Play tones on a piezo buzzer using Mbed Bit Banging - Arduino Nano 33 BLE & Portenta H7

playTone.ino

void playTone(int pin, int period_us, int duration_ms) {
  mbed::DigitalOut buzzer(digitalPinToPinName( pin ));
  static int time_on, time_off;
  unsigned long start_time, end_time;

  start_time = millis();
  end_time = start_time;
  while ((end_time - start_time) <= duration_ms) {
    time_on = period_us / 2;
    time_off = period_us - time_on;
    buzzer = 1;
    wait_us( time_on );
    buzzer = 0;
    wait_us( time_off );
    end_time = millis();
  }
}