Fix A5 after songs

quantum/audio/audio_arm.c

@@ -32,10 +32,12 @@ float frequency = 0;
 float frequency_alt = 0;
 int volume = 0;
 long position = 0;
+systime_t last_note_played_at;
 
 float frequencies[8] = {0, 0, 0, 0, 0, 0, 0, 0};
 int volumes[8] = {0, 0, 0, 0, 0, 0, 0, 0};
 bool sliding = false;
+bool dac_on = true;
 
 float place = 0;
 
@@ -78,6 +80,8 @@ bool glissando = true;
 float startup_song[][2] = STARTUP_SONG;
 
 static void gpt_cb8(GPTDriver *gptp);
+static bool should_shutoff_dac(void);
+static void shutoff_dac(void);
 
 #define DAC_BUFFER_SIZE 100
 #ifndef DAC_SAMPLE_MAX
@@ -88,16 +92,13 @@ static void gpt_cb8(GPTDriver *gptp);
   dacStart(&DACD2, &dac1cfg2); \
   dacStartConversion(&DACD1, &dacgrpcfg1, (dacsample_t *)dac_buffer, DAC_BUFFER_SIZE); \
   dacStartConversion(&DACD2, &dacgrpcfg2, (dacsample_t *)dac_buffer_2, DAC_BUFFER_SIZE); \
+  dac_on = true; \
   gptStart(&GPTD6, &gpt6cfg1); \
   gptStartContinuous(&GPTD6, 2U); \
   palSetPadMode(GPIOA, 5, PAL_MODE_INPUT_ANALOG);
 #define START_CHANNEL_2() gptStart(&GPTD7, &gpt7cfg1); \
     gptStartContinuous(&GPTD7, 2U)
-#define STOP_CHANNEL_1() gptStopTimer(&GPTD6); \
-  dacStopConversion(&DACD2); \
-  dacStop(&DACD2); \
-  palSetPadMode(GPIOA, 5, PAL_MODE_OUTPUT_PUSHPULL ); \
-  palSetPad(GPIOA, 5)
+#define STOP_CHANNEL_1() gptStopTimer(&GPTD6)
 #define STOP_CHANNEL_2() gptStopTimer(&GPTD7)
 #define RESTART_CHANNEL_1() STOP_CHANNEL_1(); \
     START_CHANNEL_1()
@@ -416,11 +417,11 @@ float vibrato(float average_freq) {
 }
 
 #endif
-
 static void gpt_cb8(GPTDriver *gptp) {
   float freq;
 
   if (playing_note) {
+    last_note_played_at = chVTGetSystemTime();
     if (voices > 0) {
 
       float freq_alt = 0;
@@ -530,6 +531,7 @@ static void gpt_cb8(GPTDriver *gptp) {
   }
 
   if (playing_notes) {
+    last_note_played_at = chVTGetSystemTime();
     if (note_frequency > 0) {
       #ifdef VIBRATO_ENABLE
         if (vibrato_strength > 0) {
@@ -606,6 +608,22 @@ static void gpt_cb8(GPTDriver *gptp) {
     playing_notes = false;
     playing_note = false;
   }
+
+  if(should_shutoff_dac()) {
+    shutoff_dac();
+  }
+}
+
+bool should_shutoff_dac() {
+  return ST2MS(chVTTimeElapsedSinceX(last_note_played_at)) > 5 && dac_on;
+}
+
+void shutoff_dac() {
+  dacStopConversion(&DACD2);
+  dacStop(&DACD2);
+  palSetPadMode(GPIOA, 5, PAL_MODE_OUTPUT_PUSHPULL );
+  palSetPad(GPIOA, 5);
+  dac_on = false;
 }
 
 void play_note(float freq, int vol) {