# ESP32 Serial Swiss Army Knife

![ESP32 Serial Swiss Army Knife logo](/images/logo.png "ESP32 Serial Swiss Army Knife")

Universal wireless serial adaptor firmware for the ESP32-S3.

## Initial hardware target

- ESP32-S3-DevKitC-1
- ESP32-S3-WROOM-1-N16R8 module
- 16 MB flash
- 8 MB octal PSRAM

The initial smoke-test firmware continuously sweeps the onboard addressable RGB LED through the color wheel at reduced brightness. The official ESP32-S3-DevKitC-1 v1.0 uses GPIO48 for the LED data signal, while official v1.1 boards use GPIO38. Compatible boards and clones may vary.

## Hardware wiring

See [`wiring.md`](wiring.md) for hardware-specific wiring profiles. The initial profile covers the ESP32-S3-DevKitC-1 N16R8 and the Adafruit MAX3243 full-pinout RS-232 breakout.

## Build

```sh
pio run
```

## Upload and monitor

Connect the board's USB-to-UART port, then run:

```sh
pio run --target upload
pio device monitor
```

The application logs its startup, detected PSRAM size, and configured RGB LED GPIO at 115200 baud. Expected output includes:

```text
ESP32-S3 build-chain smoke test started
PSRAM initialized: 8388608 bytes
Sweeping the onboard RGB LED on GPIO48
```

If the firmware runs but the RGB LED remains dark, verify the board revision. The project defaults to GPIO48, commonly used by DevKitC-compatible boards and official v1.0 boards. For an official v1.1 board — or another board wired that way — change `RGB_LED_GPIO` in `platformio.ini` from `48` to `38`, rebuild, and upload again.

## License

This project is licensed under the [GNU General Public License version 3 only](LICENSE) (`GPL-3.0-only`). This is compatible with using the GPLv3 releases of wolfSSL and wolfSSH later. Third-party components remain subject to their respective licenses.