FIX SWAPPED PINS: GPIO 9 is 74HC165 data, GPIO 12 is WS2812C data. Product docs: DAT/LD/CLK = 74HC165, + WS2812C data.

src/main.cpp

@@ -10,7 +10,7 @@
 #include "switch_stub.h"
 #include "app_task.h"
 
-PixelStompMux mux(9, 10, 11, 12);
+PixelStompMux mux(12, 10, 11, 9);
 
 DefaultLedStub led_driver;
 DefaultSwitchStub switch_driver;
@@ -99,10 +99,10 @@ void handle_serial_command(const String& cmd) {
             int fl = digitalRead(pin);
             Serial.printf("  %s: PULLUP=%d PULLDOWN=%d FLOAT=%d\n", names[p], hi, lo, fl);
         }
-        Serial.println("  Testing DAT(9) output toggle...");
-        pinMode(9, OUTPUT);
+        Serial.println("  Testing WS2812(12) output toggle...");
+        pinMode(12, OUTPUT);
         for (int i = 0; i < 5; i++) {
-            digitalWrite(9, HIGH);
+            digitalWrite(12, HIGH);
             delayMicroseconds(100);
             int readback = digitalRead(9);
             Serial.printf("    HIGH -> readback=%d\n", readback);
@@ -140,7 +140,7 @@ void handle_serial_command(const String& cmd) {
         mux.clear_all();
         Serial.println("[CMD] Animation done");
     } else if (cmd == "rawled") {
-        uint8_t pin = 9;
+        uint8_t pin = 12;
         Serial.println("[CMD] Bit-bang WS2812: pixel 0 = RED on GPIO 9");
         uint8_t colour[] = {0x00, 0xFF, 0x00};
         noInterrupts();

src/pixel_stomp_mux.cpp

@@ -18,7 +18,7 @@ void PixelStompMux::begin() {
 
     delay(100);
 
-    FastLED.addLeds<WS2812, 9, GRB>(leds, NUM_LEDS);
+    FastLED.addLeds<WS2812, 12, GRB>(leds, NUM_LEDS);
     FastLED.setBrightness(128);
     fill_solid(leds, NUM_LEDS, CRGB::Black);
     FastLED.show();