Add expression pedal support on GPIO5 (CC 4)

src/main.cpp

@@ -10,6 +10,7 @@
 #include "led_stub.h"
 #include "switch_stub.h"
 #include "app_task.h"
+#include "expression_pedal.h"
 
 PixelStompMux mux(12, 10, 11, 9);
 
@@ -18,6 +19,7 @@ DefaultSwitchStub switch_driver;
 UsbMidiTransport midi_transport;
 
 AppTask controller(&led_driver, &switch_driver, &midi_transport);
+ExpressionPedal exp_pedal(5);
 
 TaskHandle_t midi_task_handle = NULL;
 
@@ -26,6 +28,7 @@ void midi_task(void* parameter) {
     
     while (true) {
         midi_transport.update();
+        exp_pedal.update(midi_transport);
         vTaskDelay(1);
     }
 }
@@ -83,6 +86,9 @@ void handle_serial_command(const String& cmd) {
         mux.set_led_color(1, 255, 255, 255);
         mux.show();
         Serial.println("[CMD] Pixel 1 WHITE (max brightness)");
+    } else if (cmd == "exp") {
+        uint16_t raw = analogRead(5);
+        Serial.printf("[CMD] EXP GPIO5 ADC=%d MIDI=%d\n", raw, exp_pedal.get_value());
     } else if (cmd == "usb") {
         Serial.printf("[CMD] USB mounted: %s\n", TinyUSBDevice.mounted() ? "YES" : "NO");
         Serial.printf("[CMD] USB ready: %s\n", TinyUSBDevice.ready() ? "YES" : "NO");
@@ -126,6 +132,7 @@ void handle_serial_command(const String& cmd) {
         Serial.println("  read       - raw button read");
         Serial.println("  red/green/blue - solid colour");
         Serial.println("  pixel0/pixel1 - single pixel test");
+        Serial.println("  exp        - expression pedal ADC/MIDI value");
         Serial.println("  usb        - USB connection status and descriptor info");
         Serial.println("  gpiotest   - raw GPIO pin diagnostic");
         Serial.println("  rawled     - bit-bang WS2812 (no library)");
@@ -328,7 +335,7 @@ void setup() {
     
     Serial.println("=================================");
     Serial.println("  Loopy MIDI Controller v0.1");
-    Serial.println("  Phase 1: USB MIDI");
+    Serial.println("  Phase 1: USB MIDI + Expression Pedal");
     Serial.println("  Board: ESP32-S3-WROOM-1");
     Serial.println("=================================");
     
@@ -346,6 +353,9 @@ void setup() {
     Serial.println("[INIT] Initializing USB MIDI...");
     midi_transport.begin();
     
+    Serial.println("[INIT] Initializing Expression Pedal...");
+    exp_pedal.begin();
+    
     Serial.println("[INIT] Registering MIDI callbacks...");
     controller.begin();