Fix compilation bugs; USB MSC isn't working yet

baby_mobile_v2/baby_mobile_v2.ino

@@ -76,8 +76,9 @@
 #define PIN_BTN7         31
 #define PIN_BTN8         12
 
-// LED
-#define PIN_LED          16
+// PIN_LED is 11 (LED_R)
+// LED_B is 13/12
+// LED_G is 12/13
 
 const uint8_t BTN_PINS[] = {
     PIN_BTN1, PIN_BTN2, PIN_BTN3, PIN_BTN4,
@@ -631,7 +632,7 @@ void audioInit() {
     // Create a FreeRTOS software timer at 8kHz
     // Note: For better timing, use a hardware TIMER peripheral
     // This works well enough for 8kHz audio
-    audioTimer.begin(1000 / 8, audioTimerHandler, true); // ~8kHz
+    audioTimer.begin(1000 / 8, audioTimerHandler, NULL, true); // ~8kHz
     // Better approach: use nrf_drv_timer for precise 125µs intervals
 }
 
@@ -780,8 +781,18 @@ void setup() {
     digitalWrite(PIN_LED, HIGH);
 
     Serial.begin(115200);
-    // Don't block on serial — may not be connected
-    delay(500);
+    Serial.println("...");
+    
+    int c=0;
+    while(c<10) {
+      delay(250);
+      digitalWrite(PIN_LED, LOW);
+      // Serial.println("0");
+      delay(250);
+      digitalWrite(PIN_LED, HIGH);
+      // Serial.println("1");
+      c++;
+    }
 
     Serial.println("=== Baby Mobile v2 ===");
     Serial.println("nRF52840 + IS25LP128F + PAM8302A");
@@ -824,9 +835,9 @@ void setup() {
     // USB Mass Storage
     usb_msc.setID("BabyMobile", "Audio Drive", "2.0");
     usb_msc.setReadWriteCallback(msc_read_cb, msc_write_cb, msc_flush_cb);
-    usb_msc.setStartStopCallback(msc_start_stop_cb);
+    //usb_msc.setStartStopCallback(msc_start_stop_cb); // unused in nrf?
     usb_msc.setCapacity(MSC_BLOCK_COUNT, MSC_BLOCK_SIZE);
-    usb_msc.setReadOnly(false);
+    //usb_msc.setReadOnly(false);
     usb_msc.setUnitReady(true);
     usb_msc.begin();
 
@@ -835,7 +846,7 @@ void setup() {
 
     g_lastActivity = millis();
 
-    digitalWrite(PIN_LED, LOW);
+    digitalWrite(PIN_LED, HIGH);
     Serial.println("Ready! Plug in USB to upload audio, or press a button.");
 }