16kHz PWM EasyDMA audio, loop mode, serial p/l/r/DELETE commands, button and end-of-track fixes

baby_mobile_v2/baby_mobile_v2.ino

@@ -204,6 +204,7 @@ uint8_t  g_numTracks = 0;
 uint32_t g_trackStart[MAX_TRACKS];
 uint32_t g_trackLen[MAX_TRACKS];
 uint8_t  g_currentTrack = 0;
+bool     g_loopTracks = false;  // false = play once and stop; true = auto-advance through all tracks
 
 // Audio DMA buffers — uint16_t PWM duty-cycle values for EasyDMA
 static uint16_t   g_pwmBuf[2][AUDIO_BUF_SIZE];
@@ -348,6 +349,7 @@ void loadTrackTable() {
         if (!f.open(fname, FILE_O_READ)) break;
         g_trackLen[i] = f.size();
         f.close();
+        if (g_trackLen[i] == 0) break;  // stop at first empty file
         g_numTracks = i + 1;
     }
     Serial.print("Found ");
@@ -720,7 +722,7 @@ static void audioFillBuf(uint8_t b) {
     }
     g_bufReady[b] = true;
     // Arm stop timer on first pure-silence fill (all audio already sent to DMA)
-    if (toRead == 0 && g_trackDoneMs == 0) {
+    if (toRead == 0 && g_trackDoneMs == 0 && g_playing) {
         g_trackDoneMs = millis() + 100;  // 100ms > 3 buffer lengths (3 × 32ms)
     }
 }
@@ -871,23 +873,26 @@ void buttonsInit() {
     }
 }
 
-// Returns 1-8, or 0 if none pressed
+// Returns 1-4, or 0 if none pressed. No blocking delay — safe to call every loop().
 uint8_t buttonRead() {
     for (uint8_t i = 0; i < NUM_BUTTONS; i++) {
-        // Buttons pull to ground
+        if (digitalRead(BTN_PINS[i]) == LOW) return i + 1;
-        if (digitalRead(BTN_PINS[i]) == LOW) {
-            delay(20);  // debounce
-            if (digitalRead(BTN_PINS[i]) == LOW) {
-                return i + 1;
-            }
-        }
     }
     return 0;
 }
 
+// Wait until the button is physically released. No timeout — prevents the 800ms
+// cooldown from expiring while the button is still held and re-triggering.
 void waitButtonRelease(uint8_t btn) {
-    unsigned long deadline = millis() + 300;
+    while (buttonRead() == btn) {
-    while (buttonRead() == btn && millis() < deadline) {}
+        // Keep DMA buffers fed while waiting
+        if (g_playing) {
+            for (uint8_t b = 0; b < 2; b++) {
+                if (!g_bufReady[b]) audioFillBuf(b);
+            }
+        }
+    }
+    delay(20);  // debounce after release
 }
 
 
@@ -1102,6 +1107,26 @@ static void serUploadTick() {
                     if (g_serLineBuf[0] == 'u') g_audioGain++;
                     else if (g_audioGain > 1) g_audioGain--;
                     Serial.print("GAIN "); Serial.println(g_audioGain);
+                } else if (g_serLineLen == 1 && g_serLineBuf[0] == 'p') {
+                    if (g_playing) { audioStop(); Serial.println("STOP"); }
+                    else if (g_numTracks > 0) { audioStart(g_currentTrack); Serial.println("PLAY"); }
+                    else Serial.println("ERR no tracks");
+                } else if (g_serLineLen == 1 && g_serLineBuf[0] == 'l') {
+                    g_loopTracks = !g_loopTracks;
+                    Serial.print("LOOP "); Serial.println(g_loopTracks ? "ON" : "OFF");
+                } else if (g_serLineLen == 1 && g_serLineBuf[0] == 'r') {
+                    Serial.println("REBOOT");
+                    delay(10);
+                    NVIC_SystemReset();
+                } else if (sscanf(g_serLineBuf, "DELETE %u", &utrk) == 1) {
+                    char fname[16];
+                    pocFilename((uint8_t)utrk, fname);
+                    if (InternalFS.remove(fname)) {
+                        Serial.print("DELETED "); Serial.println(fname);
+                    } else {
+                        Serial.print("ERR no file "); Serial.println(fname);
+                    }
+                    loadTrackTable();
                 } else {
                     Serial.print("ERR bad cmd: ");
                     Serial.println(g_serLineBuf);
@@ -1192,7 +1217,7 @@ void loop() {
     if (g_playing && g_trackDoneMs != 0 && millis() >= g_trackDoneMs) {
         g_trackDoneMs = 0;
         audioStop();
-        if (g_numTracks > 0) {
+        if (g_loopTracks && g_numTracks > 0) {
             g_currentTrack = (g_currentTrack + 1) % g_numTracks;
             audioStart(g_currentTrack);
         }