Digitális mikrofon modul, eredeti INMP441, I2S, mindenirányú, 24 bites, 3,3 V

ESP Example:

#include <Arduino.h>

#include "driver/i2s.h"

// INMP441 - ESP32 connection

// SCK(BCLK) - GPIO14

// WS(LRCLK) - GPIO15

// SD(DOUT)  - GPIO32

// L/R       - GND (Left) or 3V3 (Right)

static const i2s_port_t I2S_PORT = I2S_NUM_0;

#define I2S_BCLK   14

#define I2S_LRCLK  15

#define I2S_DOUT   32

// Audio settings

#define SAMPLE_RATE     16000

#define I2S_READ_LEN    1024   // bytes per read

void setupI2S()

{

  i2s_config_t i2s_config = {

    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX),

    .sample_rate = SAMPLE_RATE,

    .bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT,   // INMP441 outputs 24 bits in a 32-bit frame

    .channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,    // if L/R is connected to GND

    .communication_format = I2S_COMM_FORMAT_I2S,

    .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,

    .dma_buf_count = 8,

    .dma_buf_len = 256,

    .use_apll = false,

    .tx_desc_auto_clear = false,

    .fixed_mclk = 0

  };

  i2s_pin_config_t pin_config = {

    .bck_io_num = I2S_BCLK,

    .ws_io_num = I2S_LRCLK,

    .data_out_num = I2S_PIN_NO_CHANGE,

    .data_in_num = I2S_DOUT

  };

  i2s_driver_install(I2S_PORT, &i2s_config, 0, NULL);

  i2s_set_pin(I2S_PORT, &pin_config);

  i2s_zero_dma_buffer(I2S_PORT);

}

void setup()

{

  Serial.begin(115200);

  delay(200);

  setupI2S();

  Serial.println("INMP441 I2S start. Reading and displaying signal level");

}

void loop()

{

  uint8_t i2sData[I2S_READ_LEN];

  size_t bytesRead = 0;

  esp_err_t result = i2s_read(I2S_PORT, i2sData, I2S_READ_LEN, &bytesRead, portMAX_DELAY);

  if (result != ESP_OK || bytesRead == 0) return;

  // Convert a few samples for a simple level measurement (peak)

  int32_t peak = 0;

  // Data is 32-bit little-endian, useful data is 24 bits

  for (int i = 0; i < (int)bytesRead; i += 4) {

    int32_t sample = (int32_t)(

      ((uint32_t)i2sData[i]) |

      ((uint32_t)i2sData[i + 1] << 8) |

      ((uint32_t)i2sData[i + 2] << 16) |

      ((uint32_t)i2sData[i + 3] << 24)

    );

    // Sometimes a shift is needed to align the 24-bit sample

    sample >>= 8;

    int32_t absS = sample < 0 ? -sample : sample;

    if (absS > peak) peak = absS;

  }

  Serial.print("Peak: ");

  Serial.println(peak);

  delay(50);

}