How to generate a simple tone on speaker about t-deck HOT 5 OPEN

void beep (int freq, int duration) {
  I2S.setAllPins(7, 5, 6, 6, 6); // sckPin, fsPin, sdPin, outSdPin, inSdPin
  const int samplerate = 8000;
  int halfwave = samplerate / freq, amplitude = 500;
  unsigned long start = millis();
  if (!I2S.begin(I2S_PHILIPS_MODE, samplerate, 16)) return; // Error
  while (millis() < start + duration) {
    if (count % halfwave == 0) amplitude = -1 * amplitude;
    I2S.write(amplitude); I2S.write(amplitude);
  }
  I2S.end();
}

#include <I2S.h>

#include "soc/periph_defs.h" // Not sure why necessary

/Users/david/Library/Arduino15/packages/esp32/hardware/esp32/2.0.12/libraries/I2S/examples/SimpleTone