Add native USB HID boot setup and status display

display.py

@@ -0,0 +1,136 @@
+"""Status display support for the LILYGO T-Dongle-S3.
+
+The board's 160x80 ST7735 panel is wired to SPI2. This driver deliberately uses
+only MicroPython's built-in ``machine`` and ``framebuf`` modules.
+"""
+
+import framebuf
+import time
+from machine import Pin, SPI
+
+WIDTH = 160
+HEIGHT = 80
+
+# Verified against LILYGO's T-Dongle-S3 factory-screen example.
+_PIN_MOSI = 3
+_PIN_SCK = 5
+_PIN_CS = 4
+_PIN_DC = 2
+_PIN_RST = 1
+_PIN_BACKLIGHT = 38
+_X_OFFSET = 1
+_Y_OFFSET = 26
+
+_SWRESET = 0x01
+_SLPOUT = 0x11
+_DISPON = 0x29
+_CASET = 0x2A
+_RASET = 0x2B
+_RAMWR = 0x2C
+_MADCTL = 0x36
+_COLMOD = 0x3A
+_INVON = 0x21
+
+_BLACK = 0x0000
+_WHITE = 0xFFFF
+_CYAN = 0x07FF
+_GREEN = 0x07E0
+_YELLOW = 0xFFE0
+_GRAY = 0x8410
+
+
+class StatusDisplay:
+    """Render the configured SSID and current DHCP address on the LCD."""
+
+    def __init__(self):
+        self._cs = Pin(_PIN_CS, Pin.OUT, value=1)
+        self._dc = Pin(_PIN_DC, Pin.OUT, value=0)
+        self._reset = Pin(_PIN_RST, Pin.OUT, value=1)
+        # The T-Dongle-S3 backlight enable is active-low.
+        self._backlight = Pin(_PIN_BACKLIGHT, Pin.OUT, value=1)
+        self._spi = SPI(2, baudrate=20_000_000, polarity=0, phase=0,
+                        sck=Pin(_PIN_SCK), mosi=Pin(_PIN_MOSI))
+        self._buffer = bytearray(WIDTH * HEIGHT * 2)
+        self._framebuffer = framebuf.FrameBuffer(
+            self._buffer, WIDTH, HEIGHT, framebuf.RGB565
+        )
+        self._shown = None
+        self._initialise()
+        self._backlight.off()
+
+    def _command(self, command, data=None):
+        self._cs.off()
+        self._dc.off()
+        self._spi.write(bytes((command,)))
+        if data is not None:
+            self._dc.on()
+            self._spi.write(data)
+        self._cs.on()
+
+    def _initialise(self):
+        self._reset.off()
+        time.sleep_ms(20)
+        self._reset.on()
+        time.sleep_ms(120)
+        self._command(_SWRESET)
+        time.sleep_ms(150)
+        self._command(_SLPOUT)
+        time.sleep_ms(120)
+        self._command(_COLMOD, b"\x05")  # 16-bit RGB565.
+        # Landscape, BGR colour order, matching the vendor panel setup.
+        self._command(_MADCTL, b"\xA8")
+        self._command(_INVON)
+        self._command(_DISPON)
+        time.sleep_ms(20)
+
+    def update(self, ssid, address=None):
+        """Redraw only when the displayed network state changed."""
+        state = (ssid, address)
+        if state == self._shown:
+            return
+        self._shown = state
+        framebuffer = self._framebuffer
+        framebuffer.fill(_BLACK)
+        framebuffer.text("PolterHID", 3, 3, _CYAN)
+        framebuffer.text("WiFi", 3, 23, _GRAY)
+        framebuffer.text(_fit(ssid, 19), 42, 23, _WHITE)
+        framebuffer.text("IP", 3, 47, _GRAY)
+        if address:
+            framebuffer.text(_fit(address, 19), 42, 47, _GREEN)
+        else:
+            framebuffer.text("connecting...", 42, 47, _YELLOW)
+        self.show()
+
+    def show(self):
+        """Transfer the RGB565 framebuffer, converting its byte order for SPI."""
+        # framebuf stores RGB565 words in native little-endian order, while the
+        # ST7735 expects the most-significant byte first on the SPI bus.
+        for index in range(0, len(self._buffer), 2):
+            low = self._buffer[index]
+            self._buffer[index] = self._buffer[index + 1]
+            self._buffer[index + 1] = low
+
+        self._command(_CASET, _coordinates(_X_OFFSET, _X_OFFSET + WIDTH - 1))
+        self._command(_RASET, _coordinates(_Y_OFFSET, _Y_OFFSET + HEIGHT - 1))
+        self._cs.off()
+        self._dc.off()
+        self._spi.write(bytes((_RAMWR,)))
+        self._dc.on()
+        self._spi.write(self._buffer)
+        self._cs.on()
+
+        # Restore native byte order before subsequent framebuf drawing.
+        for index in range(0, len(self._buffer), 2):
+            low = self._buffer[index]
+            self._buffer[index] = self._buffer[index + 1]
+            self._buffer[index + 1] = low
+
+
+def _coordinates(start, end):
+    return bytes((start >> 8, start & 0xFF, end >> 8, end & 0xFF))
+
+
+def _fit(text, maximum):
+    if len(text) <= maximum:
+        return text
+    return text[:maximum - 3] + "..."