ESP32 Forum

Posted: **Wed May 28, 2025 12:59 pm**

Hello all,

I'm working on a project where I developed my own board using the ES8374 audio codec with an ESP32-WROOM-32E. I’ve read the official datasheet thoroughly and configured the registers step-by-step based on the required clocking and output path. I am trying to get just any sound from ES8374, but no success.
I verified that:
- I2C works correctly. (I have I2C_read registers and they were same as the ones I wrote)

- I2S lines (BCLK, LRCK) have expected signals. Using osciloscope, I verified that BCLK is square wave with 512kHz and LRCK is 16kHz

Despite all this, I’m not getting any sound, not even with a basic square wave tone.

My setup details are as follows.
-I2C: SDA=21, SCL=17
-I2S: BCLK=26, LRCK=25, DOUT=27 (DIN of ES8374)
-No MCLK used. PLL is used
-Sample rate: 16 kHz
-Bits/sample: 16-bit stereo
-Output: Only DAC to SPK, mic/ADC path not used
- I set CE pin of ES8374 to LOW to set address to 0x10
- I am using 0.5W 8 ohm Speaker. Vspeaker is 5V and VDD for analog and digital part is 3V3.
- I am using SPKP and SPKN pins for speaker.

Code: Select all

#include <Wire.h>
#include "driver/i2s.h"

// === Pin Definitions ===
#define I2C_SDA 21
#define I2C_SCL 17
#define I2S_BCLK 26
#define I2S_LRCK 25
#define I2S_DOUT 27  // ESP32 -> ES8374 DIN
#define CE_PIN 16

#define ES8374_ADDR 0x10

int16_t squareWave[64];

void generateSquareWave() {
  for (int i = 0; i < 64; i += 2) {
    squareWave[i] = 8000;       
    squareWave[i + 1] = -8000;  
  }
}

void es8374_write(uint8_t reg, uint8_t val) {
  Wire.beginTransmission(ES8374_ADDR);
  Wire.write(reg);
  Wire.write(val);
  Wire.endTransmission();
}

void initES8374() {
  es8374_write(0x00, 0x1F);
  delay(10);
  es8374_write(0x00, 0x80);
  delay(10);
  es8374_write(0x01, 0x33);  //0x30
  es8374_write(0x02, 0x08);
  es8374_write(0x03, 0x20);
  //es8374_write(0x04, 0x0C);
  es8374_write(0x06, 0x03);
  es8374_write(0x07, 0x00);
  es8374_write(0x08, 0x21);
  es8374_write(0x08, 0x21);
  es8374_write(0x09, 0x03);  // PLL analog enable, reset ON 
  delay(10);
  es8374_write(0x09, 0x43);  // PLL analog enable, reset OFF , dither off, VCO divide by 2
  es8374_write(0x0A, 0x49);  //3.3V, VCO gain 1, charge pump 4
  es8374_write(0x0B, 0x48);
  es8374_write(0x0C, 0x00);
  es8374_write(0x0D, 0x00);
  es8374_write(0x0E, 0x00);
  es8374_write(0x0F, 0x00);
  es8374_write(0x11, 0x0C);  // 0b00001100
  //0x12 and 0x13 are for startup delay, not used
  es8374_write(0x14, 0x12);
  es8374_write(0x15, 0x40);
  es8374_write(0x17, 0x10);
  es8374_write(0x18, 0x12);
  es8374_write(0x1A, 0x00);  // mono off
  es8374_write(0x1B, 0x00);  // lout off
  es8374_write(0x1C, 0x88);
  es8374_write(0x1D, 0x0B);
  es8374_write(0x1E, 0xA7);  // last 4 bit is volume, enable Class D
  es8374_write(0x1F, 0x0C);
  es8374_write(0x20, 0x08);
  es8374_write(0x21, 0xC0); // neglect
  es8374_write(0x22, 0x00); // neglect
  
  es8374_write(0x36, 0x04);//DAC mute off
  es8374_write(0x37, 0x00);
  es8374_write(0x38, 0x00);
  es8374_write(0x39, 0x00);
}

void setup() {
  Serial.begin(115200);

  pinMode(CE_PIN, OUTPUT);
  digitalWrite(CE_PIN, LOW);
  delay(200);

  Wire.begin(I2C_SDA, I2C_SCL);
  delay(100);

  initES8374();
  generateSquareWave();

  // === I2S Configuration ===
  i2s_config_t i2s_config = {
    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_TX),
    .sample_rate = 16000,
    .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
    .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,  // stereo
    .communication_format = I2S_COMM_FORMAT_I2S,
    .intr_alloc_flags = 0,
    .dma_buf_count = 8,
    .dma_buf_len = 64,
    .use_apll = false,
    .tx_desc_auto_clear = true,
    .fixed_mclk = 0
  };

  i2s_pin_config_t pin_config = {
    .bck_io_num = I2S_BCLK,
    .ws_io_num = I2S_LRCK,
    .data_out_num = I2S_DOUT,
  };

  // Start I2S driver
  esp_err_t err = i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);
  if (err != ESP_OK) {
    Serial.printf("❌ i2s_driver_install failed: %d\n", err);
    while (true)
      ;
  }

  err = i2s_set_pin(I2S_NUM_0, &pin_config);
  if (err != ESP_OK) {
    Serial.printf("❌ i2s_set_pin failed: %d\n", err);
    while (true)
      ;
  }
}

void loop() {
  int16_t test_buf[64];
  static bool toggle = false;

  for (int i = 0; i < 64; i += 2) {
    test_buf[i] = toggle ? 10000 : -10000;      
    test_buf[i + 1] = toggle ? -10000 : 10000;  
  }
  toggle = !toggle;

  size_t written;
  i2s_write(I2S_NUM_0, test_buf, sizeof(test_buf), &written, portMAX_DELAY);
}

Did I miss critical register that makes speaker off, or DAC mute or are there any known issues with ES8374 and ESP32? Thank you all for your help in advance.

Regards,

Posted: **Tue Jun 03, 2025 8:31 am**

Try this sequence instead:

Code: Select all

void initES8374() {
  // Reset
  es8374_write(0x00, 0x1F);
  delay(10);
  es8374_write(0x00, 0x80);
  delay(10);

  // Clock setup
  es8374_write(0x01, 0x32);  // Use internal PLL, MCLK off
  es8374_write(0x02, 0x10);  // DAC & ADC use same clock
  es8374_write(0x03, 0x20);  // MCLK = 256*Fs
  es8374_write(0x09, 0x03);  // Reset PLL
  delay(10);
  es8374_write(0x09, 0x43);  // PLL enable
  es8374_write(0x0A, 0x49);  // PLL settings
  es8374_write(0x0B, 0x48);
  es8374_write(0x0C, 0x00);
  es8374_write(0x0D, 0x00);
  es8374_write(0x0E, 0x00);
  es8374_write(0x0F, 0x00);

  // DAC setup
  es8374_write(0x14, 0x12);  // DAC I2S, 16-bit, normal polarity
  es8374_write(0x15, 0x40);  // DAC I2S format
  es8374_write(0x1A, 0x00);  // Mono off
  es8374_write(0x1B, 0x00);  // LOUT off
  es8374_write(0x1C, 0x80);  // DAC to SPK enable
  es8374_write(0x1D, 0x02);  // SPK gain
  es8374_write(0x1E, 0xA7);  // SPK enable, volume ~7
  es8374_write(0x1F, 0x6C);  // Mixer gain

  // Unmute DAC
  es8374_write(0x36, 0x00);  // DAC mute off
}

Posted: **Wed Jun 25, 2025 2:39 pm**

Thank you for your support.

I tried your suggested register sequence, but unfortunately it still didn’t produce any sound.

I have a batch of 10 ES8374 chips and tested 4 of them so far. Since everything else checks out, I’m starting to suspect that the chips themselves might be defective.

I will try sourcing new ES8374 chips from another vendor and test again.

Regards,

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