I2S - can wroom be slave and receive pcm data?

[colinz]

I'm new to I2S and there is not much information about how to set it as slave and receive pcm data. What i've tried is two esp32 S3-wroom as i2s master and slave based on the official I2S example > FullDuplex, if i change the communication_format to I2S_COMM_FORMAT_I2S, the slave's serial will print a serials of "0", its not what i sent but it's another problem. But if i change both master and slave to I2S_COMM_FORMAT_STAND_PCM_SHORT, the slave will not print at all. Is there other thing i need to do to receive PCM data? I only wired bck, ws, and data in or out three lines, the mclk is floating. The slave code is like:

Code: Untitled.cpp Select all

#include "driver/i2s.h"



i2s_config_t i2s_config = {

  .mode = (i2s_mode_t)(I2S_MODE_SLAVE | I2S_MODE_TX | I2S_MODE_RX),

  .sample_rate = 8000,

  .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,

  .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,

  .communication_format = I2S_COMM_FORMAT_STAND_PCM_SHORT,

  .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,

  .dma_buf_count = 8,

  .dma_buf_len = 256,

  .use_apll = true,

};



i2s_pin_config_t pin_config = {

  .bck_io_num = 4,

  .ws_io_num = 5,

  .data_out_num = 7,

  .data_in_num = 6

};



uint16_t rxbuf[256];

size_t readsize = 0;



void setup(){

  i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);

  i2s_set_pin(I2S_NUM_0, &pin_config);

  Serial.begin(115200);

}



void loop(){

  readsize=0;

  i2s_read(I2S_NUM_0, &rxbuf[0], 3, &readsize, 100);

  if(readsize > 0){

    for(int i = 0; i < readsize; i++){

      Serial.print(rxbuf[i]);

      Serial.print(" ");

    }

    Serial.println();

  }

}