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Code: Select all

int j;
for (j = 0; j < 26000; j++ ) {
      dacWrite(25, sample[j]);
}

Code: Select all

const unsigned char sample[] = {
// here a lot of numbers - audio data
};

hw_timer_t * timer = NULL;
portMUX_TYPE timerMux = portMUX_INITIALIZER_UNLOCKED;

volatile uint32_t isrCounter = 0;
volatile uint32_t lastIsrAt = 0;

void IRAM_ATTR onTimer(){
  // Increment the counter and set the time of ISR
  portENTER_CRITICAL_ISR(&timerMux);
  isrCounter++;
  lastIsrAt = millis();
  portEXIT_CRITICAL_ISR(&timerMux);
  // It is safe to use digitalRead/Write here if you want to toggle an output
  if (isrCounter > 25000) { // hardcoded end...
      if (timer) {
      // Stop and free timer
      timerEnd(timer);
      timer = NULL;
      }
    }
  dacWrite(25, sample[isrCounter]);
}

void setup() {
  // Use 1st timer of 4 (counted from zero).
  // Set 80 divider for prescaler (see ESP32 Technical Reference Manual for more
  // info).
  timer = timerBegin(0, 80, true);

  // Attach onTimer function to our timer.
  timerAttachInterrupt(timer, &onTimer, true);

  // Set alarm to call onTimer function every second (value in microseconds).
  // Repeat the alarm (third parameter)
  timerAlarmWrite(timer, 125, true);

  // Start an alarm
  timerAlarmEnable(timer);
}

void loop() {
  
}