                                                +0.1                                                 2                     1
+                                       Two, 1      0 dia.           5±0.1
+
+
+
+Note:   Unless otherwise specified, a tolerance of ±0.4 mm applies to all dimensions. No terminal numbers are indicated on the Switches.
+
+
+
+                                                                                                                                                                                                                 7
+B3F                                                                                                                                                                                                           B3F
+
+
+Flat Plunger Type                                               6±0.3
+(with Ground Terminal)
+B3F-6120, B3F-6122                              6±0.3                                   2
+                                                                                                                                                    12.7±1
+                                                                                                                                                 6.35±1
+                                                                                                                                                                                                    2 max.
+
+                                                        3.5 dia.
+                                                                                                  0.5 max.
+
+                                                                                                                                 0.9   Support                                         11
+                                                (1)                                           5
+                                                                                                    3.4                                tape                               0.5 max.
+                                                                                                                                                                                            20±0.5
+                                                                                        3.1
+                                                                                                                     0.2 max.                                                   6
+                                                                                                                                                                                    9±0.5
+                                                  0.5                   5±0.2                                0.3
+                                                                                                                                                                                                      +1
+                                                                  +0.8
+                                                                5-0.2                                        0.6                                                                                   18-0.5
+
+                                                                                                                                                         4±0.2 dia.
+                               PCB Processing Dimensions                                      Terminal Arrangement
+                               (Reference Only) (Top View)                                    /Internal Connections                                                       Carrier tape
+                                                                                                                                                             12.7±0.3
+                               (PCB thickness, t=1.6)                                         (Top View)
+
+
+                                           +0.1                                                      2                   1
+                               Three, 1      0 dia.            5±0.1                                                         3
+                                                                        5±0.1
+
+
+
+
+Projected Plunger Type                                          6±0.3           Surface B
+(without Ground Terminal)
+B3F-6050, B3F-6052
+                                                6±0.3
+
+                                                                                                                                                    12.7±1
+                                                        3.5 dia.                Surface A                                                        6.35±1
+                                                                                                                   2.4                                                                               2 max.
+
+
+                                                                                                  0.5 max.
+                                                                                            7.3                                  0.9
+                                                                                  (1)                3.4
+                                                                                                                                       Support                                          9
+                                                                                                                                       tape                                 0.5 dia.           +1
+                                                                                                                                                                                            18 0
+                                                                                                                     0.2 max.
+                                                  0.5
+                                                                  +0.8                                             0.3                                                          6
+                                                                5-0.2                                                                                                                  9±0.5
+                                                                                                                                                                                                       +1
+                                                                                                                                                                                                   18-0.5
+                            PCB Processing Dimensions                                         Terminal Arrang ement
+                            (Reference Only) (Top View)                                       /Internal Connections                                          4±0.2 dia.
+                            (PCB thickness, t=1.6)                                            (Top View)
+                                                                                                                                                              12.7±0.3    Carrier tape
+                                     +0.1
+                            Two, 1     0 dia.          5±0.1                                   2                     1
+
+
+    Note: The tape is random between surface A
+          and surface B.
+
+
+    Projected Plunger Type                                      6±0.3
+    (with Ground Terminal)
+    B3F-6150, B3F-6152
+                                                6±0.3                                   2                                                           12.7±1
+                                                                                                                                                 6.35±1
+                                                                                                                                                                                                    2 max.
+
+                                                        3.5 dia.                                                   2.4
+
+
+                                                                                                  0.5 max.
+                                                                                              7.3                                0.9
+                                                 (1)                                                 3.4                               Support                                         11
+                                                                                                                                       tape                                0.5 max.
+                                                                                                                                                                                            20±0.5
+                                                                                        3.1
+                                                                                                                     0.2 max.
+                                                                                                                                                                                6
+                                                                                                                                                                                       9±0.5
+                                                   0.5                  5±0.2                                0.3
+                                                                  +0.8                                                                                                                                +1
+                                                                5 -0.2                                       0.6                                                                                   18-0.5
+
+
+                                                                                                    Terminal Arrangement                                 4±0.2 dia.
+                                     PCB Processing Dimensions
+                                     (Reference Only) (Top View)                                    /Internal Connections
+                                     (PCB thickness, t=1.6)                                         (Top View)                                                12.7±0.3    Carrier tape
+
+
+
+                                                +0.1
+                                 Three, 1 0 dia.                 5±0.1                                   2                   1
+                                                                                                                                  3
+                                                                          5±0.1
+
+
+
+Note:     Unless otherwise specified, a tolerance of ±0.4 mm applies to all dimensions. No terminal numbers are indicated on the Switches.
+
+
+
+8
+B3F                                                                                                                                                                       B3F
+
+■ Key Tops
+B32-series Key Tops are available for projected plungers. Refer to the Datasheet of B32 for details.
+
+■ Precautions
+Be sure to read the safety precautions common to all Tactile Switches for correct use.
+
+
+
+
+• Application examples provided in this document are for reference only. In actual applications, confirm equipment functions and safety before using the product.
+• Consult your OMRON representative before using the product under conditions which are not described in the manual or applying the product to nuclear control systems, railroad
+  systems, aviation systems, vehicles, combustion systems, medical equipment, amusement machines, safety equipment, and other systems or equipment that may have a serious
+  influence on lives and property if used improperly. Make sure that the ratings and performance characteristics of the product provide a margin of safety for the system or
+  equipment, and be sure to provide the system or equipment with double safety mechanisms.
+
+
+                                                                                                      Note: Do not use this document to operate the Unit.
+
+OMRON Corporation
+Electronic and Mechanical Components Company                                          Contact: www.omron.com/ecb                                       Cat. No. A070-E1-08
+                                                                                                                                                             1014(0207)(O)
+
+
+
+                                                                                                                                                                               9
+

hardware/PCB/reference/db9-cad/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2016 Adafruit Industries
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

hardware/PCB/reference/db9-cad/README.md

@@ -0,0 +1,2 @@
+# Adafruit_CAD_Parts
+STEP, Fusion 360, and STL files for various boards, components and parts

hardware/PCB/reference/db9-cad/extract.py

@@ -0,0 +1,86 @@
+"""Read pinned STEP B-rep; write reproducible solid/face measurements beside it."""
+import json
+import re
+from pathlib import Path
+from OCP.STEPControl import STEPControl_Reader
+from OCP.IFSelect import IFSelect_RetDone
+from OCP.TopExp import TopExp_Explorer
+from OCP.TopAbs import TopAbs_SOLID, TopAbs_FACE
+from OCP.TopoDS import TopoDS
+from OCP.Bnd import Bnd_Box
+from OCP.BRepBndLib import BRepBndLib
+from OCP.BRepAdaptor import BRepAdaptor_Surface
+from OCP.GeomAbs import GeomAbs_Cylinder, GeomAbs_Plane
+from OCP.BRepCheck import BRepCheck_Analyzer
+
+HERE = Path(__file__).resolve().parent
+
+def bounds(s):
+    b = Bnd_Box()
+    BRepBndLib.AddOptimal_s(s, b, False, False)
+    return list(b.Get())
+
+def xyz(p):
+    return [p.X(), p.Y(), p.Z()]
+
+r = STEPControl_Reader()
+assert r.ReadFile(str(HERE / '5988 RS-232 Level Shifter.step')) == IFSelect_RetDone
+r.TransferRoots()
+entities = dict(re.findall(r'#(\d+)\s*=\s*(.*?);', (HERE / '5988 RS-232 Level Shifter.step').read_text(), re.S))
+styles = {}
+for text in entities.values():
+    if text.startswith('STYLED_ITEM('):
+        refs = re.findall(r'#(\d+)', text)
+        styles[refs[-1]] = refs[:-1]
+
+def colors(refs, seen=None):
+    seen = set() if seen is None else seen
+    result = []
+    for ref in refs:
+        if ref in seen:
+            continue
+        seen.add(ref)
+        text = entities[ref]
+        if text.startswith('COLOUR_RGB('):
+            result.append(text.replace('\n', ''))
+        else:
+            result.extend(colors(re.findall(r'#(\d+)', text), seen))
+    return result
+
+e = TopExp_Explorer(r.OneShape(), TopAbs_SOLID)
+out = []
+while e.More():
+    s = TopoDS.Solid_s(e.Current())
+    item = dict(id=len(out)+1, bounds=bounds(s), valid=BRepCheck_Analyzer(s).IsValid(), faces=[])
+    f = TopExp_Explorer(s, TopAbs_FACE)
+    while f.More():
+        face = TopoDS.Face_s(f.Current())
+        a = BRepAdaptor_Surface(face)
+        # These unique bodies retain CLOSED_SHELL face order on this pinned import.
+        shell_id = {1: '14428', 12: '14431', 13: '14432', 14: '14433'}.get(item['id'])
+        refs = re.findall(r'#(\d+)', entities[shell_id]) if shell_id else []
+        step_id = refs[len(item['faces'])] if refs else '0'
+        if refs:
+            surface_id = re.findall(r'#(\d+)', entities[step_id])[-1]
+            surface = entities[surface_id]
+            expected = str(a.GetType()).split('_')[-1].upper()
+            assert surface.startswith({'PLANE': 'PLANE(', 'CYLINDER': 'CYLINDRICAL_SURFACE(', 'CONE': 'CONICAL_SURFACE(', 'TORUS': 'TOROIDAL_SURFACE('}[expected])
+            if a.GetType() == GeomAbs_Cylinder:
+                assert abs(float(surface.rsplit(',', 1)[1].rstrip(')')) - a.Cylinder().Radius()) < 1e-8
+        row = dict(id=len(item['faces'])+1, bounds=bounds(face), type=str(a.GetType()), orientation=str(face.Orientation()))
+        row.update(step_id=step_id, colors=colors(styles.get(step_id, [])))
+        if a.GetType() == GeomAbs_Cylinder:
+            c = a.Cylinder()
+            row.update(radius=c.Radius(), location=xyz(c.Location()), axis=xyz(c.Axis().Direction()))
+        elif a.GetType() == GeomAbs_Plane:
+            p = a.Plane()
+            row.update(location=xyz(p.Location()), normal=xyz(p.Axis().Direction()))
+        item['faces'].append(row)
+        f.Next()
+    if shell_id:
+        assert len(item['faces']) == len(refs)
+    out.append(item)
+    e.Next()
+(HERE / 'geometry.json').write_text(json.dumps(out, indent=2)+'\n')
+for s in out:
+    print(s['id'], 'valid', s['valid'], 'bounds', [round(v,6) for v in s['bounds']], 'faces', len(s['faces']))

hardware/PCB/reference/db9-cad/measurements.json

@@ -0,0 +1,207 @@
+{
+  "front_flange_exposed_faces": {
+    "solid": 12,
+    "faces": [
+      8,
+      11,
+      12,
+      13,
+      14
+    ],
+    "bounds": [
+      0.47499999999999787,
+      27.006999999999998,
+      1.5726202399843388,
+      31.275000000000002,
+      27.407,
+      14.1226202399843
+    ],
+    "dimensions": [
+      30.800000000000004,
+      0.40000000000000213,
+      12.549999999999962
+    ]
+  },
+  "shell_straight_outer_surface": {
+    "solid": 12,
+    "faces": [
+      18,
+      19,
+      20,
+      21,
+      22,
+      23,
+      24,
+      25
+    ],
+    "bounds": [
+      8.035981107410171,
+      28.006999999999998,
+      3.89762023998434,
+      23.71401889258985,
+      32.607,
+      11.79762023998434
+    ],
+    "dimensions": [
+      15.678037785179677,
+      4.600000000000001,
+      7.9
+    ]
+  },
+  "shell_outer_including_root_and_lip": {
+    "solid": 12,
+    "faces": [
+      18,
+      19,
+      20,
+      21,
+      22,
+      23,
+      24,
+      25,
+      81,
+      82,
+      83,
+      84,
+      85,
+      86,
+      87,
+      88,
+      103,
+      104,
+      105,
+      106,
+      107,
+      108,
+      109,
+      110
+    ],
+    "bounds": [
+      7.4359811074101705,
+      27.406999999999996,
+      3.29762023998434,
+      24.31401889258985,
+      33.207,
+      12.397620239984342
+    ],
+    "dimensions": [
+      16.87803778517968,
+      5.800000000000004,
+      9.100000000000001
+    ]
+  },
+  "left_front_hex_post": {
+    "solid": 12,
+    "faces": [
+      53,
+      54,
+      55,
+      56,
+      57,
+      58,
+      59,
+      60,
+      61,
+      89
+    ],
+    "bounds": [
+      0.7191887617277004,
+      27.407,
+      5.547620239984319,
+      6.030811238272291,
+      32.207,
+      10.147620239984366
+    ],
+    "dimensions": [
+      5.31162247654459,
+      4.800000000000001,
+      4.600000000000048
+    ]
+  },
+  "right_front_hex_post": {
+    "solid": 12,
+    "faces": [
+      62,
+      63,
+      64,
+      65,
+      66,
+      67,
+      68,
+      69,
+      70,
+      90
+    ],
+    "bounds": [
+      25.71918876172773,
+      27.407,
+      5.547620239984328,
+      31.030811238272328,
+      32.207,
+      10.14762023998434
+    ],
+    "dimensions": [
+      5.311622476544599,
+      4.800000000000001,
+      4.600000000000012
+    ]
+  },
+  "front_lock_axes": [
+    {
+      "id": 60,
+      "bounds": [
+        1.875,
+        27.407,
+        6.34762023998434,
+        4.875,
+        32.007,
+        9.34762023998434
+      ],
+      "type": "GeomAbs_SurfaceType.GeomAbs_Cylinder",
+      "orientation": "TopAbs_Orientation.TopAbs_REVERSED",
+      "step_id": "13822",
+      "colors": [
+        "COLOUR_RGB('Opaque(245,245,246)',0.96078431372549,0.96078431372549,0.964705882352941)"
+      ],
+      "radius": 1.5,
+      "location": [
+        3.375,
+        32.207,
+        7.84762023998434
+      ],
+      "axis": [
+        0.0,
+        -1.0,
+        0.0
+      ]
+    },
+    {
+      "id": 69,
+      "bounds": [
+        26.875,
+        27.407,
+        6.34762023998434,
+        29.875,
+        32.007,
+        9.34762023998434
+      ],
+      "type": "GeomAbs_SurfaceType.GeomAbs_Cylinder",
+      "orientation": "TopAbs_Orientation.TopAbs_REVERSED",
+      "step_id": "13831",
+      "colors": [
+        "COLOUR_RGB('Opaque(245,245,246)',0.96078431372549,0.96078431372549,0.964705882352941)"
+      ],
+      "radius": 1.5,
+      "location": [
+        28.375,
+        32.207,
+        7.84762023998434
+      ],
+      "axis": [
+        0.0,
+        -1.0,
+        0.0
+      ]
+    }
+  ]
+}

hardware/PCB/reference/db9-cad/sources.json

@@ -0,0 +1,17 @@
+[
+  {
+    "file": "5988 RS-232 Level Shifter.step",
+    "url": "https://raw.githubusercontent.com/adafruit/Adafruit_CAD_Parts/5b8a21fb5e2e48478faf8901077be812f5224066/5988%20RS-232%20Level%20Shifter/5988%20RS-232%20Level%20Shifter.step",
+    "sha256": "8eab9dc591a985fc987ceec2d7534e5e259263c73bebc64c0c3cd847e135906f"
+  },
+  {
+    "file": "LICENSE",
+    "url": "https://raw.githubusercontent.com/adafruit/Adafruit_CAD_Parts/5b8a21fb5e2e48478faf8901077be812f5224066/LICENSE",
+    "sha256": "f60436644e066301d4c2e8f1f0674a157b1f60e4fd5586717b99dde255cc18cd"
+  },
+  {
+    "file": "README.md",
+    "url": "https://raw.githubusercontent.com/adafruit/Adafruit_CAD_Parts/5b8a21fb5e2e48478faf8901077be812f5224066/README.md",
+    "sha256": "9ed9beac7600623b7b9bd0d02e1fdcd86610ce22966723179e6c6b618e399dce"
+  }
+]

hardware/PCB/reference/db9-cad/validate.py

@@ -0,0 +1,46 @@
+"""Validate registration and selected face subsets; no board writes."""
+import hashlib
+import json
+from pathlib import Path
+import xml.etree.ElementTree as ET
+
+HERE = Path(__file__).resolve().parent
+D = json.loads((HERE / 'geometry.json').read_text())
+assert len(D) == 15 and all(s['valid'] for s in D)
+for source in json.loads((HERE / 'sources.json').read_text()):
+    assert hashlib.sha256((HERE / source['file']).read_bytes()).hexdigest() == source['sha256']
+board = HERE.parent / 'Adafruit RS-232 Full Pinout Level-Shifter Breakout.brd'
+assert hashlib.sha256(board.read_bytes()).hexdigest() == '6a7b35ef909f5a2d243c326c34db3957aaa01275bf2aac8e0c749ff18162e870'
+root = ET.parse(board).getroot()
+b = root.find('drawing/board')
+jp = b.find("elements/element[@name='JP2']")
+pkg = b.find("libraries/library[@name='microbuilder']/packages/package[@name='1X12_ROUND_76MIL']")
+for pad in pkg.findall('pad'):
+    x, y = float(jp.get('x')) + float(pad.get('x')), float(jp.get('y')) + float(pad.get('y'))
+    assert any(abs(f.get('radius', 0)-0.5)<1e-8 and abs(f['location'][0]-x)<1e-8 and abs(f['location'][1]-y)<1e-8 for f in D[0]['faces'])
+for x in [3.81, 27.94]:
+    assert any(abs(f.get('radius',0)-1.5)<1e-8 and abs(f['location'][0]-x)<1e-8 and abs(f['location'][1]-11.43)<1e-8 for f in D[0]['faces'])
+assert all(abs(a-b)<1e-8 for a,b in zip(D[0]['bounds'], [0,0,0,31.75,29.337,1.57]))
+
+subsets = {
+    'front_flange_exposed_faces': [8,11,12,13,14],
+    'shell_straight_outer_surface': list(range(18,26)),
+    'shell_outer_including_root_and_lip': list(range(18,26))+list(range(81,89))+list(range(103,111)),
+    'left_front_hex_post': list(range(53,62))+[89],
+    'right_front_hex_post': list(range(62,71))+[90],
+}
+result = {}
+for name, ids in subsets.items():
+    faces = [D[11]['faces'][i-1] for i in ids]
+    assert all(any('Opaque(245,245,246)' in c for c in f['colors']) for f in faces)
+    bounds = [min(f['bounds'][i] for f in faces) for i in range(3)] + [max(f['bounds'][i] for f in faces) for i in range(3,6)]
+    result[name] = dict(solid=12, faces=ids, bounds=bounds, dimensions=[bounds[i+3]-bounds[i] for i in range(3)])
+left, right = [D[11]['faces'][i-1] for i in [60,69]]
+assert abs(right['location'][0]-left['location'][0]-25)<1e-8
+assert left['radius'] == right['radius'] == 1.5
+result['front_lock_axes'] = [left, right]
+(HERE / 'measurements.json').write_text(json.dumps(result,indent=2)+'\n')
+print('PASS: source hashes, 15 valid solids, all 12 Eagle header centres, PCB bounds, mounting holes, metal-appearance subsets and front lock cylinders.')
+for name, row in result.items():
+    if isinstance(row,dict):
+        print(name, [round(v,6) for v in row['bounds']], 'size', [round(v,6) for v in row['dimensions']])

hardware/PCB/reference/license.txt

@@ -0,0 +1,359 @@
+Creative Commons Legal Code
+
+Attribution-ShareAlike 3.0 Unported
+
+    CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE
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hardware/PCB/route_pcb_draft.py

@@ -0,0 +1,369 @@
+#!/usr/bin/python3
+"""Bounded, board-specific two-layer draft router. Requires pcbnew and numpy.
+
+Dry-run by default. --route --overwrite explicitly permits saving routing;
+existing copper additionally requires --replace-routes. Never edits the project,
+schematic, footprint libraries or generator. Review actual KiCad DRC afterwards.
+This is not a production autorouter or a fabrication qualification.
+"""
+import argparse
+from collections import defaultdict
+import hashlib
+import heapq
+import json
+import math
+from pathlib import Path
+import time
+
+import numpy as np
+import pcbnew as p
+
+ROOT = Path(__file__).resolve().parent
+PCB = ROOT / 'serial-carrier.kicad_pcb'
+STEP = 0.05
+NX, NY = int(82 / STEP) + 1, int(80 / STEP) + 1
+N = NX * NY
+CLEARANCE = 0.25
+MARGIN = 0.02
+LAYERS = (p.F_Cu, p.B_Cu)
+X = 100 + np.arange(NX)[None, :] * STEP
+Y = 100 + np.arange(NY)[:, None] * STEP
+
+
+def mm(v):
+    return p.FromMM(v)
+
+
+def point(xy):
+    return p.VECTOR2I(mm(xy[0]), mm(xy[1]))
+
+
+def pos(item):
+    v = item.GetPosition()
+    return (p.ToMM(v.x), p.ToMM(v.y))
+
+
+def identity(board):
+    """Immutable geometry/linkage snapshot, independent of serialization order."""
+    footprints = []
+    for f in board.GetFootprints():
+        pads = sorted((a.m_Uuid.AsString(), a.GetNumber(), a.GetNetname(),
+                       pos(a), (a.GetSize().x, a.GetSize().y),
+                       (a.GetDrillSize().x, a.GetDrillSize().y),
+                       a.GetShape(), a.GetAttribute(), a.GetLayerSet().FmtHex(),
+                       a.GetOrientationDegrees(), a.GetPinFunction(), a.GetPinType())
+                      for a in f.Pads())
+        footprints.append((f.m_Uuid.AsString(), f.GetReference(), f.GetValue(),
+                           f.GetFPIDAsString(), f.GetPath().AsString(), pos(f),
+                           f.GetOrientationDegrees(), f.GetLayer(), pads))
+    edges = sorted((a.m_Uuid.AsString(), a.GetShape(), a.GetStart().x,
+                    a.GetStart().y, a.GetEnd().x, a.GetEnd().y, a.GetWidth())
+                   for a in board.GetDrawings() if a.GetLayer() == p.Edge_Cuts)
+    zones = sorted((z.m_Uuid.AsString(), z.GetLayerSet().FmtHex(),
+                    z.GetIsRuleArea(), z.GetDoNotAllowTracks(),
+                    z.GetDoNotAllowVias(), z.GetDoNotAllowZoneFills(),
+                    tuple((z.Outline().COutline(0).CPoint(i).x,
+                           z.Outline().COutline(0).CPoint(i).y)
+                          for i in range(z.Outline().COutline(0).PointCount())))
+                   for z in board.Zones())
+    nets = sorted((n.GetNetCode(), n.GetNetname()) for n in board.GetNetsByNetcode().values())
+    return (board.GetCopperLayerCount(), sorted(footprints), edges, zones, nets)
+
+
+def window(x0, y0, x1, y1):
+    ix0 = max(0, int(math.floor((x0 - 100) / STEP)))
+    iy0 = max(0, int(math.floor((y0 - 100) / STEP)))
+    ix1 = min(NX, int(math.ceil((x1 - 100) / STEP)) + 1)
+    iy1 = min(NY, int(math.ceil((y1 - 100) / STEP)) + 1)
+    return slice(iy0, iy1), slice(ix0, ix1)
+
+
+def capsule(mask, a, b, radius):
+    sy, sx = window(min(a[0], b[0]) - radius, min(a[1], b[1]) - radius,
+                    max(a[0], b[0]) + radius, max(a[1], b[1]) + radius)
+    xx, yy = X[:, sx], Y[sy, :]
+    dx, dy = b[0] - a[0], b[1] - a[1]
+    length2 = dx * dx + dy * dy
+    t = np.clip(((xx - a[0]) * dx + (yy - a[1]) * dy) / length2, 0, 1) if length2 else 0
+    mask[sy, sx] |= (xx - a[0] - t * dx)**2 + (yy - a[1] - t * dy)**2 <= radius**2
+
+
+def pad_obstacle(mask, pad, extra, hole_only=False):
+    xy = pos(pad)
+    size = pad.GetDrillSize() if hole_only else pad.GetSize()
+    rx, ry = p.ToMM(size.x) / 2, p.ToMM(size.y) / 2
+    if not rx or not ry:
+        return
+    if abs(rx - ry) < 1e-6 and (hole_only or pad.GetShape() == p.PAD_SHAPE_CIRCLE):
+        capsule(mask, xy, xy, rx + extra)
+    else:
+        # Bounding rectangle deliberately overestimates non-circular pad shapes.
+        box = pad.GetBoundingBox()
+        x0, y0 = p.ToMM(box.GetX()) - extra, p.ToMM(box.GetY()) - extra
+        x1, y1 = p.ToMM(box.GetRight()) + extra, p.ToMM(box.GetBottom()) + extra
+        sy, sx = window(x0, y0, x1, y1)
+        mask[sy, sx] |= (X[:, sx] >= x0) & (X[:, sx] <= x1) & (Y[sy, :] >= y0) & (Y[sy, :] <= y1)
+
+
+def boundary(radius):
+    edge = 0.5 + radius + MARGIN
+    mask = np.broadcast_to((X < 100 + edge) | (X > 182 - edge) |
+                           (Y < 100 + edge) | (Y > 180 - edge), (NY, NX)).copy()
+    mask |= (X < 136 + edge) & (Y < 119 + edge)
+    # Expand the RF reservation by copper radius plus numerical safety margin.
+    r = radius + MARGIN
+    mask |= (X >= 110 - r) & (X <= 131 + r) & (Y >= 119 - r) & (Y <= 132 + r)
+    return mask
+
+
+def masks(board, pads, net, width):
+    blocked = np.stack([boundary(width / 2)] * 2)
+    via = boundary(0.35)
+    for pad in pads:
+        if pad.GetNetCode() != net or not pad.GetNumber():
+            for z, layer in enumerate(LAYERS):
+                if pad.IsOnLayer(layer):
+                    pad_obstacle(blocked[z], pad, CLEARANCE + width / 2 + MARGIN)
+            pad_obstacle(via, pad, CLEARANCE + 0.35 + MARGIN)
+        # Even same-net holes must not receive a drilled via.
+        pad_obstacle(via, pad, CLEARANCE + 0.35 + MARGIN, hole_only=True)
+    for track in board.GetTracks():
+        if track.GetNetCode() == net:
+            if isinstance(track, p.PCB_VIA):
+                capsule(via, pos(track), pos(track), 0.7 + CLEARANCE + MARGIN)
+            continue
+        a = (p.ToMM(track.GetStart().x), p.ToMM(track.GetStart().y))
+        b = (p.ToMM(track.GetEnd().x), p.ToMM(track.GetEnd().y))
+        radius = p.ToMM(track.GetWidth(p.F_Cu) if isinstance(track, p.PCB_VIA) else track.GetWidth()) / 2
+        for z, layer in enumerate(LAYERS):
+            if isinstance(track, p.PCB_VIA) or track.GetLayer() == layer:
+                capsule(blocked[z], a, b, radius + CLEARANCE + width / 2 + MARGIN)
+        capsule(via, a, b, radius + CLEARANCE + 0.35 + MARGIN)
+    return blocked.reshape(-1), via.reshape(-1)
+
+
+def node(xy, layer=0):
+    x, y = (int(round((v - 100) / STEP)) for v in xy)
+    return layer * N + y * NX + x
+
+
+def decode(i):
+    z, q = divmod(i, N)
+    y, x = divmod(q, NX)
+    return (100 + x * STEP, 100 + y * STEP), z
+
+
+def astar(blocked, via, start, target, deadline, max_expansions):
+    tx = int(round((target[0] - 100) / STEP))
+    ty = int(round((target[1] - 100) / STEP))
+    targetq = ty * NX + tx
+
+    def h(q):
+        y, x = divmod(q, NX)
+        dx, dy = abs(x - tx), abs(y - ty)
+        return 10 * max(dx, dy) + 4 * min(dx, dy)
+
+    dist = np.full(2 * N, 2147483647, dtype=np.int32)
+    parent = np.full(2 * N, -1, dtype=np.int32)
+    heap = []
+    for z in (0, 1):
+        i = node(start, z)
+        if not blocked[i]:
+            dist[i] = 0
+            heapq.heappush(heap, (h(i % N), 0, i))
+    expanded = 0
+    moves = ((1, 0, 10), (-1, 0, 10), (0, 1, 10), (0, -1, 10),
+             (1, 1, 14), (1, -1, 14), (-1, 1, 14), (-1, -1, 14))
+    while heap:
+        _, cost, i = heapq.heappop(heap)
+        if cost != dist[i]:
+            continue
+        z, q = divmod(i, N)
+        if q == targetq:
+            path = [i]
+            while parent[path[-1]] >= 0:
+                path.append(int(parent[path[-1]]))
+            return path[::-1], expanded
+        expanded += 1
+        if expanded >= max_expansions or (expanded % 1024 == 0 and time.monotonic() >= deadline):
+            return None, expanded
+        y, x = divmod(q, NX)
+        for dx, dy, stepcost in moves:
+            if not (0 <= x + dx < NX and 0 <= y + dy < NY):
+                continue
+            j = i + dy * NX + dx
+            if blocked[j] or (dx and dy and (blocked[i + dx] or blocked[i + dy * NX])):
+                continue
+            # Mild layer preference prevents needless coincident layer choices.
+            penalty = int((z == 0 and dx == 0) or (z == 1 and dy == 0))
+            nc = cost + stepcost + penalty
+            if nc < dist[j]:
+                dist[j], parent[j] = nc, i
+                heapq.heappush(heap, (nc + h(j % N), nc, j))
+        j = (1 - z) * N + q
+        if not via[q] and not blocked[j]:
+            nc = cost + int(18 / STEP)  # 1.8 mm equivalent cost for a layer change.
+            if nc < dist[j]:
+                dist[j], parent[j] = nc, i
+                heapq.heappush(heap, (nc + h(q), nc, j))
+    return None, expanded
+
+
+def add_path(board, path, start, target, net, width):
+    points = [decode(i) for i in path]
+    points = [(start, points[0][1])] + points + [(target, points[-1][1])]
+    # Only merge exactly collinear grid runs; never shortcut obstacle checks.
+    simple = []
+    for item in points:
+        if simple and item == simple[-1]:
+            continue
+        while len(simple) >= 2 and item[1] == simple[-1][1] == simple[-2][1]:
+            a, b, c = simple[-2][0], simple[-1][0], item[0]
+            cross = (b[0]-a[0])*(c[1]-b[1]) - (b[1]-a[1])*(c[0]-b[0])
+            dot = (b[0]-a[0])*(c[0]-b[0]) + (b[1]-a[1])*(c[1]-b[1])
+            if abs(cross) > 1e-8 or dot < 0:
+                break
+            simple.pop()
+        simple.append(item)
+    for (a, z), (b, zz) in zip(simple, simple[1:]):
+        if z != zz:
+            assert a == b
+            item = p.PCB_VIA(board)
+            item.SetPosition(point(a))
+            item.SetWidth(mm(0.7))
+            item.SetDrill(mm(0.3))
+            item.SetViaType(p.VIATYPE_THROUGH)
+            item.SetLayerPair(p.F_Cu, p.B_Cu)
+        else:
+            if a == b:
+                continue
+            item = p.PCB_TRACK(board)
+            item.SetStart(point(a))
+            item.SetEnd(point(b))
+            item.SetWidth(mm(width))
+            item.SetLayer(LAYERS[z])
+        item.SetNetCode(net)
+        board.Add(item)
+
+
+def pairs_for_net(pads):
+    # Minimum spanning tree includes duplicate switch contacts explicitly.
+    connected = {0}
+    todo = set(range(1, len(pads)))
+    pairs = []
+    while todo:
+        length, a, b = min((math.dist(pos(pads[a]), pos(pads[b])), a, b)
+                           for a in connected for b in todo)
+        pairs.append((length, pads[a], pads[b]))
+        connected.add(b)
+        todo.remove(b)
+    return pairs
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--route', action='store_true')
+    parser.add_argument('--overwrite', action='store_true')
+    parser.add_argument('--replace-routes', action='store_true')
+    parser.add_argument('--seconds', type=float, default=240)
+    parser.add_argument('--max-expansions', type=int, default=1200000)
+    args = parser.parse_args()
+    if args.route and not args.overwrite:
+        parser.error('--route requires --overwrite; back up manual routing first')
+    if not 0 < args.seconds <= 900 or not 0 < args.max_expansions <= 1500000:
+        parser.error('bounds: seconds (0,900], max-expansions (0,1500000]')
+    if ROOT.joinpath('~serial-carrier.kicad_pcb.lck').exists():
+        parser.error('PCB editor lock exists; close the PCB before routing')
+    original_bytes = PCB.read_bytes()
+    project = ROOT / 'serial-carrier.kicad_pro'
+    project_before = project.read_bytes()
+    board = p.LoadBoard(str(PCB))
+    before = identity(board)
+    if board.GetCopperLayerCount() != 2 or len(board.GetFootprints()) != 13:
+        parser.error('unexpected board structure; review router assumptions')
+    if len(board.Zones()) != 1 or not board.Zones()[0].GetIsRuleArea():
+        parser.error('unexpected zones; router supports only the original RF rule area')
+    outline = [(136, 100), (182, 100), (182, 180), (100, 180), (100, 119), (136, 119)]
+    expected_edges = {frozenset((a, b)) for a, b in zip(outline, outline[1:] + outline[:1])}
+    actual_edges = {frozenset(((p.ToMM(e.GetStart().x), p.ToMM(e.GetStart().y)),
+                               (p.ToMM(e.GetEnd().x), p.ToMM(e.GetEnd().y))))
+                    for e in board.GetDrawings() if e.GetLayer() == p.Edge_Cuts}
+    if actual_edges != expected_edges:
+        parser.error('outline differs from the board-specific routing envelope')
+    reserve = board.Zones()[0]
+    contour = reserve.Outline().COutline(0)
+    rf_points = {(p.ToMM(contour.CPoint(i).x), p.ToMM(contour.CPoint(i).y))
+                 for i in range(contour.PointCount())}
+    if (rf_points != {(110, 119), (131, 119), (131, 132), (110, 132)} or
+            not all(reserve.IsOnLayer(layer) for layer in LAYERS) or
+            not all((reserve.GetDoNotAllowTracks(), reserve.GetDoNotAllowVias(),
+                     reserve.GetDoNotAllowZoneFills()))):
+        parser.error('RF rule area differs from the board-specific reservation')
+    if board.GetTracks() and not args.replace_routes:
+        parser.error('existing routing protected; --replace-routes required even for preview')
+    for track in list(board.GetTracks()):
+        board.Delete(track)
+    pads = [a for f in board.GetFootprints() for a in f.Pads()]
+    if any(a.GetOrientationDegrees() % 90 or not all(a.IsOnLayer(l) for l in LAYERS) for a in pads):
+        parser.error('router requires axis-aligned through-hole pads')
+    nets = defaultdict(list)
+    for pad in pads:
+        if pad.GetNumber() and pad.GetNetCode():
+            nets[pad.GetNetCode()].append(pad)
+    work = []
+    for net, netpads in nets.items():
+        if len(netpads) > 1:
+            name = netpads[0].GetNetname()
+            for length, a, b in pairs_for_net(netpads):
+                # Reserve short ground escapes before signal fanout can box them in.
+                # Long ground links still run last, preserving space for signal paths.
+                priority = (name == '/GND' and length > 15, length)
+                work.append((priority, net, name, a, b))
+    work.sort(key=lambda w: (w[0], w[2]))
+    start_time = time.monotonic()
+    deadline = start_time + args.seconds
+    results = []
+    for _, net, name, a, b in work:
+        width = 0.5 if name in ('/+3V3', '/GND') else 0.25
+        path, expanded = None, 0
+        if time.monotonic() < deadline:
+            blocked, via = masks(board, pads, net, width)
+            path, expanded = astar(blocked, via, pos(a), pos(b), deadline, args.max_expansions)
+        fallback = False
+        if path is None and width == 0.5 and time.monotonic() < deadline:
+            width, fallback = 0.25, True
+            blocked, via = masks(board, pads, net, width)
+            path, more = astar(blocked, via, pos(a), pos(b), deadline, args.max_expansions)
+            expanded += more
+        label = lambda pad: pad.GetParentFootprint().GetReference() + '.' + pad.GetNumber()
+        result = dict(net=name, start=label(a), end=label(b), start_mm=pos(a), end_mm=pos(b),
+                      routed=path is not None, width_mm=width, power_fallback=fallback, expansions=expanded)
+        results.append(result)
+        if path is not None:
+            add_path(board, path, pos(a), pos(b), net, width)
+        print(json.dumps(result), flush=True)
+    assert identity(board) == before, 'immutable board data changed'
+    report = dict(draft_only=True, saved=args.route, grid_mm=STEP, clearance_mm=CLEARANCE,
+                  safety_margin_mm=MARGIN, via_diameter_mm=0.7, via_drill_mm=0.3,
+                  elapsed_seconds=time.monotonic()-start_time, connections=results,
+                  routed_tree_edges=sum(r['routed'] for r in results), total_tree_edges=len(results),
+                  tracks=sum(not isinstance(t, p.PCB_VIA) for t in board.GetTracks()),
+                  vias=sum(isinstance(t, p.PCB_VIA) for t in board.GetTracks()),
+                  immutable_identity_sha256=hashlib.sha256(repr(before).encode()).hexdigest(),
+                  input_sha256=hashlib.sha256(original_bytes).hexdigest(),
+                  validation='KiCad DRC must be run separately; tree-edge counts are not DRC connectivity')
+    if args.route:
+        if PCB.read_bytes() != original_bytes or ROOT.joinpath('~serial-carrier.kicad_pcb.lck').exists():
+            raise RuntimeError('PCB changed or editor opened during routing; refusing overwrite')
+        # Check a serialized candidate before replacing the user's board.
+        candidate = ROOT / 'validation/pcb-routing-candidate.kicad_pcb'
+        assert p.SaveBoard(str(candidate), board, True)
+        assert project.read_bytes() == project_before, 'project settings changed'
+        assert identity(p.LoadBoard(str(candidate))) == before, 'saved identity mismatch'
+        candidate.replace(PCB)
+        ROOT.joinpath('validation/pcb-routing-run.json').write_text(json.dumps(report, indent=2)+'\n')
+    print(json.dumps({k: v for k, v in report.items() if k != 'connections'}, indent=2))
+
+
+if __name__ == '__main__':
+    main()

hardware/PCB/rs232-footprint-notes.md

@@ -0,0 +1,119 @@
+# MAX3243 carrier — PROVISIONAL female CAD reference / VERIFY MALE
+
+Footprint: `Carrier:MAX3243_Reference_Provisional` in
+`Carrier.pretty/MAX3243_Reference_Provisional.kicad_mod`.
+Intended only for a <=100 × 100 mm, two-copper-layer carrier PCB draft.
+No schematic assignment or edits are made. This footprint does not establish
+whole-board fit, connector access, DRC compliance, or fabrication readiness.
+
+## Evidence and scope
+
+The user reports that the male **6253** module has the same dimensions. This is
+not confirmation of its pad map. Geometry below is taken from published **female
+5988** Eagle CAD, not verified male-specific CAD. Confirm the purchased module's
+identity, orientation, header numbering, outline and mounting geometry before
+release. Never infer header order from DE-9 gender or mating-face numbering.
+
+Source: [Adafruit PCB repository](https://github.com/adafruit/Adafruit-RS-232-Level-Shifter-Breakout-PCB),
+commit `63c6200bb3ef17d491089cfa6441b1810d79bb20`.
+Local original: `reference/Adafruit RS-232 Full Pinout Level-Shifter Breakout.brd`;
+SHA-256 `6a7b35ef909f5a2d243c326c34db3957aaa01275bf2aac8e0c749ff18162e870`
+was rechecked against the file. See `adafruit-research.md` for provenance and
+female/male distinctions.
+
+CAD-derived geometry adapted from the design by **Limor Fried/Ladyada for Adafruit
+Industries**, under **CC BY-SA 3.0 Unported**:
+https://creativecommons.org/licenses/by-sa/3.0/ . The CAD-derived footprint and
+these CAD-derived notes use that license. Preserve the full upstream notices in
+`reference/README.md` and `reference/license.txt` when redistributing this adaptation.
+Changes: coordinate transformation, carrier pad convention, NPTH carrier holes,
+and provisional annotations; no module circuitry or connector package copied.
+
+## View, origin and exact nominal geometry
+
+Front/component top view, module facing up, DE-9 toward the top (**negative Y**).
+Origin is header JP2 pin 1, not a PCB corner. X increases rightward; Y downward.
+Transform Eagle board coordinates in mm with:
+
+`x = X - 1.905; y = 2.667 - Y`.
+
+- Pads 1…12: `(2.54 × (N - 1), 0)`, first-to-last span 27.94 mm.
+- Full bare-module outline is on `F.Fab`, **not carrier `Edge.Cuts`**.
+  Bounds: X = -1.905…29.845, Y = -26.670…2.667 (31.750 × 29.337 mm).
+  Top corners are square. Bottom corners retain the source 2.540 mm radius arcs.
+- Left arc: (-1.905, 0.127) to (0.635, 2.667), centre (0.635, 0.127).
+  Right arc: (27.305, 2.667) to (29.845, 0.127), centre (27.305, 0.127).
+  Midpoints use radius/sqrt(2), rounded to nine decimal places in the file;
+  the arcs are not chamfers or a bounding-box approximation.
+- Two unnumbered **3.00 mm NPTH carrier holes**: (1.905, -8.763) and
+  (26.035, -8.763), spacing 24.130 mm. These transfer module-hole centres and
+  drill diameter only. The source module holes are actually plated, 3.60 mm
+  copper / 3.00 mm drill, unconnected in the source signal map. Carrier NPTH
+  deliberately does not copy that plating or assign electrical connections.
+  No screw, washer, standoff or tool-access clearance is implied.
+
+## Provisional carrier pads and female reference map
+
+Same convention documented in `footprint-notes.md` for the other carrier modules:
+**1.70 × 1.70 mm PTH pads / 1.00 mm drills**, rectangular pad 1, circular pads
+2…12, `*.Cu` and `*.Mask`, unused copper layers retained. That convention derives
+from the installed KiCad `PinHeader_1x04_P2.54mm_Vertical`; it is not a selected
+header/socket qualification. The source module itself uses 1.9304 mm round pads.
+Confirm actual pins/sockets, finished-hole tolerances, annular rings and assembly
+height before fabrication. Square pad 1 is a carrier marker, not source evidence.
+
+| Pad | X (mm), Y=0 | Female label | Female CAD net |
+|---:|---:|---|---|
+| 1 | 0.00 | Vin | VCC |
+| 2 | 2.54 | GND | GND |
+| 3 | 5.08 | DCD | DCD |
+| 4 | 7.62 | RX | RXD |
+| 5 | 10.16 | TX | TXD |
+| 6 | 12.70 | DTR | DTR |
+| 7 | 15.24 | DSR | DSR |
+| 8 | 17.78 | RTS | RTS |
+| 9 | 20.32 | CTS | CTS |
+| 10 | 22.86 | RI | RI |
+| 11 | 25.40 | VLD | !INVALID |
+| 12 | 27.94 | OFF | !FORCEOFF |
+
+**This is the female reference map, NOT a confirmed male map.** Footprint pads
+have numbers only, no assigned nets. OFF is active low; VLD indicates valid input
+when high. This project's logic interface requires 3.3 V Vin.
+
+## Intentionally omitted / release gates
+
+The footprint F.Fab outline still describes only the bare module PCB. Subsequent
+STEP B-rep measurements now establish nominal shell/flange/hex-post envelopes and
+registration; see `db9-mechanical-notes.md`. The user explicitly confirms identical
+male/female external dimensions. A1 board-local Dwgs.User projections show those
+nominal bounds, without changing this footprint's pads or deriving drills from
+the 3D model. Mating-plug/cable, case wall/cutout, assembly height and actual fit
+remain unqualified. No guessed complete courtyard or 3D mounting offset is added.
+There is **no fake courtyard**; courtyard checks cannot establish assembly fit.
+Short silkscreen labels identify PROVISIONAL / FEMALE CAD REF / VERIFY MALE.
+
+Before layout release: verify male pad map and orientation against the actual
+module or authoritative male CAD; perform a 1:1 fit check; select headers and
+mounting hardware; verify assembled and mating envelopes; then establish real
+clearances/courtyard and check the complete <=100 × 100 mm two-layer layout.
+
+## Validation performed
+
+KiCad **10.0.6** `pcbnew.FootprintLoad` successfully loaded the footprint using
+system Python (`/usr/bin/python3 -B`) in a read-only inline check. Assertions passed
+for all 12 numbered pad positions against source JP2 package/element coordinates,
+female signal-contactref order, pad sizes/drills/shapes and copper/mask presence,
+no assigned header nets, both NPTH centres/sizes/drills, and all six transformed
+source outline segments including both 90-degree, 2.540 mm radius arcs and centres.
+Also checked absence of courtyard, Edge.Cuts, zones and 3D models.
+
+The first check assumed arc endpoint order was preserved; KiCad normalizes arc
+orientation. The corrected check matches endpoint pairs independent of order and
+verifies radius, angle and centre; it passed without changing geometry. The
+binding emitted the same three startup `PROPERTY_ENUM` assertions documented for
+other module validation; these did not prevent loading or successful checks.
+No hardware fit test, male electrical verification, board DRC or firmware build
+was performed. Existing `validate_footprints.py` was not changed and does not
+cover this new footprint. Only this notes file and the new footprint were written;
+schematic, project and lock files were left untouched.

hardware/PCB/serial-carrier.kicad_pro

@@ -0,0 +1,703 @@
+{
+  "board": {
+    "3dviewports": [],
+    "design_settings": {
+      "defaults": {
+        "apply_defaults_to_fp_barcodes": false,
+        "apply_defaults_to_fp_dimensions": false,
+        "apply_defaults_to_fp_fields": false,
+        "apply_defaults_to_fp_shapes": false,
+        "apply_defaults_to_fp_text": false,
+        "board_outline_line_width": 0.05,
+        "copper_line_width": 0.2,
+        "copper_text_italic": false,
+        "copper_text_size_h": 1.5,
+        "copper_text_size_v": 1.5,
+        "copper_text_thickness": 0.3,
+        "copper_text_upright": false,
+        "courtyard_line_width": 0.05,
+        "dimension_precision": 4,
+        "dimension_units": 3,
+        "dimensions": {
+          "arrow_length": 1270000,
+          "extension_offset": 500000,
+          "keep_text_aligned": true,
+          "suppress_zeroes": true,
+          "text_position": 0,
+          "units_format": 0
+        },
+        "fab_line_width": 0.1,
+        "fab_text_italic": false,
+        "fab_text_size_h": 1.0,
+        "fab_text_size_v": 1.0,
+        "fab_text_thickness": 0.15,
+        "fab_text_upright": false,
+        "other_line_width": 0.1,
+        "other_text_italic": false,
+        "other_text_size_h": 1.0,
+        "other_text_size_v": 1.0,
+        "other_text_thickness": 0.15,
+        "other_text_upright": false,
+        "pads": {
+          "drill": 0.8,
+          "height": 1.27,
+          "width": 1.27
+        },
+        "silk_line_width": 0.1,
+        "silk_text_italic": false,
+        "silk_text_size_h": 1.0,
+        "silk_text_size_v": 1.0,
+        "silk_text_thickness": 0.1,
+        "silk_text_upright": false,
+        "zones": {
+          "border_display_style": 2,
+          "border_hatch_pitch": 0.5,
+          "corner_radius": 0.0,
+          "corner_smoothing": 0,
+          "fill_mode": 0,
+          "hatch_gap": 1.5,
+          "hatch_orientation": 0.0,
+          "hatch_smoothing_level": 0,
+          "hatch_smoothing_value": 0.1,
+          "hatch_thickness": 1.0,
+          "min_clearance": 0.5,
+          "min_island_area": 10.0,
+          "min_thickness": 0.25,
+          "pad_connection": 1,
+          "remove_islands": 0,
+          "thermal_relief_gap": 0.5,
+          "thermal_relief_spoke_width": 0.5
+        }
+      },
+      "diff_pair_dimensions": [],
+      "drc_exclusions": [],
+      "meta": {
+        "version": 2
+      },
+      "rule_severities": {
+        "annular_width": "error",
+        "clearance": "error",
+        "connection_width": "warning",
+        "copper_edge_clearance": "error",
+        "copper_sliver": "warning",
+        "courtyards_overlap": "error",
+        "creepage": "error",
+        "diff_pair_gap_out_of_range": "error",
+        "diff_pair_uncoupled_length_too_long": "error",
+        "drill_out_of_range": "error",
+        "duplicate_footprints": "warning",
+        "extra_footprint": "warning",
+        "footprint": "error",
+        "footprint_filters_mismatch": "ignore",
+        "footprint_symbol_field_mismatch": "warning",
+        "footprint_symbol_mismatch": "warning",
+        "footprint_type_mismatch": "ignore",
+        "hole_clearance": "error",
+        "hole_to_hole": "warning",
+        "holes_co_located": "warning",
+        "invalid_outline": "error",
+        "isolated_copper": "warning",
+        "item_on_disabled_layer": "error",
+        "items_not_allowed": "error",
+        "length_out_of_range": "error",
+        "lib_footprint_issues": "warning",
+        "lib_footprint_mismatch": "warning",
+        "malformed_courtyard": "error",
+        "microvia_drill_out_of_range": "error",
+        "mirrored_text_on_front_layer": "warning",
+        "missing_courtyard": "ignore",
+        "missing_footprint": "warning",
+        "missing_tuning_profile": "warning",
+        "net_conflict": "warning",
+        "nonmirrored_text_on_back_layer": "warning",
+        "npth_inside_courtyard": "error",
+        "padstack": "warning",
+        "pth_inside_courtyard": "error",
+        "shorting_items": "error",
+        "silk_edge_clearance": "warning",
+        "silk_over_copper": "warning",
+        "silk_overlap": "warning",
+        "skew_out_of_range": "error",
+        "solder_mask_bridge": "error",
+        "starved_thermal": "error",
+        "text_height": "warning",
+        "text_on_edge_cuts": "error",
+        "text_thickness": "warning",
+        "through_hole_pad_without_hole": "error",
+        "too_many_vias": "error",
+        "track_angle": "error",
+        "track_dangling": "warning",
+        "track_not_centered_on_via": "ignore",
+        "track_on_post_machined_layer": "error",
+        "track_segment_length": "error",
+        "track_width": "error",
+        "tracks_crossing": "error",
+        "tuning_profile_track_geometries": "ignore",
+        "unconnected_items": "error",
+        "unresolved_variable": "error",
+        "via_dangling": "warning",
+        "zones_intersect": "error"
+      },
+      "rules": {
+        "max_error": 0.005,
+        "min_clearance": 0.25,
+        "min_connection": 0.0,
+        "min_copper_edge_clearance": 0.5,
+        "min_groove_width": 0.0,
+        "min_hole_clearance": 0.25,
+        "min_hole_to_hole": 0.25,
+        "min_microvia_diameter": 0.2,
+        "min_microvia_drill": 0.1,
+        "min_resolved_spokes": 2,
+        "min_silk_clearance": 0.0,
+        "min_text_height": 0.8,
+        "min_text_thickness": 0.08,
+        "min_through_hole_diameter": 0.3,
+        "min_track_width": 0.25,
+        "min_via_annular_width": 0.1,
+        "min_via_diameter": 0.7,
+        "solder_mask_to_copper_clearance": 0.0,
+        "use_height_for_length_calcs": true
+      },
+      "teardrop_options": [
+        {
+          "td_onpthpad": true,
+          "td_onroundshapesonly": false,
+          "td_onsmdpad": true,
+          "td_ontrackend": false,
+          "td_onvia": true
+        }
+      ],
+      "teardrop_parameters": [
+        {
+          "td_allow_use_two_tracks": true,
+          "td_curve_segcount": 0,
+          "td_height_ratio": 1.0,
+          "td_length_ratio": 0.5,
+          "td_maxheight": 2.0,
+          "td_maxlen": 1.0,
+          "td_on_pad_in_zone": false,
+          "td_target_name": "td_round_shape",
+          "td_width_to_size_filter_ratio": 0.9
+        },
+        {
+          "td_allow_use_two_tracks": true,
+          "td_curve_segcount": 0,
+          "td_height_ratio": 1.0,
+          "td_length_ratio": 0.5,
+          "td_maxheight": 2.0,
+          "td_maxlen": 1.0,
+          "td_on_pad_in_zone": false,
+          "td_target_name": "td_rect_shape",
+          "td_width_to_size_filter_ratio": 0.9
+        },
+        {
+          "td_allow_use_two_tracks": true,
+          "td_curve_segcount": 0,
+          "td_height_ratio": 1.0,
+          "td_length_ratio": 0.5,
+          "td_maxheight": 2.0,
+          "td_maxlen": 1.0,
+          "td_on_pad_in_zone": false,
+          "td_target_name": "td_track_end",
+          "td_width_to_size_filter_ratio": 0.9
+        }
+      ],
+      "track_widths": [],
+      "tuning_pattern_settings": {
+        "diff_pair_defaults": {
+          "corner_radius_percentage": 80,
+          "corner_style": 1,
+          "max_amplitude": 1.0,
+          "min_amplitude": 0.2,
+          "single_sided": false,
+          "spacing": 1.0
+        },
+        "diff_pair_skew_defaults": {
+          "corner_radius_percentage": 80,
+          "corner_style": 1,
+          "max_amplitude": 1.0,
+          "min_amplitude": 0.2,
+          "single_sided": false,
+          "spacing": 0.6
+        },
+        "single_track_defaults": {
+          "corner_radius_percentage": 80,
+          "corner_style": 1,
+          "max_amplitude": 1.0,
+          "min_amplitude": 0.2,
+          "single_sided": false,
+          "spacing": 0.6
+        }
+      },
+      "via_dimensions": [],
+      "zones_allow_external_fillets": false
+    },
+    "ipc2581": {
+      "bom_rev": "",
+      "dist": "",
+      "distpn": "",
+      "internal_id": "",
+      "mfg": "",
+      "mpn": "",
+      "sch_revision": ""
+    },
+    "layer_pairs": [],
+    "layer_presets": [],
+    "viewports": []
+  },
+  "boards": [],
+  "component_class_settings": {
+    "assignments": [],
+    "meta": {
+      "version": 0
+    },
+    "sheet_component_classes": {
+      "enabled": false
+    }
+  },
+  "cvpcb": {
+    "equivalence_files": []
+  },
+  "erc": {
+    "erc_exclusions": [],
+    "meta": {
+      "version": 0
+    },
+    "pin_map": [
+      [
+        0,
+        0,
+        0,
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+      ]
+    ],
+    "rule_severities": {
+      "bus_definition_conflict": "error",
+      "bus_entry_needed": "error",
+      "bus_to_bus_conflict": "error",
+      "bus_to_net_conflict": "error",
+      "different_unit_footprint": "error",
+      "different_unit_net": "error",
+      "duplicate_reference": "error",
+      "duplicate_sheet_names": "error",
+      "endpoint_off_grid": "warning",
+      "extra_units": "error",
+      "field_name_whitespace": "warning",
+      "footprint_filter": "ignore",
+      "footprint_link_issues": "warning",
+      "four_way_junction": "ignore",
+      "ground_pin_not_ground": "warning",
+      "hier_label_mismatch": "error",
+      "isolated_pin_label": "warning",
+      "label_dangling": "error",
+      "label_multiple_wires": "warning",
+      "lib_symbol_issues": "warning",
+      "lib_symbol_mismatch": "warning",
+      "missing_bidi_pin": "warning",
+      "missing_input_pin": "warning",
+      "missing_power_pin": "error",
+      "missing_unit": "warning",
+      "multiple_net_names": "warning",
+      "net_not_bus_member": "warning",
+      "no_connect_connected": "warning",
+      "no_connect_dangling": "warning",
+      "pin_not_connected": "error",
+      "pin_not_driven": "error",
+      "pin_to_pin": "warning",
+      "power_pin_not_driven": "error",
+      "same_local_global_label": "warning",
+      "similar_label_and_power": "warning",
+      "similar_labels": "warning",
+      "similar_power": "warning",
+      "simulation_model_issue": "ignore",
+      "single_global_label": "ignore",
+      "stacked_pin_name": "warning",
+      "unannotated": "error",
+      "unconnected_wire_endpoint": "warning",
+      "undefined_netclass": "error",
+      "unit_value_mismatch": "error",
+      "unresolved_variable": "error",
+      "wire_dangling": "error"
+    }
+  },
+  "libraries": {
+    "pinned_footprint_libs": [],
+    "pinned_symbol_libs": []
+  },
+  "meta": {
+    "filename": "serial-carrier.kicad_pro",
+    "version": 3
+  },
+  "net_settings": {
+    "classes": [
+      {
+        "bus_width": 12,
+        "clearance": 0.25,
+        "diff_pair_gap": 0.25,
+        "diff_pair_via_gap": 0.25,
+        "diff_pair_width": 0.2,
+        "line_style": 0,
+        "microvia_diameter": 0.3,
+        "microvia_drill": 0.1,
+        "name": "Default",
+        "pcb_color": "rgba(0, 0, 0, 0.000)",
+        "priority": 2147483647,
+        "schematic_color": "rgba(0, 0, 0, 0.000)",
+        "track_width": 0.25,
+        "tuning_profile": "",
+        "via_diameter": 0.7,
+        "via_drill": 0.3,
+        "wire_width": 6
+      },
+      {
+        "bus_width": 12,
+        "clearance": 0.25,
+        "diff_pair_gap": 0.25,
+        "diff_pair_via_gap": 0.25,
+        "diff_pair_width": 0.25,
+        "line_style": 0,
+        "microvia_diameter": 0.3,
+        "microvia_drill": 0.1,
+        "name": "Power",
+        "pcb_color": "rgba(0, 0, 0, 0.000)",
+        "priority": 0,
+        "schematic_color": "rgba(0, 0, 0, 0.000)",
+        "track_width": 0.5,
+        "tuning_profile": "",
+        "via_diameter": 0.7,
+        "via_drill": 0.3,
+        "wire_width": 6
+      }
+    ],
+    "meta": {
+      "version": 5
+    },
+    "net_colors": null,
+    "netclass_assignments": null,
+    "netclass_patterns": [
+      {
+        "netclass": "Power",
+        "pattern": "/+3V3"
+      },
+      {
+        "netclass": "Power",
+        "pattern": "/GND"
+      }
+    ]
+  },
+  "pcbnew": {
+    "last_paths": {
+      "idf": "",
+      "netlist": "",
+      "plot": "",
+      "specctra_dsn": "",
+      "step": "",
+      "vrml": ""
+    },
+    "page_layout_descr_file": ""
+  },
+  "schematic": {
+    "annotate_start_num": 0,
+    "annotation": {
+      "method": 0,
+      "sort_order": 0
+    },
+    "bom_export_filename": "${PROJECTNAME}.csv",
+    "bom_fmt_presets": [],
+    "bom_fmt_settings": {
+      "field_delimiter": ",",
+      "keep_line_breaks": false,
+      "keep_tabs": false,
+      "name": "CSV",
+      "ref_delimiter": ",",
+      "ref_range_delimiter": "",
+      "string_delimiter": "\""
+    },
+    "bom_presets": [],
+    "bom_settings": {
+      "exclude_dnp": false,
+      "fields_ordered": [
+        {
+          "group_by": false,
+          "label": "Reference",
+          "name": "Reference",
+          "show": true
+        },
+        {
+          "group_by": false,
+          "label": "Qty",
+          "name": "${QUANTITY}",
+          "show": true
+        },
+        {
+          "group_by": true,
+          "label": "Value",
+          "name": "Value",
+          "show": true
+        },
+        {
+          "group_by": true,
+          "label": "DNP",
+          "name": "${DNP}",
+          "show": true
+        },
+        {
+          "group_by": true,
+          "label": "Exclude from BOM",
+          "name": "${EXCLUDE_FROM_BOM}",
+          "show": true
+        },
+        {
+          "group_by": true,
+          "label": "Exclude from Board",
+          "name": "${EXCLUDE_FROM_BOARD}",
+          "show": true
+        },
+        {
+          "group_by": true,
+          "label": "Exclude from Simulation",
+          "name": "${EXCLUDE_FROM_SIM}",
+          "show": true
+        },
+        {
+          "group_by": true,
+          "label": "Exclude from Position Files",
+          "name": "${EXCLUDE_FROM_POS_FILES}",
+          "show": true
+        },
+        {
+          "group_by": true,
+          "label": "Footprint",
+          "name": "Footprint",
+          "show": true
+        },
+        {
+          "group_by": false,
+          "label": "Datasheet",
+          "name": "Datasheet",
+          "show": true
+        }
+      ],
+      "filter_string": "",
+      "group_symbols": true,
+      "include_excluded_from_bom": true,
+      "name": "Default Editing",
+      "sort_asc": true,
+      "sort_field": "Referenz"
+    },
+    "bus_aliases": {},
+    "connection_grid_size": 50.0,
+    "drawing": {
+      "dashed_lines_dash_length_ratio": 12.0,
+      "dashed_lines_gap_length_ratio": 3.0,
+      "default_line_thickness": 6.0,
+      "default_text_size": 50.0,
+      "field_names": [],
+      "hop_over_size_choice": 0,
+      "intersheets_ref_own_page": false,
+      "intersheets_ref_prefix": "",
+      "intersheets_ref_short": false,
+      "intersheets_ref_show": false,
+      "intersheets_ref_suffix": "",
+      "junction_size_choice": 3,
+      "label_size_ratio": 0.375,
+      "operating_point_overlay_i_precision": 3,
+      "operating_point_overlay_i_range": "~A",
+      "operating_point_overlay_v_precision": 3,
+      "operating_point_overlay_v_range": "~V",
+      "overbar_offset_ratio": 1.23,
+      "pin_symbol_size": 25.0,
+      "text_offset_ratio": 0.15
+    },
+    "legacy_lib_dir": "",
+    "legacy_lib_list": [],
+    "meta": {
+      "version": 1
+    },
+    "page_layout_descr_file": "",
+    "plot_directory": "",
+    "reuse_designators": true,
+    "subpart_first_id": 65,
+    "subpart_id_separator": 0,
+    "top_level_sheets": [
+      {
+        "filename": "serial-carrier.kicad_sch",
+        "name": "serial-carrier",
+        "uuid": "00000000-0000-0000-0000-000000000000"
+      }
+    ],
+    "used_designators": "",
+    "variants": []
+  },
+  "sheets": [],
+  "text_variables": {},
+  "tuning_profiles": {
+    "meta": {
+      "version": 0
+    },
+    "tuning_profiles_impedance_geometric": []
+  }
+}

hardware/PCB/serial-carrier.kicad_sch

@@ -0,0 +1,400 @@
+(kicad_sch (version 20250114) (generator "eeschema") (uuid "c86e0d56-4290-5f2b-b790-14926c8cdeea") (paper "A3")
+(title_block (title "ESP32 Serial Swiss Army Knife - Module Carrier") (date "2026-09-20") (rev "A0 DRAFT") (comment 1 "Not fabrication-ready: provisional module footprints and male RS-232 mapping"))
+(lib_symbols (symbol "Carrier:HW678_N16R8" (pin_names (offset 0.762)) (in_bom yes) (on_board yes)
+(property "Reference" "U" (at 0 34.29 0) (effects (font (size 1.27 1.27)) ))
+(property "Value" "HW678_N16R8" (at 0 31.75 0) (effects (font (size 1.27 1.27)) ))
+(property "Footprint" "Carrier:HW678_2x22_Provisional" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Datasheet" "" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Description" "HW-678 V0.0.0 / N16R8 carrier interface; project numbering; onboard USB/regulator retained" (at 0 0 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(symbol "HW678_N16R8_0_1" (rectangle (start -17.78 29.21) (end 17.78 -29.21) (stroke (width 0.254) (type default)) (fill (type background))))
+(symbol "HW678_N16R8_1_1"
+(pin power_out line (at -22.86 26.67 0) (length 5.08) (name "3V3" (effects (font (size 1.016 1.016)) )) (number "1" (effects (font (size 1.016 1.016)) )))
+(pin passive line (at -22.86 24.13 0) (length 5.08) (name "3V3" (effects (font (size 1.016 1.016)) )) (number "2" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 21.59 0) (length 5.08) (name "EN" (effects (font (size 1.016 1.016)) )) (number "3" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 19.05 0) (length 5.08) (name "GPIO4" (effects (font (size 1.016 1.016)) )) (number "4" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 16.51 0) (length 5.08) (name "GPIO5" (effects (font (size 1.016 1.016)) )) (number "5" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 13.97 0) (length 5.08) (name "GPIO6" (effects (font (size 1.016 1.016)) )) (number "6" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -22.86 11.43 0) (length 5.08) (name "GPIO7" (effects (font (size 1.016 1.016)) )) (number "7" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -22.86 8.89 0) (length 5.08) (name "GPIO15" (effects (font (size 1.016 1.016)) )) (number "8" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 6.35 0) (length 5.08) (name "GPIO16" (effects (font (size 1.016 1.016)) )) (number "9" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -22.86 3.81 0) (length 5.08) (name "GPIO17" (effects (font (size 1.016 1.016)) )) (number "10" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 1.27 0) (length 5.08) (name "GPIO18" (effects (font (size 1.016 1.016)) )) (number "11" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 -1.27 0) (length 5.08) (name "GPIO8" (effects (font (size 1.016 1.016)) )) (number "12" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at -22.86 -3.81 0) (length 5.08) (name "GPIO3" (effects (font (size 1.016 1.016)) )) (number "13" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at -22.86 -6.35 0) (length 5.08) (name "GPIO46" (effects (font (size 1.016 1.016)) )) (number "14" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at -22.86 -8.89 0) (length 5.08) (name "GPIO9" (effects (font (size 1.016 1.016)) )) (number "15" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 -11.43 0) (length 5.08) (name "GPIO10" (effects (font (size 1.016 1.016)) )) (number "16" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at -22.86 -13.97 0) (length 5.08) (name "GPIO11" (effects (font (size 1.016 1.016)) )) (number "17" (effects (font (size 1.016 1.016)) )))
+(pin output line (at -22.86 -16.51 0) (length 5.08) (name "GPIO12" (effects (font (size 1.016 1.016)) )) (number "18" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 -19.05 0) (length 5.08) (name "GPIO13" (effects (font (size 1.016 1.016)) )) (number "19" (effects (font (size 1.016 1.016)) )))
+(pin input line (at -22.86 -21.59 0) (length 5.08) (name "GPIO14" (effects (font (size 1.016 1.016)) )) (number "20" (effects (font (size 1.016 1.016)) )))
+(pin passive line (at -22.86 -24.13 0) (length 5.08) (name "5V" (effects (font (size 1.016 1.016)) )) (number "21" (effects (font (size 1.016 1.016)) )))
+(pin power_out line (at -22.86 -26.67 0) (length 5.08) (name "GND" (effects (font (size 1.016 1.016)) )) (number "22" (effects (font (size 1.016 1.016)) )))
+(pin passive line (at 22.86 26.67 180) (length 5.08) (name "GND" (effects (font (size 1.016 1.016)) )) (number "23" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 24.13 180) (length 5.08) (name "GPIO43" (effects (font (size 1.016 1.016)) )) (number "24" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 21.59 180) (length 5.08) (name "GPIO44" (effects (font (size 1.016 1.016)) )) (number "25" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 19.05 180) (length 5.08) (name "GPIO1" (effects (font (size 1.016 1.016)) )) (number "26" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 16.51 180) (length 5.08) (name "GPIO2" (effects (font (size 1.016 1.016)) )) (number "27" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 13.97 180) (length 5.08) (name "GPIO42" (effects (font (size 1.016 1.016)) )) (number "28" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 11.43 180) (length 5.08) (name "GPIO41" (effects (font (size 1.016 1.016)) )) (number "29" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 8.89 180) (length 5.08) (name "GPIO40" (effects (font (size 1.016 1.016)) )) (number "30" (effects (font (size 1.016 1.016)) )))
+(pin bidirectional line (at 22.86 6.35 180) (length 5.08) (name "GPIO39" (effects (font (size 1.016 1.016)) )) (number "31" (effects (font (size 1.016 1.016)) )))
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+(wire (pts (xy 332.74 160.02) (xy 345.44 160.02)) (stroke (width 0) (type default)) (uuid "7a2af359-d23d-5777-9193-ff203ac538d8"))
+(label "BTN_NEXT" (at 345.44 160.02 0) (effects (font (size 1.016 1.016)) (justify left bottom)) (uuid "5011a121-e49f-5298-8cc1-2998dfa40f7d"))
+(symbol (lib_id "Carrier:SW_NO") (at 327.66 175.26 0) (unit 1) (in_bom yes) (on_board yes) (dnp no) (uuid "35caa6bb-42a6-512c-848c-f1e4457aa97f")
+(property "Reference" "SW3" (at 327.66 167.64 0) (effects (font (size 1.27 1.27)) ))
+(property "Value" "B3F-1000" (at 327.66 170.18 0) (effects (font (size 1.27 1.27)) ))
+(property "Footprint" "Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x" (at 327.66 175.26 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Datasheet" "" (at 327.66 175.26 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Manufacturer" "Omron" (at 327.66 175.26 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "MPN" "B3F-1000" (at 327.66 175.26 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Function" "Next" (at 327.66 175.26 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(property "Procurement" "Live stock not verified" (at 327.66 175.26 0) (effects (font (size 1.27 1.27)) (hide yes)))
+(pin "1" (uuid "85beb3b7-e16f-5450-ba94-5711245a7b25"))
+(pin "2" (uuid "300c4196-eb91-5e58-a9aa-c84b8f7c4219"))
+(instances (project "serial-carrier" (path "/c86e0d56-4290-5f2b-b790-14926c8cdeea" (reference "SW3") (unit 1)))))
+(wire (pts (xy 322.58 175.26) (xy 309.88 175.26)) (stroke (width 0) (type default)) (uuid "899495f9-e27d-5c7f-9961-bda42dd5b5b5"))
+(label "BTN_NEXT" (at 309.88 175.26 0) (effects (font (size 1.016 1.016)) (justify left bottom)) (uuid "4917cd5a-7d37-54f4-8139-7ae4739c44c4"))
+(wire (pts (xy 332.74 175.26) (xy 345.44 175.26)) (stroke (width 0) (type default)) (uuid "f48c99dc-9974-5205-8a87-3b1278a4fdfd"))
+(label "GND" (at 345.44 175.26 0) (effects (font (size 1.016 1.016)) (justify left bottom)) (uuid "3c7713ca-d8f2-53fd-8e98-6fd376e4570c"))
+(text "Next" (at 302.26 181.61 0) (effects (font (size 1.016 1.016)) (justify left top)) (uuid "0db41e9e-455f-5007-82ee-b485aacda4c4"))
+(text "MODULE CARRIER - INITIAL SCHEMATIC" (at 15.24 15.24 0) (effects (font (size 2.54 2.54)) (justify left top)) (uuid "81374533-4a9c-521b-8834-9fa30bb907b5"))
+(text "Native KiCad 10 schematic. Named wire labels join matching nets on this sheet.\nRead hardware/PCB/README.md before layout or fabrication." (at 15.24 24.13 0) (effects (font (size 1.27 1.27)) (justify left top)) (uuid "d9d89d85-2a9c-5e76-bd60-48c81ac7f524"))
+(text "U1: complete development board" (at 53.34 57.15 0) (effects (font (size 1.778 1.778)) (justify left top)) (uuid "320a8f4e-ff8b-5100-845b-dfe249b39a2e"))
+(text "Antenna up / USB down: left row 1-22, right row 23-44.\nNC marks mean unused on carrier, not unused inside module." (at 53.34 64.77 0) (effects (font (size 1.016 1.016)) (justify left top)) (uuid "649df1fa-48c0-580d-aeb8-d019ffd0b61d"))
+(text "U2: complete RS-232 breakout" (at 177.8 57.15 0) (effects (font (size 1.778 1.778)) (justify left top)) (uuid "5226007c-1904-547d-8ddb-008d14b83d51"))
+(text "Male 6253 selected. Numbers from published 5988 female CAD.\nVERIFY male header before routing; no footprint assigned.\nDE-9 and charge pump are already on the module." (at 177.8 64.77 0) (effects (font (size 1.016 1.016)) (justify left top)) (uuid "9b62e7ca-695a-51af-bbbe-e7ee4ee45c08"))
+(text "Controls: active-low, firmware-debounced" (at 292.1 57.15 0) (effects (font (size 1.778 1.778)) (justify left top)) (uuid "9d91985c-7375-5177-9a5e-8280e3bcaff6"))
+(text "External 2.2k pull-ups: ~1.5 mA pressed at 3.3 V.\nChosen for B3F-1000 rated contact load; internal\npull-ups may remain enabled. Exact resistor MPN pending." (at 292.1 64.77 0) (effects (font (size 1.016 1.016)) (justify left top)) (uuid "b2dd72f5-86fc-5ce1-b09a-67a6fe9404d4"))
+(text "DS1: front view GND / VCC / SCL / SDA" (at 177.8 128.27 0) (effects (font (size 1.524 1.524)) (justify left top)) (uuid "7b57748d-38ca-5712-97f9-bf6dab6dafaf"))
+(text "Power at 3.3 V only. Verify on-module I2C pull-ups;\nexternal values intentionally not guessed." (at 177.8 165.1 0) (effects (font (size 1.016 1.016)) (justify left top)) (uuid "fb23ec11-40f8-56c7-b78b-0da2d40e4b72"))
+(text "POWER / RECOVERY\nPower only through U1's existing USB ports. No carrier 5 V input.\nU1 regulator supplies +3V3; GND pins are common on the module.\nPin 1 +3V3 and pin 22 GND model the onboard supply for ERC.\nGPIO19/20 native USB and GPIO43/44 UART0 remain onboard.\nVerify USB power isolation before attaching two powered hosts.\nKeep both USB connectors and reset/boot buttons accessible." (at 15.24 185.42 0) (effects (font (size 1.27 1.27)) (justify left top)) (uuid "cadf6b77-e888-5f04-b4f6-3873114844ca"))
+(text "RS-232 / ELECTRICAL LIMITS\nTX/RX and modem labels are at the ESP32 logic side.\nOFF_N is active low; GPIO9 must remain open-drain.\nBreakout provides its OFF pull-up. No galvanic isolation.\nNo carrier connection to raw RS-232 voltages.\nCarrier GND, USB GND and RS-232 signal ground are common.\nNever power OLED or MAX3243 logic from 5 V." (at 152.4 185.42 0) (effects (font (size 1.27 1.27)) (justify left top)) (uuid "0f7da388-3edb-5cc3-9937-13492397a221"))
+(text "BEFORE PCB RELEASE\nVerify male breakout pin order/footprint.\nConfirm header/socket finished-hole requirements.\nComplete module courtyards and antenna clearance.\nVerify 3.3 V budget, OLED pull-ups and USB power path.\nChoose mounting hardware and confirm button stock.\nERC is not hardware or fabrication approval." (at 292.1 185.42 0) (effects (font (size 1.27 1.27)) (justify left top)) (uuid "1df2bd9e-fbff-5047-92a9-09f33d7cd7ac"))
+)

hardware/PCB/sym-lib-table

@@ -0,0 +1,3 @@
+(sym_lib_table (version 7)
+ (lib (name "Carrier")(type "KiCad")(uri "${KIPRJMOD}/Carrier.kicad_sym")(options "")(descr "Project-local module interfaces"))
+)

hardware/PCB/validate_footprints.py

@@ -0,0 +1,129 @@
+#!/usr/bin/env python3
+"""Read-only regression checks for the two provisional module footprints.
+
+Run with the system Python that provides KiCad's installed pcbnew binding:
+    /usr/bin/python3 -B hardware/PCB/validate_footprints.py
+
+Paths resolve relative to this script, independent of the working directory.
+No board, reports, or footprint files are written. Passing checks do not establish
+physical connector fit, electrical correctness, DRC, or fabrication readiness.
+"""
+
+from collections import Counter
+from pathlib import Path
+import sys
+import unittest
+
+try:
+    import pcbnew as k
+except ImportError as exc:
+    raise SystemExit(
+        "KiCad pcbnew binding unavailable. Use the system Python associated with "
+        "your KiCad installation (on this machine: /usr/bin/python3)."
+    ) from exc
+
+
+LIBRARY = Path(__file__).resolve().parent / "Carrier.pretty"
+
+
+def xy(vector):
+    """Keep native integer coordinates so comparisons do not hide deviations."""
+    return vector.x, vector.y
+
+
+def mm(x, y):
+    return k.FromMM(x), k.FromMM(y)
+
+
+class FootprintRegression(unittest.TestCase):
+    def load(self, name):
+        self.assertTrue((LIBRARY / (name + ".kicad_mod")).is_file(), name)
+        footprint = k.FootprintLoad(str(LIBRARY), name)
+        self.assertIsNotNone(footprint, f"KiCad could not parse {name}")
+        self.assertEqual(footprint.GetValue(), name)
+        self.assertEqual(footprint.GetLayer(), k.F_Cu)
+        self.assertIn("PROVISIONAL connector fit", footprint.GetLibDescription())
+        self.assertEqual(len(list(footprint.Zones())), 0, "Unexpected zone/keepout")
+        self.assertEqual(len(list(footprint.Models())), 0, "Unexpected 3D envelope")
+        graphics = list(footprint.GraphicalItems())
+        for item in graphics:
+            self.assertNotIn(item.GetLayer(), (k.F_CrtYd, k.B_CrtYd, k.Edge_Cuts))
+            self.assertIsInstance(item, (k.PCB_TEXT, k.PCB_SHAPE),
+                                  "Unexpected graphic/envelope type")
+        self.assertTrue(any(isinstance(item, k.PCB_TEXT)
+                            and item.GetText() == "PROVISIONAL CONNECTOR FIT"
+                            for item in graphics), "Missing visible provisional label")
+        return footprint
+
+    def check_header(self, footprint, positions, hole_count=0):
+        pads = list(footprint.Pads())
+        self.assertEqual(len(pads), len(positions) + hole_count)
+        numbered = [pad for pad in pads if pad.GetNumber()]
+        # Compare multiplicities so duplicate numbers cannot hide missing pads.
+        self.assertEqual(Counter(p.GetNumber() for p in numbered),
+                         Counter({str(n): 1 for n in positions}))
+        for pad in numbered:
+            number = int(pad.GetNumber())
+            with self.subTest(pad=number):
+                self.assertEqual(xy(pad.GetPosition()), mm(*positions[number]))
+                self.assertEqual(xy(pad.GetSize()), mm(1.7, 1.7))
+                self.assertEqual(xy(pad.GetDrillSize()), mm(1, 1))
+                self.assertEqual(pad.GetDrillShape(), k.PAD_DRILL_SHAPE_CIRCLE)
+                self.assertEqual(pad.GetAttribute(), k.PAD_ATTRIB_PTH)
+                self.assertEqual(pad.GetShape(),
+                                 k.PAD_SHAPE_RECT if number == 1 else k.PAD_SHAPE_CIRCLE)
+                self.assertEqual(pad.GetNetCode(), 0, "Unexpected assigned net")
+                for layer in (k.F_Cu, k.B_Cu, k.F_Mask, k.B_Mask):
+                    self.assertTrue(pad.IsOnLayer(layer), "Missing copper/mask layer")
+                for layer in (k.F_Paste, k.B_Paste):
+                    self.assertFalse(pad.IsOnLayer(layer), "Unexpected paste layer")
+        return [pad for pad in pads if not pad.GetNumber()]
+
+    def test_oled(self):
+        footprint = self.load("OLED_26mm_I2C_Provisional")
+        positions = {n: (x, 1.5) for n, x in
+                     enumerate((9.19, 11.73, 14.27, 16.81), 1)}
+        holes = self.check_header(footprint, positions, hole_count=4)
+        self.assertEqual(Counter(xy(p.GetPosition()) for p in holes),
+                         Counter(mm(x, y) for x, y in (
+                             (1.75, 1.75), (24.25, 1.75),
+                             (1.75, 24.25), (24.25, 24.25))))
+        for pad in holes:
+            with self.subTest(hole=xy(pad.GetPosition())):
+                self.assertEqual(pad.GetAttribute(), k.PAD_ATTRIB_NPTH)
+                self.assertEqual(pad.GetShape(), k.PAD_SHAPE_CIRCLE)
+                self.assertEqual(pad.GetDrillShape(), k.PAD_DRILL_SHAPE_CIRCLE)
+                self.assertEqual(xy(pad.GetSize()), mm(2, 2))
+                self.assertEqual(xy(pad.GetDrillSize()), mm(2, 2))
+                self.assertEqual(pad.GetNetCode(), 0)
+        shapes = [g for g in footprint.GraphicalItems() if isinstance(g, k.PCB_SHAPE)]
+        self.assertEqual(len(shapes), 2, "Only board/display rectangles are verified")
+        self.assertEqual(Counter((xy(g.GetStart()), xy(g.GetEnd())) for g in shapes),
+                         Counter([(mm(0, 0), mm(26, 26)),
+                                  (mm(1, 4.5), mm(25.5, 21))]))
+        for shape in shapes:
+            self.assertEqual(shape.GetShape(), k.SHAPE_T_RECT)
+            self.assertEqual(shape.GetLayer(), k.F_Fab)
+            self.assertEqual(shape.GetWidth(), k.FromMM(0.1))
+            self.assertFalse(shape.IsAnyFill())
+        # Stroke styles are not checked: this binding returns opaque LINE_STYLE
+        # pointers, so comparing GetLineStyle() results would compare identities,
+        # not the solid/dash values, and also emits SWIG leak warnings.
+
+    def test_hw678(self):
+        footprint = self.load("HW678_2x22_Provisional")
+        positions = {
+            row * 22 + index + 1: (x, round(index * 2.54, 2))
+            for row, x in enumerate((0, 25.4)) for index in range(22)
+        }
+        self.check_header(footprint, positions)
+        self.assertFalse(any(isinstance(g, k.PCB_SHAPE)
+                             for g in footprint.GraphicalItems()),
+                         "HW678 must not acquire guessed outlines or envelopes")
+
+
+if __name__ == "__main__":
+    print(f"KiCad {k.GetBuildVersion()}; library: {LIBRARY}", flush=True)
+    suite = unittest.defaultTestLoader.loadTestsFromTestCase(FootprintRegression)
+    result = unittest.TextTestRunner(verbosity=2).run(suite)
+    sys.exit(0 if result.wasSuccessful() else 1)

hardware/PCB/validate_pcb_draft.py

@@ -0,0 +1,129 @@
+#!/usr/bin/env python3
+"""Read-only PCB checks and fresh KiCad reports; does not regenerate or save PCB.
+
+Requires KiCad's pcbnew binding in system Python. The known U2 footprint parity
+warning is reported explicitly, not hidden or added to KiCad's exclusions.
+"""
+import hashlib
+import json
+from pathlib import Path
+import subprocess
+import xml.etree.ElementTree as ET
+import pcbnew as p
+
+ROOT=Path(__file__).resolve().parent
+PCB=ROOT/"serial-carrier.kicad_pcb"
+OUT=ROOT/"validation"
+
+def run(*args):
+    subprocess.run(args,check=True,cwd=ROOT)
+
+run("kicad-cli","sch","export","netlist","--format","kicadxml","-o",str(OUT/"pcb-source-netlist.xml"),str(ROOT/"serial-carrier.kicad_sch"))
+run("kicad-cli","pcb","drc","--format","json","--all-track-errors","--severity-all","--schematic-parity","-o",str(OUT/"pcb-parity-drc.json"),str(PCB))
+board=p.LoadBoard(str(PCB))
+source=ET.parse(OUT/"pcb-source-netlist.xml").getroot()
+comps={c.get("ref"):c for c in source.findall("components/comp")}
+footprints={f.GetReference():f for f in board.GetFootprints()}
+assert set(footprints)==set(comps)|{"H1","H2","H3","H4"}
+assert board.GetCopperLayerCount()==2
+assert p.ToMM(board.GetDesignSettings().GetBoardThickness())==1.6
+outline=[d for d in board.GetDrawings() if d.GetLayer()==p.Edge_Cuts]
+assert len(outline)==6
+points={(round(p.ToMM(v.x)-100,5),round(p.ToMM(v.y)-100,5)) for d in outline for v in (d.GetStart(),d.GetEnd())}
+expected_outline=[(36,0),(82,0),(82,80),(0,80),(0,19),(36,19)]
+assert points==set(expected_outline)
+expected_edges={frozenset((a,b)) for a,b in zip(expected_outline,expected_outline[1:]+expected_outline[:1])}
+actual_edges={frozenset((round(p.ToMM(v.x)-100,5),round(p.ToMM(v.y)-100,5))
+                        for v in (d.GetStart(),d.GetEnd())) for d in outline}
+assert actual_edges==expected_edges
+placements={"U1":(8,23),"U2":(43,26.670),"DS1":(43,36),
+            "R1":(43,34),"R2":(54,34),"R3":(65,34),
+            "SW1":(43,68),"SW2":(55,68),"SW3":(67,68),
+            "H1":(3.5,22.5),"H2":(3.5,75),"H3":(78,4),"H4":(78,76)}
+for ref,(x,y) in placements.items():
+    position=footprints[ref].GetPosition()
+    assert position.x==p.FromMM(x+100) and position.y==p.FromMM(y+100),ref
+    assert footprints[ref].GetOrientationDegrees()==0,ref
+assert len(board.Zones())==1
+reserve=board.Zones()[0]
+assert reserve.GetIsRuleArea() and reserve.IsOnLayer(p.F_Cu) and reserve.IsOnLayer(p.B_Cu)
+assert reserve.GetDoNotAllowTracks() and reserve.GetDoNotAllowVias() and reserve.GetDoNotAllowZoneFills()
+contour=reserve.Outline().COutline(0)
+assert {(p.ToMM(contour.CPoint(i).x),p.ToMM(contour.CPoint(i).y)) for i in range(contour.PointCount())}=={(110,119),(131,119),(131,132),(110,132)}
+# Reference bare-PCB front is 26.670 mm above the U2 pad-row origin.
+u2_front=p.ToMM(footprints['U2'].GetPosition().y)-26.670
+assert abs(u2_front-100)<1e-6
+assert any(isinstance(g,p.PCB_SHAPE) and g.GetLayer()==p.F_Fab and
+           g.GetShape()==p.SHAPE_T_SEGMENT and
+           g.GetStart().y==p.FromMM(100) and g.GetEnd().y==p.FromMM(100)
+           for g in footprints['U2'].GraphicalItems()), 'U2 bare-PCB front not flush'
+assert max(x for x,y in points)-min(x for x,y in points)==82
+assert max(y for x,y in points)-min(y for x,y in points)==80
+padnets={}
+for net in source.findall("nets/net"):
+    for node in net.findall("node"):
+        padnets[(node.get("ref"),node.get("pin"))]=net.get("name")
+seen=set()
+for ref,comp in comps.items():
+    fp=footprints[ref]
+    assert fp.GetValue()==comp.findtext("value"),ref
+    assert fp.GetPath().AsString().endswith("/"+comp.findtext("tstamps")),ref
+    wanted=comp.findtext("footprint")
+    if ref=="U2":
+        assert not wanted
+        assert fp.GetFPIDAsString()=="Carrier:MAX3243_Reference_Provisional"
+    else:
+        assert fp.GetFPIDAsString()==wanted,ref
+    for pad in fp.Pads():
+        if not pad.GetNumber():
+            continue
+        key=ref,pad.GetNumber()
+        assert pad.GetNetname()==padnets[key],(key,pad.GetNetname(),padnets[key])
+        seen.add(key)
+assert seen==set(padnets),"Missing or extra electrical pads"
+for ref in ("H1","H2","H3","H4"):
+    assert footprints[ref].IsBoardOnly()
+    pads=list(footprints[ref].Pads())
+    assert len(pads)==1 and pads[0].GetDrillSize().x==p.FromMM(3.2)
+    assert pads[0].GetAttribute()==p.PAD_ATTRIB_NPTH
+tracks=list(board.GetTracks())
+assert tracks,"Draft unexpectedly unrouted"
+for track in tracks:
+    if isinstance(track,p.PCB_VIA):
+        assert track.GetDrillValue()==p.FromMM(0.3)
+        assert track.GetWidth(p.F_Cu)==p.FromMM(0.7)
+    else:
+        assert track.GetLayer() in (p.F_Cu,p.B_Cu)
+        expected=0.5 if track.GetNetname() in ("/+3V3","/GND") else 0.25
+        assert track.GetWidth()==p.FromMM(expected)
+report=json.loads((OUT/"pcb-parity-drc.json").read_text())
+assert not report["violations"],report["violations"]
+assert not report["unconnected_items"],report["unconnected_items"]
+parity=report["schematic_parity"]
+assert len(parity)==1 and parity[0]["type"]=="footprint_symbol_mismatch",parity
+assert len(parity[0]["items"])==1 and parity[0]["items"][0]["uuid"]==footprints["U2"].m_Uuid.AsString()
+summary={
+    "carrier_bounds_mm":[82,80],
+        "outline_local_mm":expected_outline,
+        "placements_local_mm":placements,
+        "rf_reserve_absolute_mm":[110,119,131,132],
+        "u2_bare_pcb_front_local_y_mm":round(u2_front-100,6),
+        "nominal_user_confirmed_rs232_metal_mm":{"shell_overhang":3.870,"hex_mouth_overhang":2.870,"flange_front_inset":1.930},
+        "tracks":sum(not isinstance(t,p.PCB_VIA) for t in tracks),
+        "vias":sum(isinstance(t,p.PCB_VIA) for t in tracks),
+    "copper_layers":2,
+    "draft_thickness_mm":1.6,
+    "electrical_footprints":len(comps),
+    "proposed_M3_mounts":4,
+    "physical_DRC_violations":0,
+    "unconnected_items":0,
+    "schematic_pad_nets_match":True,
+    "known_parity_warning":"U2 reference footprint assigned on PCB only; schematic footprint intentionally blank; nominal male external metal dimensions user-confirmed",
+        "project_settings_sha256":hashlib.sha256((ROOT/'serial-carrier.kicad_pro').read_bytes()).hexdigest(),
+    "ignored_DRC_checks":report["ignored_checks"],
+    "not_validated":["male module pin map/header fit", "ESP32 geometry and complete assembly envelope/heights", "header/socket fit", "RF performance and antenna clearance", "power/return-path integrity", "USB power path", "OLED pull-ups", "fabrication process", "hardware operation"],
+}
+(OUT/"pcb-validation-summary.json").write_text(json.dumps(summary,indent=2)+"\n")
+print("PCB draft verified: 82 x 80 mm; 2 copper layers; 0 physical DRC violations; 0 unrouted.")
+print("All schematic pad nets match. One expected U2 footprint parity warning remains visible.")
+print("Not fabrication-ready; see pcb-draft-notes.md and ignored checks in the DRC report.")

hardware/PCB/validate_schematic.py

@@ -0,0 +1,94 @@
+#!/usr/bin/env python3
+"""Export and validate the checked-in schematic; never regenerates the design."""
+import json
+from pathlib import Path
+import re
+import subprocess
+import xml.etree.ElementTree as ET
+
+ROOT = Path(__file__).resolve().parent
+OUT = ROOT / "validation"
+SCHEMATIC = ROOT / "serial-carrier.kicad_sch"
+
+def run(*args):
+    subprocess.run(args, check=True, cwd=ROOT)
+
+run("kicad-cli", "sch", "export", "netlist", "--format", "kicadxml", "-o", str(OUT / "serial-carrier.xml"), str(SCHEMATIC))
+run("kicad-cli", "sch", "erc", "--format", "json", "--exit-code-violations", "-o", str(OUT / "erc.json"), str(SCHEMATIC))
+root = ET.parse(OUT / "serial-carrier.xml").getroot()
+nets = {net.get("name").removeprefix("/"): net.findall("node") for net in root.findall("nets/net")}
+members = {name: sorted((node.get("ref"), node.get("pin")) for node in nodes) for name, nodes in nets.items()}
+components = {comp.get("ref"): comp for comp in root.findall("components/comp")}
+assert set(components) == {"U1", "U2", "DS1", "SW1", "SW2", "SW3", "R1", "R2", "R3"}
+
+# Independent firmware-to-module contract, not imported from the schematic generator.
+contracts = [
+    ("RS_TX", "RS232_TX_GPIO", "TX", "5"),
+    ("RS_RX", "RS232_RX_GPIO", "RX", "4"),
+    ("RS_RTS", "RS232_RTS_GPIO", "RTS", "8"),
+    ("RS_CTS", "RS232_CTS_GPIO", "CTS", "9"),
+    ("RS_DTR", "RS232_DTR_GPIO", "DTR", "6"),
+    ("RS_DSR", "RS232_DSR_GPIO", "DSR", "7"),
+    ("RS_DCD", "RS232_DCD_GPIO", "DCD", "3"),
+    ("RS_RI", "RS232_RI_GPIO", "RI", "10"),
+    ("RS_VALID", "RS232_VALID_GPIO", "VLD", "11"),
+    ("RS_OFF_N", "RS232_FORCE_OFF_N_GPIO", "OFF_N", "12"),
+    ("OLED_SDA", "LOCAL_UI_DISPLAY_SDA_GPIO", "SDA", "4"),
+    ("OLED_SCL", "LOCAL_UI_DISPLAY_SCL_GPIO", "SCL", "3"),
+    ("BTN_PREVIOUS", "LOCAL_UI_BUTTON_PREVIOUS_GPIO", None, None),
+    ("BTN_SELECT", "LOCAL_UI_BUTTON_SELECT_GPIO", None, None),
+    ("BTN_NEXT", "LOCAL_UI_BUTTON_NEXT_GPIO", None, None),
+]
+firmware = ROOT.parents[1].joinpath("src/board_pins.h").read_text()
+for net, macro, peripheral_name, peripheral_pin in contracts:
+    match = re.search(r"^#define\s+" + re.escape(macro) + r"\s+GPIO_NUM_(\d+)\s*$", firmware, re.MULTILINE)
+    assert match, macro
+    gpio = "GPIO" + match.group(1)
+    mcu = [node for node in nets[net] if node.get("ref") == "U1"]
+    assert len(mcu) == 1 and mcu[0].get("pinfunction") == gpio + "_" + mcu[0].get("pin"), (net, gpio)
+    if peripheral_name:
+        ref = "DS1" if net.startswith("OLED_") else "U2"
+        node = [node for node in nets[net] if node.get("ref") == ref]
+        assert len(node) == 1 and node[0].get("pin") == peripheral_pin
+        assert node[0].get("pinfunction") == peripheral_name + "_" + peripheral_pin
+        assert len(nets[net]) == 2, (net, members[net])
+
+for i, net in enumerate(("BTN_PREVIOUS", "BTN_SELECT", "BTN_NEXT"), 1):
+    assert len(nets[net]) == 3
+    assert (f"SW{i}", "1") in members[net] and (f"R{i}", "2") in members[net]
+    assert components[f"SW{i}"].findtext("value") == "B3F-1000"
+    assert components[f"R{i}"].findtext("value") == "2.2k 1%"
+assert members["+3V3"] == sorted([("U1","1"),("U1","2"),("U2","1"),("DS1","2"),("R1","1"),("R2","1"),("R3","1")])
+assert members["GND"] == sorted([("U1","22"),("U1","23"),("U1","43"),("U1","44"),("U2","2"),("DS1","1"),("SW1","2"),("SW2","2"),("SW3","2")])
+active = {name for name in nets if not name.startswith("unconnected-")}
+assert active == {"+3V3", "GND"} | {row[0] for row in contracts}
+for name, nodes in nets.items():
+    if name.startswith("unconnected-"):
+        assert len(nodes) == 1 and nodes[0].get("ref") == "U1"
+# All 44 MCU header pins must occur exactly once, including deliberate no-connects.
+assert sorted(int(node.get("pin")) for nodes in nets.values() for node in nodes if node.get("ref") == "U1") == list(range(1,45))
+# USB/UART0, 5 V and PSRAM-conflicting pins must never be carrier nets.
+for name in active:
+    assert not any(node.get("ref") == "U1" and node.get("pin") in ("21","24","25","33","34","35","41","42") for node in nets[name])
+# U2's physical male footprint must stay explicitly unresolved in this draft.
+assert not components["U2"].findtext("footprint")
+expected = json.loads((OUT / "expected-nets.json").read_text())
+assert set(expected) == active
+for net, nodes in expected.items():
+    assert members[net] == sorted(tuple(node) for node in nodes), net
+report = json.loads((OUT / "erc.json").read_text())
+assert not any(sheet["violations"] for sheet in report["sheets"])
+run("kicad-cli", "sch", "export", "pdf", "-o", str(ROOT / "serial-carrier.pdf"), str(SCHEMATIC))
+run("kicad-cli", "sch", "export", "svg", "-o", str(OUT) + "/", str(SCHEMATIC))
+summary = "\n".join([
+    "Native schematic validation passed.",
+    "KiCad ERC: zero reported errors/warnings; no project exclusions added.",
+    "17 connected nets, 9 components; exact net memberships verified.",
+    "15 firmware GPIO definitions independently checked against exported pin functions.",
+    "All 44 MCU header pins accounted for; USB/UART0/5V/PSRAM pins unused on carrier.",
+    "PDF and SVG exported successfully.",
+    "Not validated: male-module physical mapping, power budget/path, OLED pull-ups,",
+    "selected connector fit, PCB DRC/layout, procurement, or assembled hardware.",
+]) + "\n"
+(OUT / "summary.txt").write_text(summary)
+print(summary)

hardware/PCB/validation/erc.json

@@ -0,0 +1,36 @@
+{
+    "$schema": "https://schemas.kicad.org/erc.v1.json",
+    "coordinate_units": "mm",
+    "date": "2026-09-20T20:14:47",
+    "ignored_checks": [
+        {
+            "description": "Global label only appears once in the schematic",
+            "key": "single_global_label"
+        },
+        {
+            "description": "Four connection points are joined together",
+            "key": "four_way_junction"
+        },
+        {
+            "description": "SPICE model issue",
+            "key": "simulation_model_issue"
+        },
+        {
+            "description": "Assigned footprint doesn't match footprint filters",
+            "key": "footprint_filter"
+        }
+    ],
+    "included_severities": [
+        "error",
+        "warning"
+    ],
+    "kicad_version": "10.0.6",
+    "sheets": [
+        {
+            "path": "/",
+            "uuid_path": "/c86e0d56-4290-5f2b-b790-14926c8cdeea",
+            "violations": []
+        }
+    ],
+    "source": "serial-carrier.kicad_sch"
+}

hardware/PCB/validation/expected-nets.json

@@ -0,0 +1,232 @@
+{
+  "+3V3": [
+    [
+      "U1",
+      "1"
+    ],
+    [
+      "U1",
+      "2"
+    ],
+    [
+      "U2",
+      "1"
+    ],
+    [
+      "DS1",
+      "2"
+    ],
+    [
+      "R1",
+      "1"
+    ],
+    [
+      "R2",
+      "1"
+    ],
+    [
+      "R3",
+      "1"
+    ]
+  ],
+  "BTN_NEXT": [
+    [
+      "U1",
+      "20"
+    ],
+    [
+      "R3",
+      "2"
+    ],
+    [
+      "SW3",
+      "1"
+    ]
+  ],
+  "BTN_PREVIOUS": [
+    [
+      "U1",
+      "16"
+    ],
+    [
+      "R1",
+      "2"
+    ],
+    [
+      "SW1",
+      "1"
+    ]
+  ],
+  "BTN_SELECT": [
+    [
+      "U1",
+      "19"
+    ],
+    [
+      "R2",
+      "2"
+    ],
+    [
+      "SW2",
+      "1"
+    ]
+  ],
+  "GND": [
+    [
+      "U1",
+      "22"
+    ],
+    [
+      "U1",
+      "23"
+    ],
+    [
+      "U1",
+      "43"
+    ],
+    [
+      "U1",
+      "44"
+    ],
+    [
+      "U2",
+      "2"
+    ],
+    [
+      "DS1",
+      "1"
+    ],
+    [
+      "SW1",
+      "2"
+    ],
+    [
+      "SW2",
+      "2"
+    ],
+    [
+      "SW3",
+      "2"
+    ]
+  ],
+  "OLED_SCL": [
+    [
+      "U1",
+      "18"
+    ],
+    [
+      "DS1",
+      "3"
+    ]
+  ],
+  "OLED_SDA": [
+    [
+      "U1",
+      "17"
+    ],
+    [
+      "DS1",
+      "4"
+    ]
+  ],
+  "RS_CTS": [
+    [
+      "U1",
+      "9"
+    ],
+    [
+      "U2",
+      "9"
+    ]
+  ],
+  "RS_DCD": [
+    [
+      "U1",
+      "4"
+    ],
+    [
+      "U2",
+      "3"
+    ]
+  ],
+  "RS_DSR": [
+    [
+      "U1",
+      "5"
+    ],
+    [
+      "U2",
+      "7"
+    ]
+  ],
+  "RS_DTR": [
+    [
+      "U1",
+      "7"
+    ],
+    [
+      "U2",
+      "6"
+    ]
+  ],
+  "RS_OFF_N": [
+    [
+      "U1",
+      "15"
+    ],
+    [
+      "U2",
+      "12"
+    ]
+  ],
+  "RS_RI": [
+    [
+      "U1",
+      "6"
+    ],
+    [
+      "U2",
+      "10"
+    ]
+  ],
+  "RS_RTS": [
+    [
+      "U1",
+      "8"
+    ],
+    [
+      "U2",
+      "8"
+    ]
+  ],
+  "RS_RX": [
+    [
+      "U1",
+      "11"
+    ],
+    [
+      "U2",
+      "4"
+    ]
+  ],
+  "RS_TX": [
+    [
+      "U1",
+      "10"
+    ],
+    [
+      "U2",
+      "5"
+    ]
+  ],
+  "RS_VALID": [
+    [
+      "U1",
+      "12"
+    ],
+    [
+      "U2",
+      "11"
+    ]
+  ]
+}

hardware/PCB/validation/pcb-parity-drc.json

@@ -0,0 +1,53 @@
+{
+    "$schema": "https://schemas.kicad.org/drc.v1.json",
+    "coordinate_units": "mm",
+    "date": "2026-09-21T11:39:10",
+    "ignored_checks": [
+        {
+            "description": "Footprint has no courtyard defined",
+            "key": "missing_courtyard"
+        },
+        {
+            "description": "Track endpoint not centered on via",
+            "key": "track_not_centered_on_via"
+        },
+        {
+            "description": "Tuning profile track geometries",
+            "key": "tuning_profile_track_geometries"
+        },
+        {
+            "description": "Footprint doesn't match symbol's footprint filters",
+            "key": "footprint_filters_mismatch"
+        },
+        {
+            "description": "Footprint component type doesn't match footprint pads",
+            "key": "footprint_type_mismatch"
+        }
+    ],
+    "included_severities": [
+        "error",
+        "warning",
+        "exclusion"
+    ],
+    "kicad_version": "10.0.6",
+    "schematic_parity": [
+        {
+            "description": "Carrier:MAX3243_Reference_Provisional stimmt nicht mit dem Footprint des Symbols () überein.",
+            "items": [
+                {
+                    "description": "Footprint U2",
+                    "pos": {
+                        "x": 143.0,
+                        "y": 126.67
+                    },
+                    "uuid": "812387f6-6524-459e-8102-fe9c55122668"
+                }
+            ],
+            "severity": "warning",
+            "type": "footprint_symbol_mismatch"
+        }
+    ],
+    "source": "serial-carrier.kicad_pcb",
+    "unconnected_items": [],
+    "violations": []
+}

hardware/PCB/validation/pcb-routing-a1-pass1.log

@@ -0,0 +1,70 @@
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+{"net": "/+3V3", "start": "U1.1", "end": "U1.2", "start_mm": [108.0, 123.0], "end_mm": [108.0, 125.54], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 52}
+{"net": "/+3V3", "start": "R2.1", "end": "DS1.2", "start_mm": [154.0, 134.0], "end_mm": [154.73, 137.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 911}
+{"net": "/BTN_NEXT", "start": "SW3.1", "end": "SW3.1", "start_mm": [167.0, 168.0], "end_mm": [173.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/BTN_PREVIOUS", "start": "SW1.1", "end": "SW1.1", "start_mm": [143.0, 168.0], "end_mm": [149.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "SW2.1", "start_mm": [155.0, 168.0], "end_mm": [161.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/+3V3", "start": "U2.1", "end": "R1.1", "start_mm": [143.0, 126.67], "end_mm": [143.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 148}
+{"net": "/+3V3", "start": "DS1.2", "end": "R3.1", "start_mm": [154.73, 137.5], "end_mm": [165.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 5139}
+{"net": "/+3V3", "start": "R1.1", "end": "R2.1", "start_mm": [143.0, 134.0], "end_mm": [154.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 14153}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "R2.2", "start_mm": [161.5, 168.0], "end_mm": [161.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 2039}
+{"net": "/BTN_NEXT", "start": "SW3.1", "end": "R3.2", "start_mm": [173.5, 168.0], "end_mm": [172.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 12615}
+{"net": "/BTN_PREVIOUS", "start": "SW1.1", "end": "R1.2", "start_mm": [149.5, 168.0], "end_mm": [150.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 15179}
+{"net": "/+3V3", "start": "U1.2", "end": "U2.1", "start_mm": [108.0, 125.54], "end_mm": [143.0, 126.67], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 297043}
+{"net": "/BTN_PREVIOUS", "start": "U1.16", "end": "SW1.1", "start_mm": [108.0, 161.1], "end_mm": [143.0, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 70393}
+{"net": "/RS_DCD", "start": "U1.4", "end": "U2.3", "start_mm": [108.0, 130.62], "end_mm": [148.08, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 54772}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "U1.19", "start_mm": [155.0, 168.0], "end_mm": [108.0, 168.72], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 36364}
+{"net": "/RS_RX", "start": "U1.11", "end": "U2.4", "start_mm": [108.0, 148.4], "end_mm": [150.62, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 119946}
+{"net": "/RS_TX", "start": "U1.10", "end": "U2.5", "start_mm": [108.0, 145.86], "end_mm": [153.16, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 297203}
+{"net": "/RS_DTR", "start": "U1.7", "end": "U2.6", "start_mm": [108.0, 138.24], "end_mm": [155.7, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 217446}
+{"net": "/RS_DSR", "start": "U1.5", "end": "U2.7", "start_mm": [108.0, 133.16], "end_mm": [158.24, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 177204}
+{"net": "/RS_RTS", "start": "U1.8", "end": "U2.8", "start_mm": [108.0, 140.78], "end_mm": [160.78, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 268999}
+{"net": "/OLED_SCL", "start": "U1.18", "end": "DS1.3", "start_mm": [108.0, 166.18], "end_mm": [157.27, 137.5], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 453162}
+{"net": "/RS_CTS", "start": "U1.9", "end": "U2.9", "start_mm": [108.0, 143.32], "end_mm": [163.32, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 336768}
+{"net": "/OLED_SDA", "start": "U1.17", "end": "DS1.4", "start_mm": [108.0, 163.64], "end_mm": [159.81, 137.5], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 574321}
+{"net": "/RS_RI", "start": "U1.6", "end": "U2.10", "start_mm": [108.0, 135.7], "end_mm": [165.86, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 221877}
+{"net": "/BTN_NEXT", "start": "U1.20", "end": "SW3.1", "start_mm": [108.0, 171.26], "end_mm": [167.0, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 69853}
+{"net": "/RS_VALID", "start": "U1.12", "end": "U2.11", "start_mm": [108.0, 150.94], "end_mm": [168.4, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 344679}
+{"net": "/RS_OFF_N", "start": "U1.15", "end": "U2.12", "start_mm": [108.0, 158.56], "end_mm": [170.94, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 690965}
+{"net": "/GND", "start": "U1.43", "end": "U1.44", "start_mm": [133.4, 173.8], "end_mm": [133.4, 176.34], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 52}
+{"net": "/GND", "start": "SW2.2", "end": "SW1.2", "start_mm": [155.0, 172.5], "end_mm": [149.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 111}
+{"net": "/GND", "start": "SW2.2", "end": "SW3.2", "start_mm": [161.5, 172.5], "end_mm": [167.0, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 111}
+{"net": "/GND", "start": "SW2.2", "end": "SW2.2", "start_mm": [155.0, 172.5], "end_mm": [161.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "SW3.2", "end": "SW3.2", "start_mm": [167.0, 172.5], "end_mm": [173.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "SW1.2", "end": "SW1.2", "start_mm": [149.5, 172.5], "end_mm": [143.0, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "SW1.2", "end": "U1.43", "start_mm": [143.0, 172.5], "end_mm": [133.4, 173.8], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 2466}
+{"net": "/GND", "start": "U2.2", "end": "U1.23", "start_mm": [145.54, 126.67], "end_mm": [133.4, 123.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 7318}
+{"net": "/GND", "start": "DS1.1", "end": "U2.2", "start_mm": [152.19, 137.5], "end_mm": [145.54, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": true, "expansions": 2378118}
+{"net": "/GND", "start": "U1.44", "end": "U1.22", "start_mm": [133.4, 176.34], "end_mm": [108.0, 176.34], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 509}
+{"net": "/GND", "start": "SW1.2", "end": "DS1.1", "start_mm": [149.5, 172.5], "end_mm": [152.19, 137.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 19033}
+10:59:13: Debug: Adding duplicate image handler for 'PNG file'
+10:59:13: Debug: Adding duplicate image handler for 'JPEG file'
+10:59:13: Debug: Adding duplicate image handler for 'TIFF file'
+10:59:13: Debug: Adding duplicate image handler for 'GIF file'
+10:59:13: Debug: Adding duplicate image handler for 'PNM file'
+10:59:13: Debug: Adding duplicate image handler for 'PCX file'
+10:59:13: Debug: Adding duplicate image handler for 'IFF file'
+10:59:13: Debug: Adding duplicate image handler for 'Windows icon file'
+10:59:13: Debug: Adding duplicate image handler for 'Windows cursor file'
+10:59:13: Debug: Adding duplicate image handler for 'Windows animated cursor file'
+10:59:13: Debug: Adding duplicate image handler for 'TGA file'
+10:59:13: Debug: Adding duplicate image handler for 'XPM file'
+{
+  "draft_only": true,
+  "saved": true,
+  "grid_mm": 0.05,
+  "clearance_mm": 0.25,
+  "safety_margin_mm": 0.02,
+  "via_diameter_mm": 0.7,
+  "via_drill_mm": 0.3,
+  "elapsed_seconds": 31.17737436400057,
+  "routed_tree_edges": 38,
+  "total_tree_edges": 38,
+  "tracks": 674,
+  "vias": 16,
+  "immutable_identity_sha256": "783ce7e212880e0836c93e1782d39bbfbc505fae856d9720ee6c50f5ba8f6275",
+  "input_sha256": "df62a5aeb64a6d871a477a8c9fe94c100210d5b239a0617558907d9d3d9a6007",
+  "validation": "KiCad DRC must be run separately; tree-edge counts are not DRC connectivity"
+}

hardware/PCB/validation/pcb-routing-a1-pass2.log

@@ -0,0 +1,70 @@
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+{"net": "/GND", "start": "U1.43", "end": "U1.44", "start_mm": [133.4, 173.8], "end_mm": [133.4, 176.34], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 52}
+{"net": "/+3V3", "start": "U1.1", "end": "U1.2", "start_mm": [108.0, 123.0], "end_mm": [108.0, 125.54], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 52}
+{"net": "/+3V3", "start": "R2.1", "end": "DS1.2", "start_mm": [154.0, 134.0], "end_mm": [154.73, 137.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 911}
+{"net": "/GND", "start": "SW2.2", "end": "SW1.2", "start_mm": [155.0, 172.5], "end_mm": [149.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 111}
+{"net": "/GND", "start": "SW2.2", "end": "SW3.2", "start_mm": [161.5, 172.5], "end_mm": [167.0, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 111}
+{"net": "/BTN_NEXT", "start": "SW3.1", "end": "SW3.1", "start_mm": [167.0, 168.0], "end_mm": [173.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/BTN_PREVIOUS", "start": "SW1.1", "end": "SW1.1", "start_mm": [143.0, 168.0], "end_mm": [149.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "SW2.1", "start_mm": [155.0, 168.0], "end_mm": [161.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "SW2.2", "end": "SW2.2", "start_mm": [155.0, 172.5], "end_mm": [161.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "SW3.2", "end": "SW3.2", "start_mm": [167.0, 172.5], "end_mm": [173.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "SW1.2", "end": "SW1.2", "start_mm": [149.5, 172.5], "end_mm": [143.0, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/+3V3", "start": "U2.1", "end": "R1.1", "start_mm": [143.0, 126.67], "end_mm": [143.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 148}
+{"net": "/GND", "start": "SW1.2", "end": "U1.43", "start_mm": [143.0, 172.5], "end_mm": [133.4, 173.8], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 4535}
+{"net": "/+3V3", "start": "DS1.2", "end": "R3.1", "start_mm": [154.73, 137.5], "end_mm": [165.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 5139}
+{"net": "/+3V3", "start": "R1.1", "end": "R2.1", "start_mm": [143.0, 134.0], "end_mm": [154.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 14153}
+{"net": "/GND", "start": "U2.2", "end": "U1.23", "start_mm": [145.54, 126.67], "end_mm": [133.4, 123.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 9372}
+{"net": "/GND", "start": "DS1.1", "end": "U2.2", "start_mm": [152.19, 137.5], "end_mm": [145.54, 126.67], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 8327}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "R2.2", "start_mm": [161.5, 168.0], "end_mm": [161.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 2039}
+{"net": "/BTN_NEXT", "start": "SW3.1", "end": "R3.2", "start_mm": [173.5, 168.0], "end_mm": [172.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 12615}
+{"net": "/BTN_PREVIOUS", "start": "SW1.1", "end": "R1.2", "start_mm": [149.5, 168.0], "end_mm": [150.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 15179}
+{"net": "/+3V3", "start": "U1.2", "end": "U2.1", "start_mm": [108.0, 125.54], "end_mm": [143.0, 126.67], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 332527}
+{"net": "/BTN_PREVIOUS", "start": "U1.16", "end": "SW1.1", "start_mm": [108.0, 161.1], "end_mm": [143.0, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 70393}
+{"net": "/RS_DCD", "start": "U1.4", "end": "U2.3", "start_mm": [108.0, 130.62], "end_mm": [148.08, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 21855}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "U1.19", "start_mm": [155.0, 168.0], "end_mm": [108.0, 168.72], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 36364}
+{"net": "/RS_RX", "start": "U1.11", "end": "U2.4", "start_mm": [108.0, 148.4], "end_mm": [150.62, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 123675}
+{"net": "/RS_TX", "start": "U1.10", "end": "U2.5", "start_mm": [108.0, 145.86], "end_mm": [153.16, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 397389}
+{"net": "/RS_DTR", "start": "U1.7", "end": "U2.6", "start_mm": [108.0, 138.24], "end_mm": [155.7, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 294174}
+{"net": "/RS_DSR", "start": "U1.5", "end": "U2.7", "start_mm": [108.0, 133.16], "end_mm": [158.24, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 294332}
+{"net": "/RS_RTS", "start": "U1.8", "end": "U2.8", "start_mm": [108.0, 140.78], "end_mm": [160.78, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 378833}
+{"net": "/OLED_SCL", "start": "U1.18", "end": "DS1.3", "start_mm": [108.0, 166.18], "end_mm": [157.27, 137.5], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 442107}
+{"net": "/RS_CTS", "start": "U1.9", "end": "U2.9", "start_mm": [108.0, 143.32], "end_mm": [163.32, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 409990}
+{"net": "/OLED_SDA", "start": "U1.17", "end": "DS1.4", "start_mm": [108.0, 163.64], "end_mm": [159.81, 137.5], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 567654}
+{"net": "/RS_RI", "start": "U1.6", "end": "U2.10", "start_mm": [108.0, 135.7], "end_mm": [165.86, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 436874}
+{"net": "/BTN_NEXT", "start": "U1.20", "end": "SW3.1", "start_mm": [108.0, 171.26], "end_mm": [167.0, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 273975}
+{"net": "/RS_VALID", "start": "U1.12", "end": "U2.11", "start_mm": [108.0, 150.94], "end_mm": [168.4, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 425742}
+{"net": "/RS_OFF_N", "start": "U1.15", "end": "U2.12", "start_mm": [108.0, 158.56], "end_mm": [170.94, 126.67], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 645804}
+{"net": "/GND", "start": "U1.44", "end": "U1.22", "start_mm": [133.4, 176.34], "end_mm": [108.0, 176.34], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 509}
+{"net": "/GND", "start": "SW1.2", "end": "DS1.1", "start_mm": [149.5, 172.5], "end_mm": [152.19, 137.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 617019}
+11:12:00: Debug: Adding duplicate image handler for 'PNG file'
+11:12:00: Debug: Adding duplicate image handler for 'JPEG file'
+11:12:00: Debug: Adding duplicate image handler for 'TIFF file'
+11:12:00: Debug: Adding duplicate image handler for 'GIF file'
+11:12:00: Debug: Adding duplicate image handler for 'PNM file'
+11:12:00: Debug: Adding duplicate image handler for 'PCX file'
+11:12:00: Debug: Adding duplicate image handler for 'IFF file'
+11:12:00: Debug: Adding duplicate image handler for 'Windows icon file'
+11:12:00: Debug: Adding duplicate image handler for 'Windows cursor file'
+11:12:00: Debug: Adding duplicate image handler for 'Windows animated cursor file'
+11:12:00: Debug: Adding duplicate image handler for 'TGA file'
+11:12:00: Debug: Adding duplicate image handler for 'XPM file'
+{
+  "draft_only": true,
+  "saved": true,
+  "grid_mm": 0.05,
+  "clearance_mm": 0.25,
+  "safety_margin_mm": 0.02,
+  "via_diameter_mm": 0.7,
+  "via_drill_mm": 0.3,
+  "elapsed_seconds": 32.44472043699898,
+  "routed_tree_edges": 38,
+  "total_tree_edges": 38,
+  "tracks": 565,
+  "vias": 22,
+  "immutable_identity_sha256": "783ce7e212880e0836c93e1782d39bbfbc505fae856d9720ee6c50f5ba8f6275",
+  "input_sha256": "0ea7f0abff371eacc81262dc949f768cd42128f389ea4af9facee5034368d884",
+  "validation": "KiCad DRC must be run separately; tree-edge counts are not DRC connectivity"
+}

hardware/PCB/validation/pcb-routing-all-drc.json

@@ -0,0 +1,37 @@
+{
+    "$schema": "https://schemas.kicad.org/drc.v1.json",
+    "coordinate_units": "mm",
+    "date": "2026-09-21T11:16:44",
+    "ignored_checks": [
+        {
+            "description": "Footprint has no courtyard defined",
+            "key": "missing_courtyard"
+        },
+        {
+            "description": "Track endpoint not centered on via",
+            "key": "track_not_centered_on_via"
+        },
+        {
+            "description": "Tuning profile track geometries",
+            "key": "tuning_profile_track_geometries"
+        },
+        {
+            "description": "Footprint doesn't match symbol's footprint filters",
+            "key": "footprint_filters_mismatch"
+        },
+        {
+            "description": "Footprint component type doesn't match footprint pads",
+            "key": "footprint_type_mismatch"
+        }
+    ],
+    "included_severities": [
+        "error",
+        "warning",
+        "exclusion"
+    ],
+    "kicad_version": "10.0.6",
+    "schematic_parity": [],
+    "source": "serial-carrier.kicad_pcb",
+    "unconnected_items": [],
+    "violations": []
+}

hardware/PCB/validation/pcb-routing-baseline.json

@@ -0,0 +1,911 @@
+{
+    "$schema": "https://schemas.kicad.org/drc.v1.json",
+    "coordinate_units": "mm",
+    "date": "2026-09-20T22:39:18",
+    "ignored_checks": [
+        {
+            "description": "Footprint has no courtyard defined",
+            "key": "missing_courtyard"
+        },
+        {
+            "description": "Track endpoint not centered on via",
+            "key": "track_not_centered_on_via"
+        },
+        {
+            "description": "Tuning profile track geometries",
+            "key": "tuning_profile_track_geometries"
+        },
+        {
+            "description": "Footprint doesn't match symbol's footprint filters",
+            "key": "footprint_filters_mismatch"
+        },
+        {
+            "description": "Footprint component type doesn't match footprint pads",
+            "key": "footprint_type_mismatch"
+        }
+    ],
+    "included_severities": [
+        "error",
+        "warning"
+    ],
+    "kicad_version": "10.0.6",
+    "schematic_parity": [],
+    "source": "serial-carrier.kicad_pcb",
+    "unconnected_items": [
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 19 [/BTN_SELECT] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 149.72
+                    },
+                    "uuid": "f7b9badd-1db5-4575-9da8-979a7c8f3946"
+                },
+                {
+                    "description": "Durchsteckpad 1 [/BTN_SELECT] von SW2",
+                    "pos": {
+                        "x": 155.0,
+                        "y": 168.0
+                    },
+                    "uuid": "574d93e4-d3fc-4c28-b2d5-4e7d8682c22f"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 1 [/BTN_SELECT] von SW2",
+                    "pos": {
+                        "x": 155.0,
+                        "y": 168.0
+                    },
+                    "uuid": "574d93e4-d3fc-4c28-b2d5-4e7d8682c22f"
+                },
+                {
+                    "description": "Durchsteckpad 1 [/BTN_SELECT] von SW2",
+                    "pos": {
+                        "x": 161.5,
+                        "y": 168.0
+                    },
+                    "uuid": "0398530b-79dc-45b1-886c-51343182e1d3"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 1 [/BTN_SELECT] von SW2",
+                    "pos": {
+                        "x": 161.5,
+                        "y": 168.0
+                    },
+                    "uuid": "0398530b-79dc-45b1-886c-51343182e1d3"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/BTN_SELECT] von R2",
+                    "pos": {
+                        "x": 161.62,
+                        "y": 134.0
+                    },
+                    "uuid": "c118f27f-8ad4-4abe-b9c0-a30a22fe60c9"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 22 [/GND] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 157.34
+                    },
+                    "uuid": "9d509ec2-7588-4c77-9146-8d03c8646e37"
+                },
+                {
+                    "description": "Durchsteckpad 44 [/GND] von U1",
+                    "pos": {
+                        "x": 133.4,
+                        "y": 157.34
+                    },
+                    "uuid": "91b9e8e9-7e2c-43ab-b2ef-ec8ba16a25f1"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 23 [/GND] von U1",
+                    "pos": {
+                        "x": 133.4,
+                        "y": 104.0
+                    },
+                    "uuid": "b66490f6-5d60-415d-babb-215c70511b77"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/GND] von U2",
+                    "pos": {
+                        "x": 145.54,
+                        "y": 130.0
+                    },
+                    "uuid": "7744910d-b37b-4fd5-a46a-95ee262d2a08"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 43 [/GND] von U1",
+                    "pos": {
+                        "x": 133.4,
+                        "y": 154.8
+                    },
+                    "uuid": "23b353d7-7ede-43a0-a655-57496d4f8aee"
+                },
+                {
+                    "description": "Durchsteckpad 1 [/GND] von DS1",
+                    "pos": {
+                        "x": 152.19,
+                        "y": 137.5
+                    },
+                    "uuid": "0d95ad6d-f278-4240-9618-08ad8fcb5e1c"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 44 [/GND] von U1",
+                    "pos": {
+                        "x": 133.4,
+                        "y": 157.34
+                    },
+                    "uuid": "91b9e8e9-7e2c-43ab-b2ef-ec8ba16a25f1"
+                },
+                {
+                    "description": "Durchsteckpad 43 [/GND] von U1",
+                    "pos": {
+                        "x": 133.4,
+                        "y": 154.8
+                    },
+                    "uuid": "23b353d7-7ede-43a0-a655-57496d4f8aee"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 2 [/GND] von SW1",
+                    "pos": {
+                        "x": 143.0,
+                        "y": 172.5
+                    },
+                    "uuid": "cc9a376c-9410-4f75-a7a6-3a849cc384b3"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/GND] von SW1",
+                    "pos": {
+                        "x": 149.5,
+                        "y": 172.5
+                    },
+                    "uuid": "24c82a41-4f9f-4c94-aaaf-2a3df71bbd08"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 2 [/GND] von SW1",
+                    "pos": {
+                        "x": 143.0,
+                        "y": 172.5
+                    },
+                    "uuid": "cc9a376c-9410-4f75-a7a6-3a849cc384b3"
+                },
+                {
+                    "description": "Durchsteckpad 44 [/GND] von U1",
+                    "pos": {
+                        "x": 133.4,
+                        "y": 157.34
+                    },
+                    "uuid": "91b9e8e9-7e2c-43ab-b2ef-ec8ba16a25f1"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 2 [/GND] von SW1",
+                    "pos": {
+                        "x": 149.5,
+                        "y": 172.5
+                    },
+                    "uuid": "24c82a41-4f9f-4c94-aaaf-2a3df71bbd08"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/GND] von SW2",
+                    "pos": {
+                        "x": 155.0,
+                        "y": 172.5
+                    },
+                    "uuid": "970e56ae-cc93-46cd-8807-ccc9cf082aa1"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 1 [/GND] von DS1",
+                    "pos": {
+                        "x": 152.19,
+                        "y": 137.5
+                    },
+                    "uuid": "0d95ad6d-f278-4240-9618-08ad8fcb5e1c"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/GND] von U2",
+                    "pos": {
+                        "x": 145.54,
+                        "y": 130.0
+                    },
+                    "uuid": "7744910d-b37b-4fd5-a46a-95ee262d2a08"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 2 [/GND] von SW2",
+                    "pos": {
+                        "x": 155.0,
+                        "y": 172.5
+                    },
+                    "uuid": "970e56ae-cc93-46cd-8807-ccc9cf082aa1"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/GND] von SW2",
+                    "pos": {
+                        "x": 161.5,
+                        "y": 172.5
+                    },
+                    "uuid": "2f44f580-c7e4-4f03-ba46-49605735875c"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 2 [/GND] von SW2",
+                    "pos": {
+                        "x": 161.5,
+                        "y": 172.5
+                    },
+                    "uuid": "2f44f580-c7e4-4f03-ba46-49605735875c"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/GND] von SW3",
+                    "pos": {
+                        "x": 167.0,
+                        "y": 172.5
+                    },
+                    "uuid": "3cdbd911-6e07-4f86-8887-5953fa3d2a01"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 2 [/GND] von SW3",
+                    "pos": {
+                        "x": 167.0,
+                        "y": 172.5
+                    },
+                    "uuid": "3cdbd911-6e07-4f86-8887-5953fa3d2a01"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/GND] von SW3",
+                    "pos": {
+                        "x": 173.5,
+                        "y": 172.5
+                    },
+                    "uuid": "8e780381-cbfb-4f62-ae3b-8b0b8fa2a6a8"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 1 [/+3V3] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 104.0
+                    },
+                    "uuid": "9aaad355-039f-439b-9cd7-308d07ace02e"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/+3V3] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 106.54
+                    },
+                    "uuid": "2c8cc7c5-7b73-4bc2-a384-b3a5ac459c92"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 1 [/+3V3] von U2",
+                    "pos": {
+                        "x": 143.0,
+                        "y": 130.0
+                    },
+                    "uuid": "f8aafd85-e635-47cd-ba22-ddf4a036d1cd"
+                },
+                {
+                    "description": "Durchsteckpad 1 [/+3V3] von R1",
+                    "pos": {
+                        "x": 143.0,
+                        "y": 134.0
+                    },
+                    "uuid": "56ff90bc-b894-4f81-8274-7a34384229e7"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 1 [/+3V3] von U2",
+                    "pos": {
+                        "x": 143.0,
+                        "y": 130.0
+                    },
+                    "uuid": "f8aafd85-e635-47cd-ba22-ddf4a036d1cd"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/+3V3] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 106.54
+                    },
+                    "uuid": "2c8cc7c5-7b73-4bc2-a384-b3a5ac459c92"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 1 [/+3V3] von R2",
+                    "pos": {
+                        "x": 154.0,
+                        "y": 134.0
+                    },
+                    "uuid": "73a249ed-c3b1-46fb-afd5-f8bfe0e3fa65"
+                },
+                {
+                    "description": "Durchsteckpad 1 [/+3V3] von R1",
+                    "pos": {
+                        "x": 143.0,
+                        "y": 134.0
+                    },
+                    "uuid": "56ff90bc-b894-4f81-8274-7a34384229e7"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 2 [/+3V3] von DS1",
+                    "pos": {
+                        "x": 154.73,
+                        "y": 137.5
+                    },
+                    "uuid": "62a98206-7a36-4b20-a201-d4ca10b404df"
+                },
+                {
+                    "description": "Durchsteckpad 1 [/+3V3] von R2",
+                    "pos": {
+                        "x": 154.0,
+                        "y": 134.0
+                    },
+                    "uuid": "73a249ed-c3b1-46fb-afd5-f8bfe0e3fa65"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 2 [/+3V3] von DS1",
+                    "pos": {
+                        "x": 154.73,
+                        "y": 137.5
+                    },
+                    "uuid": "62a98206-7a36-4b20-a201-d4ca10b404df"
+                },
+                {
+                    "description": "Durchsteckpad 1 [/+3V3] von R3",
+                    "pos": {
+                        "x": 165.0,
+                        "y": 134.0
+                    },
+                    "uuid": "72b8a1ea-1fa7-480b-8122-aceb08f4bb4b"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 4 [/RS_DCD] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 111.62
+                    },
+                    "uuid": "d9f0d2af-a701-43e9-9d1e-58a6c7cb5250"
+                },
+                {
+                    "description": "Durchsteckpad 3 [/RS_DCD] von U2",
+                    "pos": {
+                        "x": 148.08,
+                        "y": 130.0
+                    },
+                    "uuid": "d589a6a4-0d53-4c2a-8f68-fb4407d9f10e"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 5 [/RS_DSR] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 114.16
+                    },
+                    "uuid": "0ceca603-53a8-4a53-85cc-f7f8e7be90e4"
+                },
+                {
+                    "description": "Durchsteckpad 7 [/RS_DSR] von U2",
+                    "pos": {
+                        "x": 158.24,
+                        "y": 130.0
+                    },
+                    "uuid": "e2d6b2cb-6025-490c-8371-d7cc34ac37f6"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 6 [/RS_RI] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 116.7
+                    },
+                    "uuid": "f35f1696-b778-437b-8cce-67b8c4d5f5d0"
+                },
+                {
+                    "description": "Durchsteckpad 10 [/RS_RI] von U2",
+                    "pos": {
+                        "x": 165.86,
+                        "y": 130.0
+                    },
+                    "uuid": "e28de6f2-fb85-4849-ba1a-e98e2a231492"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 7 [/RS_DTR] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 119.24
+                    },
+                    "uuid": "354ab122-85b1-4c9c-9385-d5091fe12303"
+                },
+                {
+                    "description": "Durchsteckpad 6 [/RS_DTR] von U2",
+                    "pos": {
+                        "x": 155.7,
+                        "y": 130.0
+                    },
+                    "uuid": "81e8ad67-4bdc-4f57-90b1-68cff6a95261"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 8 [/RS_RTS] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 121.78
+                    },
+                    "uuid": "55162730-46fd-465d-a1c5-20aed09ed534"
+                },
+                {
+                    "description": "Durchsteckpad 8 [/RS_RTS] von U2",
+                    "pos": {
+                        "x": 160.78,
+                        "y": 130.0
+                    },
+                    "uuid": "5c304724-2bc6-409d-9c59-2e40adc557b9"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 9 [/RS_CTS] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 124.32
+                    },
+                    "uuid": "f75c20f8-d3b5-4c3b-9919-cb044b2da5c3"
+                },
+                {
+                    "description": "Durchsteckpad 9 [/RS_CTS] von U2",
+                    "pos": {
+                        "x": 163.32,
+                        "y": 130.0
+                    },
+                    "uuid": "a8411036-6859-4041-84b8-2c80c326c58e"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 10 [/RS_TX] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 126.86
+                    },
+                    "uuid": "22c323db-7146-44af-951b-04a1d7dbb2fe"
+                },
+                {
+                    "description": "Durchsteckpad 5 [/RS_TX] von U2",
+                    "pos": {
+                        "x": 153.16,
+                        "y": 130.0
+                    },
+                    "uuid": "f919098b-4ad7-4600-9e8b-3375a1cff050"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 11 [/RS_RX] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 129.4
+                    },
+                    "uuid": "6573852d-5714-4c8d-8793-0be87f5a052a"
+                },
+                {
+                    "description": "Durchsteckpad 4 [/RS_RX] von U2",
+                    "pos": {
+                        "x": 150.62,
+                        "y": 130.0
+                    },
+                    "uuid": "3d90cce4-14d8-46a0-b560-09524f11698f"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 12 [/RS_VALID] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 131.94
+                    },
+                    "uuid": "2fbc596b-c88f-4fc6-aa94-5dad4fcac9cc"
+                },
+                {
+                    "description": "Durchsteckpad 11 [/RS_VALID] von U2",
+                    "pos": {
+                        "x": 168.4,
+                        "y": 130.0
+                    },
+                    "uuid": "9ad42f44-160f-4aa5-bcf0-a4466c090438"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 15 [/RS_OFF_N] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 139.56
+                    },
+                    "uuid": "34e1afe9-b3fc-4d3a-9e33-38b32244f19e"
+                },
+                {
+                    "description": "Durchsteckpad 12 [/RS_OFF_N] von U2",
+                    "pos": {
+                        "x": 170.94,
+                        "y": 130.0
+                    },
+                    "uuid": "a43ba2f2-477d-4850-87de-e1591119d5ae"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 1 [/BTN_PREVIOUS] von SW1",
+                    "pos": {
+                        "x": 143.0,
+                        "y": 168.0
+                    },
+                    "uuid": "5214c011-545b-4ae7-9cdb-852ade815805"
+                },
+                {
+                    "description": "Durchsteckpad 1 [/BTN_PREVIOUS] von SW1",
+                    "pos": {
+                        "x": 149.5,
+                        "y": 168.0
+                    },
+                    "uuid": "84202d30-b2fe-4170-8146-69b68d3b82a1"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 1 [/BTN_PREVIOUS] von SW1",
+                    "pos": {
+                        "x": 149.5,
+                        "y": 168.0
+                    },
+                    "uuid": "84202d30-b2fe-4170-8146-69b68d3b82a1"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/BTN_PREVIOUS] von R1",
+                    "pos": {
+                        "x": 150.62,
+                        "y": 134.0
+                    },
+                    "uuid": "8237f507-f5c7-4eb6-9aa1-f46af2981e7c"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 2 [/BTN_PREVIOUS] von R1",
+                    "pos": {
+                        "x": 150.62,
+                        "y": 134.0
+                    },
+                    "uuid": "8237f507-f5c7-4eb6-9aa1-f46af2981e7c"
+                },
+                {
+                    "description": "Durchsteckpad 16 [/BTN_PREVIOUS] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 142.1
+                    },
+                    "uuid": "fc705960-92fa-4d8f-bb0e-ce2b82d1e7fc"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 17 [/OLED_SDA] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 144.64
+                    },
+                    "uuid": "1f91549c-5cb2-465f-86df-b2f1b0c16ed8"
+                },
+                {
+                    "description": "Durchsteckpad 4 [/OLED_SDA] von DS1",
+                    "pos": {
+                        "x": 159.81,
+                        "y": 137.5
+                    },
+                    "uuid": "91a4dcef-1b36-4e3d-a15c-c4578077c27b"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 18 [/OLED_SCL] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 147.18
+                    },
+                    "uuid": "1c55fd03-0b3e-494f-a37b-6e0b3496cfc9"
+                },
+                {
+                    "description": "Durchsteckpad 3 [/OLED_SCL] von DS1",
+                    "pos": {
+                        "x": 157.27,
+                        "y": 137.5
+                    },
+                    "uuid": "704668d0-88bf-4b51-840a-60a35804fafd"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 20 [/BTN_NEXT] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 152.26
+                    },
+                    "uuid": "e7159c90-4e8d-4b21-8e84-a7f59f793440"
+                },
+                {
+                    "description": "Durchsteckpad 1 [/BTN_NEXT] von SW3",
+                    "pos": {
+                        "x": 167.0,
+                        "y": 168.0
+                    },
+                    "uuid": "c67d0b07-c47f-48b3-9e79-7aed82edbbfc"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 1 [/BTN_NEXT] von SW3",
+                    "pos": {
+                        "x": 167.0,
+                        "y": 168.0
+                    },
+                    "uuid": "c67d0b07-c47f-48b3-9e79-7aed82edbbfc"
+                },
+                {
+                    "description": "Durchsteckpad 1 [/BTN_NEXT] von SW3",
+                    "pos": {
+                        "x": 173.5,
+                        "y": 168.0
+                    },
+                    "uuid": "62f3da3b-8297-4232-92ee-88f3ce4a7d36"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 1 [/BTN_NEXT] von SW3",
+                    "pos": {
+                        "x": 173.5,
+                        "y": 168.0
+                    },
+                    "uuid": "62f3da3b-8297-4232-92ee-88f3ce4a7d36"
+                },
+                {
+                    "description": "Durchsteckpad 2 [/BTN_NEXT] von R3",
+                    "pos": {
+                        "x": 172.62,
+                        "y": 134.0
+                    },
+                    "uuid": "9e9dfe49-4b68-472b-a86c-bfcee913a81b"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        }
+    ],
+    "violations": []
+}

hardware/PCB/validation/pcb-routing-check.json

@@ -0,0 +1,85 @@
+{
+  "immutable_geometry_nets_pads_linkage_preserved": true,
+  "board_sha256": "53e36538c0669604457b9e1a9ff1b1e20422970e8f9f356088c4581868ad5045",
+  "independent_min_different_net_or_npth_clearance_mm": 0.2705441169852849,
+  "closest_items": [
+    "U1.38:4b8eabef-8493-437d-bd02-cb9ff4afd7cd",
+    "d95f45cb-7fa4-4203-a786-0a069425e2b8"
+  ],
+  "min_copper_or_npth_edge_gap_mm": 1.9,
+  "min_rf_gap_mm": 0.025000000000005684,
+  "min_via_to_other_drilled_hole_gap_mm": 0.8205441169852848,
+  "track_width_counts": {
+    "0.25": 451,
+    "0.5": 114
+  },
+  "routed_length_mm_by_net": {
+    "/BTN_SELECT": 88.94832552628598,
+    "/GND": 141.68412246223386,
+    "/+3V3": 90.29604731966161,
+    "/RS_DCD": 43.068490178879834,
+    "/RS_DSR": 55.09398706495997,
+    "/RS_RI": 67.91373841554615,
+    "/RS_DTR": 52.53487761643567,
+    "/RS_RTS": 60.056714985368814,
+    "/RS_CTS": 63.65082753507114,
+    "/RS_TX": 53.135260491559045,
+    "/RS_RX": 51.637429252872906,
+    "/RS_VALID": 72.10630197626116,
+    "/RS_OFF_N": 78.04100118378895,
+    "/BTN_PREVIOUS": 78.83370879187974,
+    "/OLED_SDA": 62.65168524184884,
+    "/OLED_SCL": 61.1779295330028,
+    "/BTN_NEXT": 101.24898628384834
+  },
+  "tracks": 565,
+  "vias": 22,
+  "copper_zones": 0,
+  "drc_freshly_run": true,
+  "drc_violations": 0,
+  "unconnected_items": 0,
+  "drc_ignored_checks": [
+    {
+      "description": "Footprint has no courtyard defined",
+      "key": "missing_courtyard"
+    },
+    {
+      "description": "Track endpoint not centered on via",
+      "key": "track_not_centered_on_via"
+    },
+    {
+      "description": "Tuning profile track geometries",
+      "key": "tuning_profile_track_geometries"
+    },
+    {
+      "description": "Footprint doesn't match symbol's footprint filters",
+      "key": "footprint_filters_mismatch"
+    },
+    {
+      "description": "Footprint component type doesn't match footprint pads",
+      "key": "footprint_type_mismatch"
+    }
+  ],
+  "overwrite_guard_tests": [
+    {
+      "args": [
+        "--route"
+      ],
+      "exit_code": 2,
+      "reason": "route_pcb_draft.py: error: --route requires --overwrite; back up manual routing first"
+    },
+    {
+      "args": [
+        "--route",
+        "--overwrite"
+      ],
+      "exit_code": 2,
+      "reason": "route_pcb_draft.py: error: existing routing protected; --replace-routes required even for preview"
+    },
+    {
+      "args": [],
+      "exit_code": 2,
+      "reason": "route_pcb_draft.py: error: existing routing protected; --replace-routes required even for preview"
+    }
+  ]
+}

hardware/PCB/validation/pcb-routing-check.py

@@ -0,0 +1,122 @@
+#!/usr/bin/python3
+"""Read-only draft audit; needs pcbnew, numpy, shapely and kicad-cli.
+Writes fresh DRC and audit JSON reports, never modifies the board.
+
+Independent continuous centreline/radius checks complement KiCad DRC. Restricted
+here to the existing circle/axis-aligned rectangular THT pads and straight tracks.
+"""
+from collections import Counter
+import hashlib
+import importlib.util
+import json
+from pathlib import Path
+import subprocess
+
+import pcbnew as p
+from shapely.geometry import Point, LineString, Polygon, box
+
+ROOT = Path(__file__).resolve().parent.parent
+spec = importlib.util.spec_from_file_location('router', ROOT / 'route_pcb_draft.py')
+r = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(r)
+board = p.LoadBoard(str(r.PCB))
+original = p.LoadBoard(str(ROOT / 'validation/pcb-routing-input.kicad_pcb'))
+assert r.identity(board) == r.identity(original), 'immutable source geometry/linkage changed'
+items, holes = [], []
+for f in board.GetFootprints():
+    for pad in f.Pads():
+        xy = r.pos(pad)
+        assert pad.GetOrientationDegrees() % 90 == 0
+        assert pad.GetShape() in (p.PAD_SHAPE_CIRCLE, p.PAD_SHAPE_RECT)
+        if pad.GetShape() == p.PAD_SHAPE_CIRCLE:
+            assert pad.GetSize().x == pad.GetSize().y
+            geom, radius = Point(xy), p.ToMM(pad.GetSize().x) / 2
+        else:
+            bb = pad.GetBoundingBox()
+            geom = box(p.ToMM(bb.GetX()), p.ToMM(bb.GetY()),
+                       p.ToMM(bb.GetRight()), p.ToMM(bb.GetBottom()))
+            radius = 0
+        label = f.GetReference() + '.' + pad.GetNumber() + ':' + pad.m_Uuid.AsString()
+        layers = {l for l in r.LAYERS if pad.IsOnLayer(l)}
+        items.append((label, pad.GetNetCode(), layers, geom, radius))
+        if pad.GetDrillSize().x:
+            assert pad.GetDrillSize().x == pad.GetDrillSize().y
+            holes.append((label, Point(xy), p.ToMM(pad.GetDrillSize().x) / 2, False))
+track_lengths = Counter()
+widths = Counter()
+for t in board.GetTracks():
+    is_via = isinstance(t, p.PCB_VIA)
+    if is_via:
+        geom, radius, layers = Point(r.pos(t)), p.ToMM(t.GetWidth(p.F_Cu)) / 2, set(r.LAYERS)
+        assert abs(radius - 0.35) < 1e-8 and t.GetDrillValue() == r.mm(0.3)
+        holes.append((t.m_Uuid.AsString(), geom, 0.15, True))
+    else:
+        geom = LineString([(p.ToMM(t.GetStart().x), p.ToMM(t.GetStart().y)),
+                           (p.ToMM(t.GetEnd().x), p.ToMM(t.GetEnd().y))])
+        radius, layers = p.ToMM(t.GetWidth()) / 2, {t.GetLayer()}
+        expected = 0.5 if t.GetNetname() in ('/+3V3', '/GND') else 0.25
+        assert abs(2 * radius - expected) < 1e-8
+        widths[str(2 * radius)] += 1
+        track_lengths[t.GetNetname()] += geom.length
+    items.append((t.m_Uuid.AsString(), t.GetNetCode(), layers, geom, radius))
+
+min_clearance = float('inf')
+closest = None
+for i, a in enumerate(items):
+    for b in items[i + 1:]:
+        if not a[2].intersection(b[2]) or (a[1] and a[1] == b[1]):
+            continue
+        distance = a[3].distance(b[3]) - a[4] - b[4]
+        if distance < min_clearance:
+            min_clearance, closest = distance, (a[0], b[0])
+assert min_clearance >= 0.25 - 1e-6, (min_clearance, closest)
+outline = Polygon([(136,100),(182,100),(182,180),(100,180),(100,119),(136,119)])
+rf = box(110, 119, 131, 132)
+min_edge, min_rf = float('inf'), float('inf')
+for label, net, layers, geom, radius in items:
+    assert outline.covers(geom), label
+    edge_gap = outline.boundary.distance(geom) - radius
+    rf_gap = rf.distance(geom) - radius
+    min_edge, min_rf = min(min_edge, edge_gap), min(min_rf, rf_gap)
+    assert edge_gap >= 0.5 - 1e-6, (label, edge_gap)
+    assert rf_gap > 0, (label, rf_gap)
+min_via_hole_gap = float('inf')
+for i, a in enumerate(holes):
+    for b in holes[i + 1:]:
+        if not (a[3] or b[3]):
+            continue
+        gap = a[1].distance(b[1]) - a[2] - b[2]
+        min_via_hole_gap = min(min_via_hole_gap, gap)
+        assert gap >= 0.25 - 1e-6, (a[0], b[0], gap)
+
+# Refusal paths must leave the routed board byte-for-byte unchanged.
+before = r.PCB.read_bytes()
+guards = []
+for args in (['--route'], ['--route', '--overwrite'], []):
+    result = subprocess.run(['/usr/bin/python3', '-B', str(ROOT/'route_pcb_draft.py'), *args],
+                            capture_output=True, text=True, timeout=20)
+    assert result.returncode == 2, (args, result.stdout, result.stderr)
+    assert r.PCB.read_bytes() == before
+    guards.append({'args': args, 'exit_code': result.returncode,
+                   'reason': result.stderr.splitlines()[-1]})
+subprocess.run(['kicad-cli', 'pcb', 'drc', '--format', 'json', '--all-track-errors',
+                '--severity-all', '--exit-code-violations', '-o',
+                str(ROOT/'validation/pcb-routing-drc.json'), str(r.PCB)],
+               check=True, timeout=60)
+assert r.PCB.read_bytes() == before, 'board changed during audit'
+drc = json.loads(ROOT.joinpath('validation/pcb-routing-drc.json').read_text())
+assert not drc['violations'] and not drc['unconnected_items']
+report = dict(immutable_geometry_nets_pads_linkage_preserved=True,
+              board_sha256=hashlib.sha256(before).hexdigest(),
+              independent_min_different_net_or_npth_clearance_mm=min_clearance,
+              closest_items=closest, min_copper_or_npth_edge_gap_mm=min_edge,
+              min_rf_gap_mm=min_rf, min_via_to_other_drilled_hole_gap_mm=min_via_hole_gap,
+              track_width_counts=widths, routed_length_mm_by_net=track_lengths,
+              tracks=sum(not isinstance(t,p.PCB_VIA) for t in board.GetTracks()),
+              vias=sum(isinstance(t,p.PCB_VIA) for t in board.GetTracks()),
+              copper_zones=sum(not z.GetIsRuleArea() for z in board.Zones()),
+              drc_freshly_run=True,
+              drc_violations=len(drc['violations']), unconnected_items=len(drc['unconnected_items']),
+              drc_ignored_checks=drc['ignored_checks'], overwrite_guard_tests=guards)
+ROOT.joinpath('validation/pcb-routing-check.json').write_text(json.dumps(report, indent=2)+'\n')
+print(json.dumps(report, indent=2))

hardware/PCB/validation/pcb-routing-drc.json

@@ -0,0 +1,37 @@
+{
+    "$schema": "https://schemas.kicad.org/drc.v1.json",
+    "coordinate_units": "mm",
+    "date": "2026-09-21T11:39:13",
+    "ignored_checks": [
+        {
+            "description": "Footprint has no courtyard defined",
+            "key": "missing_courtyard"
+        },
+        {
+            "description": "Track endpoint not centered on via",
+            "key": "track_not_centered_on_via"
+        },
+        {
+            "description": "Tuning profile track geometries",
+            "key": "tuning_profile_track_geometries"
+        },
+        {
+            "description": "Footprint doesn't match symbol's footprint filters",
+            "key": "footprint_filters_mismatch"
+        },
+        {
+            "description": "Footprint component type doesn't match footprint pads",
+            "key": "footprint_type_mismatch"
+        }
+    ],
+    "included_severities": [
+        "error",
+        "warning",
+        "exclusion"
+    ],
+    "kicad_version": "10.0.6",
+    "schematic_parity": [],
+    "source": "serial-carrier.kicad_pcb",
+    "unconnected_items": [],
+    "violations": []
+}

hardware/PCB/validation/pcb-routing-dry-run.log

@@ -0,0 +1,58 @@
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+{"net": "/+3V3", "start": "U1.1", "end": "U1.2", "start_mm": [108.0, 104.0], "end_mm": [108.0, 106.54], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 52}
+{"net": "/+3V3", "start": "R2.1", "end": "DS1.2", "start_mm": [154.0, 134.0], "end_mm": [154.73, 137.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 911}
+{"net": "/+3V3", "start": "U2.1", "end": "R1.1", "start_mm": [143.0, 130.0], "end_mm": [143.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 81}
+{"net": "/BTN_NEXT", "start": "SW3.1", "end": "SW3.1", "start_mm": [167.0, 168.0], "end_mm": [173.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/BTN_PREVIOUS", "start": "SW1.1", "end": "SW1.1", "start_mm": [149.5, 168.0], "end_mm": [143.0, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "SW2.1", "start_mm": [155.0, 168.0], "end_mm": [161.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/+3V3", "start": "DS1.2", "end": "R3.1", "start_mm": [154.73, 137.5], "end_mm": [165.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 5139}
+{"net": "/+3V3", "start": "R1.1", "end": "R2.1", "start_mm": [143.0, 134.0], "end_mm": [154.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 14153}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "R2.2", "start_mm": [161.5, 168.0], "end_mm": [161.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 2039}
+{"net": "/BTN_NEXT", "start": "SW3.1", "end": "R3.2", "start_mm": [173.5, 168.0], "end_mm": [172.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 12615}
+{"net": "/BTN_PREVIOUS", "start": "R1.2", "end": "SW1.1", "start_mm": [150.62, 134.0], "end_mm": [149.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 15179}
+{"net": "/+3V3", "start": "U1.2", "end": "U2.1", "start_mm": [108.0, 106.54], "end_mm": [143.0, 130.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 894511}
+{"net": "/RS_RX", "start": "U1.11", "end": "U2.4", "start_mm": [108.0, 129.4], "end_mm": [150.62, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 51516}
+{"net": "/BTN_PREVIOUS", "start": "U1.16", "end": "R1.2", "start_mm": [108.0, 142.1], "end_mm": [150.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 94479}
+{"net": "/RS_DCD", "start": "U1.4", "end": "U2.3", "start_mm": [108.0, 111.62], "end_mm": [148.08, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 266031}
+{"net": "/RS_TX", "start": "U1.10", "end": "U2.5", "start_mm": [108.0, 126.86], "end_mm": [153.16, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 175689}
+{"net": "/RS_DTR", "start": "U1.7", "end": "U2.6", "start_mm": [108.0, 119.24], "end_mm": [155.7, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 326823}
+{"net": "/OLED_SCL", "start": "U1.18", "end": "DS1.3", "start_mm": [108.0, 147.18], "end_mm": [157.27, 137.5], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 82557}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "U1.19", "start_mm": [155.0, 168.0], "end_mm": [108.0, 149.72], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 147997}
+{"net": "/OLED_SDA", "start": "U1.17", "end": "DS1.4", "start_mm": [108.0, 144.64], "end_mm": [159.81, 137.5], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 266428}
+{"net": "/RS_DSR", "start": "U1.5", "end": "U2.7", "start_mm": [108.0, 114.16], "end_mm": [158.24, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 372014}
+{"net": "/RS_RTS", "start": "U1.8", "end": "U2.8", "start_mm": [108.0, 121.78], "end_mm": [160.78, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 298514}
+{"net": "/RS_CTS", "start": "U1.9", "end": "U2.9", "start_mm": [108.0, 124.32], "end_mm": [163.32, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 265272}
+{"net": "/RS_RI", "start": "U1.6", "end": "U2.10", "start_mm": [108.0, 116.7], "end_mm": [165.86, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 332506}
+{"net": "/RS_VALID", "start": "U1.12", "end": "U2.11", "start_mm": [108.0, 131.94], "end_mm": [168.4, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 348384}
+{"net": "/BTN_NEXT", "start": "U1.20", "end": "SW3.1", "start_mm": [108.0, 152.26], "end_mm": [167.0, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 272795}
+{"net": "/RS_OFF_N", "start": "U1.15", "end": "U2.12", "start_mm": [108.0, 139.56], "end_mm": [170.94, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 351630}
+{"net": "/GND", "start": "U1.44", "end": "U1.43", "start_mm": [133.4, 157.34], "end_mm": [133.4, 154.8], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 52}
+{"net": "/GND", "start": "SW2.2", "end": "SW1.2", "start_mm": [155.0, 172.5], "end_mm": [149.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 111}
+{"net": "/GND", "start": "SW2.2", "end": "SW3.2", "start_mm": [161.5, 172.5], "end_mm": [167.0, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 111}
+{"net": "/GND", "start": "SW2.2", "end": "SW2.2", "start_mm": [155.0, 172.5], "end_mm": [161.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "SW3.2", "end": "SW3.2", "start_mm": [167.0, 172.5], "end_mm": [173.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "SW1.2", "end": "SW1.2", "start_mm": [149.5, 172.5], "end_mm": [143.0, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "DS1.1", "end": "U2.2", "start_mm": [152.19, 137.5], "end_mm": [145.54, 130.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 17468}
+{"net": "/GND", "start": "SW1.2", "end": "U1.44", "start_mm": [143.0, 172.5], "end_mm": [133.4, 157.34], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 27488}
+{"net": "/GND", "start": "U1.44", "end": "U1.22", "start_mm": [133.4, 157.34], "end_mm": [108.0, 157.34], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 73753}
+{"net": "/GND", "start": "U1.43", "end": "DS1.1", "start_mm": [133.4, 154.8], "end_mm": [152.19, 137.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 54021}
+{"net": "/GND", "start": "U2.2", "end": "U1.23", "start_mm": [145.54, 130.0], "end_mm": [133.4, 104.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 98250}
+{
+  "draft_only": true,
+  "saved": false,
+  "grid_mm": 0.05,
+  "clearance_mm": 0.25,
+  "safety_margin_mm": 0.02,
+  "via_diameter_mm": 0.7,
+  "via_drill_mm": 0.3,
+  "elapsed_seconds": 27.992941715005145,
+  "routed_tree_edges": 38,
+  "total_tree_edges": 38,
+  "tracks": 569,
+  "vias": 20,
+  "immutable_identity_sha256": "81def52e6c1d574b4d3ab1a5859a5266b893df0ea6c5b9aa7d7b688cc4a98519",
+  "input_sha256": "bf94b6c9b00c43a97f933054758a2c9d6541981ae09f2f285dcdb567bd73d9b1",
+  "validation": "KiCad DRC must be run separately; tree-edge counts are not DRC connectivity"
+}

hardware/PCB/validation/pcb-routing-pass1-drc.json

@@ -0,0 +1,244 @@
+{
+    "$schema": "https://schemas.kicad.org/drc.v1.json",
+    "coordinate_units": "mm",
+    "date": "2026-09-20T22:43:07",
+    "ignored_checks": [
+        {
+            "description": "Footprint has no courtyard defined",
+            "key": "missing_courtyard"
+        },
+        {
+            "description": "Track endpoint not centered on via",
+            "key": "track_not_centered_on_via"
+        },
+        {
+            "description": "Tuning profile track geometries",
+            "key": "tuning_profile_track_geometries"
+        },
+        {
+            "description": "Footprint doesn't match symbol's footprint filters",
+            "key": "footprint_filters_mismatch"
+        },
+        {
+            "description": "Footprint component type doesn't match footprint pads",
+            "key": "footprint_type_mismatch"
+        }
+    ],
+    "included_severities": [
+        "error",
+        "warning"
+    ],
+    "kicad_version": "10.0.6",
+    "schematic_parity": [],
+    "source": "serial-carrier.kicad_pcb",
+    "unconnected_items": [
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 5 [/RS_DSR] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 114.16
+                    },
+                    "uuid": "0ceca603-53a8-4a53-85cc-f7f8e7be90e4"
+                },
+                {
+                    "description": "Durchsteckpad 7 [/RS_DSR] von U2",
+                    "pos": {
+                        "x": 158.24,
+                        "y": 130.0
+                    },
+                    "uuid": "e2d6b2cb-6025-490c-8371-d7cc34ac37f6"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 6 [/RS_RI] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 116.7
+                    },
+                    "uuid": "f35f1696-b778-437b-8cce-67b8c4d5f5d0"
+                },
+                {
+                    "description": "Durchsteckpad 10 [/RS_RI] von U2",
+                    "pos": {
+                        "x": 165.86,
+                        "y": 130.0
+                    },
+                    "uuid": "e28de6f2-fb85-4849-ba1a-e98e2a231492"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 7 [/RS_DTR] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 119.24
+                    },
+                    "uuid": "354ab122-85b1-4c9c-9385-d5091fe12303"
+                },
+                {
+                    "description": "Durchsteckpad 6 [/RS_DTR] von U2",
+                    "pos": {
+                        "x": 155.7,
+                        "y": 130.0
+                    },
+                    "uuid": "81e8ad67-4bdc-4f57-90b1-68cff6a95261"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 8 [/RS_RTS] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 121.78
+                    },
+                    "uuid": "55162730-46fd-465d-a1c5-20aed09ed534"
+                },
+                {
+                    "description": "Durchsteckpad 8 [/RS_RTS] von U2",
+                    "pos": {
+                        "x": 160.78,
+                        "y": 130.0
+                    },
+                    "uuid": "5c304724-2bc6-409d-9c59-2e40adc557b9"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 9 [/RS_CTS] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 124.32
+                    },
+                    "uuid": "f75c20f8-d3b5-4c3b-9919-cb044b2da5c3"
+                },
+                {
+                    "description": "Durchsteckpad 9 [/RS_CTS] von U2",
+                    "pos": {
+                        "x": 163.32,
+                        "y": 130.0
+                    },
+                    "uuid": "a8411036-6859-4041-84b8-2c80c326c58e"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 10 [/RS_TX] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 126.86
+                    },
+                    "uuid": "22c323db-7146-44af-951b-04a1d7dbb2fe"
+                },
+                {
+                    "description": "Durchsteckpad 5 [/RS_TX] von U2",
+                    "pos": {
+                        "x": 153.16,
+                        "y": 130.0
+                    },
+                    "uuid": "f919098b-4ad7-4600-9e8b-3375a1cff050"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 11 [/RS_RX] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 129.4
+                    },
+                    "uuid": "6573852d-5714-4c8d-8793-0be87f5a052a"
+                },
+                {
+                    "description": "Durchsteckpad 4 [/RS_RX] von U2",
+                    "pos": {
+                        "x": 150.62,
+                        "y": 130.0
+                    },
+                    "uuid": "3d90cce4-14d8-46a0-b560-09524f11698f"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 12 [/RS_VALID] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 131.94
+                    },
+                    "uuid": "2fbc596b-c88f-4fc6-aa94-5dad4fcac9cc"
+                },
+                {
+                    "description": "Durchsteckpad 11 [/RS_VALID] von U2",
+                    "pos": {
+                        "x": 168.4,
+                        "y": 130.0
+                    },
+                    "uuid": "9ad42f44-160f-4aa5-bcf0-a4466c090438"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 15 [/RS_OFF_N] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 139.56
+                    },
+                    "uuid": "34e1afe9-b3fc-4d3a-9e33-38b32244f19e"
+                },
+                {
+                    "description": "Durchsteckpad 12 [/RS_OFF_N] von U2",
+                    "pos": {
+                        "x": 170.94,
+                        "y": 130.0
+                    },
+                    "uuid": "a43ba2f2-477d-4850-87de-e1591119d5ae"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        }
+    ],
+    "violations": []
+}

hardware/PCB/validation/pcb-routing-pass2-drc.json

@@ -0,0 +1,221 @@
+{
+    "$schema": "https://schemas.kicad.org/drc.v1.json",
+    "coordinate_units": "mm",
+    "date": "2026-09-20T22:46:03",
+    "ignored_checks": [
+        {
+            "description": "Footprint has no courtyard defined",
+            "key": "missing_courtyard"
+        },
+        {
+            "description": "Track endpoint not centered on via",
+            "key": "track_not_centered_on_via"
+        },
+        {
+            "description": "Tuning profile track geometries",
+            "key": "tuning_profile_track_geometries"
+        },
+        {
+            "description": "Footprint doesn't match symbol's footprint filters",
+            "key": "footprint_filters_mismatch"
+        },
+        {
+            "description": "Footprint component type doesn't match footprint pads",
+            "key": "footprint_type_mismatch"
+        }
+    ],
+    "included_severities": [
+        "error",
+        "warning"
+    ],
+    "kicad_version": "10.0.6",
+    "schematic_parity": [],
+    "source": "serial-carrier.kicad_pcb",
+    "unconnected_items": [
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 5 [/RS_DSR] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 114.16
+                    },
+                    "uuid": "0ceca603-53a8-4a53-85cc-f7f8e7be90e4"
+                },
+                {
+                    "description": "Durchsteckpad 7 [/RS_DSR] von U2",
+                    "pos": {
+                        "x": 158.24,
+                        "y": 130.0
+                    },
+                    "uuid": "e2d6b2cb-6025-490c-8371-d7cc34ac37f6"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 6 [/RS_RI] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 116.7
+                    },
+                    "uuid": "f35f1696-b778-437b-8cce-67b8c4d5f5d0"
+                },
+                {
+                    "description": "Durchsteckpad 10 [/RS_RI] von U2",
+                    "pos": {
+                        "x": 165.86,
+                        "y": 130.0
+                    },
+                    "uuid": "e28de6f2-fb85-4849-ba1a-e98e2a231492"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 8 [/RS_RTS] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 121.78
+                    },
+                    "uuid": "55162730-46fd-465d-a1c5-20aed09ed534"
+                },
+                {
+                    "description": "Durchsteckpad 8 [/RS_RTS] von U2",
+                    "pos": {
+                        "x": 160.78,
+                        "y": 130.0
+                    },
+                    "uuid": "5c304724-2bc6-409d-9c59-2e40adc557b9"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 9 [/RS_CTS] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 124.32
+                    },
+                    "uuid": "f75c20f8-d3b5-4c3b-9919-cb044b2da5c3"
+                },
+                {
+                    "description": "Durchsteckpad 9 [/RS_CTS] von U2",
+                    "pos": {
+                        "x": 163.32,
+                        "y": 130.0
+                    },
+                    "uuid": "a8411036-6859-4041-84b8-2c80c326c58e"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 12 [/RS_VALID] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 131.94
+                    },
+                    "uuid": "2fbc596b-c88f-4fc6-aa94-5dad4fcac9cc"
+                },
+                {
+                    "description": "Durchsteckpad 11 [/RS_VALID] von U2",
+                    "pos": {
+                        "x": 168.4,
+                        "y": 130.0
+                    },
+                    "uuid": "9ad42f44-160f-4aa5-bcf0-a4466c090438"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 15 [/RS_OFF_N] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 139.56
+                    },
+                    "uuid": "34e1afe9-b3fc-4d3a-9e33-38b32244f19e"
+                },
+                {
+                    "description": "Durchsteckpad 12 [/RS_OFF_N] von U2",
+                    "pos": {
+                        "x": 170.94,
+                        "y": 130.0
+                    },
+                    "uuid": "a43ba2f2-477d-4850-87de-e1591119d5ae"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 17 [/OLED_SDA] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 144.64
+                    },
+                    "uuid": "1f91549c-5cb2-465f-86df-b2f1b0c16ed8"
+                },
+                {
+                    "description": "Durchsteckpad 4 [/OLED_SDA] von DS1",
+                    "pos": {
+                        "x": 159.81,
+                        "y": 137.5
+                    },
+                    "uuid": "91a4dcef-1b36-4e3d-a15c-c4578077c27b"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        },
+        {
+            "description": "Missing connection between items",
+            "items": [
+                {
+                    "description": "Durchsteckpad 20 [/BTN_NEXT] von U1",
+                    "pos": {
+                        "x": 108.0,
+                        "y": 152.26
+                    },
+                    "uuid": "e7159c90-4e8d-4b21-8e84-a7f59f793440"
+                },
+                {
+                    "description": "Leiterbahn [/BTN_NEXT] auf F.Cu, Länge 6,5000 mm",
+                    "pos": {
+                        "x": 167.0,
+                        "y": 168.0
+                    },
+                    "uuid": "97cfdf4d-f068-4e4a-8684-aae638a809ad"
+                }
+            ],
+            "severity": "error",
+            "type": "unconnected_items"
+        }
+    ],
+    "violations": []
+}

hardware/PCB/validation/pcb-routing-pass2.log

@@ -0,0 +1,70 @@
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+{"net": "/+3V3", "start": "U1.1", "end": "U1.2", "start_mm": [108.0, 104.0], "end_mm": [108.0, 106.54], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 26}
+{"net": "/+3V3", "start": "R2.1", "end": "DS1.2", "start_mm": [154.0, 134.0], "end_mm": [154.73, 137.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 239}
+{"net": "/+3V3", "start": "U2.1", "end": "R1.1", "start_mm": [143.0, 130.0], "end_mm": [143.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 41}
+{"net": "/BTN_NEXT", "start": "SW3.1", "end": "SW3.1", "start_mm": [167.0, 168.0], "end_mm": [173.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 66}
+{"net": "/BTN_PREVIOUS", "start": "SW1.1", "end": "SW1.1", "start_mm": [149.5, 168.0], "end_mm": [143.0, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 66}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "SW2.1", "start_mm": [155.0, 168.0], "end_mm": [161.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 66}
+{"net": "/+3V3", "start": "DS1.2", "end": "R3.1", "start_mm": [154.73, 137.5], "end_mm": [165.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 1334}
+{"net": "/+3V3", "start": "R1.1", "end": "R2.1", "start_mm": [143.0, 134.0], "end_mm": [154.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 3711}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "R2.2", "start_mm": [161.5, 168.0], "end_mm": [161.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 681}
+{"net": "/BTN_NEXT", "start": "SW3.1", "end": "R3.2", "start_mm": [173.5, 168.0], "end_mm": [172.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 3329}
+{"net": "/BTN_PREVIOUS", "start": "R1.2", "end": "SW1.1", "start_mm": [150.62, 134.0], "end_mm": [149.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 3971}
+{"net": "/+3V3", "start": "U1.2", "end": "U2.1", "start_mm": [108.0, 106.54], "end_mm": [143.0, 130.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 224476}
+{"net": "/RS_RX", "start": "U1.11", "end": "U2.4", "start_mm": [108.0, 129.4], "end_mm": [150.62, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 274662}
+{"net": "/BTN_PREVIOUS", "start": "U1.16", "end": "R1.2", "start_mm": [108.0, 142.1], "end_mm": [150.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 227867}
+{"net": "/RS_DCD", "start": "U1.4", "end": "U2.3", "start_mm": [108.0, 111.62], "end_mm": [148.08, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 201896}
+{"net": "/RS_TX", "start": "U1.10", "end": "U2.5", "start_mm": [108.0, 126.86], "end_mm": [153.16, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 271117}
+{"net": "/RS_DTR", "start": "U1.7", "end": "U2.6", "start_mm": [108.0, 119.24], "end_mm": [155.7, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 307013}
+{"net": "/OLED_SCL", "start": "U1.18", "end": "DS1.3", "start_mm": [108.0, 147.18], "end_mm": [157.27, 137.5], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 127246}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "U1.19", "start_mm": [155.0, 168.0], "end_mm": [108.0, 149.72], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 73189}
+{"net": "/OLED_SDA", "start": "U1.17", "end": "DS1.4", "start_mm": [108.0, 144.64], "end_mm": [159.81, 137.5], "routed": false, "width_mm": 0.25, "power_fallback": false, "expansions": 272010}
+{"net": "/RS_DSR", "start": "U1.5", "end": "U2.7", "start_mm": [108.0, 114.16], "end_mm": [158.24, 130.0], "routed": false, "width_mm": 0.25, "power_fallback": false, "expansions": 272046}
+{"net": "/RS_RTS", "start": "U1.8", "end": "U2.8", "start_mm": [108.0, 121.78], "end_mm": [160.78, 130.0], "routed": false, "width_mm": 0.25, "power_fallback": false, "expansions": 272010}
+{"net": "/RS_CTS", "start": "U1.9", "end": "U2.9", "start_mm": [108.0, 124.32], "end_mm": [163.32, 130.0], "routed": false, "width_mm": 0.25, "power_fallback": false, "expansions": 272000}
+{"net": "/RS_RI", "start": "U1.6", "end": "U2.10", "start_mm": [108.0, 116.7], "end_mm": [165.86, 130.0], "routed": false, "width_mm": 0.25, "power_fallback": false, "expansions": 272008}
+{"net": "/RS_VALID", "start": "U1.12", "end": "U2.11", "start_mm": [108.0, 131.94], "end_mm": [168.4, 130.0], "routed": false, "width_mm": 0.25, "power_fallback": false, "expansions": 272015}
+{"net": "/BTN_NEXT", "start": "U1.20", "end": "SW3.1", "start_mm": [108.0, 152.26], "end_mm": [167.0, 168.0], "routed": false, "width_mm": 0.25, "power_fallback": false, "expansions": 272010}
+{"net": "/RS_OFF_N", "start": "U1.15", "end": "U2.12", "start_mm": [108.0, 139.56], "end_mm": [170.94, 130.0], "routed": false, "width_mm": 0.25, "power_fallback": false, "expansions": 272010}
+{"net": "/GND", "start": "U1.44", "end": "U1.43", "start_mm": [133.4, 157.34], "end_mm": [133.4, 154.8], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 26}
+{"net": "/GND", "start": "SW2.2", "end": "SW1.2", "start_mm": [155.0, 172.5], "end_mm": [149.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 56}
+{"net": "/GND", "start": "SW2.2", "end": "SW3.2", "start_mm": [161.5, 172.5], "end_mm": [167.0, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 56}
+{"net": "/GND", "start": "SW2.2", "end": "SW2.2", "start_mm": [155.0, 172.5], "end_mm": [161.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 66}
+{"net": "/GND", "start": "SW3.2", "end": "SW3.2", "start_mm": [167.0, 172.5], "end_mm": [173.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 66}
+{"net": "/GND", "start": "SW1.2", "end": "SW1.2", "start_mm": [149.5, 172.5], "end_mm": [143.0, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 66}
+{"net": "/GND", "start": "DS1.1", "end": "U2.2", "start_mm": [152.19, 137.5], "end_mm": [145.54, 130.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 3234}
+{"net": "/GND", "start": "SW1.2", "end": "U1.44", "start_mm": [143.0, 172.5], "end_mm": [133.4, 157.34], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 29110}
+{"net": "/GND", "start": "U1.44", "end": "U1.22", "start_mm": [133.4, 157.34], "end_mm": [108.0, 157.34], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 16915}
+{"net": "/GND", "start": "U1.43", "end": "DS1.1", "start_mm": [133.4, 154.8], "end_mm": [152.19, 137.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 57470}
+{"net": "/GND", "start": "U2.2", "end": "U1.23", "start_mm": [145.54, 130.0], "end_mm": [133.4, 104.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 34158}
+22:45:50: Debug: Adding duplicate image handler for 'PNG file'
+22:45:50: Debug: Adding duplicate image handler for 'JPEG file'
+22:45:50: Debug: Adding duplicate image handler for 'TIFF file'
+22:45:50: Debug: Adding duplicate image handler for 'GIF file'
+22:45:50: Debug: Adding duplicate image handler for 'PNM file'
+22:45:50: Debug: Adding duplicate image handler for 'PCX file'
+22:45:50: Debug: Adding duplicate image handler for 'IFF file'
+22:45:50: Debug: Adding duplicate image handler for 'Windows icon file'
+22:45:50: Debug: Adding duplicate image handler for 'Windows cursor file'
+22:45:50: Debug: Adding duplicate image handler for 'Windows animated cursor file'
+22:45:50: Debug: Adding duplicate image handler for 'TGA file'
+22:45:50: Debug: Adding duplicate image handler for 'XPM file'
+{
+  "draft_only": true,
+  "saved": true,
+  "grid_mm": 0.1,
+  "clearance_mm": 0.25,
+  "safety_margin_mm": 0.04,
+  "via_diameter_mm": 0.7,
+  "via_drill_mm": 0.3,
+  "elapsed_seconds": 20.799824999005068,
+  "routed_tree_edges": 30,
+  "total_tree_edges": 38,
+  "tracks": 248,
+  "vias": 13,
+  "immutable_identity_sha256": "81def52e6c1d574b4d3ab1a5859a5266b893df0ea6c5b9aa7d7b688cc4a98519",
+  "input_sha256": "ab3f0775dee575a11d06f80996169f5097dfff672b69152ad9b559707f70009b",
+  "validation": "KiCad DRC must be run separately; tree-edge counts are not DRC connectivity"
+}

hardware/PCB/validation/pcb-routing-pass3.log

@@ -0,0 +1,70 @@
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+/builddir/build/BUILD/kicad-10.0.6-build/kicad-10.0.6/include/properties/property.h(607): assert "m_choices.GetCount() > 0" failed in PROPERTY_ENUM(): No enum choices defined
+{"net": "/+3V3", "start": "U1.1", "end": "U1.2", "start_mm": [108.0, 104.0], "end_mm": [108.0, 106.54], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 52}
+{"net": "/+3V3", "start": "R2.1", "end": "DS1.2", "start_mm": [154.0, 134.0], "end_mm": [154.73, 137.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 911}
+{"net": "/+3V3", "start": "U2.1", "end": "R1.1", "start_mm": [143.0, 130.0], "end_mm": [143.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 81}
+{"net": "/BTN_NEXT", "start": "SW3.1", "end": "SW3.1", "start_mm": [167.0, 168.0], "end_mm": [173.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/BTN_PREVIOUS", "start": "SW1.1", "end": "SW1.1", "start_mm": [149.5, 168.0], "end_mm": [143.0, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "SW2.1", "start_mm": [155.0, 168.0], "end_mm": [161.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 131}
+{"net": "/+3V3", "start": "DS1.2", "end": "R3.1", "start_mm": [154.73, 137.5], "end_mm": [165.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 5139}
+{"net": "/+3V3", "start": "R1.1", "end": "R2.1", "start_mm": [143.0, 134.0], "end_mm": [154.0, 134.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 14153}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "R2.2", "start_mm": [161.5, 168.0], "end_mm": [161.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 2039}
+{"net": "/BTN_NEXT", "start": "SW3.1", "end": "R3.2", "start_mm": [173.5, 168.0], "end_mm": [172.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 12615}
+{"net": "/BTN_PREVIOUS", "start": "R1.2", "end": "SW1.1", "start_mm": [150.62, 134.0], "end_mm": [149.5, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 15179}
+{"net": "/+3V3", "start": "U1.2", "end": "U2.1", "start_mm": [108.0, 106.54], "end_mm": [143.0, 130.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 894511}
+{"net": "/RS_RX", "start": "U1.11", "end": "U2.4", "start_mm": [108.0, 129.4], "end_mm": [150.62, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 51516}
+{"net": "/BTN_PREVIOUS", "start": "U1.16", "end": "R1.2", "start_mm": [108.0, 142.1], "end_mm": [150.62, 134.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 94479}
+{"net": "/RS_DCD", "start": "U1.4", "end": "U2.3", "start_mm": [108.0, 111.62], "end_mm": [148.08, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 266031}
+{"net": "/RS_TX", "start": "U1.10", "end": "U2.5", "start_mm": [108.0, 126.86], "end_mm": [153.16, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 175689}
+{"net": "/RS_DTR", "start": "U1.7", "end": "U2.6", "start_mm": [108.0, 119.24], "end_mm": [155.7, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 326823}
+{"net": "/OLED_SCL", "start": "U1.18", "end": "DS1.3", "start_mm": [108.0, 147.18], "end_mm": [157.27, 137.5], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 82557}
+{"net": "/BTN_SELECT", "start": "SW2.1", "end": "U1.19", "start_mm": [155.0, 168.0], "end_mm": [108.0, 149.72], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 147997}
+{"net": "/OLED_SDA", "start": "U1.17", "end": "DS1.4", "start_mm": [108.0, 144.64], "end_mm": [159.81, 137.5], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 266428}
+{"net": "/RS_DSR", "start": "U1.5", "end": "U2.7", "start_mm": [108.0, 114.16], "end_mm": [158.24, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 372014}
+{"net": "/RS_RTS", "start": "U1.8", "end": "U2.8", "start_mm": [108.0, 121.78], "end_mm": [160.78, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 298514}
+{"net": "/RS_CTS", "start": "U1.9", "end": "U2.9", "start_mm": [108.0, 124.32], "end_mm": [163.32, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 265272}
+{"net": "/RS_RI", "start": "U1.6", "end": "U2.10", "start_mm": [108.0, 116.7], "end_mm": [165.86, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 332506}
+{"net": "/RS_VALID", "start": "U1.12", "end": "U2.11", "start_mm": [108.0, 131.94], "end_mm": [168.4, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 348384}
+{"net": "/BTN_NEXT", "start": "U1.20", "end": "SW3.1", "start_mm": [108.0, 152.26], "end_mm": [167.0, 168.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 272795}
+{"net": "/RS_OFF_N", "start": "U1.15", "end": "U2.12", "start_mm": [108.0, 139.56], "end_mm": [170.94, 130.0], "routed": true, "width_mm": 0.25, "power_fallback": false, "expansions": 351630}
+{"net": "/GND", "start": "U1.44", "end": "U1.43", "start_mm": [133.4, 157.34], "end_mm": [133.4, 154.8], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 52}
+{"net": "/GND", "start": "SW2.2", "end": "SW1.2", "start_mm": [155.0, 172.5], "end_mm": [149.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 111}
+{"net": "/GND", "start": "SW2.2", "end": "SW3.2", "start_mm": [161.5, 172.5], "end_mm": [167.0, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 111}
+{"net": "/GND", "start": "SW2.2", "end": "SW2.2", "start_mm": [155.0, 172.5], "end_mm": [161.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "SW3.2", "end": "SW3.2", "start_mm": [167.0, 172.5], "end_mm": [173.5, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "SW1.2", "end": "SW1.2", "start_mm": [149.5, 172.5], "end_mm": [143.0, 172.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 131}
+{"net": "/GND", "start": "DS1.1", "end": "U2.2", "start_mm": [152.19, 137.5], "end_mm": [145.54, 130.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 17468}
+{"net": "/GND", "start": "SW1.2", "end": "U1.44", "start_mm": [143.0, 172.5], "end_mm": [133.4, 157.34], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 27488}
+{"net": "/GND", "start": "U1.44", "end": "U1.22", "start_mm": [133.4, 157.34], "end_mm": [108.0, 157.34], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 73753}
+{"net": "/GND", "start": "U1.43", "end": "DS1.1", "start_mm": [133.4, 154.8], "end_mm": [152.19, 137.5], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 54021}
+{"net": "/GND", "start": "U2.2", "end": "U1.23", "start_mm": [145.54, 130.0], "end_mm": [133.4, 104.0], "routed": true, "width_mm": 0.5, "power_fallback": false, "expansions": 98250}
+22:47:09: Debug: Adding duplicate image handler for 'PNG file'
+22:47:09: Debug: Adding duplicate image handler for 'JPEG file'
+22:47:09: Debug: Adding duplicate image handler for 'TIFF file'
+22:47:09: Debug: Adding duplicate image handler for 'GIF file'
+22:47:09: Debug: Adding duplicate image handler for 'PNM file'
+22:47:09: Debug: Adding duplicate image handler for 'PCX file'
+22:47:09: Debug: Adding duplicate image handler for 'IFF file'
+22:47:09: Debug: Adding duplicate image handler for 'Windows icon file'
+22:47:09: Debug: Adding duplicate image handler for 'Windows cursor file'
+22:47:09: Debug: Adding duplicate image handler for 'Windows animated cursor file'
+22:47:09: Debug: Adding duplicate image handler for 'TGA file'
+22:47:09: Debug: Adding duplicate image handler for 'XPM file'
+{
+  "draft_only": true,
+  "saved": true,
+  "grid_mm": 0.05,
+  "clearance_mm": 0.25,
+  "safety_margin_mm": 0.02,
+  "via_diameter_mm": 0.7,
+  "via_drill_mm": 0.3,
+  "elapsed_seconds": 26.517815405000874,
+  "routed_tree_edges": 38,
+  "total_tree_edges": 38,
+  "tracks": 569,
+  "vias": 20,
+  "immutable_identity_sha256": "81def52e6c1d574b4d3ab1a5859a5266b893df0ea6c5b9aa7d7b688cc4a98519",
+  "input_sha256": "41643d6089dae5ef2eee1a2071a6d11ae4c00f3c922eddfeaafff619fc5fab19",
+  "validation": "KiCad DRC must be run separately; tree-edge counts are not DRC connectivity"
+}

hardware/PCB/validation/pcb-routing-preservation.json

@@ -0,0 +1,27 @@
+{
+  "a0_snapshot_unchanged": true,
+  "a1_unrouted_snapshot_unchanged": true,
+  "protected_files_unchanged": [
+    "serial-carrier.kicad_pro",
+    "serial-carrier.kicad_sch",
+    "serial-carrier.kicad_prl",
+    "fp-lib-table",
+    "sym-lib-table",
+    "Carrier.kicad_sym",
+    "Carrier.pretty/OLED_26mm_I2C_Provisional.kicad_mod",
+    "Carrier.pretty/HW678_2x22_Provisional.kicad_mod",
+    "Carrier.pretty/MAX3243_Reference_Provisional.kicad_mod"
+  ],
+  "intentional_documentation_updates": [
+    "README.md",
+    "pcb-draft-notes.md"
+  ],
+  "cad_projection_graphics": 7,
+  "footprints_identical_except_authorized_placement": true,
+  "footprint_count": 13,
+  "unrelated_board_graphics_preserved": 5,
+  "non_owned_board_graphic_uuids_preserved": true,
+  "refreshed_device_silkscreen_items": 91,
+  "pcb_editor_lock_absent": true,
+  "final_board_sha256": "53e36538c0669604457b9e1a9ff1b1e20422970e8f9f356088c4581868ad5045"
+}

hardware/PCB/validation/pcb-routing-preservation.py

@@ -0,0 +1,99 @@
+#!/usr/bin/python3
+"""Compare A1 against the untouched A0 snapshot, including unrelated graphics."""
+import hashlib
+import json
+from pathlib import Path
+import re
+import uuid
+
+ROOT=Path(__file__).resolve().parent.parent
+OUT=ROOT/'validation'
+
+
+def parse(path):
+    tokens=iter(re.findall(r'"(?:\\.|[^"\\])*"|[()]|[^\s()]+',path.read_text()))
+    def group():
+        result=[]
+        for token in tokens:
+            if token==')':
+                return result
+            result.append(group() if token=='(' else token)
+        raise ValueError('unterminated S-expression')
+    assert next(tokens)=='('
+    return group()
+
+
+def child(item,key):
+    return next(v for v in item if isinstance(v,list) and v[0]==key)
+
+
+def ident(item):
+    return child(item,'uuid')[1].strip('"')
+
+
+def sha(path):
+    return hashlib.sha256(path.read_bytes()).hexdigest()
+
+
+report=json.loads(OUT.joinpath('pcb-routing-reposition.json').read_text())
+a0=OUT/'pcb-a0-before-reposition.kicad_pcb'
+a1=ROOT/'serial-carrier.kicad_pcb'
+assert sha(a0)==report['a0_snapshot_sha256'], 'A0 snapshot changed'
+assert sha(OUT/'pcb-routing-input.kicad_pcb')==report['a1_unrouted_sha256'], 'A1 routing input changed'
+# These two handoff documents are intentionally updated during A1 integration.
+protected={name:digest for name,digest in report['protected_file_sha256'].items()
+           if name not in ('README.md','pcb-draft-notes.md')}
+for name,digest in protected.items():
+    assert sha(ROOT/name)==digest, 'protected file changed: '+name
+old,new=parse(a0),parse(a1)
+old_fp={ident(x):x for x in old if isinstance(x,list) and x[0]=='footprint'}
+new_fp={ident(x):x for x in new if isinstance(x,list) and x[0]=='footprint'}
+assert set(old_fp)==set(new_fp)
+for key,fp in old_fp.items():
+    # Footprint geometry, fields, UUIDs and connectivity must be identical;
+    # only the top-level placement may differ, and only for the four moves.
+    ref=next(v[2].strip('"') for v in fp if isinstance(v,list) and v[:2]==['property','"Reference"'])
+    cleaned=lambda f:[v for v in f if not isinstance(v,list) or v[0]!='at']
+    assert cleaned(fp)==cleaned(new_fp[key]), 'footprint content changed: '+ref
+    if ref not in report['moves_local_mm']:
+        assert child(fp,'at')==child(new_fp[key],'at'),ref
+    else:
+        expected=report['moves_local_mm'][ref][1]
+        assert [round(float(v)-100,6) for v in child(new_fp[key],'at')[1:3]]==expected,ref
+ns=uuid.UUID('67964aa4-c3a5-45d8-9b54-250fb68e7c41')
+owned={str(uuid.uuid5(ns,str(i))) for i in range(4096)}
+cad_ns=uuid.UUID('ba7274a8-c35d-46bc-908d-cd86708fc6c4')
+cad_owned={str(uuid.uuid5(cad_ns,str(i))) for i in range(7)}
+changed_texts=set(report['changed_board_text_uuids'])
+for item in old:
+    if isinstance(item,list) and item[0]=='gr_text':
+        value=json.loads(item[1])
+        if value=='82 x 80 mm / 2 copper layers' or value.startswith('DE-9 OUT /'):
+            changed_texts.add(ident(item))
+
+def drawings(tree):
+    return {ident(x):x for x in tree if isinstance(x,list) and
+            (x[0].startswith('gr_') or x[0] in ('dimension','target','image'))}
+
+old_gr,new_gr=drawings(old),drawings(new)
+edge_ids={key for key,value in old_gr.items() if child(value,'layer')[1]=='"Edge.Cuts"'}
+assert cad_owned <= set(new_gr), 'missing CAD projection graphics'
+assert all(child(new_gr[key],'layer')[1]=='"Dwgs.User"' for key in cad_owned)
+excluded=owned|cad_owned|changed_texts|edge_ids
+unchanged_old={key:value for key,value in old_gr.items() if key not in excluded}
+unchanged_new={key:value for key,value in new_gr.items() if key not in excluded}
+assert unchanged_old==unchanged_new, 'unrelated board graphics changed'
+assert set(old_gr)-owned==set(new_gr)-owned-cad_owned, 'non-owned board graphic UUID set changed'
+assert [x for x in old if isinstance(x,list) and x[0]=='net']==[x for x in new if isinstance(x,list) and x[0]=='net']
+assert not (ROOT/'~serial-carrier.kicad_pcb.lck').exists(), 'PCB reopened before handoff'
+result=dict(a0_snapshot_unchanged=True,a1_unrouted_snapshot_unchanged=True,
+            protected_files_unchanged=list(protected),
+            intentional_documentation_updates=['README.md','pcb-draft-notes.md'],
+            cad_projection_graphics=len(cad_owned),
+            footprints_identical_except_authorized_placement=True,
+            footprint_count=len(old_fp),unrelated_board_graphics_preserved=len(unchanged_old),
+            non_owned_board_graphic_uuids_preserved=True,
+            refreshed_device_silkscreen_items=len(set(new_gr)&owned),
+            pcb_editor_lock_absent=True,final_board_sha256=sha(a1))
+OUT.joinpath('pcb-routing-preservation.json').write_text(json.dumps(result,indent=2)+'\n')
+print(json.dumps(result,indent=2))

hardware/PCB/validation/pcb-routing-reposition.json

@@ -0,0 +1,98 @@
+{
+  "revision": "A1",
+  "a0_snapshot_sha256": "25669051086d6a5315650580ead8ce847f42ae07b8d08af5d76f0a813131ff18",
+  "a1_unrouted_sha256": "df62a5aeb64a6d871a477a8c9fe94c100210d5b239a0617558907d9d3d9a6007",
+  "outline_local_mm": [
+    [
+      36,
+      0
+    ],
+    [
+      82,
+      0
+    ],
+    [
+      82,
+      80
+    ],
+    [
+      0,
+      80
+    ],
+    [
+      0,
+      19
+    ],
+    [
+      36,
+      19
+    ]
+  ],
+  "moves_local_mm": {
+    "U1": [
+      [
+        8,
+        4
+      ],
+      [
+        8,
+        23
+      ]
+    ],
+    "U2": [
+      [
+        43,
+        30
+      ],
+      [
+        43,
+        26.67
+      ]
+    ],
+    "H1": [
+      [
+        3.5,
+        3.5
+      ],
+      [
+        3.5,
+        22.5
+      ]
+    ],
+    "H2": [
+      [
+        3.5,
+        56
+      ],
+      [
+        3.5,
+        75
+      ]
+    ]
+  },
+  "changed_board_text_uuids": [
+    "e8228b54-6114-48a6-80ef-7f0a68175b1d",
+    "ce061da3-831a-4fb1-9676-9177435d649e",
+    "f45876c7-f270-4231-bfa4-b69ded09f3a4",
+    "c695eb94-004e-4a56-801a-0ca6797a46b2",
+    "94303a67-2a65-4a16-9499-2b409a657ba6",
+    "fa700fde-d4f3-437c-9b51-4322d0fd68e0",
+    "de46e0e9-8a3a-42d0-b1c7-8915a9856836"
+  ],
+  "normalized_footprints_preserved": true,
+  "nets_preserved": true,
+  "protected_file_sha256": {
+    "serial-carrier.kicad_pro": "9ad5b992785ebfe01fa7ea4e1aa391a2c7d7f1f2c3b1c13136173c301ecb6516",
+    "serial-carrier.kicad_sch": "1876ef30aae16d9eb4a421efea7c090c50cddd16a59a9bfe866ed5c802e2571c",
+    "serial-carrier.kicad_prl": "b448331403441aabec6e4718d3c82f4fac4073fa9430762d6bb0b5b34c16def9",
+    "README.md": "d3339535217e2c2e214a620e7826878d2ae635eec288041f57012966e95765ca",
+    "pcb-draft-notes.md": "7be3fa469867b98530a84a61fc978b89d853a1652963a8d24373a64f367f8360",
+    "fp-lib-table": "a56dc436d1442de03c7953b426a90444dce078d57b24f70f1675d0beb19acd4e",
+    "sym-lib-table": "f3520b095a4f6238fb7a46dd5c8ab460a8e842dc085a53d2c7f912609015b5ae",
+    "Carrier.kicad_sym": "ba642459312b5b5cb5b5021d0b573c427c3ab93a2cde51941f018bbcba07716a",
+    "Carrier.pretty/OLED_26mm_I2C_Provisional.kicad_mod": "ab2aa7cb0e84d31f18e2493088830964b04764f44873dfb0e30a4c7faa43ef37",
+    "Carrier.pretty/HW678_2x22_Provisional.kicad_mod": "87a32630a388ebd1646ca04a1152e29833735a62e2fca980eaa187c7ca386e20",
+    "Carrier.pretty/MAX3243_Reference_Provisional.kicad_mod": "90c7c0b24007a7e8cb6815641363880fe420fe60e76ea7670c83c217a6d47ecd"
+  },
+  "remaining_tracks": 0
+}

hardware/PCB/validation/pcb-routing-reposition.py

@@ -0,0 +1,133 @@
+#!/usr/bin/python3
+"""One-shot A0 -> A1 placement migration of the existing board, never regeneration.
+
+Requires --apply and the untouched pcb-a0-before-reposition.kicad_pcb snapshot.
+Never replaces the snapshot or accepts an already edited/migrated input.
+"""
+import argparse
+import hashlib
+import json
+from pathlib import Path
+import sys
+
+import pcbnew as p
+
+ROOT = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(ROOT))
+from route_pcb_draft import identity
+
+PCB = ROOT / 'serial-carrier.kicad_pcb'
+BACKUP = ROOT / 'validation/pcb-a0-before-reposition.kicad_pcb'
+LOCK = ROOT / '~serial-carrier.kicad_pcb.lck'
+OLD = [(0,0),(82,0),(82,80),(36,80),(36,61),(0,61)]
+NEW = [(36,0),(82,0),(82,80),(0,80),(0,19),(36,19)]
+MOVES = {'U1': ((8,4),(8,23)), 'U2': ((43,30),(43,26.670)),
+         'H1': ((3.5,3.5),(3.5,22.5)), 'H2': ((3.5,56),(3.5,75))}
+TEXT_MOVES = {'RF RESERVE':19, 'VERIFY ANTENNA':19, 'ESP32 HW678':19,
+              'USB ACCESS - VERIFY':19, 'DE-9 OUT / VERIFY MALE':-3.330,
+              'MAX3243 REF':-3.330}
+
+
+def vec(x,y):
+    return p.VECTOR2I(p.FromMM(x),p.FromMM(y))
+
+
+def local(v):
+    return (round(p.ToMM(v.x)-100,6),round(p.ToMM(v.y)-100,6))
+
+
+def sha(path):
+    return hashlib.sha256(path.read_bytes()).hexdigest()
+
+
+def normalized_footprints(board):
+    # Normalize placement only, retaining UUIDs, local pad geometry and linkage.
+    entries = identity(board)[1]
+    normalized = []
+    for entry in entries:
+        fields = list(entry)
+        x,y = fields[5]
+        fields[5] = (0,0)
+        pads = []
+        for pad in fields[-1]:
+            values = list(pad)
+            values[3] = (round(values[3][0]-x,6),round(values[3][1]-y,6))
+            pads.append(tuple(values))
+        fields[-1] = pads
+        normalized.append(tuple(fields))
+    return normalized
+
+
+def main():
+    parser=argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--apply',action='store_true')
+    args=parser.parse_args()
+    if not args.apply:
+        parser.error('explicit --apply required; only accepts the original A0 snapshot')
+    assert not LOCK.exists(), 'PCB Editor lock exists'
+    assert BACKUP.exists(), 'make the one-time A0 snapshot first'
+    before=PCB.read_bytes()
+    assert before==BACKUP.read_bytes(), 'current board differs from A0 snapshot; refusing migration'
+    protected=[ROOT/name for name in ('serial-carrier.kicad_pro','serial-carrier.kicad_sch',
+                'serial-carrier.kicad_prl','README.md','pcb-draft-notes.md','fp-lib-table',
+                'sym-lib-table','Carrier.kicad_sym')]
+    protected+=list((ROOT/'Carrier.pretty').glob('*'))
+    hashes={str(path.relative_to(ROOT)):sha(path) for path in protected if path.is_file()}
+    board=p.LoadBoard(str(PCB))
+    immutable=normalized_footprints(board)
+    net_table=identity(board)[-1]
+    footprints={f.GetReference():f for f in board.GetFootprints()}
+    for ref,(old,new) in MOVES.items():
+        fp=footprints[ref]
+        assert local(fp.GetPosition())==old,(ref,local(fp.GetPosition()))
+        fp.SetPosition(vec(new[0]+100,new[1]+100))
+    for track in list(board.GetTracks()):
+        board.Delete(track)
+    edges=[d for d in board.GetDrawings() if d.GetLayer()==p.Edge_Cuts]
+    assert len(edges)==6
+    for i,(a,b) in enumerate(zip(OLD,OLD[1:]+OLD[:1])):
+        edge=next(e for e in edges if frozenset((local(e.GetStart()),local(e.GetEnd())))==frozenset((a,b)))
+        aa,bb=NEW[i],NEW[(i+1)%6]
+        edge.SetStart(vec(aa[0]+100,aa[1]+100))
+        edge.SetEnd(vec(bb[0]+100,bb[1]+100))
+    assert len(board.Zones())==1 and board.Zones()[0].GetIsRuleArea()
+    zone=board.Zones()[0]
+    contour=zone.Outline().COutline(0)
+    assert {local(contour.CPoint(i)) for i in range(contour.PointCount())}=={(10,0),(31,0),(31,13),(10,13)}
+    zone.Move(vec(0,19))
+    changed_texts=[]
+    for text,dy in TEXT_MOVES.items():
+        found=[d for d in board.GetDrawings() if isinstance(d,p.PCB_TEXT) and d.GetText()==text]
+        assert len(found)==1,(text,len(found))
+        drawing=found[0]
+        drawing.Move(vec(0,dy))
+        if text=='DE-9 OUT / VERIFY MALE':
+            drawing.SetText('DE-9 OUT / NOMINAL MALE')
+        changed_texts.append(drawing.m_Uuid.AsString())
+    for d in board.GetDrawings():
+        if isinstance(d,p.PCB_TEXT) and d.GetText()=='Carrier envelope only; module overhang and connector clearance not qualified':
+            d.SetText('Nominal RS-232 metal verified; ESP32 USB / antenna / assembly clearance pending')
+            changed_texts.append(d.m_Uuid.AsString())
+    title=board.GetTitleBlock()
+    title.SetRevision('A1 DRAFT')
+    title.SetComment(0,'NOT FOR FABRICATION - USB / antenna geometry pending; verify module pinout / assembly')
+    assert normalized_footprints(board)==immutable
+    assert identity(board)[-1]==net_table
+    candidate=ROOT/'validation/pcb-routing-reposition-candidate.kicad_pcb'
+    assert p.SaveBoard(str(candidate),board,True)
+    saved=p.LoadBoard(str(candidate))
+    assert normalized_footprints(saved)==immutable
+    assert identity(saved)==identity(board)
+    assert not LOCK.exists() and PCB.read_bytes()==before
+    assert all(sha(ROOT/name)==digest for name,digest in hashes.items()), 'protected input changed'
+    candidate.replace(PCB)
+    report=dict(revision='A1',a0_snapshot_sha256=sha(BACKUP),a1_unrouted_sha256=sha(PCB),
+                outline_local_mm=NEW,moves_local_mm=MOVES,changed_board_text_uuids=changed_texts,
+                normalized_footprints_preserved=True,nets_preserved=True,
+                protected_file_sha256=hashes,remaining_tracks=len(saved.GetTracks()))
+    ROOT.joinpath('validation/pcb-routing-reposition.json').write_text(json.dumps(report,indent=2)+'\n')
+    print(json.dumps(report,indent=2))
+
+
+if __name__=='__main__':
+    main()

hardware/PCB/validation/pcb-routing-run.json

@@ -0,0 +1,665 @@
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+  "routed_tree_edges": 38,
+  "total_tree_edges": 38,
+  "tracks": 565,
+  "vias": 22,
+  "immutable_identity_sha256": "783ce7e212880e0836c93e1782d39bbfbc505fae856d9720ee6c50f5ba8f6275",
+  "input_sha256": "0ea7f0abff371eacc81262dc949f768cd42128f389ea4af9facee5034368d884",
+  "validation": "KiCad DRC must be run separately; tree-edge counts are not DRC connectivity"
+}

hardware/PCB/validation/pcb-routing-summary.md

@@ -0,0 +1,253 @@
+# A1 top-left-notch / bottom-USB routing — current result
+
+Date: 2026-09-21. Actual revised board: `../serial-carrier.kicad_pcb`.
+
+**38/38 connections across 17 multi-pad nets; 0 physical DRC violations,
+0 unconnected items; exactly 1 expected U2 footprint parity warning.**
+The warning is the board-only `Carrier:MAX3243_Reference_Provisional` assignment
+versus the intentionally blank schematic footprint, not a net mismatch.
+
+## Geometry and preservation
+
+Coordinates below are local to absolute origin (100,100) mm; all dimensions mm.
+
+- Carrier: 82 x 80, outline `[(36,0),(82,0),(82,80),(0,80),(0,19),(36,19)]`.
+- U1 origin: (8,23), formerly (8,4). Header end-pad centres now Y=76.340;
+  USB guide Y=83 is 3 mm below the bottom edge. No ESP32 body was invented.
+- U2 origin: (43,26.670), formerly (43,30). Actual reference F.Fab bare-PCB
+  front edge is absolute Y=100.000, flush with carrier local Y=0.
+- Nominal male metal external dimensions are user-confirmed: shell overhang
+  3.870, hex-mouth overhang 2.870, flange front 1.930 behind the carrier edge.
+  With this placement their local Y positions are -3.870, -2.870 and +1.930.
+  Integration added seven board-local Dwgs.User graphics for the CAD metal
+  projections and screw-lock axes.
+- H1: (3.5,22.5), H2: (3.5,75). H3/H4 unchanged at (78,4)/(78,76).
+- OLED, resistors and switches unchanged.
+- RF reserve: local X=10..31 / Y=19..32, absolute X=110..131 / Y=119..132,
+  both layers; no tracks, vias or fills inside it. Boundary remains provisional.
+
+The existing A0 board was mutated, **not regenerated**. The one-time
+`pcb-a0-before-reposition.kicad_pcb` backup remains byte-for-byte intact.
+`pcb-routing-input.kicad_pcb` is now the A1 unrouted audit input, not A0.
+`pcb-routing-preservation.py` verified all 13 complete serialized footprints
+identical except the four authorized top-level placements, including schematic
+fields, pad/net definitions, electrical UUID paths and all footprint graphics.
+Non-owned board-graphic UUIDs and unrelated graphics are preserved. ESP/RS/RF
+annotations moved with placement; the post-routing silkscreen refresh replaced
+91 owned graphics. Its edge clipping avoids silk across U2's flush front edge.
+
+All board saves used `SaveBoard(..., True)`. Project `.pro`, `.prl`, schematic,
+symbol/footprint libraries and library tables retain their original hashes.
+README and pcb-draft-notes were intentionally updated during integration. The generator's constants/text were updated but it was **not
+run**; its automatic project/netclass writes were removed. PCB Editor lock was
+absent at migration, routing, silkscreen refresh and final preservation check.
+
+## Routing and independent measurements
+
+- F.Cu/B.Cu; **565 segments, 22 through vias**.
+- **451 signal segments at 0.25 mm; 114 +3V3/GND segments at 0.5 mm**.
+- Vias: 0.7 mm copper / 0.3 mm drill. No copper pours needed.
+- Continuous measured minimum different-net/NPTH clearance: **0.270544 mm**.
+- Minimum copper/NPTH-to-edge gap: **1.900 mm**.
+- Minimum copper/NPTH-to-RF-reservation gap: **0.025 mm**.
+- Minimum via-drill edge to other drilled-hole edge: **0.820544 mm**.
+
+Two bounded passes, each with 240 seconds / 1,200,000 expansions per search:
+
+1. 31.18 seconds, 38/38, 674 segments / 16 vias, physical DRC clean. One GND
+   connection required the router's 0.25 mm fallback; strict width validation
+   correctly failed. Retained as `pcb-routing-a1-pass1.kicad_pcb` for evidence.
+2. 32.44 seconds, 38/38, 565 segments / 22 vias. Short GND connections (<=15 mm)
+   now route before longer signal fanout; long GND links remain last. All power
+   and ground now use 0.5 mm; no fallback. This is the saved current result.
+
+The grid remains 0.05 mm, physical clearance 0.25 mm plus 0.02 mm routing margin.
+No rip-up/unbounded retry or external network router was used.
+
+## Validation / rerun commands
+
+From `hardware/PCB`:
+
+```sh
+/usr/bin/python3 -B validate_pcb_draft.py
+/usr/bin/python3 -B validation/pcb-routing-check.py
+/usr/bin/python3 -B validation/pcb-routing-preservation.py
+kicad-cli pcb drc --format json --all-track-errors --severity-all --exit-code-violations -o validation/pcb-routing-all-drc.json serial-carrier.kicad_pcb
+```
+
+All passed on A1. Validators perform fresh KiCad DRC, fresh schematic-netlist
+comparison, geometry checks, continuous copper-distance checks, and routing
+save-refusal tests. DRC was read-only to preserve project settings; no copper
+zones exist to refill. Existing ignored DRC checks were not changed; see reports.
+The preservation audit includes the intentional documentation updates and seven
+CAD projection graphics while retaining electrical and project preservation checks.
+
+Rerouting remains explicitly destructive to existing/manual copper and requires:
+
+```sh
+/usr/bin/python3 -B route_pcb_draft.py --route --overwrite --replace-routes --seconds 240 --max-expansions 1200000
+/usr/bin/python3 -B add_device_silkscreen.py
+```
+
+Then rerun the validators. The one-shot `pcb-routing-reposition.py --apply`
+refuses anything except the original A0 snapshot and must **not** be rerun on A1.
+
+Current evidence: `pcb-routing-a1-pass2.log`, `pcb-routing-run.json`,
+`pcb-routing-drc.json`, `pcb-routing-all-drc.json`, `pcb-parity-drc.json`,
+`pcb-validation-summary.json`, `pcb-routing-check.json`,
+`pcb-routing-reposition.json`, and `pcb-routing-preservation.json`.
+The current post-integration board SHA-256 is recorded in
+`pcb-routing-check.json`; the CAD projection additions do not change copper.
+
+**Still a draft, not fabrication-ready.** ESP32 geometry/antenna/USB access,
+module pinout/header fit, full assembly/height clearances, power integrity and
+hardware operation remain unqualified. Nominal RS-232 metal dimensions alone
+are not assembly qualification. Placement PDF, SVG/PNG and carrier-only 3D
+preview were refreshed after CAD envelope integration. No Gerbers generated.
+
+---
+
+# Historical A0 routing result — superseded by A1 above
+
+The following records the earlier A0 routing/integration. Its dimensions, counts,
+measurements and no-save reproduction do not describe current A1. A0 `pass1`,
+`pass2`, `pass3`, `baseline` and `dry-run` files are historical; use the A1 and
+current reports listed above.
+
+Date: 2026-09-20. KiCad 10.0.6; system `/usr/bin/python3`.
+
+## Saved result
+
+Actual copper routing is saved in `../serial-carrier.kicad_pcb`, not just a preview
+or an exported proposal. **38/38 required spanning-tree connections across 17
+multi-pad nets routed; KiCad reports 0 unconnected items, 0 errors, 0 warnings.**
+Intentional single-pad `unconnected-(...)` nets retain their original names and
+are not connected to anything else.
+
+- Two copper layers, F.Cu and B.Cu.
+- 569 straight track segments: 425 at 0.25 mm for signals and 144 at 0.5 mm for
+  +3V3/GND. No narrow power-track fallback was necessary.
+- 20 through vias, 0.7 mm copper diameter / 0.3 mm drill.
+- No copper pours: all ground connections were routed explicitly.
+- Original RF rule area, x110..131 / y100..113 mm on both copper layers, preserved.
+  No tracks, vias or fills enter the reservation. Minimum copper-to-reservation
+  gap measured independently is 0.025 mm; this is geometric compliance with the
+  specified provisional boundary, **not validation of an antenna's RF needs**.
+- All 9 electrical footprints and 4 standalone mounting footprints preserved.
+  Pad positions, shapes, sizes, drills, types, nets, functions, pin types and UUIDs;
+  footprint placement, orientation, library IDs, values, UUIDs and schematic UUID
+  paths; net table, outline and RF rule-area geometry/flags match the input.
+- Generator, README, schematic, project and libraries were not edited by routing.
+  No external network dependency or manufacturing exports were used.
+
+## Validation performed
+
+From `hardware/PCB`:
+
+```sh
+kicad-cli pcb drc --format json --refill-zones --save-board -o validation/pcb-routing-drc.json serial-carrier.kicad_pcb
+kicad-cli pcb drc --format json --all-track-errors --severity-all --exit-code-violations -o validation/pcb-routing-all-drc.json serial-carrier.kicad_pcb
+/usr/bin/python3 -B validation/pcb-routing-check.py
+```
+
+Both DRC runs: **0 violations and 0 unconnected items**. No DRC settings or
+exclusions were added or changed. Existing project rules specify 0.25 mm minimum
+clearance, 0.5 mm copper-edge clearance, 0.25 mm minimum track width and 0.7 mm
+minimum via diameter.
+
+Independent continuous-geometry audit (`pcb-routing-check.json`):
+
+| Check | Measured minimum | Requirement |
+|---|---:|---:|
+| Different-net copper / copper-to-NPTH clearance | 0.275 mm | 0.25 mm |
+| Copper or NPTH edge to board edge | 0.525 mm | 0.5 mm |
+| Copper / NPTH edge to RF reserve | 0.025 mm | No intersection |
+| Via drill edge to another drilled hole edge | 0.840175 mm | 0.25 mm |
+
+The audit uses exact straight-line/point/rectangle distance calculations with
+copper radii, rather than the router's raster masks. It also verifies dimensions,
+source-preservation invariants, and three overwrite-refusal cases. Requires
+locally installed `pcbnew`, NumPy and Shapely; the router itself only needs
+`pcbnew` and NumPy.
+
+DRC still honors the project's pre-existing ignored checks:
+`missing_courtyard`, `track_not_centered_on_via`,
+`tuning_profile_track_geometries`, `footprint_filters_mismatch`, and
+`footprint_type_mismatch`. `--severity-all` does not enable ignored checks.
+The routing subtask compared electrical UUID linkage and pad-net assignments
+with the input board. Subsequent integration also ran fresh schematic-parity DRC
+and added missing symbol metadata fields to the PCB without changing copper.
+That check reports exactly one expected U2 footprint warning (provisional PCB
+footprint versus intentionally blank schematic assignment); no net mismatch.
+See `pcb-parity-drc.json` and `pcb-validation-summary.json`.
+
+## Method and bounded passes
+
+`../route_pcb_draft.py` uses a two-layer 8-direction raster A* search, an explicit
+via cost, exact-pad-centre terminal stubs, conservative foreign-copper and hole
+obstacles, and only collinear path compression. It preserves the L-shaped edge
+and RF reservation. Per-net minimum spanning trees connect every physical pad,
+including duplicate switch contacts; short links precede longer links and GND is
+last. It does not optimize return-current paths, topology or total via count.
+
+1. Initial 0.1 mm raster / 0.04 mm safety margin / 250,000 expansions per search:
+   29/38 connections; DRC 0 violations, 9 unconnected.
+2. Increased search allowance to 1,200,000 expansions: 30/38; DRC 0 violations,
+   8 unconnected. Some raster header passages were blocked, not just expensive.
+3. Final 0.05 mm raster / 0.02 mm additional safety margin, with 0.25 mm physical
+   clearance unchanged: 38/38 in approximately 26.5 seconds; DRC fully connected.
+   Each pass had a 240-second routing deadline. No unresolved routing remains.
+
+A KiCad Python binding ownership problem in the first replacement attempt caused
+an exception/segfault before any board save. Replacement now uses `board.Delete`
+instead of `board.Remove`; the subsequent save and no-save rerun both passed.
+The known startup PROPERTY_ENUM assertions do not prevent validation.
+
+## Rerun safety
+
+By default the script never saves. The existing routed board is protected even
+from a preview unless `--replace-routes` is given. A preview can be run with:
+
+```sh
+/usr/bin/python3 -B route_pcb_draft.py --replace-routes --seconds 240
+```
+
+This exact no-save workflow was tested: it again found 38/38 connections, 569
+segments and 20 vias, and left the board byte-for-byte unchanged.
+
+**The following command discards all existing/manual tracks and vias**, then
+replaces them with fresh draft routing. Back up manual work first:
+
+```sh
+/usr/bin/python3 -B route_pcb_draft.py --route --overwrite --replace-routes --seconds 240 --max-expansions 1200000
+```
+
+The script refuses a PCB-editor lock, unexpected outline/RF/board structure,
+unsupported pad orientation/layers, unapproved existing routes, or detected board
+changes before save. Candidate serialization must preserve immutable geometry
+and linkage before replacing the board. It deliberately does not run DRC itself:
+rerun the validation commands after any routing change. Runtime/expansion limits
+can produce a partial board; inspect both the run report and actual DRC, not just
+the script exit status.
+
+## Evidence and remaining limitations
+
+- `pcb-routing-input.kicad_pcb`: unrouted input snapshot, after baseline DRC save.
+- `pcb-routing-baseline.json`: 38 unconnected / no violations before routing.
+- `pcb-routing-pass1-drc.json`, `pcb-routing-pass2-drc.json`: intermediate DRC.
+- `pcb-routing-pass2.log`, `pcb-routing-pass3.log`: bounded routing progress.
+- `pcb-routing-run.json`: final saved-route metrics and connection list.
+- `pcb-routing-drc.json`, `pcb-routing-all-drc.json`: final KiCad DRC evidence.
+- `pcb-routing-check.py`, `pcb-routing-check.json`: repeatable independent audit.
+- `pcb-routing-dry-run.log`: successful final no-save reproduction.
+
+Routing-only DRC-saved snapshot SHA-256 (before integration copied schematic
+metadata fields): `bf94b6c9b00c43a97f933054758a2c9d6541981ae09f2f285dcdb567bd73d9b1`.
+The current post-integration hash is recorded by `pcb-routing-check.json`;
+geometry, pad-net linkage and copper are unchanged by the metadata copy.
+
+**Still DRAFT / NOT FOR FABRICATION.** Provisional module/connector geometry,
+antenna envelope, assembly/courtyard clearances, USB access, male RS-232 connector
+fit, physical pin mapping, power integrity, EMI and hardware operation are not
+qualified by routing or DRC. All previously documented mechanical/electrical
+release gates remain. No physical-device or manufacturing validation performed.

hardware/PCB/validation/pcb-source-netlist.xml

@@ -0,0 +1,604 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<export version="E">
+  <design>
+    <source>/home/mscholz/Repos/ESP32_serial_swiss_army_knife/hardware/PCB/serial-carrier.kicad_sch</source>
+    <date>2026-09-21T11:39:08</date>
+    <tool>Eeschema 10.0.6-1.fc44</tool>
+    <sheet number="1" name="/" tstamps="/">
+      <title_block>
+        <title>ESP32 Serial Swiss Army Knife - Module Carrier</title>
+        <company/>
+        <rev>A0 DRAFT</rev>
+        <date>2026-09-20</date>
+        <source>serial-carrier.kicad_sch</source>
+        <comment number="1" value="Not fabrication-ready: provisional module footprints and male RS-232 mapping"/>
+        <comment number="2" value=""/>
+        <comment number="3" value=""/>
+        <comment number="4" value=""/>
+        <comment number="5" value=""/>
+        <comment number="6" value=""/>
+        <comment number="7" value=""/>
+        <comment number="8" value=""/>
+        <comment number="9" value=""/>
+      </title_block>
+    </sheet>
+  </design>
+  <components>
+    <comp ref="DS1">
+      <value>128x64 I2C OLED / 0x3C</value>
+      <footprint>Carrier:OLED_26mm_I2C_Provisional</footprint>
+      <fields>
+        <field name="Status">Module outline/header/display user fit-verified; pad/drill fit provisional</field>
+        <field name="Footprint">Carrier:OLED_26mm_I2C_Provisional</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="OLED_I2C_26mm" description="User fit-verified 26 mm OLED; front/top header GND VCC SCL SDA"/>
+      <property name="Status" value="Module outline/header/display user fit-verified; pad/drill fit provisional"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>0ae411c1-94cc-5551-9037-1d59c01a8ee5</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+            <pin num="3"/>
+            <pin num="4"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="R1">
+      <value>2.2k 1%</value>
+      <footprint>Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</footprint>
+      <fields>
+        <field name="Rating">At least 0.125 W; exact resistor MPN pending</field>
+        <field name="Footprint">Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="R" description="Resistor, axial DIN0207 footprint; exact MPN pending"/>
+      <property name="Rating" value="At least 0.125 W; exact resistor MPN pending"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>defb78eb-632f-5f9d-a59d-dffbb1d31dec</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="R2">
+      <value>2.2k 1%</value>
+      <footprint>Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</footprint>
+      <fields>
+        <field name="Rating">At least 0.125 W; exact resistor MPN pending</field>
+        <field name="Footprint">Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="R" description="Resistor, axial DIN0207 footprint; exact MPN pending"/>
+      <property name="Rating" value="At least 0.125 W; exact resistor MPN pending"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>405055c0-35ab-5334-ad4d-30d45c5ef6f2</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="R3">
+      <value>2.2k 1%</value>
+      <footprint>Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</footprint>
+      <fields>
+        <field name="Rating">At least 0.125 W; exact resistor MPN pending</field>
+        <field name="Footprint">Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="R" description="Resistor, axial DIN0207 footprint; exact MPN pending"/>
+      <property name="Rating" value="At least 0.125 W; exact resistor MPN pending"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>78f9a74f-5d91-5687-b50e-68176333df23</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="SW1">
+      <value>B3F-1000</value>
+      <footprint>Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</footprint>
+      <fields>
+        <field name="Manufacturer">Omron</field>
+        <field name="MPN">B3F-1000</field>
+        <field name="Function">Previous / back</field>
+        <field name="Procurement">Live stock not verified</field>
+        <field name="Footprint">Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="SW_NO" description="Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs"/>
+      <property name="Manufacturer" value="Omron"/>
+      <property name="MPN" value="B3F-1000"/>
+      <property name="Function" value="Previous / back"/>
+      <property name="Procurement" value="Live stock not verified"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>dd5f1f75-0093-55fc-9814-437ed26871eb</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="SW2">
+      <value>B3F-1000</value>
+      <footprint>Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</footprint>
+      <fields>
+        <field name="Manufacturer">Omron</field>
+        <field name="MPN">B3F-1000</field>
+        <field name="Function">Select / confirm</field>
+        <field name="Procurement">Live stock not verified</field>
+        <field name="Footprint">Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="SW_NO" description="Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs"/>
+      <property name="Manufacturer" value="Omron"/>
+      <property name="MPN" value="B3F-1000"/>
+      <property name="Function" value="Select / confirm"/>
+      <property name="Procurement" value="Live stock not verified"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>c522a716-55a4-584d-a12e-ab135b4c08eb</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="SW3">
+      <value>B3F-1000</value>
+      <footprint>Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</footprint>
+      <fields>
+        <field name="Manufacturer">Omron</field>
+        <field name="MPN">B3F-1000</field>
+        <field name="Function">Next</field>
+        <field name="Procurement">Live stock not verified</field>
+        <field name="Footprint">Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="SW_NO" description="Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs"/>
+      <property name="Manufacturer" value="Omron"/>
+      <property name="MPN" value="B3F-1000"/>
+      <property name="Function" value="Next"/>
+      <property name="Procurement" value="Live stock not verified"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>35caa6bb-42a6-512c-848c-f1e4457aa97f</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="U1">
+      <value>HW678 / S3-N16R8</value>
+      <footprint>Carrier:HW678_2x22_Provisional</footprint>
+      <fields>
+        <field name="Status">Header geometry nominal; outline/antenna clearance pending</field>
+        <field name="Pin_numbering">Left 1-22; right 23-44; both top-to-bottom, antenna up</field>
+        <field name="Footprint">Carrier:HW678_2x22_Provisional</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="HW678_N16R8" description="HW-678 V0.0.0 / N16R8 carrier interface; project numbering; onboard USB/regulator retained"/>
+      <property name="Status" value="Header geometry nominal; outline/antenna clearance pending"/>
+      <property name="Pin_numbering" value="Left 1-22; right 23-44; both top-to-bottom, antenna up"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>3ab265d0-7fd3-5891-94eb-d39426c6a8a3</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+            <pin num="3"/>
+            <pin num="4"/>
+            <pin num="5"/>
+            <pin num="6"/>
+            <pin num="7"/>
+            <pin num="8"/>
+            <pin num="9"/>
+            <pin num="10"/>
+            <pin num="11"/>
+            <pin num="12"/>
+            <pin num="13"/>
+            <pin num="14"/>
+            <pin num="15"/>
+            <pin num="16"/>
+            <pin num="17"/>
+            <pin num="18"/>
+            <pin num="19"/>
+            <pin num="20"/>
+            <pin num="21"/>
+            <pin num="22"/>
+            <pin num="23"/>
+            <pin num="24"/>
+            <pin num="25"/>
+            <pin num="26"/>
+            <pin num="27"/>
+            <pin num="28"/>
+            <pin num="29"/>
+            <pin num="30"/>
+            <pin num="31"/>
+            <pin num="32"/>
+            <pin num="33"/>
+            <pin num="34"/>
+            <pin num="35"/>
+            <pin num="36"/>
+            <pin num="37"/>
+            <pin num="38"/>
+            <pin num="39"/>
+            <pin num="40"/>
+            <pin num="41"/>
+            <pin num="42"/>
+            <pin num="43"/>
+            <pin num="44"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="U2">
+      <value>Adafruit MAX3243 / male 6253</value>
+      <fields>
+        <field name="Status">VERIFY male header numbering; footprint intentionally unassigned</field>
+        <field name="Datasheet_source">adafruit-research.md; reference female 5988 CAD</field>
+        <field name="Footprint"/>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="MAX3243_Module_Reference" description="Adafruit male 6253 intended; physical numbering from published female 5988 CAD, VERIFY MALE"/>
+      <property name="Status" value="VERIFY male header numbering; footprint intentionally unassigned"/>
+      <property name="Datasheet_source" value="adafruit-research.md; reference female 5988 CAD"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>1127195e-e393-5d1d-9119-b25d10556144</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+            <pin num="3"/>
+            <pin num="4"/>
+            <pin num="5"/>
+            <pin num="6"/>
+            <pin num="7"/>
+            <pin num="8"/>
+            <pin num="9"/>
+            <pin num="10"/>
+            <pin num="11"/>
+            <pin num="12"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+  </components>
+  <libparts>
+    <libpart lib="Carrier" part="HW678_N16R8">
+      <description>HW-678 V0.0.0 / N16R8 carrier interface; project numbering; onboard USB/regulator retained</description>
+      <fields>
+        <field name="Reference">U</field>
+        <field name="Value">HW678_N16R8</field>
+        <field name="Footprint">Carrier:HW678_2x22_Provisional</field>
+        <field name="Datasheet"/>
+        <field name="Description">HW-678 V0.0.0 / N16R8 carrier interface; project numbering; onboard USB/regulator retained</field>
+      </fields>
+      <pins>
+        <pin num="1" name="3V3" type="power_out"/>
+        <pin num="2" name="3V3" type="passive"/>
+        <pin num="3" name="EN" type="input"/>
+        <pin num="4" name="GPIO4" type="input"/>
+        <pin num="5" name="GPIO5" type="input"/>
+        <pin num="6" name="GPIO6" type="input"/>
+        <pin num="7" name="GPIO7" type="output"/>
+        <pin num="8" name="GPIO15" type="output"/>
+        <pin num="9" name="GPIO16" type="input"/>
+        <pin num="10" name="GPIO17" type="output"/>
+        <pin num="11" name="GPIO18" type="input"/>
+        <pin num="12" name="GPIO8" type="input"/>
+        <pin num="13" name="GPIO3" type="bidirectional"/>
+        <pin num="14" name="GPIO46" type="bidirectional"/>
+        <pin num="15" name="GPIO9" type="bidirectional"/>
+        <pin num="16" name="GPIO10" type="input"/>
+        <pin num="17" name="GPIO11" type="bidirectional"/>
+        <pin num="18" name="GPIO12" type="output"/>
+        <pin num="19" name="GPIO13" type="input"/>
+        <pin num="20" name="GPIO14" type="input"/>
+        <pin num="21" name="5V" type="passive"/>
+        <pin num="22" name="GND" type="power_out"/>
+        <pin num="23" name="GND" type="passive"/>
+        <pin num="24" name="GPIO43" type="bidirectional"/>
+        <pin num="25" name="GPIO44" type="bidirectional"/>
+        <pin num="26" name="GPIO1" type="bidirectional"/>
+        <pin num="27" name="GPIO2" type="bidirectional"/>
+        <pin num="28" name="GPIO42" type="bidirectional"/>
+        <pin num="29" name="GPIO41" type="bidirectional"/>
+        <pin num="30" name="GPIO40" type="bidirectional"/>
+        <pin num="31" name="GPIO39" type="bidirectional"/>
+        <pin num="32" name="GPIO38" type="bidirectional"/>
+        <pin num="33" name="GPIO37" type="bidirectional"/>
+        <pin num="34" name="GPIO36" type="bidirectional"/>
+        <pin num="35" name="GPIO35" type="bidirectional"/>
+        <pin num="36" name="GPIO0" type="bidirectional"/>
+        <pin num="37" name="GPIO45" type="bidirectional"/>
+        <pin num="38" name="GPIO48" type="bidirectional"/>
+        <pin num="39" name="GPIO47" type="bidirectional"/>
+        <pin num="40" name="GPIO21" type="bidirectional"/>
+        <pin num="41" name="GPIO20" type="bidirectional"/>
+        <pin num="42" name="GPIO19" type="bidirectional"/>
+        <pin num="43" name="GND" type="passive"/>
+        <pin num="44" name="GND" type="passive"/>
+      </pins>
+    </libpart>
+    <libpart lib="Carrier" part="MAX3243_Module_Reference">
+      <description>Adafruit male 6253 intended; physical numbering from published female 5988 CAD, VERIFY MALE</description>
+      <fields>
+        <field name="Reference">U</field>
+        <field name="Value">MAX3243_Module_Reference</field>
+        <field name="Footprint"/>
+        <field name="Datasheet"/>
+        <field name="Description">Adafruit male 6253 intended; physical numbering from published female 5988 CAD, VERIFY MALE</field>
+      </fields>
+      <pins>
+        <pin num="1" name="Vin" type="power_in"/>
+        <pin num="2" name="GND" type="power_in"/>
+        <pin num="3" name="DCD" type="output"/>
+        <pin num="4" name="RX" type="output"/>
+        <pin num="5" name="TX" type="input"/>
+        <pin num="6" name="DTR" type="input"/>
+        <pin num="7" name="DSR" type="output"/>
+        <pin num="8" name="RTS" type="input"/>
+        <pin num="9" name="CTS" type="output"/>
+        <pin num="10" name="RI" type="output"/>
+        <pin num="11" name="VLD" type="output"/>
+        <pin num="12" name="OFF_N" type="input"/>
+      </pins>
+    </libpart>
+    <libpart lib="Carrier" part="OLED_I2C_26mm">
+      <description>User fit-verified 26 mm OLED; front/top header GND VCC SCL SDA</description>
+      <fields>
+        <field name="Reference">DS</field>
+        <field name="Value">OLED_I2C_26mm</field>
+        <field name="Footprint">Carrier:OLED_26mm_I2C_Provisional</field>
+        <field name="Datasheet"/>
+        <field name="Description">User fit-verified 26 mm OLED; front/top header GND VCC SCL SDA</field>
+      </fields>
+      <pins>
+        <pin num="1" name="GND" type="power_in"/>
+        <pin num="2" name="VCC" type="power_in"/>
+        <pin num="3" name="SCL" type="input"/>
+        <pin num="4" name="SDA" type="bidirectional"/>
+      </pins>
+    </libpart>
+    <libpart lib="Carrier" part="R">
+      <description>Resistor, axial DIN0207 footprint; exact MPN pending</description>
+      <fields>
+        <field name="Reference">R</field>
+        <field name="Value">R</field>
+        <field name="Footprint">Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</field>
+        <field name="Datasheet"/>
+        <field name="Description">Resistor, axial DIN0207 footprint; exact MPN pending</field>
+      </fields>
+      <pins>
+        <pin num="1" name="" type="passive"/>
+        <pin num="2" name="" type="passive"/>
+      </pins>
+    </libpart>
+    <libpart lib="Carrier" part="SW_NO">
+      <description>Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs</description>
+      <fields>
+        <field name="Reference">SW</field>
+        <field name="Value">SW_NO</field>
+        <field name="Footprint">Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</field>
+        <field name="Datasheet"/>
+        <field name="Description">Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs</field>
+      </fields>
+      <pins>
+        <pin num="1" name="" type="passive"/>
+        <pin num="2" name="" type="passive"/>
+      </pins>
+    </libpart>
+  </libparts>
+  <libraries>
+    <library logical="Carrier">
+      <uri>${KIPRJMOD}/Carrier.kicad_sym</uri>
+    </library>
+  </libraries>
+  <nets>
+    <net code="1" name="/+3V3" class="Power">
+      <node ref="DS1" pin="2" pinfunction="VCC_2" pintype="power_in"/>
+      <node ref="R1" pin="1" pintype="passive"/>
+      <node ref="R2" pin="1" pintype="passive"/>
+      <node ref="R3" pin="1" pintype="passive"/>
+      <node ref="U1" pin="1" pinfunction="3V3_1" pintype="power_out"/>
+      <node ref="U1" pin="2" pinfunction="3V3_2" pintype="passive"/>
+      <node ref="U2" pin="1" pinfunction="Vin_1" pintype="power_in"/>
+    </net>
+    <net code="2" name="/BTN_NEXT" class="Default">
+      <node ref="R3" pin="2" pintype="passive"/>
+      <node ref="SW3" pin="1" pintype="passive"/>
+      <node ref="U1" pin="20" pinfunction="GPIO14_20" pintype="input"/>
+    </net>
+    <net code="3" name="/BTN_PREVIOUS" class="Default">
+      <node ref="R1" pin="2" pintype="passive"/>
+      <node ref="SW1" pin="1" pintype="passive"/>
+      <node ref="U1" pin="16" pinfunction="GPIO10_16" pintype="input"/>
+    </net>
+    <net code="4" name="/BTN_SELECT" class="Default">
+      <node ref="R2" pin="2" pintype="passive"/>
+      <node ref="SW2" pin="1" pintype="passive"/>
+      <node ref="U1" pin="19" pinfunction="GPIO13_19" pintype="input"/>
+    </net>
+    <net code="5" name="/GND" class="Power">
+      <node ref="DS1" pin="1" pinfunction="GND_1" pintype="power_in"/>
+      <node ref="SW1" pin="2" pintype="passive"/>
+      <node ref="SW2" pin="2" pintype="passive"/>
+      <node ref="SW3" pin="2" pintype="passive"/>
+      <node ref="U1" pin="22" pinfunction="GND_22" pintype="power_out"/>
+      <node ref="U1" pin="23" pinfunction="GND_23" pintype="passive"/>
+      <node ref="U1" pin="43" pinfunction="GND_43" pintype="passive"/>
+      <node ref="U1" pin="44" pinfunction="GND_44" pintype="passive"/>
+      <node ref="U2" pin="2" pinfunction="GND_2" pintype="power_in"/>
+    </net>
+    <net code="6" name="/OLED_SCL" class="Default">
+      <node ref="DS1" pin="3" pinfunction="SCL_3" pintype="input"/>
+      <node ref="U1" pin="18" pinfunction="GPIO12_18" pintype="output"/>
+    </net>
+    <net code="7" name="/OLED_SDA" class="Default">
+      <node ref="DS1" pin="4" pinfunction="SDA_4" pintype="bidirectional"/>
+      <node ref="U1" pin="17" pinfunction="GPIO11_17" pintype="bidirectional"/>
+    </net>
+    <net code="8" name="/RS_CTS" class="Default">
+      <node ref="U1" pin="9" pinfunction="GPIO16_9" pintype="input"/>
+      <node ref="U2" pin="9" pinfunction="CTS_9" pintype="output"/>
+    </net>
+    <net code="9" name="/RS_DCD" class="Default">
+      <node ref="U1" pin="4" pinfunction="GPIO4_4" pintype="input"/>
+      <node ref="U2" pin="3" pinfunction="DCD_3" pintype="output"/>
+    </net>
+    <net code="10" name="/RS_DSR" class="Default">
+      <node ref="U1" pin="5" pinfunction="GPIO5_5" pintype="input"/>
+      <node ref="U2" pin="7" pinfunction="DSR_7" pintype="output"/>
+    </net>
+    <net code="11" name="/RS_DTR" class="Default">
+      <node ref="U1" pin="7" pinfunction="GPIO7_7" pintype="output"/>
+      <node ref="U2" pin="6" pinfunction="DTR_6" pintype="input"/>
+    </net>
+    <net code="12" name="/RS_OFF_N" class="Default">
+      <node ref="U1" pin="15" pinfunction="GPIO9_15" pintype="bidirectional"/>
+      <node ref="U2" pin="12" pinfunction="OFF_N_12" pintype="input"/>
+    </net>
+    <net code="13" name="/RS_RI" class="Default">
+      <node ref="U1" pin="6" pinfunction="GPIO6_6" pintype="input"/>
+      <node ref="U2" pin="10" pinfunction="RI_10" pintype="output"/>
+    </net>
+    <net code="14" name="/RS_RTS" class="Default">
+      <node ref="U1" pin="8" pinfunction="GPIO15_8" pintype="output"/>
+      <node ref="U2" pin="8" pinfunction="RTS_8" pintype="input"/>
+    </net>
+    <net code="15" name="/RS_RX" class="Default">
+      <node ref="U1" pin="11" pinfunction="GPIO18_11" pintype="input"/>
+      <node ref="U2" pin="4" pinfunction="RX_4" pintype="output"/>
+    </net>
+    <net code="16" name="/RS_TX" class="Default">
+      <node ref="U1" pin="10" pinfunction="GPIO17_10" pintype="output"/>
+      <node ref="U2" pin="5" pinfunction="TX_5" pintype="input"/>
+    </net>
+    <net code="17" name="/RS_VALID" class="Default">
+      <node ref="U1" pin="12" pinfunction="GPIO8_12" pintype="input"/>
+      <node ref="U2" pin="11" pinfunction="VLD_11" pintype="output"/>
+    </net>
+    <net code="18" name="unconnected-(U1-5V-Pad21)" class="Default">
+      <node ref="U1" pin="21" pinfunction="5V_21" pintype="passive+no_connect"/>
+    </net>
+    <net code="19" name="unconnected-(U1-EN-Pad3)" class="Default">
+      <node ref="U1" pin="3" pinfunction="EN_3" pintype="input+no_connect"/>
+    </net>
+    <net code="20" name="unconnected-(U1-GPIO0-Pad36)" class="Default">
+      <node ref="U1" pin="36" pinfunction="GPIO0_36" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="21" name="unconnected-(U1-GPIO1-Pad26)" class="Default">
+      <node ref="U1" pin="26" pinfunction="GPIO1_26" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="22" name="unconnected-(U1-GPIO2-Pad27)" class="Default">
+      <node ref="U1" pin="27" pinfunction="GPIO2_27" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="23" name="unconnected-(U1-GPIO3-Pad13)" class="Default">
+      <node ref="U1" pin="13" pinfunction="GPIO3_13" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="24" name="unconnected-(U1-GPIO19-Pad42)" class="Default">
+      <node ref="U1" pin="42" pinfunction="GPIO19_42" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="25" name="unconnected-(U1-GPIO20-Pad41)" class="Default">
+      <node ref="U1" pin="41" pinfunction="GPIO20_41" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="26" name="unconnected-(U1-GPIO21-Pad40)" class="Default">
+      <node ref="U1" pin="40" pinfunction="GPIO21_40" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="27" name="unconnected-(U1-GPIO35-Pad35)" class="Default">
+      <node ref="U1" pin="35" pinfunction="GPIO35_35" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="28" name="unconnected-(U1-GPIO36-Pad34)" class="Default">
+      <node ref="U1" pin="34" pinfunction="GPIO36_34" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="29" name="unconnected-(U1-GPIO37-Pad33)" class="Default">
+      <node ref="U1" pin="33" pinfunction="GPIO37_33" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="30" name="unconnected-(U1-GPIO38-Pad32)" class="Default">
+      <node ref="U1" pin="32" pinfunction="GPIO38_32" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="31" name="unconnected-(U1-GPIO39-Pad31)" class="Default">
+      <node ref="U1" pin="31" pinfunction="GPIO39_31" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="32" name="unconnected-(U1-GPIO40-Pad30)" class="Default">
+      <node ref="U1" pin="30" pinfunction="GPIO40_30" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="33" name="unconnected-(U1-GPIO41-Pad29)" class="Default">
+      <node ref="U1" pin="29" pinfunction="GPIO41_29" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="34" name="unconnected-(U1-GPIO42-Pad28)" class="Default">
+      <node ref="U1" pin="28" pinfunction="GPIO42_28" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="35" name="unconnected-(U1-GPIO43-Pad24)" class="Default">
+      <node ref="U1" pin="24" pinfunction="GPIO43_24" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="36" name="unconnected-(U1-GPIO44-Pad25)" class="Default">
+      <node ref="U1" pin="25" pinfunction="GPIO44_25" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="37" name="unconnected-(U1-GPIO45-Pad37)" class="Default">
+      <node ref="U1" pin="37" pinfunction="GPIO45_37" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="38" name="unconnected-(U1-GPIO46-Pad14)" class="Default">
+      <node ref="U1" pin="14" pinfunction="GPIO46_14" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="39" name="unconnected-(U1-GPIO47-Pad39)" class="Default">
+      <node ref="U1" pin="39" pinfunction="GPIO47_39" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="40" name="unconnected-(U1-GPIO48-Pad38)" class="Default">
+      <node ref="U1" pin="38" pinfunction="GPIO48_38" pintype="bidirectional+no_connect"/>
+    </net>
+  </nets>
+</export>

hardware/PCB/validation/pcb-validation-summary.json

@@ -0,0 +1,142 @@
+{
+  "carrier_bounds_mm": [
+    82,
+    80
+  ],
+  "outline_local_mm": [
+    [
+      36,
+      0
+    ],
+    [
+      82,
+      0
+    ],
+    [
+      82,
+      80
+    ],
+    [
+      0,
+      80
+    ],
+    [
+      0,
+      19
+    ],
+    [
+      36,
+      19
+    ]
+  ],
+  "placements_local_mm": {
+    "U1": [
+      8,
+      23
+    ],
+    "U2": [
+      43,
+      26.67
+    ],
+    "DS1": [
+      43,
+      36
+    ],
+    "R1": [
+      43,
+      34
+    ],
+    "R2": [
+      54,
+      34
+    ],
+    "R3": [
+      65,
+      34
+    ],
+    "SW1": [
+      43,
+      68
+    ],
+    "SW2": [
+      55,
+      68
+    ],
+    "SW3": [
+      67,
+      68
+    ],
+    "H1": [
+      3.5,
+      22.5
+    ],
+    "H2": [
+      3.5,
+      75
+    ],
+    "H3": [
+      78,
+      4
+    ],
+    "H4": [
+      78,
+      76
+    ]
+  },
+  "rf_reserve_absolute_mm": [
+    110,
+    119,
+    131,
+    132
+  ],
+  "u2_bare_pcb_front_local_y_mm": 0.0,
+  "nominal_user_confirmed_rs232_metal_mm": {
+    "shell_overhang": 3.87,
+    "hex_mouth_overhang": 2.87,
+    "flange_front_inset": 1.93
+  },
+  "tracks": 565,
+  "vias": 22,
+  "copper_layers": 2,
+  "draft_thickness_mm": 1.6,
+  "electrical_footprints": 9,
+  "proposed_M3_mounts": 4,
+  "physical_DRC_violations": 0,
+  "unconnected_items": 0,
+  "schematic_pad_nets_match": true,
+  "known_parity_warning": "U2 reference footprint assigned on PCB only; schematic footprint intentionally blank; nominal male external metal dimensions user-confirmed",
+  "project_settings_sha256": "9ad5b992785ebfe01fa7ea4e1aa391a2c7d7f1f2c3b1c13136173c301ecb6516",
+  "ignored_DRC_checks": [
+    {
+      "description": "Footprint has no courtyard defined",
+      "key": "missing_courtyard"
+    },
+    {
+      "description": "Track endpoint not centered on via",
+      "key": "track_not_centered_on_via"
+    },
+    {
+      "description": "Tuning profile track geometries",
+      "key": "tuning_profile_track_geometries"
+    },
+    {
+      "description": "Footprint doesn't match symbol's footprint filters",
+      "key": "footprint_filters_mismatch"
+    },
+    {
+      "description": "Footprint component type doesn't match footprint pads",
+      "key": "footprint_type_mismatch"
+    }
+  ],
+  "not_validated": [
+    "male module pin map/header fit",
+    "ESP32 geometry and complete assembly envelope/heights",
+    "header/socket fit",
+    "RF performance and antenna clearance",
+    "power/return-path integrity",
+    "USB power path",
+    "OLED pull-ups",
+    "fabrication process",
+    "hardware operation"
+  ]
+}

hardware/PCB/validation/serial-carrier.xml

@@ -0,0 +1,604 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<export version="E">
+  <design>
+    <source>/home/mscholz/Repos/ESP32_serial_swiss_army_knife/hardware/PCB/serial-carrier.kicad_sch</source>
+    <date>2026-09-20T20:14:45</date>
+    <tool>Eeschema 10.0.6-1.fc44</tool>
+    <sheet number="1" name="/" tstamps="/">
+      <title_block>
+        <title>ESP32 Serial Swiss Army Knife - Module Carrier</title>
+        <company/>
+        <rev>A0 DRAFT</rev>
+        <date>2026-09-20</date>
+        <source>serial-carrier.kicad_sch</source>
+        <comment number="1" value="Not fabrication-ready: provisional module footprints and male RS-232 mapping"/>
+        <comment number="2" value=""/>
+        <comment number="3" value=""/>
+        <comment number="4" value=""/>
+        <comment number="5" value=""/>
+        <comment number="6" value=""/>
+        <comment number="7" value=""/>
+        <comment number="8" value=""/>
+        <comment number="9" value=""/>
+      </title_block>
+    </sheet>
+  </design>
+  <components>
+    <comp ref="DS1">
+      <value>128x64 I2C OLED / 0x3C</value>
+      <footprint>Carrier:OLED_26mm_I2C_Provisional</footprint>
+      <fields>
+        <field name="Status">Module outline/header/display user fit-verified; pad/drill fit provisional</field>
+        <field name="Footprint">Carrier:OLED_26mm_I2C_Provisional</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="OLED_I2C_26mm" description="User fit-verified 26 mm OLED; front/top header GND VCC SCL SDA"/>
+      <property name="Status" value="Module outline/header/display user fit-verified; pad/drill fit provisional"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>0ae411c1-94cc-5551-9037-1d59c01a8ee5</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+            <pin num="3"/>
+            <pin num="4"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="R1">
+      <value>2.2k 1%</value>
+      <footprint>Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</footprint>
+      <fields>
+        <field name="Rating">At least 0.125 W; exact resistor MPN pending</field>
+        <field name="Footprint">Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="R" description="Resistor, axial DIN0207 footprint; exact MPN pending"/>
+      <property name="Rating" value="At least 0.125 W; exact resistor MPN pending"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>defb78eb-632f-5f9d-a59d-dffbb1d31dec</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="R2">
+      <value>2.2k 1%</value>
+      <footprint>Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</footprint>
+      <fields>
+        <field name="Rating">At least 0.125 W; exact resistor MPN pending</field>
+        <field name="Footprint">Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="R" description="Resistor, axial DIN0207 footprint; exact MPN pending"/>
+      <property name="Rating" value="At least 0.125 W; exact resistor MPN pending"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>405055c0-35ab-5334-ad4d-30d45c5ef6f2</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="R3">
+      <value>2.2k 1%</value>
+      <footprint>Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</footprint>
+      <fields>
+        <field name="Rating">At least 0.125 W; exact resistor MPN pending</field>
+        <field name="Footprint">Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="R" description="Resistor, axial DIN0207 footprint; exact MPN pending"/>
+      <property name="Rating" value="At least 0.125 W; exact resistor MPN pending"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>78f9a74f-5d91-5687-b50e-68176333df23</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="SW1">
+      <value>B3F-1000</value>
+      <footprint>Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</footprint>
+      <fields>
+        <field name="Manufacturer">Omron</field>
+        <field name="MPN">B3F-1000</field>
+        <field name="Function">Previous / back</field>
+        <field name="Procurement">Live stock not verified</field>
+        <field name="Footprint">Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="SW_NO" description="Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs"/>
+      <property name="Manufacturer" value="Omron"/>
+      <property name="MPN" value="B3F-1000"/>
+      <property name="Function" value="Previous / back"/>
+      <property name="Procurement" value="Live stock not verified"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>dd5f1f75-0093-55fc-9814-437ed26871eb</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="SW2">
+      <value>B3F-1000</value>
+      <footprint>Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</footprint>
+      <fields>
+        <field name="Manufacturer">Omron</field>
+        <field name="MPN">B3F-1000</field>
+        <field name="Function">Select / confirm</field>
+        <field name="Procurement">Live stock not verified</field>
+        <field name="Footprint">Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="SW_NO" description="Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs"/>
+      <property name="Manufacturer" value="Omron"/>
+      <property name="MPN" value="B3F-1000"/>
+      <property name="Function" value="Select / confirm"/>
+      <property name="Procurement" value="Live stock not verified"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>c522a716-55a4-584d-a12e-ab135b4c08eb</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="SW3">
+      <value>B3F-1000</value>
+      <footprint>Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</footprint>
+      <fields>
+        <field name="Manufacturer">Omron</field>
+        <field name="MPN">B3F-1000</field>
+        <field name="Function">Next</field>
+        <field name="Procurement">Live stock not verified</field>
+        <field name="Footprint">Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="SW_NO" description="Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs"/>
+      <property name="Manufacturer" value="Omron"/>
+      <property name="MPN" value="B3F-1000"/>
+      <property name="Function" value="Next"/>
+      <property name="Procurement" value="Live stock not verified"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>35caa6bb-42a6-512c-848c-f1e4457aa97f</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="U1">
+      <value>HW678 / S3-N16R8</value>
+      <footprint>Carrier:HW678_2x22_Provisional</footprint>
+      <fields>
+        <field name="Status">Header geometry nominal; outline/antenna clearance pending</field>
+        <field name="Pin_numbering">Left 1-22; right 23-44; both top-to-bottom, antenna up</field>
+        <field name="Footprint">Carrier:HW678_2x22_Provisional</field>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="HW678_N16R8" description="HW-678 V0.0.0 / N16R8 carrier interface; project numbering; onboard USB/regulator retained"/>
+      <property name="Status" value="Header geometry nominal; outline/antenna clearance pending"/>
+      <property name="Pin_numbering" value="Left 1-22; right 23-44; both top-to-bottom, antenna up"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>3ab265d0-7fd3-5891-94eb-d39426c6a8a3</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+            <pin num="3"/>
+            <pin num="4"/>
+            <pin num="5"/>
+            <pin num="6"/>
+            <pin num="7"/>
+            <pin num="8"/>
+            <pin num="9"/>
+            <pin num="10"/>
+            <pin num="11"/>
+            <pin num="12"/>
+            <pin num="13"/>
+            <pin num="14"/>
+            <pin num="15"/>
+            <pin num="16"/>
+            <pin num="17"/>
+            <pin num="18"/>
+            <pin num="19"/>
+            <pin num="20"/>
+            <pin num="21"/>
+            <pin num="22"/>
+            <pin num="23"/>
+            <pin num="24"/>
+            <pin num="25"/>
+            <pin num="26"/>
+            <pin num="27"/>
+            <pin num="28"/>
+            <pin num="29"/>
+            <pin num="30"/>
+            <pin num="31"/>
+            <pin num="32"/>
+            <pin num="33"/>
+            <pin num="34"/>
+            <pin num="35"/>
+            <pin num="36"/>
+            <pin num="37"/>
+            <pin num="38"/>
+            <pin num="39"/>
+            <pin num="40"/>
+            <pin num="41"/>
+            <pin num="42"/>
+            <pin num="43"/>
+            <pin num="44"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+    <comp ref="U2">
+      <value>Adafruit MAX3243 / male 6253</value>
+      <fields>
+        <field name="Status">VERIFY male header numbering; footprint intentionally unassigned</field>
+        <field name="Datasheet_source">adafruit-research.md; reference female 5988 CAD</field>
+        <field name="Footprint"/>
+        <field name="Datasheet"/>
+        <field name="Description"/>
+      </fields>
+      <libsource lib="Carrier" part="MAX3243_Module_Reference" description="Adafruit male 6253 intended; physical numbering from published female 5988 CAD, VERIFY MALE"/>
+      <property name="Status" value="VERIFY male header numbering; footprint intentionally unassigned"/>
+      <property name="Datasheet_source" value="adafruit-research.md; reference female 5988 CAD"/>
+      <property name="Sheetname" value="serial-carrier"/>
+      <property name="Sheetfile" value="serial-carrier.kicad_sch"/>
+      <sheetpath names="/" tstamps="/"/>
+      <tstamps>1127195e-e393-5d1d-9119-b25d10556144</tstamps>
+      <units>
+        <unit name="A">
+          <pins>
+            <pin num="1"/>
+            <pin num="2"/>
+            <pin num="3"/>
+            <pin num="4"/>
+            <pin num="5"/>
+            <pin num="6"/>
+            <pin num="7"/>
+            <pin num="8"/>
+            <pin num="9"/>
+            <pin num="10"/>
+            <pin num="11"/>
+            <pin num="12"/>
+          </pins>
+        </unit>
+      </units>
+    </comp>
+  </components>
+  <libparts>
+    <libpart lib="Carrier" part="HW678_N16R8">
+      <description>HW-678 V0.0.0 / N16R8 carrier interface; project numbering; onboard USB/regulator retained</description>
+      <fields>
+        <field name="Reference">U</field>
+        <field name="Value">HW678_N16R8</field>
+        <field name="Footprint">Carrier:HW678_2x22_Provisional</field>
+        <field name="Datasheet"/>
+        <field name="Description">HW-678 V0.0.0 / N16R8 carrier interface; project numbering; onboard USB/regulator retained</field>
+      </fields>
+      <pins>
+        <pin num="1" name="3V3" type="power_out"/>
+        <pin num="2" name="3V3" type="passive"/>
+        <pin num="3" name="EN" type="input"/>
+        <pin num="4" name="GPIO4" type="input"/>
+        <pin num="5" name="GPIO5" type="input"/>
+        <pin num="6" name="GPIO6" type="input"/>
+        <pin num="7" name="GPIO7" type="output"/>
+        <pin num="8" name="GPIO15" type="output"/>
+        <pin num="9" name="GPIO16" type="input"/>
+        <pin num="10" name="GPIO17" type="output"/>
+        <pin num="11" name="GPIO18" type="input"/>
+        <pin num="12" name="GPIO8" type="input"/>
+        <pin num="13" name="GPIO3" type="bidirectional"/>
+        <pin num="14" name="GPIO46" type="bidirectional"/>
+        <pin num="15" name="GPIO9" type="bidirectional"/>
+        <pin num="16" name="GPIO10" type="input"/>
+        <pin num="17" name="GPIO11" type="bidirectional"/>
+        <pin num="18" name="GPIO12" type="output"/>
+        <pin num="19" name="GPIO13" type="input"/>
+        <pin num="20" name="GPIO14" type="input"/>
+        <pin num="21" name="5V" type="passive"/>
+        <pin num="22" name="GND" type="power_out"/>
+        <pin num="23" name="GND" type="passive"/>
+        <pin num="24" name="GPIO43" type="bidirectional"/>
+        <pin num="25" name="GPIO44" type="bidirectional"/>
+        <pin num="26" name="GPIO1" type="bidirectional"/>
+        <pin num="27" name="GPIO2" type="bidirectional"/>
+        <pin num="28" name="GPIO42" type="bidirectional"/>
+        <pin num="29" name="GPIO41" type="bidirectional"/>
+        <pin num="30" name="GPIO40" type="bidirectional"/>
+        <pin num="31" name="GPIO39" type="bidirectional"/>
+        <pin num="32" name="GPIO38" type="bidirectional"/>
+        <pin num="33" name="GPIO37" type="bidirectional"/>
+        <pin num="34" name="GPIO36" type="bidirectional"/>
+        <pin num="35" name="GPIO35" type="bidirectional"/>
+        <pin num="36" name="GPIO0" type="bidirectional"/>
+        <pin num="37" name="GPIO45" type="bidirectional"/>
+        <pin num="38" name="GPIO48" type="bidirectional"/>
+        <pin num="39" name="GPIO47" type="bidirectional"/>
+        <pin num="40" name="GPIO21" type="bidirectional"/>
+        <pin num="41" name="GPIO20" type="bidirectional"/>
+        <pin num="42" name="GPIO19" type="bidirectional"/>
+        <pin num="43" name="GND" type="passive"/>
+        <pin num="44" name="GND" type="passive"/>
+      </pins>
+    </libpart>
+    <libpart lib="Carrier" part="MAX3243_Module_Reference">
+      <description>Adafruit male 6253 intended; physical numbering from published female 5988 CAD, VERIFY MALE</description>
+      <fields>
+        <field name="Reference">U</field>
+        <field name="Value">MAX3243_Module_Reference</field>
+        <field name="Footprint"/>
+        <field name="Datasheet"/>
+        <field name="Description">Adafruit male 6253 intended; physical numbering from published female 5988 CAD, VERIFY MALE</field>
+      </fields>
+      <pins>
+        <pin num="1" name="Vin" type="power_in"/>
+        <pin num="2" name="GND" type="power_in"/>
+        <pin num="3" name="DCD" type="output"/>
+        <pin num="4" name="RX" type="output"/>
+        <pin num="5" name="TX" type="input"/>
+        <pin num="6" name="DTR" type="input"/>
+        <pin num="7" name="DSR" type="output"/>
+        <pin num="8" name="RTS" type="input"/>
+        <pin num="9" name="CTS" type="output"/>
+        <pin num="10" name="RI" type="output"/>
+        <pin num="11" name="VLD" type="output"/>
+        <pin num="12" name="OFF_N" type="input"/>
+      </pins>
+    </libpart>
+    <libpart lib="Carrier" part="OLED_I2C_26mm">
+      <description>User fit-verified 26 mm OLED; front/top header GND VCC SCL SDA</description>
+      <fields>
+        <field name="Reference">DS</field>
+        <field name="Value">OLED_I2C_26mm</field>
+        <field name="Footprint">Carrier:OLED_26mm_I2C_Provisional</field>
+        <field name="Datasheet"/>
+        <field name="Description">User fit-verified 26 mm OLED; front/top header GND VCC SCL SDA</field>
+      </fields>
+      <pins>
+        <pin num="1" name="GND" type="power_in"/>
+        <pin num="2" name="VCC" type="power_in"/>
+        <pin num="3" name="SCL" type="input"/>
+        <pin num="4" name="SDA" type="bidirectional"/>
+      </pins>
+    </libpart>
+    <libpart lib="Carrier" part="R">
+      <description>Resistor, axial DIN0207 footprint; exact MPN pending</description>
+      <fields>
+        <field name="Reference">R</field>
+        <field name="Value">R</field>
+        <field name="Footprint">Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal</field>
+        <field name="Datasheet"/>
+        <field name="Description">Resistor, axial DIN0207 footprint; exact MPN pending</field>
+      </fields>
+      <pins>
+        <pin num="1" name="" type="passive"/>
+        <pin num="2" name="" type="passive"/>
+      </pins>
+    </libpart>
+    <libpart lib="Carrier" part="SW_NO">
+      <description>Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs</description>
+      <fields>
+        <field name="Reference">SW</field>
+        <field name="Value">SW_NO</field>
+        <field name="Footprint">Button_Switch_THT:SW_TH_Tactile_Omron_B3F-100x</field>
+        <field name="Datasheet"/>
+        <field name="Description">Normally open contact; footprint duplicates pads 1 and 2 for internally common terminal pairs</field>
+      </fields>
+      <pins>
+        <pin num="1" name="" type="passive"/>
+        <pin num="2" name="" type="passive"/>
+      </pins>
+    </libpart>
+  </libparts>
+  <libraries>
+    <library logical="Carrier">
+      <uri>${KIPRJMOD}/Carrier.kicad_sym</uri>
+    </library>
+  </libraries>
+  <nets>
+    <net code="1" name="/+3V3" class="Default">
+      <node ref="DS1" pin="2" pinfunction="VCC_2" pintype="power_in"/>
+      <node ref="R1" pin="1" pintype="passive"/>
+      <node ref="R2" pin="1" pintype="passive"/>
+      <node ref="R3" pin="1" pintype="passive"/>
+      <node ref="U1" pin="1" pinfunction="3V3_1" pintype="power_out"/>
+      <node ref="U1" pin="2" pinfunction="3V3_2" pintype="passive"/>
+      <node ref="U2" pin="1" pinfunction="Vin_1" pintype="power_in"/>
+    </net>
+    <net code="2" name="/BTN_NEXT" class="Default">
+      <node ref="R3" pin="2" pintype="passive"/>
+      <node ref="SW3" pin="1" pintype="passive"/>
+      <node ref="U1" pin="20" pinfunction="GPIO14_20" pintype="input"/>
+    </net>
+    <net code="3" name="/BTN_PREVIOUS" class="Default">
+      <node ref="R1" pin="2" pintype="passive"/>
+      <node ref="SW1" pin="1" pintype="passive"/>
+      <node ref="U1" pin="16" pinfunction="GPIO10_16" pintype="input"/>
+    </net>
+    <net code="4" name="/BTN_SELECT" class="Default">
+      <node ref="R2" pin="2" pintype="passive"/>
+      <node ref="SW2" pin="1" pintype="passive"/>
+      <node ref="U1" pin="19" pinfunction="GPIO13_19" pintype="input"/>
+    </net>
+    <net code="5" name="/GND" class="Default">
+      <node ref="DS1" pin="1" pinfunction="GND_1" pintype="power_in"/>
+      <node ref="SW1" pin="2" pintype="passive"/>
+      <node ref="SW2" pin="2" pintype="passive"/>
+      <node ref="SW3" pin="2" pintype="passive"/>
+      <node ref="U1" pin="22" pinfunction="GND_22" pintype="power_out"/>
+      <node ref="U1" pin="23" pinfunction="GND_23" pintype="passive"/>
+      <node ref="U1" pin="43" pinfunction="GND_43" pintype="passive"/>
+      <node ref="U1" pin="44" pinfunction="GND_44" pintype="passive"/>
+      <node ref="U2" pin="2" pinfunction="GND_2" pintype="power_in"/>
+    </net>
+    <net code="6" name="/OLED_SCL" class="Default">
+      <node ref="DS1" pin="3" pinfunction="SCL_3" pintype="input"/>
+      <node ref="U1" pin="18" pinfunction="GPIO12_18" pintype="output"/>
+    </net>
+    <net code="7" name="/OLED_SDA" class="Default">
+      <node ref="DS1" pin="4" pinfunction="SDA_4" pintype="bidirectional"/>
+      <node ref="U1" pin="17" pinfunction="GPIO11_17" pintype="bidirectional"/>
+    </net>
+    <net code="8" name="/RS_CTS" class="Default">
+      <node ref="U1" pin="9" pinfunction="GPIO16_9" pintype="input"/>
+      <node ref="U2" pin="9" pinfunction="CTS_9" pintype="output"/>
+    </net>
+    <net code="9" name="/RS_DCD" class="Default">
+      <node ref="U1" pin="4" pinfunction="GPIO4_4" pintype="input"/>
+      <node ref="U2" pin="3" pinfunction="DCD_3" pintype="output"/>
+    </net>
+    <net code="10" name="/RS_DSR" class="Default">
+      <node ref="U1" pin="5" pinfunction="GPIO5_5" pintype="input"/>
+      <node ref="U2" pin="7" pinfunction="DSR_7" pintype="output"/>
+    </net>
+    <net code="11" name="/RS_DTR" class="Default">
+      <node ref="U1" pin="7" pinfunction="GPIO7_7" pintype="output"/>
+      <node ref="U2" pin="6" pinfunction="DTR_6" pintype="input"/>
+    </net>
+    <net code="12" name="/RS_OFF_N" class="Default">
+      <node ref="U1" pin="15" pinfunction="GPIO9_15" pintype="bidirectional"/>
+      <node ref="U2" pin="12" pinfunction="OFF_N_12" pintype="input"/>
+    </net>
+    <net code="13" name="/RS_RI" class="Default">
+      <node ref="U1" pin="6" pinfunction="GPIO6_6" pintype="input"/>
+      <node ref="U2" pin="10" pinfunction="RI_10" pintype="output"/>
+    </net>
+    <net code="14" name="/RS_RTS" class="Default">
+      <node ref="U1" pin="8" pinfunction="GPIO15_8" pintype="output"/>
+      <node ref="U2" pin="8" pinfunction="RTS_8" pintype="input"/>
+    </net>
+    <net code="15" name="/RS_RX" class="Default">
+      <node ref="U1" pin="11" pinfunction="GPIO18_11" pintype="input"/>
+      <node ref="U2" pin="4" pinfunction="RX_4" pintype="output"/>
+    </net>
+    <net code="16" name="/RS_TX" class="Default">
+      <node ref="U1" pin="10" pinfunction="GPIO17_10" pintype="output"/>
+      <node ref="U2" pin="5" pinfunction="TX_5" pintype="input"/>
+    </net>
+    <net code="17" name="/RS_VALID" class="Default">
+      <node ref="U1" pin="12" pinfunction="GPIO8_12" pintype="input"/>
+      <node ref="U2" pin="11" pinfunction="VLD_11" pintype="output"/>
+    </net>
+    <net code="18" name="unconnected-(U1-5V-Pad21)" class="Default">
+      <node ref="U1" pin="21" pinfunction="5V_21" pintype="passive+no_connect"/>
+    </net>
+    <net code="19" name="unconnected-(U1-EN-Pad3)" class="Default">
+      <node ref="U1" pin="3" pinfunction="EN_3" pintype="input+no_connect"/>
+    </net>
+    <net code="20" name="unconnected-(U1-GPIO0-Pad36)" class="Default">
+      <node ref="U1" pin="36" pinfunction="GPIO0_36" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="21" name="unconnected-(U1-GPIO1-Pad26)" class="Default">
+      <node ref="U1" pin="26" pinfunction="GPIO1_26" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="22" name="unconnected-(U1-GPIO2-Pad27)" class="Default">
+      <node ref="U1" pin="27" pinfunction="GPIO2_27" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="23" name="unconnected-(U1-GPIO3-Pad13)" class="Default">
+      <node ref="U1" pin="13" pinfunction="GPIO3_13" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="24" name="unconnected-(U1-GPIO19-Pad42)" class="Default">
+      <node ref="U1" pin="42" pinfunction="GPIO19_42" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="25" name="unconnected-(U1-GPIO20-Pad41)" class="Default">
+      <node ref="U1" pin="41" pinfunction="GPIO20_41" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="26" name="unconnected-(U1-GPIO21-Pad40)" class="Default">
+      <node ref="U1" pin="40" pinfunction="GPIO21_40" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="27" name="unconnected-(U1-GPIO35-Pad35)" class="Default">
+      <node ref="U1" pin="35" pinfunction="GPIO35_35" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="28" name="unconnected-(U1-GPIO36-Pad34)" class="Default">
+      <node ref="U1" pin="34" pinfunction="GPIO36_34" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="29" name="unconnected-(U1-GPIO37-Pad33)" class="Default">
+      <node ref="U1" pin="33" pinfunction="GPIO37_33" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="30" name="unconnected-(U1-GPIO38-Pad32)" class="Default">
+      <node ref="U1" pin="32" pinfunction="GPIO38_32" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="31" name="unconnected-(U1-GPIO39-Pad31)" class="Default">
+      <node ref="U1" pin="31" pinfunction="GPIO39_31" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="32" name="unconnected-(U1-GPIO40-Pad30)" class="Default">
+      <node ref="U1" pin="30" pinfunction="GPIO40_30" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="33" name="unconnected-(U1-GPIO41-Pad29)" class="Default">
+      <node ref="U1" pin="29" pinfunction="GPIO41_29" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="34" name="unconnected-(U1-GPIO42-Pad28)" class="Default">
+      <node ref="U1" pin="28" pinfunction="GPIO42_28" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="35" name="unconnected-(U1-GPIO43-Pad24)" class="Default">
+      <node ref="U1" pin="24" pinfunction="GPIO43_24" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="36" name="unconnected-(U1-GPIO44-Pad25)" class="Default">
+      <node ref="U1" pin="25" pinfunction="GPIO44_25" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="37" name="unconnected-(U1-GPIO45-Pad37)" class="Default">
+      <node ref="U1" pin="37" pinfunction="GPIO45_37" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="38" name="unconnected-(U1-GPIO46-Pad14)" class="Default">
+      <node ref="U1" pin="14" pinfunction="GPIO46_14" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="39" name="unconnected-(U1-GPIO47-Pad39)" class="Default">
+      <node ref="U1" pin="39" pinfunction="GPIO47_39" pintype="bidirectional+no_connect"/>
+    </net>
+    <net code="40" name="unconnected-(U1-GPIO48-Pad38)" class="Default">
+      <node ref="U1" pin="38" pinfunction="GPIO48_38" pintype="bidirectional+no_connect"/>
+    </net>
+  </nets>
+</export>

hardware/PCB/validation/summary.txt

@@ -0,0 +1,8 @@
+Native schematic validation passed.
+KiCad ERC: zero reported errors/warnings; no project exclusions added.
+17 connected nets, 9 components; exact net memberships verified.
+15 firmware GPIO definitions independently checked against exported pin functions.
+All 44 MCU header pins accounted for; USB/UART0/5V/PSRAM pins unused on carrier.
+PDF and SVG exported successfully.
+Not validated: male-module physical mapping, power budget/path, OLED pull-ups,
+selected connector fit, PCB DRC/layout, procurement, or assembled hardware.

src/console_completion.c

@@ -164,8 +164,22 @@ static const char *const s_completion_candidates[] = {
     "wifi ap secret",
     "wifi ap show-secret",
     "wifi ping",
+    "wifi ping -4",
+    "wifi ping -6",
     "wifi nslookup",
+    "wifi nslookup -4",
+    "wifi nslookup -6",
     "wifi traceroute",
+    "wifi traceroute -4",
+    "wifi traceroute -6",
+
+    /* Shared diagnostics: fixed family flags only, never guessed hosts. */
+    "ping -4",
+    "ping -6",
+    "nslookup -4",
+    "nslookup -6",
+    "traceroute -4",
+    "traceroute -6",
 
     /* Station mDNS hostname configuration. */
     "mdns status",

src/network_console.c

@@ -5,6 +5,7 @@
 
 #include <errno.h>
 #include <inttypes.h>
+#include <net/if.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -13,6 +14,8 @@
 #include "esp_console.h"
 #include "esp_err.h"
 #include "esp_heap_caps.h"
+#include "esp_netif.h"
+#include "esp_idf_version.h"
 #include "esp_timer.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/queue.h"
@@ -21,6 +24,7 @@
 #include "lwip/inet_chksum.h"
 #include "lwip/ip_addr.h"
 #include "lwip/netdb.h"
+#include "lwip/netif.h"
 #include "lwip/prot/icmp.h"
 #include "lwip/prot/ip4.h"
 #include "lwip/sockets.h"
@@ -35,21 +39,25 @@
 #define TRACEROUTE_TIMEOUT_US INT64_C(1000000)
 #define NUMERIC_ADDRESS_CAPACITY 48U
 
-/* This covers two maximum-size IPv4 headers plus both required ICMP headers. */
+/* Raw receive framing and IP_TTL-for-IPv6 are SDK-specific; re-audit on upgrade. */
-#define TRACEROUTE_REPLY_CAPACITY \
+#if ESP_IDF_VERSION != ESP_IDF_VERSION_VAL(5, 5, 0)
-    (IP_HLEN_MAX + sizeof(struct icmp_hdr) + IP_HLEN_MAX + sizeof(struct icmp_echo_hdr))
+#error "Re-audit network diagnostics raw sockets for this ESP-IDF version"
+#endif
+#define TRACEROUTE_REPLY_CAPACITY 1280U
 
 static void print_command_usage(const char *command)
 {
     if (command != NULL && strcmp(command, "ping") == 0) {
-        printf("Usage: ping <host> [count]  (count: 1..20, default: 4)\n");
+        printf("Usage: ping [-4|-6] <host> [count]  (count: 1..20, default: 4)\n");
     } else if (command != NULL && strcmp(command, "nslookup") == 0) {
-        printf("Usage: nslookup <host>\n");
+        printf("Usage: nslookup [-4|-6] <host>\n");
     } else if (command != NULL && strcmp(command, "traceroute") == 0) {
-        printf("Usage: traceroute <host> [max-hops]  (IPv4 only; 1..30, default: 16)\n");
+        printf("Usage: traceroute [-4|-6] <host> [max-hops]  (1..30, default: 16)\n");
     } else {
         printf("Network commands: ping, nslookup, traceroute\n");
     }
+    printf("One -4 or -6 may appear before or after the host; defaults prefer IPv4 for probes.\n"
+           "Link-local IPv6 probes require %%sta, %%ap, or a device interface index/name.\n");
 }
 
 static bool parse_bounded_u32(const char *text, uint32_t minimum,
@@ -97,8 +105,19 @@ static bool sockaddr_to_numeric(const struct sockaddr *address,
         return false;
     }
 
-    return inet_ntop(address->sa_family, numeric_address, buffer,
+    if (inet_ntop(address->sa_family, numeric_address, buffer,
-                     (socklen_t)buffer_size) != NULL;
+                  (socklen_t)buffer_size) == NULL) {
+        return false;
+    }
+    if (address->sa_family == AF_INET6) {
+        uint32_t zone = ((const struct sockaddr_in6 *)address)->sin6_scope_id;
+        if (zone != 0U) {
+            size_t used = strlen(buffer);
+            int written = snprintf(buffer + used, buffer_size - used, "%%%" PRIu32, zone);
+            return written >= 0 && (size_t)written < buffer_size - used;
+        }
+    }
+    return true;
 }
 
 static bool addrinfo_to_ip_addr(const struct addrinfo *entry, ip_addr_t *target)
@@ -124,6 +143,7 @@ static bool addrinfo_to_ip_addr(const struct addrinfo *entry, ip_addr_t *target)
             (const struct sockaddr_in6 *)entry->ai_addr;
         ip6_addr_t ipv6;
         inet6_addr_to_ip6addr(&ipv6, &socket_address->sin6_addr);
+        ip6_addr_set_zone(&ipv6, socket_address->sin6_scope_id);
         ip_addr_copy_from_ip6(*target, ipv6);
         return true;
     }
@@ -132,34 +152,178 @@ static bool addrinfo_to_ip_addr(const struct addrinfo *entry, ip_addr_t *target)
     return false;
 }
 
-static int resolve_ping_target(const char *host, ip_addr_t *target,
+typedef struct {
-                               char *numeric, size_t numeric_size)
+    const char *host;
+    int family;
+    uint32_t limit;
+} diagnostic_arguments_t;
+
+typedef struct {
+    struct sockaddr_storage address;
+    socklen_t length;
+} diagnostic_target_t;
+
+static bool parse_arguments(int argc, char **argv, uint32_t default_limit,
+                            uint32_t maximum, diagnostic_arguments_t *args)
 {
-    struct addrinfo hints = {
+    *args = (diagnostic_arguments_t){.family = AF_UNSPEC, .limit = default_limit};
-        .ai_family = AF_UNSPEC,
+    bool have_limit = false;
-        .ai_socktype = SOCK_RAW,
+    for (int i = 1; i < argc; ++i) {
-    };
+        const char *word = argv[i];
-    struct addrinfo *results = NULL;
+        if (word == NULL || *word == '\0') {
-    int resolver_result = getaddrinfo(host, NULL, &hints, &results);
+            return false;
-    if (resolver_result != 0) {
+        }
-        printf("ping: could not resolve '%s' (getaddrinfo error %d)\n",
+        if (*word == '-') {
-               host, resolver_result);
+            if (args->family != AF_UNSPEC ||
+                (strcmp(word, "-4") != 0 && strcmp(word, "-6") != 0)) {
+                return false;
+            }
+            args->family = word[1] == '4' ? AF_INET : AF_INET6;
+        } else if (args->host == NULL) {
+            args->host = word;
+        } else if (have_limit || maximum == 0U ||
+                   !parse_bounded_u32(word, 1U, maximum, &args->limit)) {
+            return false;
+        } else {
+            have_limit = true;
+        }
+    }
+    return args->host != NULL;
+}
+
+static unsigned int device_zone(const char *name)
+{
+    if (strcmp(name, "sta") == 0 || strcmp(name, "ap") == 0) {
+        esp_netif_t *netif = esp_netif_get_handle_from_ifkey(
+            strcmp(name, "sta") == 0 ? "WIFI_STA_DEF" : "WIFI_AP_DEF");
+        int index = netif != NULL ? esp_netif_get_netif_impl_index(netif) : 0;
+        return index > 0 && index <= UINT8_MAX ? (unsigned int)index : 0U;
+    }
+    uint32_t index;
+    char interface_name[IF_NAMESIZE];
+    if (parse_bounded_u32(name, 1U, UINT8_MAX, &index)) {
+        return if_indextoname(index, interface_name) != NULL ? index : 0U;
+    }
+    return if_nametoindex(name);
+}
+
+/* Return 1 for a literal, 0 for a hostname, -1 for invalid literals.
+ * Missing link-local zones are valid for display, but not for probing.
+ * Never pass '%' through DNS: zones belong to this device, not the client. */
+static int parse_literal(const char *host, int family, diagnostic_target_t *target)
+{
+    char address[INET6_ADDRSTRLEN];
+    const char *percent = strchr(host, '%');
+    size_t length = percent != NULL ? (size_t)(percent - host) : strlen(host);
+    if (length >= sizeof(address)) {
+        return percent != NULL || strchr(host, ':') != NULL ? -1 : 0;
+    }
+    memcpy(address, host, length);
+    address[length] = '\0';
+    memset(target, 0, sizeof(*target));
+    struct sockaddr_in *v4 = (struct sockaddr_in *)&target->address;
+    if (inet_pton(AF_INET, address, &v4->sin_addr) == 1) {
+        if (percent != NULL || family == AF_INET6) {
+            return -1;
+        }
+        v4->sin_family = AF_INET;
+        target->length = sizeof(*v4);
         return 1;
     }
+    struct sockaddr_in6 *v6 = (struct sockaddr_in6 *)&target->address;
+    if (inet_pton(AF_INET6, address, &v6->sin6_addr) != 1) {
+        return percent != NULL || strchr(host, ':') != NULL ? -1 : 0;
+    }
+    if (family == AF_INET || IN6_IS_ADDR_V4MAPPED(&v6->sin6_addr)) {
+        return -1;
+    }
+    v6->sin6_family = AF_INET6;
+    target->length = sizeof(*v6);
+    if (percent != NULL) {
+        v6->sin6_scope_id = device_zone(percent + 1);
+        if (v6->sin6_scope_id == 0U) {
+            return -1;
+        }
+    }
+    return 1;
+}
 
-    bool found = false;
+static bool target_needs_scope(const diagnostic_target_t *target)
+{
+    if (target->address.ss_family != AF_INET6) {
+        return false;
+    }
+    const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)&target->address;
+    return IN6_IS_ADDR_LINKLOCAL(&v6->sin6_addr) && v6->sin6_scope_id == 0U;
+}
+
+static void print_scope_requirement(const char *numeric)
+{
+    printf("Link-local %s needs an explicit device scope for probes: %s%%sta or %s%%ap\n"
+           "(choose the device interface, not the SSH/browser client's; a valid device index/name also works).\n",
+           numeric, numeric, numeric);
+}
+
+static int resolve_family(const char *host, int family, diagnostic_target_t *target)
+{
+    struct addrinfo hints = {.ai_family = family, .ai_socktype = SOCK_RAW};
+    struct addrinfo *results = NULL;
+    int error = getaddrinfo(host, NULL, &hints, &results);
+    if (error != 0) {
+        return error;
+    }
+    error = EAI_NONAME;
     for (const struct addrinfo *entry = results; entry != NULL; entry = entry->ai_next) {
-        if (addrinfo_to_ip_addr(entry, target) &&
+        size_t required = family == AF_INET ? sizeof(struct sockaddr_in) :
-            sockaddr_to_numeric(entry->ai_addr, entry->ai_addrlen,
+                                             sizeof(struct sockaddr_in6);
-                                numeric, numeric_size)) {
+        if (entry->ai_family != family || entry->ai_addr == NULL ||
-            found = true;
+            entry->ai_addr->sa_family != family || entry->ai_addrlen < required) {
+            continue;
+        }
+        memset(target, 0, sizeof(*target));
+        memcpy(&target->address, entry->ai_addr, required);
+        target->length = required;
+        if (family == AF_INET6) {
+            const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)&target->address;
+            if (IN6_IS_ADDR_V4MAPPED(&v6->sin6_addr)) {
+                continue;
+            }
+        }
+        error = 0;
         break;
     }
-    }
     freeaddrinfo(results);
+    return error;
+}
 
-    if (!found) {
+static int resolve_target(const diagnostic_arguments_t *args, diagnostic_target_t *target,
-        printf("ping: '%s' did not resolve to a supported IPv4 or IPv6 address\n", host);
+                          char *numeric, size_t numeric_size)
+{
+    int literal = parse_literal(args->host, args->family, target);
+    if (literal < 0) {
+        printf("Invalid address/family/zone. Link-local IPv6 requires %%sta, %%ap, or a valid\n"
+               "device interface index/name (not the SSH/browser client's interface).\n");
+        return 1;
+    }
+    if (literal == 0) {
+        int first = args->family == AF_UNSPEC ? AF_INET : args->family;
+        int error = resolve_family(args->host, first, target);
+        /* IDF collapses DNS absence, timeout and server failure into EAI_FAIL.
+         * Fall back only after resolution returned no address, never after IO. */
+        if (args->family == AF_UNSPEC && (error == EAI_NONAME || error == EAI_FAIL)) {
+            error = resolve_family(args->host, AF_INET6, target);
+        }
+        if (error != 0) {
+            printf("Could not resolve '%s' (getaddrinfo error %d).\n", args->host, error);
+            return 1;
+        }
+    }
+    if (!sockaddr_to_numeric((const struct sockaddr *)&target->address, target->length,
+                              numeric, numeric_size)) {
+        return 1;
+    }
+    if (target_needs_scope(target)) {
+        print_scope_requirement(numeric);
         return 1;
     }
     return 0;
@@ -191,6 +355,11 @@ static StaticQueue_t s_ping_queue_storage;
  * storage cannot dangle. Queue control stays internal. No internal-RAM fallback. */
 static uint8_t *s_ping_queue_bytes;
 static QueueHandle_t s_ping_queue;
+/* SDK ping deletion is asynchronous. Keep callback context alive even if the
+ * console deadline expires; END permits callback queue reuse, not proof that
+ * the retiring SDK task/socket has been destroyed. */
+static ping_wait_context_t s_ping_context;
+static bool s_ping_pending;
 
 static void ping_on_success(esp_ping_handle_t handle, void *arguments)
 {
@@ -274,21 +443,35 @@ static void ping_on_end(esp_ping_handle_t handle, void *arguments)
 
 static int execute_ping(int argc, char **argv)
 {
-    if ((argc != 2 && argc != 3) || argv[1] == NULL || *argv[1] == '\0') {
+    if (s_ping_pending) {
+        ping_event_t pending;
+        while (xQueueReceive(s_ping_queue, &pending, 0U) == pdTRUE) {
+            if (pending.kind == PING_EVENT_END) {
+                s_ping_pending = false;
+                break;
+            }
+        }
+        if (s_ping_pending) {
+            printf("ping: previous SDK session has not completed; no new session started\n");
+            return 1;
+        }
+    }
+    diagnostic_arguments_t args;
+    if (!parse_arguments(argc, argv, PING_DEFAULT_COUNT, PING_MAX_COUNT, &args)) {
         print_command_usage("ping");
         return 1;
     }
-
+    uint32_t count = args.limit;
-    uint32_t count = PING_DEFAULT_COUNT;
+    diagnostic_target_t resolved;
-    if (argc == 3 &&
-        !parse_bounded_u32(argv[2], PING_MIN_COUNT, PING_MAX_COUNT, &count)) {
-        print_command_usage("ping");
-        return 1;
-    }
-
-    ip_addr_t target;
     char numeric[NUMERIC_ADDRESS_CAPACITY];
-    if (resolve_ping_target(argv[1], &target, numeric, sizeof(numeric)) != 0) {
+    if (resolve_target(&args, &resolved, numeric, sizeof(numeric)) != 0) {
+        return 1;
+    }
+    ip_addr_t target;
+    struct addrinfo entry = {.ai_family = resolved.address.ss_family,
+                            .ai_addr = (struct sockaddr *)&resolved.address,
+                            .ai_addrlen = resolved.length};
+    if (!addrinfo_to_ip_addr(&entry, &target)) {
         return 1;
     }
 
@@ -311,14 +494,20 @@ static int execute_ping(int argc, char **argv)
         printf("ping: could not allocate event queue\n");
         return 1;
     }
-    ping_wait_context_t context = {.queue = s_ping_queue};
+    s_ping_context.queue = s_ping_queue;
 
     esp_ping_config_t config = ESP_PING_DEFAULT_CONFIG();
     config.count = count;
+    config.interval_ms = 1000U;
+    config.timeout_ms = 1000U;
     config.target_addr = target;
+    if (resolved.address.ss_family == AF_INET6) {
+        /* IDF 5.5 ping omits sin6_scope_id when constructing sendto's address. */
+        config.interface = ((const struct sockaddr_in6 *)&resolved.address)->sin6_scope_id;
+    }
 
     const esp_ping_callbacks_t callbacks = {
-        .cb_args = &context,
+        .cb_args = &s_ping_context,
         .on_ping_success = ping_on_success,
         .on_ping_timeout = ping_on_timeout,
         .on_ping_end = ping_on_end,
@@ -331,24 +520,32 @@ static int execute_ping(int argc, char **argv)
         return 1;
     }
 
-    printf("PING %s (%s): %" PRIu32 " probes\n", argv[1], numeric, count);
+    printf("PING %s (%s): %" PRIu32 " probes\n", args.host, numeric, count);
+    s_ping_pending = true;
     error = esp_ping_start(session);
     if (error != ESP_OK) {
         printf("ping: could not start session: %s\n", esp_err_to_name(error));
         (void)esp_ping_delete_session(session);
+        s_ping_pending = false;
         return 1;
     }
 
+    int64_t deadline = esp_timer_get_time() + ((int64_t)count * 2000 + 2000) * 1000;
     for (;;) {
         ping_event_t event;
-        if (xQueueReceive(s_ping_queue, &event, portMAX_DELAY) != pdTRUE) {
+        int64_t remaining = deadline - esp_timer_get_time();
-            printf("ping: wait for session completion failed\n");
+        TickType_t wait = remaining > 0 ? pdMS_TO_TICKS((uint32_t)((remaining + 999) / 1000)) : 0;
+        if (remaining <= 0 || xQueueReceive(s_ping_queue, &event, wait ? wait : 1U) != pdTRUE) {
+            /* Do not touch the handle here: END may concurrently delete it.
+             * SDK receive may outlive its configured timeout under ICMP noise. */
+            printf("ping: console deadline exceeded; SDK session retained until completion\n");
             return 1;
         }
         if (event.kind == PING_EVENT_LINE) {
             printf("%s\n", event.line);
             continue;
         }
+        s_ping_pending = false;
         if (event.profile_error != ESP_OK) {
             printf("ping: session ended, but summary profile retrieval failed: %s\n",
                    esp_err_to_name(event.profile_error));
@@ -371,134 +568,53 @@ static int execute_ping(int argc, char **argv)
     }
 }
 
-static bool socket_addresses_equal(const struct addrinfo *left,
-                                   const struct addrinfo *right)
-{
-    if (left == NULL || right == NULL || left->ai_addr == NULL ||
-        right->ai_addr == NULL || left->ai_family != right->ai_family) {
-        return false;
-    }
-
-    if (left->ai_family == AF_INET &&
-        left->ai_addrlen >= (socklen_t)sizeof(struct sockaddr_in) &&
-        right->ai_addrlen >= (socklen_t)sizeof(struct sockaddr_in)) {
-        const struct sockaddr_in *left_address =
-            (const struct sockaddr_in *)left->ai_addr;
-        const struct sockaddr_in *right_address =
-            (const struct sockaddr_in *)right->ai_addr;
-        return left_address->sin_addr.s_addr == right_address->sin_addr.s_addr;
-    }
-
-#if defined(CONFIG_LWIP_IPV6) && CONFIG_LWIP_IPV6
-    if (left->ai_family == AF_INET6 &&
-        left->ai_addrlen >= (socklen_t)sizeof(struct sockaddr_in6) &&
-        right->ai_addrlen >= (socklen_t)sizeof(struct sockaddr_in6)) {
-        const struct sockaddr_in6 *left_address =
-            (const struct sockaddr_in6 *)left->ai_addr;
-        const struct sockaddr_in6 *right_address =
-            (const struct sockaddr_in6 *)right->ai_addr;
-        return memcmp(&left_address->sin6_addr, &right_address->sin6_addr,
-                      sizeof(left_address->sin6_addr)) == 0;
-    }
-#endif
-
-    return false;
-}
-
-static bool address_appeared_earlier(const struct addrinfo *first,
-                                     const struct addrinfo *current)
-{
-    for (const struct addrinfo *entry = first;
-         entry != NULL && entry != current; entry = entry->ai_next) {
-        if (socket_addresses_equal(entry, current)) {
-            return true;
-        }
-    }
-    return false;
-}
-
 static int execute_nslookup(int argc, char **argv)
 {
-    if (argc != 2 || argv[1] == NULL || *argv[1] == '\0') {
+    diagnostic_arguments_t args;
+    if (!parse_arguments(argc, argv, 0U, 0U, &args)) {
         print_command_usage("nslookup");
         return 1;
     }
-
+    diagnostic_target_t target;
-    struct addrinfo hints = {
-        .ai_family = AF_UNSPEC,
-        .ai_socktype = SOCK_STREAM,
-    };
-    struct addrinfo *results = NULL;
-    int resolver_result = getaddrinfo(argv[1], NULL, &hints, &results);
-    if (resolver_result != 0) {
-        printf("nslookup: could not resolve '%s' (getaddrinfo error %d)\n",
-               argv[1], resolver_result);
-        return 1;
-    }
-
-    printf("Name: %s\n", argv[1]);
-    size_t printed = 0U;
-    for (const struct addrinfo *entry = results; entry != NULL; entry = entry->ai_next) {
-        if (address_appeared_earlier(results, entry)) {
-            continue;
-        }
-
     char numeric[NUMERIC_ADDRESS_CAPACITY];
-        if (!sockaddr_to_numeric(entry->ai_addr, entry->ai_addrlen,
+    int literal = parse_literal(args.host, args.family, &target);
+    if (literal != 0) {
+        if (literal < 0 ||
+            !sockaddr_to_numeric((const struct sockaddr *)&target.address, target.length,
                                  numeric, sizeof(numeric))) {
+            printf("nslookup: invalid address/family/device zone\n");
+            return 1;
+        }
+        printf("Address: %s (numeric literal; no DNS query)\n", numeric);
+        if (target_needs_scope(&target)) {
+            print_scope_requirement(numeric);
+        }
+        return 0;
+    }
+    printf("Name: %s\nResolver: lwIP getaddrinfo; one selected address per family (configured max %d), not a full DNS RRset.\n"
+           "DNS absence, timeout and server failure may share EAI_FAIL.\n", args.host,
+           CONFIG_LWIP_DNS_MAX_HOST_IP);
+    unsigned int printed = 0U;
+    const int families[] = {AF_INET, AF_INET6};
+    for (size_t i = 0; i < 2U; ++i) {
+        int family = families[i];
+        if (args.family != AF_UNSPEC && args.family != family) {
             continue;
         }
-
+        int error = resolve_family(args.host, family, &target);
-        printf("Address: %s (%s)\n", numeric,
+        if (error == 0 && sockaddr_to_numeric((const struct sockaddr *)&target.address,
-               entry->ai_family == AF_INET ? "IPv4" : "IPv6");
+                                             target.length, numeric, sizeof(numeric))) {
+            printf("%s: %s\n", family == AF_INET ? "A" : "AAAA", numeric);
+            if (target_needs_scope(&target)) {
+                print_scope_requirement(numeric);
+            }
             ++printed;
-    }
+        } else {
-    freeaddrinfo(results);
+            printf("%s: no usable address (resolver error %d; not proof of no record)\n",
-
+                   family == AF_INET ? "A" : "AAAA", error);
-    if (printed == 0U) {
-        printf("nslookup: no supported IPv4 or IPv6 addresses returned\n");
-        return 1;
-    }
-    return 0;
-}
-
-static int resolve_traceroute_target(const char *host,
-                                     struct sockaddr_in *target,
-                                     char *numeric, size_t numeric_size)
-{
-    struct addrinfo hints = {
-        .ai_family = AF_INET,
-        .ai_socktype = SOCK_RAW,
-        .ai_protocol = IPPROTO_ICMP,
-    };
-    struct addrinfo *results = NULL;
-    int resolver_result = getaddrinfo(host, NULL, &hints, &results);
-    if (resolver_result != 0) {
-        printf("traceroute: could not resolve IPv4 host '%s' (getaddrinfo error %d)\n",
-               host, resolver_result);
-        return 1;
-    }
-
-    const struct addrinfo *selected = NULL;
-    for (const struct addrinfo *entry = results; entry != NULL; entry = entry->ai_next) {
-        if (entry->ai_family == AF_INET && entry->ai_addr != NULL &&
-            entry->ai_addrlen >= (socklen_t)sizeof(struct sockaddr_in)) {
-            selected = entry;
-            break;
         }
     }
-
+    return printed != 0U ? 0 : 1;
-    if (selected == NULL ||
-        !sockaddr_to_numeric(selected->ai_addr, selected->ai_addrlen,
-                             numeric, numeric_size)) {
-        freeaddrinfo(results);
-        printf("traceroute: '%s' did not resolve to an IPv4 address\n", host);
-        return 1;
-    }
-
-    memcpy(target, selected->ai_addr, sizeof(*target));
-    freeaddrinfo(results);
-    return 0;
 }
 
 typedef enum {
@@ -508,85 +624,119 @@ typedef enum {
     TRACE_REPLY_UNREACHABLE,
 } trace_reply_kind_t;
 
+static uint16_t read_be16(const uint8_t *bytes)
+{
+    return (uint16_t)((uint16_t)bytes[0] << 8 | bytes[1]);
+}
+
+static uint32_t checksum_sum(const uint8_t *bytes, size_t length, uint32_t sum)
+{
+    while (length >= 2U) {
+        sum += read_be16(bytes);
+        bytes += 2;
+        length -= 2;
+    }
+    if (length != 0U) {
+        sum += (uint16_t)bytes[0] << 8;
+    }
+    return sum;
+}
+
+static bool checksum_valid(uint32_t sum)
+{
+    while (sum >> 16) {
+        sum = (sum & 0xffffU) + (sum >> 16);
+    }
+    return sum == 0xffffU;
+}
+
+/* IDF raw sockets include the outer IP header and deliver before ICMP checksum
+ * validation. Reject all IPv6 extension headers (including fragments), both
+ * outer and quoted: the installed raw demux only matches the base next-header.
+ * No unaligned structure loads and no inspection beyond the received bytes. */
 static trace_reply_kind_t parse_trace_reply(const uint8_t *packet, size_t length,
+                                            const diagnostic_target_t *target,
                                             uint16_t expected_id,
                                             uint16_t expected_sequence,
-                                            uint32_t expected_destination,
                                             uint8_t *unreachable_code)
 {
-    if (packet == NULL || length < IP_HLEN + sizeof(struct icmp_hdr)) {
+    bool v6 = target->address.ss_family == AF_INET6;
+    size_t header = v6 ? 40U : 20U;
+    if (packet == NULL || length < header + 8U || packet[0] >> 4 != (v6 ? 6 : 4)) {
         return TRACE_REPLY_UNRELATED;
     }
-
+    const uint8_t *destination;
-    const struct ip_hdr *outer_ip = (const struct ip_hdr *)(const void *)packet;
+    size_t address_size;
-    size_t outer_header_length = IPH_HL_BYTES(outer_ip);
+    size_t source_offset;
-    if (IPH_V(outer_ip) != 4U || outer_header_length < IP_HLEN ||
+    size_t destination_offset;
-        outer_header_length > length ||
+    size_t total;
-        length - outer_header_length < sizeof(struct icmp_hdr) ||
+    if (v6) {
-        IPH_PROTO(outer_ip) != IPPROTO_ICMP) {
+        destination = (const uint8_t *)&((const struct sockaddr_in6 *)&target->address)->sin6_addr;
+        address_size = 16U;
+        source_offset = 8U;
+        destination_offset = 24U;
+        total = 40U + read_be16(packet + 4);
+        if (packet[6] != IPPROTO_ICMPV6 || total > length || total < 48U ||
+            !checksum_valid(checksum_sum(packet + 8, 32,
+                checksum_sum(packet + 40, total - 40, (uint32_t)(total - 40) + IPPROTO_ICMPV6)))) {
             return TRACE_REPLY_UNRELATED;
         }
-
+    } else {
-    uint16_t outer_total_length = lwip_ntohs(IPH_LEN(outer_ip));
+        destination = (const uint8_t *)&((const struct sockaddr_in *)&target->address)->sin_addr;
-    if (outer_total_length < outer_header_length + sizeof(struct icmp_hdr)) {
+        address_size = 4U;
+        source_offset = 12U;
+        destination_offset = 16U;
+        header = (packet[0] & 15U) * 4U;
+        total = read_be16(packet + 2);
+        if (header < 20U || total > length || total < header + 8U ||
+            packet[9] != IPPROTO_ICMP || (read_be16(packet + 6) & 0x3fffU) != 0U ||
+            !checksum_valid(checksum_sum(packet, header, 0)) ||
+            !checksum_valid(checksum_sum(packet + header, total - header, 0))) {
             return TRACE_REPLY_UNRELATED;
         }
-    size_t available = length;
-    if ((size_t)outer_total_length < available) {
-        available = outer_total_length;
     }
-
+    const uint8_t *icmp = packet + header;
-    const uint8_t *outer_icmp_bytes = packet + outer_header_length;
+    if (icmp[0] == (v6 ? 129U : ICMP_ER)) {
-    const struct icmp_hdr *outer_icmp =
+        if (icmp[1] == 0U && memcmp(icmp + 4, &expected_id, 2) == 0 &&
-        (const struct icmp_hdr *)(const void *)outer_icmp_bytes;
+            memcmp(icmp + 6, &expected_sequence, 2) == 0 &&
-
+            memcmp(packet + source_offset, destination, address_size) == 0) {
-    if (ICMPH_TYPE(outer_icmp) == ICMP_ER) {
-        const struct icmp_echo_hdr *echo_reply =
-            (const struct icmp_echo_hdr *)(const void *)outer_icmp_bytes;
-        if (echo_reply->id == expected_id &&
-            echo_reply->seqno == expected_sequence) {
             return TRACE_REPLY_DESTINATION;
         }
         return TRACE_REPLY_UNRELATED;
     }
-
+    bool exceeded = icmp[0] == (v6 ? 3U : ICMP_TE) && icmp[1] == 0U;
-    if (ICMPH_TYPE(outer_icmp) != ICMP_TE &&
+    bool unreachable = icmp[0] == (v6 ? 1U : ICMP_DUR) && icmp[1] <= (v6 ? 7U : 15U);
-        ICMPH_TYPE(outer_icmp) != ICMP_DUR) {
+    if (!exceeded && !unreachable) {
         return TRACE_REPLY_UNRELATED;
     }
-
+    const uint8_t *inner = icmp + 8;
-    /* ICMP errors quote the original IPv4 header and at least 8 payload bytes. */
+    size_t available = total - header - 8U;
-    size_t inner_offset = outer_header_length + sizeof(struct icmp_hdr);
+    size_t inner_header = v6 ? 40U : 20U;
-    if (inner_offset > available || available - inner_offset < IP_HLEN) {
+    if (available < inner_header + 8U || inner[0] >> 4 != (v6 ? 6 : 4) ||
+        memcmp(inner + destination_offset, destination, address_size) != 0) {
         return TRACE_REPLY_UNRELATED;
     }
-
+    if (v6) {
-    const struct ip_hdr *inner_ip =
+        if (inner[6] != IPPROTO_ICMPV6 || read_be16(inner + 4) < 8U) {
-        (const struct ip_hdr *)(const void *)(packet + inner_offset);
-    size_t inner_header_length = IPH_HL_BYTES(inner_ip);
-    if (IPH_V(inner_ip) != 4U || inner_header_length < IP_HLEN ||
-        inner_header_length > available - inner_offset ||
-        available - inner_offset - inner_header_length < sizeof(struct icmp_echo_hdr) ||
-        IPH_PROTO(inner_ip) != IPPROTO_ICMP ||
-        inner_ip->dest.addr != expected_destination ||
-        lwip_ntohs(IPH_LEN(inner_ip)) <
-            inner_header_length + sizeof(struct icmp_echo_hdr)) {
             return TRACE_REPLY_UNRELATED;
         }
-
+    } else {
-    const struct icmp_echo_hdr *quoted_echo =
+        inner_header = (inner[0] & 15U) * 4U;
-        (const struct icmp_echo_hdr *)(const void *)(
+        if (inner_header < 20U || inner_header + 8U > available ||
-            packet + inner_offset + inner_header_length);
+            read_be16(inner + 2) < inner_header + 8U || inner[9] != IPPROTO_ICMP ||
-    if (ICMPH_TYPE((const struct icmp_hdr *)quoted_echo) != ICMP_ECHO ||
+            (read_be16(inner + 6) & 0x3fffU) != 0U ||
-        quoted_echo->id != expected_id ||
+            !checksum_valid(checksum_sum(inner, inner_header, 0))) {
-        quoted_echo->seqno != expected_sequence) {
             return TRACE_REPLY_UNRELATED;
         }
-
-    if (ICMPH_TYPE(outer_icmp) == ICMP_DUR) {
-        if (unreachable_code != NULL) {
-            *unreachable_code = ICMPH_CODE(outer_icmp);
     }
+    const uint8_t *echo = inner + inner_header;
+    if (echo[0] != (v6 ? 128U : ICMP_ECHO) || echo[1] != 0U ||
+        memcmp(echo + 4, &expected_id, 2) != 0 ||
+        memcmp(echo + 6, &expected_sequence, 2) != 0) {
+        return TRACE_REPLY_UNRELATED;
+    }
+    if (unreachable) {
+        *unreachable_code = icmp[1];
         return TRACE_REPLY_UNREACHABLE;
     }
     return TRACE_REPLY_HOP;
@@ -601,7 +751,7 @@ typedef enum {
 } trace_wait_result_t;
 
 static trace_wait_result_t wait_for_trace_reply(int socket_fd,
-                                                const struct sockaddr_in *target,
+                                                const diagnostic_target_t *target,
                                                 uint16_t expected_id,
                                                 uint16_t expected_sequence,
                                                 int64_t sent_at_us,
@@ -615,7 +765,9 @@ static trace_wait_result_t wait_for_trace_reply(int socket_fd,
 
     for (;;) {
         int64_t remaining_us = deadline_us - esp_timer_get_time();
-        if (remaining_us <= 0) {
+        /* IDF floors timeval to milliseconds; zero means an infinite mailbox
+         * wait. Stop up to 999 us early rather than installing that timeout. */
+        if (remaining_us < 1000) {
             return TRACE_WAIT_TIMEOUT;
         }
 
@@ -629,7 +781,7 @@ static trace_wait_result_t wait_for_trace_reply(int socket_fd,
             return TRACE_WAIT_ERROR;
         }
 
-        struct sockaddr_in source = {0};
+        struct sockaddr_storage source = {0};
         socklen_t source_length = sizeof(source);
         ssize_t received = recvfrom(socket_fd, reply, sizeof(reply), 0,
                                     (struct sockaddr *)&source, &source_length);
@@ -644,15 +796,28 @@ static trace_wait_result_t wait_for_trace_reply(int socket_fd,
         }
 
         trace_reply_kind_t kind = parse_trace_reply(
-            reply, (size_t)received, expected_id, expected_sequence,
+            reply, (size_t)received, target, expected_id, expected_sequence, unreachable_code);
-            target->sin_addr.s_addr, unreachable_code);
         if (kind == TRACE_REPLY_UNRELATED) {
             continue;
         }
 
-        /* An echo reply is the destination only when it came from our target. */
+        if (source.ss_family != target->address.ss_family || source_length < target->length) {
-        if (kind == TRACE_REPLY_DESTINATION &&
+            continue;
-            source.sin_addr.s_addr != target->sin_addr.s_addr) {
+        }
+        if (source.ss_family == AF_INET6) {
+            const struct sockaddr_in6 *from = (const struct sockaddr_in6 *)&source;
+            const struct sockaddr_in6 *to = (const struct sockaddr_in6 *)&target->address;
+            /* Bound raw sockets already enforce ingress interface. Global
+             * source addresses legitimately carry no zone in recvfrom. */
+            if ((to->sin6_scope_id != 0U && from->sin6_scope_id != 0U &&
+                 from->sin6_scope_id != to->sin6_scope_id) ||
+                (kind == TRACE_REPLY_DESTINATION &&
+                 memcmp(&from->sin6_addr, &to->sin6_addr, sizeof(to->sin6_addr)) != 0)) {
+                continue;
+            }
+        } else if (kind == TRACE_REPLY_DESTINATION &&
+                   ((const struct sockaddr_in *)&source)->sin_addr.s_addr !=
+                   ((const struct sockaddr_in *)&target->address)->sin_addr.s_addr) {
             continue;
         }
 
@@ -686,34 +851,49 @@ static void print_trace_rtt(int64_t round_trip_us)
 
 static int execute_traceroute(int argc, char **argv)
 {
-    if ((argc != 2 && argc != 3) || argv[1] == NULL || *argv[1] == '\0') {
+    diagnostic_arguments_t args;
+    if (!parse_arguments(argc, argv, TRACEROUTE_DEFAULT_HOPS, TRACEROUTE_MAX_HOPS, &args)) {
         print_command_usage("traceroute");
         return 1;
     }
-
+    uint32_t max_hops = args.limit;
-    uint32_t max_hops = TRACEROUTE_DEFAULT_HOPS;
+    diagnostic_target_t target;
-    if (argc == 3 &&
-        !parse_bounded_u32(argv[2], TRACEROUTE_MIN_HOPS,
-                           TRACEROUTE_MAX_HOPS, &max_hops)) {
-        print_command_usage("traceroute");
-        return 1;
-    }
-
-    printf("traceroute: IPv4 only (one ICMP echo probe per hop)\n");
-
-    struct sockaddr_in target = {0};
     char target_numeric[NUMERIC_ADDRESS_CAPACITY];
-    if (resolve_traceroute_target(argv[1], &target,
+    if (resolve_target(&args, &target, target_numeric, sizeof(target_numeric)) != 0) {
-                                  target_numeric, sizeof(target_numeric)) != 0) {
         return 1;
     }
-
+    bool v6 = target.address.ss_family == AF_INET6;
-    int socket_fd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
+    printf("traceroute: one ICMP echo probe per hop, 1 s receive deadline.\n");
+    if (v6) {
+        printf("IPv6 extension headers/fragments in replies or quotes are unsupported and ignored.\n");
+    }
+    int socket_fd = socket(target.address.ss_family, SOCK_RAW,
+                           v6 ? IPPROTO_ICMPV6 : IPPROTO_ICMP);
     if (socket_fd < 0) {
         printf("traceroute: could not create raw ICMP socket: %s\n", strerror(errno));
         return 1;
     }
 
+    if (v6) {
+        int only_v6 = 1;
+        if (setsockopt(socket_fd, IPPROTO_IPV6, IPV6_V6ONLY,
+                       &only_v6, sizeof(only_v6)) != 0) {
+            printf("traceroute: could not restrict socket to IPv6: %s\n", strerror(errno));
+            close(socket_fd);
+            return 1;
+        }
+        uint32_t zone = ((const struct sockaddr_in6 *)&target.address)->sin6_scope_id;
+        if (zone != 0U) {
+            struct ifreq interface = {0};
+            if (if_indextoname(zone, interface.ifr_name) == NULL ||
+                setsockopt(socket_fd, SOL_SOCKET, SO_BINDTODEVICE,
+                           &interface, sizeof(interface)) != 0) {
+                printf("traceroute: could not bind device interface: %s\n", strerror(errno));
+                close(socket_fd);
+                return 1;
+            }
+        }
+    }
     const struct timeval one_second = {
         .tv_sec = 1,
         .tv_usec = 0,
@@ -726,7 +906,7 @@ static int execute_traceroute(int argc, char **argv)
     }
 
     printf("traceroute to %s (%s), %" PRIu32 " hops max\n",
-           argv[1], target_numeric, max_hops);
+           args.host, target_numeric, max_hops);
 
     /* A per-run ID plus one sequence per hop rejects other raw-socket traffic. */
     uint16_t identifier = lwip_htons((uint16_t)esp_timer_get_time());
@@ -735,6 +915,8 @@ static int execute_traceroute(int argc, char **argv)
     uint32_t final_hop = 0U;
 
     for (uint32_t hop = 1U; hop <= max_hops; ++hop) {
+        /* IDF 5.5 lwIP uses the common PCB ttl for IPv6 hop limit too;
+         * IPV6_UNICAST_HOPS is not implemented. ICMPv6 TX checksum is automatic. */
         int ttl = (int)hop;
         if (setsockopt(socket_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)) != 0) {
             printf("traceroute: could not set TTL for hop %" PRIu32 ": %s\n",
@@ -744,17 +926,19 @@ static int execute_traceroute(int argc, char **argv)
         }
 
         struct icmp_echo_hdr probe = {
-            .type = ICMP_ECHO,
+            .type = v6 ? 128U : ICMP_ECHO,
             .code = 0U,
             .chksum = 0U,
             .id = identifier,
             .seqno = lwip_htons((uint16_t)hop),
         };
+        if (!v6) {
             probe.chksum = inet_chksum(&probe, (u16_t)sizeof(probe));
+        }
 
         int64_t sent_at_us = esp_timer_get_time();
         ssize_t sent = sendto(socket_fd, &probe, sizeof(probe), 0,
-                              (const struct sockaddr *)&target, sizeof(target));
+                              (const struct sockaddr *)&target.address, target.length);
         if (sent != (ssize_t)sizeof(probe)) {
             printf("traceroute: probe send failed at hop %" PRIu32 ": %s\n",
                    hop, strerror(errno));
@@ -844,21 +1028,21 @@ esp_err_t network_console_register_root_commands(void)
     static const esp_console_cmd_t commands[] = {
         {
             .command = "ping",
-            .help = "ping <host> [count] (count 1..20, default 4)",
+            .help = "ping [-4|-6] <host> [count] (count 1..20, default 4)",
             .hint = NULL,
             .func = &network_console_execute,
             .argtable = NULL,
         },
         {
             .command = "nslookup",
-            .help = "nslookup <host> (print unique numeric IPv4/IPv6 addresses)",
+            .help = "nslookup [-4|-6] <host> (default: query A and AAAA separately)",
             .hint = NULL,
             .func = &network_console_execute,
             .argtable = NULL,
         },
         {
             .command = "traceroute",
-            .help = "traceroute <host> [max-hops] (IPv4 only; 1..30, default 16)",
+            .help = "traceroute [-4|-6] <host> [max-hops] (1..30, default 16)",
             .hint = NULL,
             .func = &network_console_execute,
             .argtable = NULL,

src/network_console.h

@@ -16,7 +16,16 @@ esp_err_t network_console_register_root_commands(void);
 /* Return true only for a root command handled by network_console_execute(). */
 bool network_console_is_command(const char *name);
 
-/* Execute ping, nslookup, or traceroute; argv[0] selects the operation. */
+/* Canonical handler for every frontend and wifi alias; argv[0] selects:
+ *   ping [-4|-6] <host> [count]              count 1..20, default 4
+ *   traceroute [-4|-6] <host> [max-hops]     hops 1..30, default 16
+ *   nslookup [-4|-6] <host>
+ * One family flag may also follow the host/count. Probe hostnames default to
+ * IPv4, then IPv6 only if resolution returns no address; nslookup queries both.
+ * IPv6 link-local probes require a device-local %sta/%ap/index/lwIP-name zone;
+ * nslookup displays unscoped link-local records/literals without probing them.
+ * Call only through the serialized administration dispatcher.
+ */
 int network_console_execute(int argc, char **argv);
 
 #ifdef __cplusplus

src/wifi_console.c

@@ -34,9 +34,10 @@ static void print_usage(void)
     printf("  wifi ap channel <1..11>\n");
     printf("  wifi ap secret|show-secret\n");
     printf("  wifi save|load|defaults|reset\n");
-    printf("  wifi ping <host> [count]\n");
+    printf("  wifi ping [-4|-6] <host> [count] (1..20, default 4)\n");
-    printf("  wifi nslookup <host>\n");
+    printf("  wifi nslookup [-4|-6] <host> (default: A and AAAA)\n");
-    printf("  wifi traceroute <host> [max-hops]\n");
+    printf("  wifi traceroute [-4|-6] <host> [max-hops] (1..30, default 16)\n");
+    printf("  Diagnostic family flags may also follow the host or count/max-hops.\n");
 }
 
 static bool parse_u32(const char *text, uint32_t maximum, uint32_t *value)

tests/network_diagnostics/README.md

@@ -0,0 +1,160 @@
+# Shared IPv4/IPv6 diagnostics fixtures and integration handoff
+
+## Commands
+
+```text
+ping [-4|-6] <host> [count]              count 1..20, default 4
+traceroute [-4|-6] <host> [max-hops]     hops 1..30, default 16
+nslookup [-4|-6] <host>
+```
+
+One family flag may occur anywhere after the command, including after the host or
+numeric argument. Repeated/conflicting flags, unknown options, empty arguments,
+extra arguments, and non-decimal/out-of-range counts are rejected. Existing bare
+commands and aliases calling `network_console_execute()` share these semantics.
+For example: `ping fe80::1%sta -6 3`, `traceroute example.net 20 -6`.
+
+Default hostname probes resolve IPv4 first, then IPv6 only when resolution returns
+no address (`EAI_FAIL`/`EAI_NONAME`). They **never** retry another family after a
+send failure, timeout, or unreachable reply. This is not Happy Eyeballs. Explicit
+`-6` neither requests nor accepts IPv4/mapped IPv4. Default hostname `nslookup`
+makes separate A and AAAA queries, prints partial success, and explains resolver
+limits. Numeric literals do not query DNS or perform reverse lookup.
+
+Zones refer to interfaces **on the ESP32**, not on the browser/SSH client:
+`%sta`, `%ap`, a currently valid numeric lwIP index (1..255), or an existing lwIP
+interface name. Ping/traceroute reject unscoped link-local addresses (including
+DNS AAAA answers with zone zero), showing the address and scoped-literal examples;
+no default interface is guessed. `nslookup` displays those records and unscoped
+link-local literals with a note that probes require an explicit device scope.
+Mapped IPv4 literals remain rejected. Scoped ping preserves `sin6_scope_id` as the `ip6_addr_t` zone **and** sets
+`esp_ping_config_t.interface`; scoped traceroute retains the socket zone and binds
+the raw socket to that interface. Numeric output includes the zone.
+
+## Run
+
+```sh
+python3 tests/network_diagnostics/run.py
+python3 tests/network_diagnostics/run.py --sanitize  # optional installed ASan/UBSan
+python3 tests/network_diagnostics/sdk_contract.py /path/to/framework-espidf
+```
+
+`run.py` includes the actual production `src/network_console.c`, not a duplicate
+parser/implementation. SDK calls and socket operations are deterministic fakes;
+there is no networking or hardware access. It checks argument permutations and
+bounds, per-family resolution/fallback/freeing, A+AAAA queries, scope parsing and
+ping zone/interface conversion, valid echo/time-exceeded/unreachable packets,
+all truncation lengths, bad checksums/IDs/sequences/targets/codes/protocols,
+unsupported IPv6 extension headers, recv source correlation, absolute deadlines,
+1/500/999/1000-us remaining-budget boundaries and unrelated traffic leaving 500 us,
+zero-zone link-local AAAA display versus rejection before any probe socket/session,
+EINTR, all configured socket-option failure points, send/receive/create errors,
+fd-zero cleanup, PSRAM allocation failure, and ping create/start/delayed-completion
+lifetime handling. Also runs 10,000 deterministic malformed packet inputs.
+
+## Audited IDF 5.5.0 / lwIP contract
+
+`sdk_contract.py` pins seven installed source files, including the FreeRTOS mailbox
+port. It also extracts and compiles the actual SDK timeval conversion macro and
+`sys_arch_mbox_fetch()` with a fake queue boundary, checking the infinite-wait
+sentinel for sub-millisecond values and finite waits for >=1 ms at 1/10-ms ticks.
+The production module also has an IDF version guard; upgrades require re-audit.
+
+- `api/netdb.c`: `AF_INET` and `AF_INET6` choose explicit DNS address types. Current
+  generated `CONFIG_LWIP_DNS_MAX_HOST_IP=1` means one returned address per query;
+  this command prints one selected address per family, not a complete RRset.
+  DNS errors collapse into `EAI_FAIL`; NXDOMAIN, timeout, and server failure cannot
+  reliably be distinguished. Resolution itself uses SDK DNS timeouts, not a
+  command-owned deadline. `.local` depends on lwIP mDNS-query support, not client NSS.
+- `core/ipv6/ip6.c` restores the complete IPv6 header before `raw_input()`;
+  `api/api_msg.c:recv_raw()` copies it. Raw receives are **not Linux's ICMPv6-only
+  framing**. Raw delivery precedes ICMP checksum validation, so traceroute checks
+  the complete outer ICMP checksum (including IPv6 pseudoheader) itself.
+- `core/raw.c` demultiplexes the IPv6 **base** next-header. Therefore traceroute
+  explicitly rejects all outer/quoted IPv6 extension headers, including fragment,
+  routing, hop-by-hop, destination options, AH and ESP. It does not walk or guess
+  unsupported forms. Quoted packets may be incomplete after the required echo
+  header, but the complete outer packet must fit/be received and pass its checksum.
+- `api/api_msg.c` enables checksum generation at offset 2 for raw ICMPv6 sockets.
+  `api/sockets.c` refuses changing `IPV6_CHECKSUM` for ICMPv6; do not set it.
+  `IPPROTO_IP/IP_TTL` sets the common PCB TTL used for **both** IPv4 TTL and IPv6
+  hop limit. `IPV6_UNICAST_HOPS` is not implemented. Fixtures require the actual
+  supported option for both families. IPv6 traceroute also sets `IPV6_V6ONLY`.
+  SDK ping's `IPPROTO_IP/IP_TTL` use is likewise correct for IPv6; it is unchanged.
+- `api/sockets.c` floors `SO_RCVTIMEO` timeval values to milliseconds;
+  `port/freertos/sys_arch.c:sys_arch_mbox_fetch()` interprets zero milliseconds
+  as `portMAX_DELAY`, not a poll. Traceroute stops when <1000 us remain, never
+  supplying a zero-millisecond receive timeout.
+- `apps/ping/ping_sock.c` does not copy the target zone into `sin6_scope_id`;
+  `config.interface` uses `SO_BINDTODEVICE` and is required for scoped ping.
+  SDK ping is not the strict traceroute parser: its receive validation and IPv6
+  profile formatting remain upstream behavior (reply profiles do not retain the
+  interface zone). Do not infer traceroute's packet correlation guarantees for
+  SDK ping.
+
+## Bounds and remaining SDK limitation
+
+Traceroute owns one raw socket in the dispatcher, sends one eight-byte probe per
+hop, and has a one-second **absolute receive deadline** per hop (unrelated packets
+and EINTR cannot extend it). It may stop up to 999 us early to avoid lwIP's
+zero-millisecond infinite-wait sentinel. Every post-creation exit closes it. The 1280-byte
+receive buffer rejects larger/truncated outer replies rather than partially
+matching them. DNS, scheduler and synchronous send latency are not included in
+that deadline. No extra task, serial hot-path work, or persistent trace allocation.
+
+Ping keeps the existing 21-event, **4200-byte PSRAM-only**, lazily retained queue
+payload and SDK's transient task. Count <=20, timeout=1000ms, interval=1000ms.
+The console wait has an absolute `count * 2000 + 2000` ms budget after start.
+Callback context is now permanent (not a caller-stack pointer); if that deadline
+expires, the callback queue remains reserved until its END event. Until then,
+later ping calls fail busy rather than overlapping callback-producing sessions or
+resetting their queue. **END ends callback production, not SDK task/socket
+retirement:** `esp_ping_delete_session()` only requests asynchronous deletion.
+A new command may start while the previous task/socket is briefly retiring; this
+is not a guarantee that two SDK tasks/sockets can never coexist.
+
+**Hard ping socket-lifetime bounds are not available from this SDK API:** unrelated
+raw ICMP traffic can repeatedly refresh `esp_ping_receive()`'s receive timeout;
+`stop`/`delete` are asynchronous and cannot interrupt that loop. The timeout path
+must not touch a potentially concurrently deleted handle. The retained reservation
+is intentional failure isolation, not proof of synchronous cleanup. A strict hard
+socket deadline would require replacing SDK ping with a dispatcher-owned raw ping
+implementation or an SDK cancellation helper with an acknowledged lifetime
+contract. No dependency/SDK patch was made. This limitation is for the parent to
+assess; ordinary SDK completion still self-deletes and releases its transient task.
+
+## Validation and measured impact (2026-09-21)
+
+- Host production fixtures: **8027 checks + 10,000 fuzz inputs PASS**.
+- Installed seven-file SDK hash contract and actual timeout conversion/mailbox fixtures: PASS.
+- Actual target compiler: syntax-only PASS after the review fixes. Earlier isolated
+  baseline/current object compiles used the existing `network_console.c` compilation
+  arguments. No `pio` build, project build artifact writes, upload, monitor, or
+  hardware test.
+- Pre-review object measurement (not remeasured after the timeout/scope fixes):
+  `text`: 7281 -> 9917 bytes (**+2636**); `bss`: 92 -> 97 (**+5**);
+  `data`: unchanged 0. These are object measurements, **not final linked firmware**.
+- Pre-review target `-fstack-usage` frames: `execute_ping` 400 -> 464; `execute_nslookup`
+  128 -> 144; `execute_traceroute` 224 -> 256; `wait_for_trace_reply` 240 -> 1408.
+  These individual frames are not a measured runtime stack high-water mark.
+- ASan/UBSan attempt could not link: host `libasan.so.8.0.0` and
+  `libubsan.so.1.0.0` are missing. Ordinary `-Wall -Wextra -Werror` fixtures passed.
+
+## Integrated surface and build validation
+
+Wi-Fi help and root/alias completion use the syntax above. The production console
+boundary is covered by `python3 tests/network_diagnostics_surfaces/run.py`:
+432 SSH/browser root-and-alias cases, UART0 parity, role/revocation guards, and
+fixed-token completion. All surfaces forward to the same canonical handler.
+
+No new ESP-NETIF ownership helper is needed: public
+`esp_netif_get_handle_from_ifkey()` / `esp_netif_get_netif_impl_index()` map aliases.
+IPv4+IPv6, raw sockets and IPv6 scopes must remain enabled. The installed
+configuration supplies these; no configuration/dependency changes were made.
+
+Final `pio run` passed: **94,452 B linked RAM / 1,857,673 B flash**
+(+8 B / +3,188 B versus the recorded pre-follow-up build). This is not runtime
+heap or stack headroom. Host fixtures, exact SDK contract, surface tests and
+existing admin policy/Wi-Fi prompt regressions passed. No upload, packet capture,
+live DNS, multi-hop trace or hardware validation was performed. The prior Phase12
+acceptance must not be treated as acceptance of this later diagnostics change.

tests/network_diagnostics/fakes.h

@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: GPL-3.0-only */
+#pragma once
+#include <assert.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <netdb.h>
+#include <net/if.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+#define CONFIG_LWIP_IPV6 1
+#define CONFIG_LWIP_DNS_MAX_HOST_IP 1
+#define ESP_IDF_VERSION_VAL(a,b,c) (((a)<<16)|((b)<<8)|(c))
+#define ESP_IDF_VERSION ESP_IDF_VERSION_VAL(5,5,0)
+typedef int esp_err_t;
+#define ESP_OK 0
+#define MALLOC_CAP_SPIRAM 1
+#define MALLOC_CAP_8BIT 2
+#define pdTRUE 1
+#define portMAX_DELAY UINT32_MAX
+#define pdMS_TO_TICKS(x) (x)
+typedef uint32_t TickType_t;
+typedef uint16_t u16_t;
+typedef struct { int unused; } StaticQueue_t;
+typedef void *QueueHandle_t;
+typedef struct { struct in6_addr addr; uint8_t zone; } ip6_addr_t;
+typedef struct in_addr ip4_addr_t;
+typedef struct { int family; union { ip4_addr_t v4; ip6_addr_t v6; }; } ip_addr_t;
+#define inet_addr_to_ip4addr(d,s) (*(d)=*(s))
+#define inet6_addr_to_ip6addr(d,s) ((d)->addr=*(s))
+#define ip6_addr_set_zone(d,z) ((d)->zone=(z))
+#define ip_addr_copy_from_ip4(d,s) ((d).family=AF_INET,(d).v4=(s))
+#define ip_addr_copy_from_ip6(d,s) ((d).family=AF_INET6,(d).v6=(s))
+#define IP_IS_V4(d) ((d)->family==AF_INET)
+#define lwip_htons htons
+#define ICMP_ECHO 8
+#define ICMP_ER 0
+#define ICMP_TE 11
+#define ICMP_DUR 3
+struct icmp_echo_hdr { uint8_t type, code; uint16_t chksum, id, seqno; };
+typedef void *esp_ping_handle_t;
+typedef struct { uint32_t count, interface, interval_ms, timeout_ms; ip_addr_t target_addr; } esp_ping_config_t;
+#define ESP_PING_DEFAULT_CONFIG() ((esp_ping_config_t){0})
+typedef struct {
+    void *cb_args;
+    void (*on_ping_success)(esp_ping_handle_t,void *);
+    void (*on_ping_timeout)(esp_ping_handle_t,void *);
+    void (*on_ping_end)(esp_ping_handle_t,void *);
+} esp_ping_callbacks_t;
+enum { ESP_PING_PROF_SEQNO, ESP_PING_PROF_SIZE, ESP_PING_PROF_TIMEGAP,
+       ESP_PING_PROF_IPADDR, ESP_PING_PROF_TTL, ESP_PING_PROF_REQUEST,
+       ESP_PING_PROF_REPLY, ESP_PING_PROF_DURATION };
+typedef struct { const char *command, *help, *hint; int (*func)(int,char **); void *argtable; } esp_console_cmd_t;
+typedef int esp_netif_t;
+
+int fake_getaddrinfo(const char *, const char *, const struct addrinfo *, struct addrinfo **);
+void fake_freeaddrinfo(struct addrinfo *);
+int fake_socket(int,int,int);
+int fake_setsockopt(int,int,int,const void *,socklen_t);
+ssize_t fake_sendto(int,const void *,size_t,int,const struct sockaddr *,socklen_t);
+ssize_t fake_recvfrom(int,void *,size_t,int,struct sockaddr *,socklen_t *);
+int fake_close(int);
+unsigned int fake_if_nametoindex(const char *);
+char *fake_if_indextoname(unsigned int,char *);
+#define getaddrinfo fake_getaddrinfo
+#define freeaddrinfo fake_freeaddrinfo
+#define socket fake_socket
+#define setsockopt fake_setsockopt
+#define sendto fake_sendto
+#define recvfrom fake_recvfrom
+#define close fake_close
+#define if_nametoindex fake_if_nametoindex
+#define if_indextoname fake_if_indextoname
+
+size_t strlcpy(char *,const char *,size_t);
+const char *esp_err_to_name(esp_err_t);
+void *heap_caps_malloc(size_t,int);
+QueueHandle_t xQueueCreateStatic(unsigned int,unsigned int,uint8_t *,StaticQueue_t *);
+int xQueueReset(QueueHandle_t);
+int xQueueSend(QueueHandle_t,const void *,unsigned int);
+int xQueueReceive(QueueHandle_t,void *,unsigned int);
+const char *ipaddr_ntoa_r(const ip_addr_t *,char *,int);
+esp_err_t esp_ping_get_profile(esp_ping_handle_t,int,void *,size_t);
+esp_err_t esp_ping_new_session(const esp_ping_config_t *,const esp_ping_callbacks_t *,esp_ping_handle_t *);
+esp_err_t esp_ping_start(esp_ping_handle_t);
+esp_err_t esp_ping_delete_session(esp_ping_handle_t);
+esp_err_t esp_ping_stop(esp_ping_handle_t);
+int64_t esp_timer_get_time(void);
+uint16_t inet_chksum(const void *,u16_t);
+esp_netif_t *esp_netif_get_handle_from_ifkey(const char *);
+int esp_netif_get_netif_impl_index(esp_netif_t *);
+esp_err_t esp_console_cmd_register(const esp_console_cmd_t *);

tests/network_diagnostics/run.py

@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+"""Compile the actual network_console.c with deterministic boundary fakes; no networking."""
+import argparse
+import pathlib
+import subprocess
+import tempfile
+
+parser = argparse.ArgumentParser(description=__doc__)
+parser.add_argument("--sanitize", action="store_true", help="enable ASan and UBSan if installed")
+options = parser.parse_args()
+HERE = pathlib.Path(__file__).resolve().parent
+ROOT = HERE.parents[1]
+headers = [
+    "esp_console.h", "esp_err.h", "esp_heap_caps.h", "esp_netif.h",
+    "esp_idf_version.h", "esp_timer.h", "freertos/FreeRTOS.h",
+    "freertos/queue.h", "freertos/task.h", "lwip/inet.h", "lwip/inet_chksum.h",
+    "lwip/ip_addr.h", "lwip/netdb.h", "lwip/netif.h", "lwip/prot/icmp.h",
+    "lwip/prot/ip4.h", "lwip/sockets.h", "ping/ping_sock.h",
+]
+with tempfile.TemporaryDirectory(prefix="network-diagnostics-") as directory:
+    tmp = pathlib.Path(directory)
+    for header in headers:
+        path = tmp / header
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_text('#include "fakes.h"\n')
+    subprocess.run([
+        "cc", "-std=c11", "-D_DEFAULT_SOURCE", "-Wall", "-Wextra", "-Werror",
+        "-g", "-O1", *(["-fsanitize=address,undefined", "-fno-omit-frame-pointer"] if options.sanitize else []),
+        "-I", str(tmp), "-I", str(HERE),
+        str(HERE / "test.c"), "-o", str(tmp / "test"),
+    ], cwd=ROOT, check=True)
+    subprocess.run([str(tmp / "test")], cwd=ROOT, check=True)

tests/network_diagnostics/sdk_contract.py

@@ -0,0 +1,89 @@
+#!/usr/bin/env python3
+"""Fail on drift from the IDF 5.5.0 sources reviewed for raw socket diagnostics."""
+import argparse
+import hashlib
+import re
+import subprocess
+import tempfile
+from pathlib import Path
+
+parser = argparse.ArgumentParser(description=__doc__)
+parser.add_argument("idf", type=Path, help="installed framework-espidf directory")
+args = parser.parse_args()
+assert (args.idf / "version.txt").read_text().strip() == "5.5.0"
+hashes = {
+    "apps/ping/ping_sock.c": "39b4be760a2137681f9f07d077c69b8de0cc1d88bed79ccfafaa1814d1d68fa5",
+    "lwip/src/api/api_msg.c": "a793b371032ba38ca5e23fd7fede4c910aea0079ffe612d781109f203eab92a0",
+    "lwip/src/api/sockets.c": "861822d05ac60f68228279036a966c26acb1282b8f2f7bd0c4672129c7fd74a4",
+    "lwip/src/api/netdb.c": "9df1796dbd6506d52776d67f6145199a1de36cf3e8eeb657ec9230573766af0c",
+    "lwip/src/core/raw.c": "3ba4f2e5d2b61bbfbe813653c7f4e88e2542d567808d3f03be000e0876ce0392",
+    "lwip/src/core/ipv6/ip6.c": "d48495404ceea84fdc97677deff00a463b2dcee59f7ead3a7661c26344e9cea0",
+    "port/freertos/sys_arch.c": "304978233ec040c5f0e95e1a08209c038b5e03695638e1640301fa1f07c307b2",
+}
+for relative, expected in hashes.items():
+    path = args.idf / "components/lwip" / relative
+    actual = hashlib.sha256(path.read_bytes()).hexdigest()
+    assert actual == expected, f"Re-audit {path}: expected {expected}, got {actual}"
+# Compile the installed conversion macro AND mailbox implementation, not copies.
+# The queue boundary is fake so testing the infinite-wait sentinel never blocks.
+sockets = (args.idf / "components/lwip/lwip/src/api/sockets.c").read_text()
+conversion = next(line for line in sockets.splitlines()
+                  if line.startswith("#define LWIP_SO_SNDRCVTIMEO_GET_MS")
+                  and "struct timeval" in line)
+sys_arch = (args.idf / "components/lwip/port/freertos/sys_arch.c").read_text()
+mailbox = re.search(r"u32_t\nsys_arch_mbox_fetch\([^\n]*\n\{.*?\n\}", sys_arch, re.S)
+assert mailbox is not None
+fixture = r'''
+#include <assert.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <sys/time.h>
+typedef uint32_t u32_t;
+typedef uint32_t TickType_t;
+typedef int BaseType_t;
+typedef struct { void *os_mbox; } fake_mbox_t;
+typedef fake_mbox_t *sys_mbox_t;
+#define portMAX_DELAY UINT32_MAX
+#define pdTRUE 1
+#define errQUEUE_EMPTY 0
+#define SYS_ARCH_TIMEOUT UINT32_MAX
+#define LWIP_ASSERT(message, condition) assert(condition)
+static TickType_t observed_ticks;
+static BaseType_t xQueueReceive(void *queue, void *msg, TickType_t ticks)
+{
+    (void)queue; (void)msg;
+    observed_ticks=ticks;
+    return pdTRUE;
+}
+'''
+fixture += conversion + "\n" + mailbox.group() + r'''
+int main(void)
+{
+    fake_mbox_t storage={0};
+    sys_mbox_t box=&storage;
+    const long microseconds[]={0,1,500,999,1000,1500,999999};
+    for (unsigned i=0;i<sizeof(microseconds)/sizeof(microseconds[0]);++i) {
+        struct timeval value={.tv_usec=microseconds[i]};
+        long ms=LWIP_SO_SNDRCVTIMEO_GET_MS(&value);
+        assert(ms==microseconds[i]/1000);
+        assert(sys_arch_mbox_fetch(&box,NULL,(u32_t)ms)==0);
+        if (microseconds[i]<1000) {
+            assert(ms==0 && observed_ticks==portMAX_DELAY);
+        } else {
+            assert(ms>0 && observed_ticks!=portMAX_DELAY);
+            assert(observed_ticks==(u32_t)ms/portTICK_PERIOD_MS);
+        }
+    }
+    return 0;
+}
+'''
+with tempfile.TemporaryDirectory(prefix="network-sdk-timeout-") as directory:
+    path = Path(directory)
+    source = path / "timeout.c"
+    source.write_text(fixture)
+    for tick_ms in (1, 10):
+        subprocess.run(["cc", "-std=c11", "-Wall", "-Wextra", "-Werror",
+                        f"-DportTICK_PERIOD_MS={tick_ms}", str(source),
+                        "-o", str(path / "timeout")], check=True)
+        subprocess.run([str(path / "timeout")], check=True)
+print("IDF 5.5.0 network diagnostics: 7 hashes + actual timeout conversion/mailbox fixtures PASS")

tests/network_diagnostics/test.c

@@ -0,0 +1,383 @@
+/* SPDX-License-Identifier: GPL-3.0-only */
+#include "../../src/network_console.c"
+#undef close /* Output-capture descriptors are real host files, not fake sockets. */
+
+static unsigned checks;
+#define CHECK(x) do { ++checks; if (!(x)) { fprintf(stderr,"FAIL %s:%d: %s\n",__FILE__,__LINE__,#x); abort(); } } while (0)
+static int queries[8], query_count, resolver_error4, resolver_error6, freed;
+static bool resolver_linklocal;
+static long socket_timeout_ms;
+static unsigned recv_calls, ping_created;
+static struct addrinfo ai;
+static struct sockaddr_storage answer;
+static int sockets, closed, options, fail_option, send_fail, recv_error, socket_fail;
+static int socket_family, socket_protocol, sent_count, ttl_options, v6only_options, bind_options;
+static uint8_t incoming[1280];
+static size_t incoming_length;
+static struct sockaddr_storage incoming_source;
+static int64_t now;
+static esp_ping_config_t ping_config;
+static esp_ping_callbacks_t ping_callbacks;
+static int ping_create_error, ping_start_error, ping_deleted;
+static bool ping_delayed;
+static uint8_t *queue_bytes;
+static unsigned queue_size, queue_read, queue_write;
+static bool allocation_fail;
+
+static void reset(void)
+{
+    query_count = freed = resolver_error4 = resolver_error6 = 0;
+    resolver_linklocal = false;
+    socket_timeout_ms = 0;
+    recv_calls = ping_created = 0;
+    sockets = closed = options = fail_option = send_fail = recv_error = socket_fail = 0;
+    sent_count = ttl_options = v6only_options = bind_options = 0;
+    incoming_length = 0;
+    now = 0;
+    ping_create_error = ping_start_error = ping_deleted = 0;
+    ping_delayed = false;
+    allocation_fail = false;
+}
+
+int fake_getaddrinfo(const char *host, const char *service, const struct addrinfo *hints, struct addrinfo **out)
+{
+    (void)host; CHECK(service == NULL); CHECK(query_count < 8);
+    queries[query_count++] = hints->ai_family;
+    CHECK(hints->ai_flags == 0);
+    int error = hints->ai_family == AF_INET ? resolver_error4 : resolver_error6;
+    *out = NULL;
+    if (error) return error;
+    memset(&answer,0,sizeof(answer));
+    if (hints->ai_family == AF_INET) {
+        struct sockaddr_in *v4 = (void *)&answer;
+        v4->sin_family = AF_INET;
+        inet_pton(AF_INET,"192.0.2.1",&v4->sin_addr);
+    } else {
+        struct sockaddr_in6 *v6 = (void *)&answer;
+        v6->sin6_family = AF_INET6;
+        inet_pton(AF_INET6,resolver_linklocal?"fe80::1":"2001:db8::1",&v6->sin6_addr);
+        CHECK(v6->sin6_scope_id==0); /* DNS does not supply an interface zone. */
+    }
+    ai = (struct addrinfo){.ai_family=hints->ai_family,.ai_addr=(void *)&answer,.ai_addrlen=sizeof(answer)};
+    *out = &ai;
+    return 0;
+}
+void fake_freeaddrinfo(struct addrinfo *p) { CHECK(p == &ai); ++freed; }
+int fake_socket(int family,int type,int protocol)
+{
+    CHECK(type == SOCK_RAW); socket_family=family; socket_protocol=protocol;
+    if (socket_fail) { errno=ENOMEM; return -1; }
+    ++sockets; return 0; /* fd zero is valid and must be closed */
+}
+int fake_setsockopt(int fd,int level,int option,const void *value,socklen_t length)
+{
+    CHECK(fd==0); ++options;
+    if (fail_option==options) { errno=EINVAL; return -1; }
+    if (level==IPPROTO_IP && option==IP_TTL) {
+        CHECK(length==sizeof(int)); CHECK(*(const int *)value>=1 && *(const int *)value<=30); ++ttl_options;
+    } else if (level==IPPROTO_IPV6 && option==IPV6_V6ONLY) {
+        CHECK(*(const int *)value==1); ++v6only_options;
+    } else if (level==SOL_SOCKET && option==SO_BINDTODEVICE) {
+        CHECK(length==sizeof(struct ifreq)); CHECK(strcmp(((const struct ifreq *)value)->ifr_name,"st1")==0); ++bind_options;
+    } else {
+        CHECK(level==SOL_SOCKET && option==SO_RCVTIMEO);
+        CHECK(length==sizeof(struct timeval));
+        const struct timeval *timeout=value;
+        CHECK(timeout->tv_sec<=1 && timeout->tv_usec<1000000);
+        /* sdk_contract.py also compiles the installed SDK's actual conversion. */
+        socket_timeout_ms=timeout->tv_sec*1000+timeout->tv_usec/1000;
+        CHECK(socket_timeout_ms>0);
+    }
+    return 0;
+}
+ssize_t fake_sendto(int fd,const void *data,size_t length,int flags,const struct sockaddr *address,socklen_t address_length)
+{
+    (void)flags; CHECK(fd==0); CHECK(length==8); ++sent_count;
+    CHECK(address->sa_family==socket_family);
+    const struct icmp_echo_hdr *echo=data;
+    if (socket_family==AF_INET6) {
+        CHECK(socket_protocol==IPPROTO_ICMPV6); CHECK(echo->type==128); CHECK(echo->chksum==0);
+        CHECK(address_length==sizeof(struct sockaddr_in6));
+    } else {
+        CHECK(socket_protocol==IPPROTO_ICMP); CHECK(echo->type==ICMP_ECHO); CHECK(inet_chksum(data,length)==0);
+        CHECK(address_length==sizeof(struct sockaddr_in));
+    }
+    if (send_fail) { errno=ENETUNREACH; return -1; }
+    return length;
+}
+ssize_t fake_recvfrom(int fd,void *data,size_t length,int flags,struct sockaddr *source,socklen_t *source_length)
+{
+    (void)flags; CHECK(fd==0);
+    ++recv_calls;
+    CHECK(socket_timeout_ms>0); /* zero would enter portMAX_DELAY in IDF */
+    if (incoming_length) {
+        CHECK(length>=incoming_length); memcpy(data,incoming,incoming_length);
+        memcpy(source,&incoming_source,sizeof(incoming_source)); *source_length=sizeof(incoming_source);
+        size_t result=incoming_length; incoming_length=0; return result;
+    }
+    errno=recv_error ? recv_error : EAGAIN; return -1;
+}
+int fake_close(int fd) { CHECK(fd==0); ++closed; return 0; }
+unsigned int fake_if_nametoindex(const char *name) { return strcmp(name,"st1")==0 ? 2U : 0U; }
+char *fake_if_indextoname(unsigned int index,char *name) { if (index!=2 && index!=3) return NULL; strcpy(name,index==2?"st1":"ap2"); return name; }
+esp_netif_t *esp_netif_get_handle_from_ifkey(const char *key) { static int sta=2,ap=3; return strcmp(key,"WIFI_STA_DEF")==0?&sta:&ap; }
+int esp_netif_get_netif_impl_index(esp_netif_t *p) { return *p; }
+size_t strlcpy(char *dest,const char *source,size_t size) { size_t n=strlen(source); if (size) snprintf(dest,size,"%s",source); return n; }
+const char *esp_err_to_name(esp_err_t error) { (void)error; return "fake error"; }
+void *heap_caps_malloc(size_t size,int caps) { CHECK(caps==(MALLOC_CAP_SPIRAM|MALLOC_CAP_8BIT)); return allocation_fail?NULL:malloc(size); }
+QueueHandle_t xQueueCreateStatic(unsigned int count,unsigned int size,uint8_t *bytes,StaticQueue_t *control) { (void)control; CHECK(count==21); queue_bytes=bytes; queue_size=size; queue_read=queue_write=0; return bytes; }
+int xQueueReset(QueueHandle_t q) { CHECK(q==queue_bytes); queue_read=queue_write=0; return pdTRUE; }
+int xQueueSend(QueueHandle_t q,const void *event,unsigned int timeout) { CHECK(q==queue_bytes && timeout==0 && queue_write<21); memcpy(queue_bytes+queue_size*queue_write++,event,queue_size); return pdTRUE; }
+int xQueueReceive(QueueHandle_t q,void *event,unsigned int timeout) { (void)timeout; CHECK(q==queue_bytes); if (queue_read==queue_write) return 0; memcpy(event,queue_bytes+queue_size*queue_read++,queue_size); return pdTRUE; }
+const char *ipaddr_ntoa_r(const ip_addr_t *ip,char *out,int capacity) { return inet_ntop(ip->family,ip->family==AF_INET?(const void *)&ip->v4:(const void *)&ip->v6.addr,out,capacity); }
+esp_err_t esp_ping_get_profile(esp_ping_handle_t h,int profile,void *out,size_t size) { CHECK(h==&ping_config); memset(out,0,size); if (profile==ESP_PING_PROF_IPADDR) memcpy(out,&ping_config.target_addr,size); if (profile==ESP_PING_PROF_REQUEST || profile==ESP_PING_PROF_REPLY) *(uint32_t *)out=ping_config.count; return ESP_OK; }
+esp_err_t esp_ping_new_session(const esp_ping_config_t *config,const esp_ping_callbacks_t *callbacks,esp_ping_handle_t *out) { ++ping_created; ping_config=*config; ping_callbacks=*callbacks; if(ping_create_error) return -1; *out=&ping_config; return ESP_OK; }
+esp_err_t esp_ping_start(esp_ping_handle_t h) { if(ping_start_error) return -1; if(ping_delayed) return ESP_OK; ping_callbacks.on_ping_success(h,ping_callbacks.cb_args); ping_callbacks.on_ping_end(h,ping_callbacks.cb_args); return ESP_OK; }
+esp_err_t esp_ping_delete_session(esp_ping_handle_t h) { CHECK(h==&ping_config); ++ping_deleted; return ESP_OK; }
+esp_err_t esp_ping_stop(esp_ping_handle_t h) { CHECK(h==&ping_config); return ESP_OK; }
+int64_t esp_timer_get_time(void) { now+=1000; return now; }
+uint16_t inet_chksum(const void *data,u16_t length) { uint32_t sum=checksum_sum(data,length,0); while(sum>>16) sum=(sum&65535)+(sum>>16); return htons((uint16_t)~sum); }
+esp_err_t esp_console_cmd_register(const esp_console_cmd_t *cmd) { CHECK(cmd->func==network_console_execute); return ESP_OK; }
+
+static void test_arguments(void)
+{
+    diagnostic_arguments_t a;
+    char *good[]={"ping","-6","::1","20"};
+    CHECK(parse_arguments(4,good,4,20,&a) && a.family==AF_INET6 && a.limit==20);
+    char *after[]={"ping","::1","20","-6"};
+    CHECK(parse_arguments(4,after,4,20,&a));
+    char *middle[]={"ping","::1","-6","1"};
+    CHECK(parse_arguments(4,middle,4,20,&a) && a.limit==1);
+    char *bad[][5]={{"ping","-6","::1","-6",NULL},{"ping","-4","::1","-6",NULL},
+        {"ping","host","0",NULL},{"ping","host","21",NULL},{"ping","host","-1",NULL},
+        {"ping","host","42949672960",NULL},{"ping","host","1x",NULL},{"ping","",NULL},
+        {"ping","-6",NULL},{"ping","host","1","2",NULL},{"ping","--", "host",NULL}};
+    for(size_t i=0;i<sizeof(bad)/sizeof(bad[0]);++i) { int n=0; while(bad[i][n])++n; CHECK(!parse_arguments(n,bad[i],4,20,&a)); }
+    char *lookup[]={"nslookup","host","1"}; CHECK(!parse_arguments(3,lookup,0,0,&a));
+    char *trace[]={"traceroute","host","30"}; CHECK(parse_arguments(3,trace,16,30,&a)); trace[2]="31"; CHECK(!parse_arguments(3,trace,16,30,&a));
+}
+
+static diagnostic_target_t target_for(const char *text)
+{
+    diagnostic_target_t target; CHECK(parse_literal(text,AF_UNSPEC,&target)==1); return target;
+}
+static void test_resolution(void)
+{
+    diagnostic_target_t target; char numeric[48];
+    const char *valid[]={"fe80::1%sta","fe80::1%ap","fe80::1%2","fe80::1%st1","fe80::1","::1","192.0.2.1"};
+    for(size_t i=0;i<sizeof(valid)/sizeof(valid[0]);++i) CHECK(parse_literal(valid[i],AF_UNSPEC,&target)==1);
+    const char *bad[]={"fe80::1%0","fe80::1%256","fe80::1%9","fe80::1%","fe80::1%eth0","fe80::1%sta%2","example%sta","192.0.2.1%sta","::ffff:192.0.2.1","fe80:garbage"};
+    for(size_t i=0;i<sizeof(bad)/sizeof(bad[0]);++i) CHECK(parse_literal(bad[i],AF_UNSPEC,&target)==-1);
+    CHECK(parse_literal("::1",AF_INET,&target)==-1); CHECK(parse_literal("192.0.2.1",AF_INET6,&target)==-1);
+    target=target_for("fe80::1%sta"); CHECK(sockaddr_to_numeric((void *)&target.address,target.length,numeric,sizeof(numeric))); CHECK(strcmp(numeric,"fe80::1%2")==0);
+    CHECK(!sockaddr_to_numeric((void *)&target.address,target.length,numeric,4));
+    ip_addr_t ip; struct addrinfo entry={.ai_family=AF_INET6,.ai_addr=(void *)&target.address,.ai_addrlen=target.length};
+    CHECK(addrinfo_to_ip_addr(&entry,&ip)); CHECK(ip.v6.zone==2);
+    diagnostic_arguments_t args={.host="example.test",.family=AF_UNSPEC};
+    reset(); CHECK(resolve_target(&args,&target,numeric,sizeof(numeric))==0); CHECK(query_count==1 && queries[0]==AF_INET && freed==1);
+    reset(); resolver_error4=EAI_FAIL; CHECK(resolve_target(&args,&target,numeric,sizeof(numeric))==0); CHECK(query_count==2 && queries[1]==AF_INET6 && freed==1);
+    reset(); resolver_error4=EAI_MEMORY; CHECK(resolve_target(&args,&target,numeric,sizeof(numeric))!=0); CHECK(query_count==1);
+    reset(); args.family=AF_INET6; resolver_error6=EAI_FAIL; CHECK(resolve_target(&args,&target,numeric,sizeof(numeric))!=0); CHECK(query_count==1 && queries[0]==AF_INET6);
+    char *lookup[]={"nslookup","example.test"}; reset(); CHECK(network_console_execute(2,lookup)==0); CHECK(query_count==2 && freed==2);
+    char *lookup6[]={"nslookup","example.test","-6"}; reset(); CHECK(network_console_execute(3,lookup6)==0); CHECK(query_count==1 && queries[0]==AF_INET6);
+    char *lookup4[]={"nslookup","-4","example.test"}; reset(); CHECK(network_console_execute(3,lookup4)==0); CHECK(query_count==1 && queries[0]==AF_INET);
+    reset(); resolver_error4=EAI_NONAME; CHECK(network_console_execute(2,lookup)==0); CHECK(query_count==2 && queries[1]==AF_INET6);
+    reset(); resolver_error4=resolver_error6=EAI_FAIL; CHECK(network_console_execute(2,lookup)!=0); CHECK(query_count==2);
+}
+
+static int capture_command(int argc, char **argv, char *output, size_t capacity)
+{
+    fflush(stdout);
+    int saved=dup(STDOUT_FILENO);
+    FILE *capture=tmpfile();
+    CHECK(saved>=0 && capture!=NULL);
+    CHECK(dup2(fileno(capture),STDOUT_FILENO)>=0);
+    int result=network_console_execute(argc,argv);
+    fflush(stdout);
+    CHECK(fseek(capture,0,SEEK_SET)==0);
+    size_t size=fread(output,1,capacity-1,capture);
+    CHECK(size<capacity-1 && !ferror(capture));
+    output[size]='\0';
+    CHECK(dup2(saved,STDOUT_FILENO)>=0);
+    CHECK(close(saved)==0);
+    CHECK(fclose(capture)==0);
+    return result;
+}
+
+static void test_unscoped_linklocal(void)
+{
+    char output[1024];
+    diagnostic_target_t target;
+    reset(); resolver_linklocal=true;
+    CHECK(resolve_family("ll.example",AF_INET6,&target)==0);
+    CHECK(target_needs_scope(&target) && freed==1);
+    const char *hosts[]={"ll.example","fe80::1"};
+    for(size_t h=0;h<2;++h) {
+        for(int explicit6=0;explicit6<=1;++explicit6) {
+            char *lookup[]={"nslookup",(char *)hosts[h],"-6"};
+            reset(); resolver_linklocal=true;
+            CHECK(capture_command(explicit6?3:2,lookup,output,sizeof(output))==0);
+            CHECK(strstr(output,h==0?"AAAA: fe80::1":"Address: fe80::1 (numeric literal; no DNS query)")!=NULL);
+            CHECK(strstr(output,"explicit device scope")!=NULL && strstr(output,"fe80::1%sta")!=NULL);
+            CHECK(query_count==(h==0?(explicit6?1:2):0));
+            if(h==0) CHECK(queries[query_count-1]==AF_INET6);
+            CHECK(sockets==0 && ping_created==0);
+            const char *commands[]={"ping","traceroute"};
+            for(size_t c=0;c<2;++c) {
+                char *probe[]={(char *)commands[c],(char *)hosts[h],"1","-6"};
+                reset(); resolver_linklocal=true; resolver_error4=EAI_NONAME;
+                CHECK(capture_command(explicit6?4:3,probe,output,sizeof(output))!=0);
+                CHECK(strstr(output,"Link-local fe80::1")!=NULL && strstr(output,"fe80::1%sta")!=NULL);
+                CHECK(strstr(output,"device interface, not the SSH/browser client's")!=NULL);
+                CHECK(sockets==0 && sent_count==0 && ping_created==0);
+                CHECK(query_count==(h==0?(explicit6?1:2):0));
+            }
+        }
+    }
+}
+
+static void put16(uint8_t *p,uint16_t n) { p[0]=n>>8; p[1]=n; }
+static void fix_packet(uint8_t *p,size_t n,bool v6)
+{
+    size_t h=v6?40:20;
+    p[h+2]=p[h+3]=0;
+    if(v6) {
+        uint32_t sum=checksum_sum(p+8,32,checksum_sum(p+h,n-h,(uint32_t)(n-h)+58));
+        while(sum>>16) sum=(sum&65535)+(sum>>16);
+        put16(p+h+2,(uint16_t)~sum);
+    } else {
+        p[10]=p[11]=0; uint16_t c=inet_chksum(p,20); memcpy(p+10,&c,2);
+        c=inet_chksum(p+h,n-h); memcpy(p+h+2,&c,2);
+    }
+}
+static size_t packet_for(uint8_t *p,bool v6,bool error)
+{
+    size_t h=v6?40:20, n=h+8+(error?h+8:0);
+    memset(p,0,1280); p[0]=v6?0x60:0x45;
+    if(v6) { put16(p+4,n-h); p[6]=58; inet_pton(AF_INET6,"2001:db8::1",p+8); inet_pton(AF_INET6,"2001:db8::2",p+24); }
+    else { put16(p+2,n); p[9]=1; inet_pton(AF_INET,"192.0.2.1",p+12); inet_pton(AF_INET,"192.0.2.2",p+16); }
+    uint8_t *echo=p+h;
+    echo[0]=error?(v6?3:11):(v6?129:0);
+    if(error) {
+        uint8_t *inner=echo+8; inner[0]=v6?0x60:0x45;
+        if(v6) { put16(inner+4,8); inner[6]=58; inet_pton(AF_INET6,"2001:db8::1",inner+24); }
+        else { put16(inner+2,28); inner[9]=1; inet_pton(AF_INET,"192.0.2.1",inner+16); uint16_t c=inet_chksum(inner,20); memcpy(inner+10,&c,2); }
+        echo=inner+h; echo[0]=v6?128:8;
+    }
+    put16(echo+4,0x1234); put16(echo+6,7); fix_packet(p,n,v6); return n;
+}
+static void test_packets(void)
+{
+    uint8_t packet[1280],code; uint16_t id=htons(0x1234),seq=htons(7);
+    for(int v6=0;v6<=1;++v6) {
+        diagnostic_target_t target=target_for(v6?"2001:db8::1":"192.0.2.1");
+        for(int error=0;error<=1;++error) {
+            size_t n=packet_for(packet,v6,error),h=v6?40:20;
+            CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==(error?TRACE_REPLY_HOP:TRACE_REPLY_DESTINATION));
+            for(size_t truncated=0;truncated<n;++truncated) CHECK(parse_trace_reply(packet,truncated,&target,id,seq,&code)==TRACE_REPLY_UNRELATED);
+            CHECK(parse_trace_reply(packet,n,&target,id+1,seq,&code)==TRACE_REPLY_UNRELATED);
+            CHECK(parse_trace_reply(packet,n,&target,id,seq+1,&code)==TRACE_REPLY_UNRELATED);
+            packet[n-1]^=1; CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNRELATED); packet[n-1]^=1;
+            packet[h+1]=255; fix_packet(packet,n,v6);
+            CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNRELATED);
+            packet_for(packet,v6,error);
+            if(error) {
+                packet[n-7]=1; fix_packet(packet,n,v6); /* quoted echo code */
+                CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNRELATED);
+                packet_for(packet,v6,error);
+                packet[n-8]=0xff; fix_packet(packet,n,v6); /* quoted echo type */
+                CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNRELATED);
+                packet_for(packet,v6,error);
+                put16(packet+h+8+(v6?4:2),v6?7:27); fix_packet(packet,n,v6);
+                CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNRELATED);
+                packet_for(packet,v6,error);
+                packet[h]=v6?1:3; packet[h+1]=1; fix_packet(packet,n,v6);
+                CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNREACHABLE && code==1);
+                packet[h]=v6?3:11; packet[h+1]=1; fix_packet(packet,n,v6);
+                CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNRELATED);
+                packet_for(packet,v6,error); packet[h+8+(v6?24:16)]^=1; fix_packet(packet,n,v6);
+                CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNRELATED);
+                packet_for(packet,v6,error); packet[h+8+(v6?6:9)]=v6?44:17; fix_packet(packet,n,v6);
+                CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNRELATED);
+            } else {
+                packet[v6?8:12]^=1; fix_packet(packet,n,v6);
+                CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNRELATED);
+            }
+        }
+    }
+    diagnostic_target_t target=target_for("2001:db8::1");
+    for(unsigned i=0;i<6;++i) {
+        const uint8_t unsupported[]={0,43,44,50,51,60};
+        size_t n=packet_for(packet,true,true); packet[6]=unsupported[i]; fix_packet(packet,n,true);
+        CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNRELATED);
+        packet_for(packet,true,true); packet[48+6]=unsupported[i]; fix_packet(packet,n,true);
+        CHECK(parse_trace_reply(packet,n,&target,id,seq,&code)==TRACE_REPLY_UNRELATED);
+    }
+    /* Packet fuzz lengths and bytes exercise actual parser bounds deterministically. */
+    uint32_t random=7;
+    for(unsigned i=0;i<10000;++i) { random=random*1664525U+1013904223U; size_t n=random%sizeof(packet); for(size_t j=0;j<n;++j) { random=random*1664525U+1013904223U; packet[j]=random>>24; } (void)parse_trace_reply(packet,n,&target,id,seq,&code); }
+}
+
+static void test_submillisecond_deadline(void)
+{
+    const int remaining[]={1,500,999,1000};
+    for(int v6=0;v6<=1;++v6) {
+        diagnostic_target_t target=target_for(v6?"2001:db8::1":"192.0.2.1");
+        char source[48]; int64_t rtt; uint8_t code;
+        for(size_t i=0;i<sizeof(remaining)/sizeof(remaining[0]);++i) {
+            reset(); now=TRACEROUTE_TIMEOUT_US-remaining[i]-1000;
+            CHECK(wait_for_trace_reply(0,&target,0,0,0,source,sizeof(source),&rtt,&code)==TRACE_WAIT_TIMEOUT);
+            CHECK(recv_calls==(remaining[i]>=1000?1U:0U));
+            CHECK(options==(remaining[i]>=1000?1:0));
+            if(remaining[i]>=1000) CHECK(socket_timeout_ms==1);
+        }
+        /* One unrelated packet leaves exactly 500 us; no second recv allowed. */
+        reset(); now=TRACEROUTE_TIMEOUT_US-1500-1000;
+        incoming_length=packet_for(incoming,v6,false); incoming_source=target.address;
+        CHECK(wait_for_trace_reply(0,&target,0,0,0,source,sizeof(source),&rtt,&code)==TRACE_WAIT_TIMEOUT);
+        CHECK(recv_calls==1 && options==1 && socket_timeout_ms==1);
+    }
+}
+
+static void test_lifetimes(void)
+{
+    for(int v6=0;v6<=1;++v6) {
+        char *argv[]={"traceroute",v6?"2001:db8::1":"192.0.2.1","1"};
+        reset(); CHECK(network_console_execute(3,argv)==0); CHECK(sockets==1 && closed==1 && sent_count==1 && ttl_options==1); CHECK(v6only_options==v6);
+        int option_count=options;
+        for(int fail=1;fail<=option_count;++fail) { reset(); fail_option=fail; CHECK(network_console_execute(3,argv)!=0); CHECK(closed==1); }
+        reset(); send_fail=1; CHECK(network_console_execute(3,argv)!=0); CHECK(closed==1);
+        reset(); recv_error=EIO; CHECK(network_console_execute(3,argv)!=0); CHECK(closed==1);
+        reset(); socket_fail=1; CHECK(network_console_execute(3,argv)!=0); CHECK(closed==0);
+    }
+    char *scoped[]={"traceroute","fe80::1%sta","-6","1"}; reset(); CHECK(network_console_execute(4,scoped)==0); CHECK(bind_options==1 && closed==1);
+    reset(); fail_option=2; CHECK(network_console_execute(4,scoped)!=0); CHECK(closed==1);
+    char *hostname[]={"traceroute","example.test","1"}; reset(); send_fail=1; CHECK(network_console_execute(3,hostname)!=0); CHECK(query_count==1 && queries[0]==AF_INET && closed==1);
+    diagnostic_target_t target=target_for("2001:db8::1"); char source[48]; int64_t rtt; uint8_t code;
+    reset(); now=2000000; CHECK(wait_for_trace_reply(0,&target,htons(0x1234),htons(7),0,source,sizeof(source),&rtt,&code)==TRACE_WAIT_TIMEOUT); CHECK(options==0);
+    reset(); incoming_length=packet_for(incoming,true,false); incoming_source=target.address;
+    CHECK(wait_for_trace_reply(0,&target,htons(0x1234),htons(7),0,source,sizeof(source),&rtt,&code)==TRACE_WAIT_DESTINATION);
+    reset(); incoming_length=packet_for(incoming,true,false); incoming_source=target_for("2001:db8::9").address;
+    CHECK(wait_for_trace_reply(0,&target,htons(0x1234),htons(7),0,source,sizeof(source),&rtt,&code)==TRACE_WAIT_TIMEOUT);
+    char *ping[]={"ping","fe80::1%sta","-6","1"};
+    reset(); allocation_fail=true; CHECK(network_console_execute(4,ping)!=0); CHECK(s_ping_queue_bytes==NULL);
+    reset(); CHECK(network_console_execute(4,ping)==0); CHECK(ping_config.interface==2 && ping_config.target_addr.v6.zone==2 && ping_deleted==1);
+    reset(); ping_create_error=1; CHECK(network_console_execute(4,ping)!=0); CHECK(ping_deleted==0);
+    reset(); ping_start_error=1; CHECK(network_console_execute(4,ping)!=0); CHECK(ping_deleted==1);
+    reset(); ping_delayed=true; CHECK(network_console_execute(4,ping)!=0); CHECK(s_ping_pending && ping_deleted==0);
+    CHECK(ping_callbacks.cb_args==&s_ping_context);
+    CHECK(network_console_execute(4,ping)!=0); CHECK(s_ping_pending);
+    ping_callbacks.on_ping_end(&ping_config,ping_callbacks.cb_args);
+    ping_delayed=false; CHECK(network_console_execute(4,ping)==0); CHECK(!s_ping_pending && ping_deleted==2);
+    reset(); recv_error=EINTR;
+    CHECK(wait_for_trace_reply(0,&target,0,0,0,source,sizeof(source),&rtt,&code)==TRACE_WAIT_TIMEOUT);
+}
+int main(void)
+{
+    test_arguments(); test_resolution(); test_unscoped_linklocal();
+    test_packets(); test_submillisecond_deadline(); test_lifetimes();
+    CHECK(network_console_register_root_commands()==ESP_OK);
+    free(s_ping_queue_bytes);
+    printf("network diagnostics: %u checks + 10000 packet fuzz inputs PASS\n",checks);
+    return 0;
+}

tests/network_diagnostics_surfaces/completion.c

@@ -0,0 +1,53 @@
+
+static void expect_matches(const char *prefix, const char *expected)
+{
+    char output[CONSOLE_COMPLETION_OUTPUT_CAPACITY]={0}; size_t length=999;
+    assert(console_completion_format_matches(prefix,output,sizeof(output),&length));
+    assert(length==strlen(expected) && !memcmp(output,expected,length));
+}
+int main(void)
+{
+    const char *verbs[]={"ping","nslookup","traceroute"};
+    for (unsigned alias=0;alias<2;++alias)
+    for (unsigned verb=0;verb<3;++verb) {
+        char base[64], prefix[128], expected[256], expanded[128];
+        snprintf(base,sizeof(base),"%s%s",alias ? "wifi " : "",verbs[verb]);
+        snprintf(prefix,sizeof(prefix),"%s ",base);
+        snprintf(expected,sizeof(expected),"%s -4\r\n%s -6\r\n",base,base);
+        expect_matches(prefix,expected);
+        assert(console_completion_expand(prefix,expanded,sizeof(expanded)));
+        snprintf(prefix,sizeof(prefix),"%s -",base);
+        assert(!strcmp(expanded,prefix));
+        expect_matches(prefix,expected);
+        assert(!console_completion_expand(prefix,expanded,sizeof(expanded)));
+        snprintf(prefix,sizeof(prefix),"%s -6",base);
+        expect_matches(prefix,"");
+        assert(!console_completion_expand(prefix,expanded,sizeof(expanded)));
+        snprintf(prefix,sizeof(prefix),"%s -4 ",base); expect_matches(prefix,"");
+        snprintf(prefix,sizeof(prefix),"%s -6 ",base); expect_matches(prefix,"");
+        snprintf(prefix,sizeof(prefix),"%s private-host.example -",base); expect_matches(prefix,"");
+        snprintf(prefix,sizeof(prefix),"%s 2001:db8::1 ",base); expect_matches(prefix,"");
+        snprintf(prefix,sizeof(prefix),"%s -",base);
+        size_t length=123;
+        assert(!console_completion_format_matches(prefix,expanded,1,&length));
+        assert(length==123);
+        snprintf(prefix,sizeof(prefix),"%s ",base);
+        assert(!console_completion_expand(prefix,expanded,strlen(prefix)+1));
+    }
+    expect_matches("wifi profile secret 0 ","");
+    expect_matches("wifi ap secret ","");
+    expect_matches("user password admin ","");
+    expect_matches("nslook","nslookup\r\n");
+    expect_matches("wifi p","wifi profiles\r\nwifi profile\r\nwifi profile set\r\nwifi profile secret\r\nwifi profile enable\r\nwifi profile disable\r\nwifi profile delete\r\nwifi ping\r\nwifi ping -4\r\nwifi ping -6\r\n");
+    /* Every candidate prefix must still fit the shared bounded list buffer. */
+    for (size_t i=0;i<sizeof(s_completion_candidates)/sizeof(s_completion_candidates[0]);++i) {
+        char prefix[257], output[CONSOLE_COMPLETION_OUTPUT_CAPACITY]; size_t length;
+        strcpy(prefix,s_completion_candidates[i]);
+        for (size_t n=0;n<=strlen(s_completion_candidates[i]);++n) {
+            char saved=prefix[n]; prefix[n]='\0';
+            assert(console_completion_format_matches(prefix,output,sizeof(output),&length));
+            prefix[n]=saved;
+        }
+    }
+    puts("PASS: actual shared completion matcher, six diagnostic prefixes, no host/secret guessing, expansion and bounded output");
+}

tests/network_diagnostics_surfaces/routing.c

@@ -0,0 +1,80 @@
+
+static bool owner_live=true;
+static bool is_current(const admin_ssh_console_token_t *token, const user_principal_t *principal)
+{ (void)token; assert(principal->role==USER_ROLE_ADMIN); return owner_live; }
+static bool drained(const admin_ssh_console_token_t *token) { (void)token; return true; }
+static esp_err_t perform(const admin_ssh_console_token_t *token,
+                         admin_ssh_deferred_action_type_t action, uint32_t argument)
+{ (void)token; (void)action; (void)argument; assert(false); return ESP_FAIL; }
+static const admin_console_owner_t owner={.is_current=is_current,.drained=drained,.perform=perform};
+static void pump(void) { if (!setjmp(loop_done)) worker_task(NULL); }
+static void feed(const admin_ssh_console_token_t *token, const char *line)
+{
+    char input[257]; snprintf(input,sizeof(input),"%s\r",line);
+    size_t used=0;
+    assert(admin_ssh_console_feed_input(token,(const uint8_t *)input,strlen(input),&used));
+    assert(used==strlen(input));
+}
+static void discard_output(const admin_ssh_console_token_t *token)
+{
+    uint8_t output[4096]; size_t used;
+    assert(admin_ssh_console_read_output(token,output,sizeof(output),&used)==ESP_OK);
+}
+int main(void)
+{
+    assert(admin_ssh_console_init()==ESP_OK);
+    assert(admin_ssh_console_start_uart_frontend()==ESP_OK);
+    const user_principal_t admin={.role=USER_ROLE_ADMIN};
+    const user_principal_t ordinary={.role=USER_ROLE_USER};
+    const char *verbs[]={"ping","nslookup","traceroute"};
+    const char *hosts[]={"example.org","192.0.2.1","2001:db8::1","fe80::1%st1"};
+    unsigned cases=0;
+    for (unsigned transport=0;transport<2;++transport) {
+        admin_ssh_console_token_t token={.slot_index=0,.session_id=7,.slot_generation=1,
+            .transport=transport ? ADMIN_CONSOLE_TRANSPORT_WEB : ADMIN_CONSOLE_TRANSPORT_SSH};
+        assert(admin_ssh_console_open_owned(&token,&ordinary,&owner)!=ESP_OK);
+        assert(!s_sessions[0].active && !s_request_queue->count);
+        assert(admin_ssh_console_open_owned(&token,&admin,&owner)==ESP_OK);
+        for (unsigned alias=0;alias<2;++alias)
+        for (unsigned verb=0;verb<3;++verb)
+        for (unsigned host=0;host<4;++host)
+        for (unsigned family=0;family<3;++family)
+        for (unsigned position=0;position<3;++position) {
+            const char *flag=family==0 ? "" : family==1 ? "-4 " : "-6 ";
+            const char *count=verb==0 ? "20 " : verb==2 ? "30 " : "";
+            char line[257];
+            snprintf(line,sizeof(line),"%s%s %s%s %s%s%s",alias ? "wifi " : "",verbs[verb],
+                     position==0 ? flag : "",hosts[host],position==1 ? flag : "",count,
+                     position==2 ? flag : "");
+            unsigned before=runs;
+            discard_output(&token);
+            feed(&token,line); pump();
+            assert(runs==before+1 && !strcmp(dispatched,line));
+            /* Trusted UART0 arrives at exactly the same registry boundary. */
+            admin_request_t uart={.origin=ADMIN_REQUEST_UART0};
+            memcpy(uart.line,line,strlen(line)+1);
+            assert(xQueueSend(s_request_queue,&uart,0)); pump();
+            assert(runs==before+2 && !strcmp(dispatched,line));
+            ++cases;
+        }
+        const char *extra[]={"ping example.org", "wifi ping example.org", "traceroute example.org",
+            "wifi traceroute example.org", "nslookup example.org", "wifi nslookup example.org",
+            "  \"wifi\" \"ping\" \"2001:db8::1\" \"2\" \"-6\"  ",
+            "\"nslookup\" \"-6\" \"example.org\""};
+        for (unsigned i=0;i<sizeof(extra)/sizeof(extra[0]);++i) {
+            discard_output(&token); unsigned before=runs;
+            feed(&token,extra[i]); pump();
+            assert(runs==before+1 && !strcmp(dispatched,extra[i]));
+        }
+        /* Existing currentness guards deny diagnostics after revocation. */
+        unsigned before=runs;
+        feed(&token,"wifi ping -6 2001:db8::1"); principal_current=false; pump();
+        assert(runs==before && !s_sessions[0].active);
+        principal_current=true; ++token.slot_generation;
+        assert(admin_ssh_console_open_owned(&token,&admin,&owner)==ESP_OK);
+        feed(&token,"nslookup -6 example.org"); owner_live=false; pump();
+        assert(runs==before && !s_sessions[0].active);
+        owner_live=true;
+    }
+    printf("PASS: %u SSH/WEB root+Wi-Fi family/position/host cases and UART0 parity; defaults/quotes, ordinary-role and revocation guards\n",cases);
+}

tests/network_diagnostics_surfaces/run.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+"""Host surface regressions; real dispatcher/matcher, fake RTOS and console sink.
+
+No sockets, diagnostic core execution, target scheduler or hardware are exercised.
+"""
+import os
+from pathlib import Path
+import re
+import subprocess
+import tempfile
+
+ROOT = Path(__file__).resolve().parents[2]
+IDF = Path(os.environ.get("IDF_PATH", str(Path.home() / ".platformio/packages/framework-espidf")))
+
+
+def read(path):
+    return (ROOT / path).read_text()
+
+
+def stripped(text):
+    return "\n".join(line for line in text.splitlines()
+                     if not line.startswith(("#include", "#pragma once")))
+
+
+# Guard canonical registry and unchanged argv forwarding, including UART0 wiring.
+network = read("src/network_console.c")
+wifi = read("src/wifi_console.c")
+main = read("src/main.c")
+admin = read("src/admin_ssh_console.c")
+registry = network[network.index("esp_err_t network_console_register_root_commands("):]
+for name in ("ping", "nslookup", "traceroute"):
+    assert re.search(r'\.command\s*=\s*"' + name + r'"[^}]*\.func\s*=\s*&network_console_execute', registry)
+    assert f'strcmp(name, "{name}") == 0' in network
+assert re.search(r'if \(argc >= 2 && network_console_is_command\(argv\[1\]\)\)\s*\{\s*'
+                 r'/\*.*?\*/\s*return network_console_execute\(argc - 1, argv \+ 1\);\s*\}', wifi, re.S)
+assert re.search(r'\.command\s*=\s*"wifi"[^}]*\.func\s*=\s*&command_wifi', wifi)
+for registration in ("wifi_console_register_commands", "network_console_register_root_commands"):
+    assert f"ESP_ERROR_CHECK({registration}());" in main
+uart = admin[admin.index("static void uart_frontend_task("):]
+assert ".origin = ADMIN_REQUEST_UART0" in uart
+assert "request.line" in uart and "xQueueSend(s_request_queue, &request" in uart
+assert "dispatch_registered_command(&request);" in admin
+assert "esp_console_run((const char *)request->line, &command_result)" in admin
+print("PASS: root/Wi-Fi registry, exact shared argv forwarding and UART0 queue/dispatcher source contracts")
+
+with tempfile.TemporaryDirectory(prefix="network-surfaces-") as directory:
+    path = Path(directory)
+    # Observe the actual dispatcher output at the ESP-IDF registry boundary.
+    fakes = read("tests/admin_console_boundary/fakes.h")
+    old = "{ (void)s; ++runs; if (command_hook) command_hook(); *r=0; return ESP_OK; }"
+    assert old in fakes
+    fakes = fakes.replace("static esp_err_t esp_console_run(",
+                          "static char dispatched[257];\nstatic esp_err_t esp_console_run(")
+    fakes = fakes.replace(old, "{ assert(strlen(s)<sizeof(dispatched)); strcpy(dispatched,s); ++runs; if (command_hook) command_hook(); *r=0; return ESP_OK; }")
+    unit = (fakes + stripped(read("src/admin_ssh_console.h")) + "\n" + stripped(admin)
+            + read("tests/network_diagnostics_surfaces/routing.c"))
+    (path / "routing.c").write_text(unit)
+    subprocess.run(["cc", "-std=c11", "-Wall", "-Wextra", "-Werror", "-Wno-unused-variable",
+                    str(path / "routing.c"), str(IDF / "components/console/split_argv.c"),
+                    "-o", str(path / "routing")], check=True, timeout=30)
+    subprocess.run([str(path / "routing")], check=True, timeout=10)
+
+    completion = read("src/console_completion.c")
+    # All shared matching functions, excluding only UART read/linenoise adapters.
+    completion = completion[:completion.index("static ssize_t console_read_with_late_terminal_upgrade(")]
+    unit = ("#include <assert.h>\n#include <stdbool.h>\n#include <stddef.h>\n#include <stdio.h>\n#include <string.h>\n"
+            + stripped(read("src/console_completion.h")) + "\n" + stripped(completion)
+            + read("tests/network_diagnostics_surfaces/completion.c"))
+    (path / "completion.c").write_text(unit)
+    subprocess.run(["cc", "-std=c11", "-Wall", "-Wextra", "-Werror",
+                    str(path / "completion.c"), "-o", str(path / "completion")], check=True, timeout=30)
+    subprocess.run([str(path / "completion")], check=True, timeout=10)