ESP32 I2S microphone or line in

[dr pepper]

I'm not new to the esp32 however I've never messed with I2S audio.
I have a working example program that interfaces to a I2S microphone.
Can I switch the mems I2S mic module for a I2S audio line in module, or do I need different a driver library.

 

[betwixt]

In theory but probably not in practice, all I2S devices are compatible. So input devices should be interchangeable and likewise output devices. If your microphone needs special initializing data you might have to send it from your program.

Brian.

 

[dr pepper]

There doesnt seem to be anything specific in the init routine for a mic,

void setupMic() {
  Serial.println("Configuring I2S...");
  esp_err_t err;

  // The I2S config as per the example
  const i2s_config_t i2s_config = {
      .mode = i2s_mode_t(I2S_MODE_MASTER | I2S_MODE_RX), // Receive, not transfer
      .sample_rate = samplingFrequency,                       
      .bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT, // could only get it to work with 32bits
      .channel_format = I2S_CHANNEL_FMT_ONLY_RIGHT, // although the SEL config should be left, it seems to transmit on right
      .communication_format = i2s_comm_format_t(I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB),
      .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,     // Interrupt level 1
      .dma_buf_count = 4,                           // number of buffers
      .dma_buf_len = BLOCK_SIZE                     // samples per buffer
  };

  // The pin config as per the setup
    i2s_pin_config_t pin_config = {
        .bck_io_num = 26,  // IIS_SCLK
        .ws_io_num = 32,   // IIS_LCLK
        .data_out_num = -1,// IIS_DSIN
        .data_in_num = 33  // IIS_DOUT
    };

  // Configuring the I2S driver and pins.
  // This function must be called before any I2S driver read/write operations.
  err = i2s_driver_install(I2S_PORT, &i2s_config, 0, NULL);
  if (err != ESP_OK) {
    Serial.printf("Failed installing driver: %d\n", err);
    while (true);
  }
  err = i2s_set_pin(I2S_PORT, &pin_config);
  if (err != ESP_OK) {
    Serial.printf("Failed setting pin: %d\n", err);
    while (true);
  }
  Serial.println("I2S driver installed.");
}