I2S - No audio output

[VanKurt]

I'm trying to send I2S data from my ESP32 DevKit 1 to a MAX98357A I2S audio amplifier. The data is read from the SPIFFS file system and sent to the I2S memory. The problem is, that there is no audio output at all, the speaker is totally silent.

(I already tested my hardware setup with some library I found online, which worked fine. So the hardware is OK, and the error must be in my code...)

My code is rather simple:

Code: Select all

#include <Arduino.h>
#include "SPIFFS.h"
#include "driver/i2s.h"
#include "driver/gpio.h"

// Pins
#define PIN_OUT_AUDIO_BCLK 23
#define PIN_OUT_AUDIO_LCLK 22
#define PIN_OUT_AUDIO_DATA 4

// I2S configuration
static const i2s_port_t i2s_num = i2s_port_t::I2S_NUM_0;
i2s_mode_t i2s_mode = (i2s_mode_t)(i2s_mode_t::I2S_MODE_MASTER | i2s_mode_t::I2S_MODE_TX);

static const i2s_config_t i2s_config = {
    .mode = i2s_mode,
    .sample_rate = 44100,
    .bits_per_sample = i2s_bits_per_sample_t::I2S_BITS_PER_SAMPLE_8BIT,
    .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
    .communication_format = (i2s_comm_format_t)(I2S_COMM_FORMAT_STAND_MSB),
    .intr_alloc_flags = 0, // default interrupt priority
    .dma_buf_count = 8,
    .dma_buf_len = 64,
    .use_apll = false};

static const i2s_pin_config_t pin_config = {
    .bck_io_num = PIN_OUT_AUDIO_BCLK,
    .ws_io_num = PIN_OUT_AUDIO_LCLK,
    .data_out_num = PIN_OUT_AUDIO_DATA,
    .data_in_num = I2S_PIN_NO_CHANGE};

void setup()
{
  SPIFFS.begin();

  fs::File file = SPIFFS.open("/click2.wav");

  i2s_driver_install(i2s_num, &i2s_config, 0, NULL);
  i2s_set_pin(i2s_num, &pin_config);

  while (file.available())
  {
    uint8_t sample = file.read();

    size_t bytesWritten = 0;
    i2s_write(i2s_num, &sample, 1, &bytesWritten, 100);

    delayMicroseconds(3); // Just for testing
  }
}

void loop()
{
}