Changing ESP32 I2S_SAMPLE_RATE during execution

Projects Programming
1

Does anybody know how to change the I2S sample rate dynamically ?

2

Is this forum the right place for questions about high level ESP32 programming ?

3

Have you checked the documentation?
https://docs.espressif.com/projects/arduino-esp32/en/latest/api/i2s.html#arduino-esp32-i2s-api

Or, perhaps in the Programming Guide:
https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-reference/peripherals/i2s.html#functional-overview

4

Yes I checked every page at espressif.com site. The chinese documentation is too poor and very confuse. What I need to know is not there !!!

5

Then you should provide more detail about what you want to do and provide the code that you have.

6

Bellow the code and the problem:

#include <driver/i2s.h>

#define I2S_SAMPLE_RATE (1250000)
#define ADC_INPUT (ADC1_CHANNEL_4)    //pin 32
#define I2S_DMA_BUF_LEN (720)

size_t bytes_read;
uint16_t buffer[I2S_DMA_BUF_LEN] = {0};

void i2sInit() {
  i2s_config_t i2s_config = {
    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX | I2S_MODE_ADC_BUILT_IN),
    .sample_rate =  I2S_SAMPLE_RATE,
    .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
    .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
    .communication_format = I2S_COMM_FORMAT_I2S_MSB,
    .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
    .dma_buf_count = 2,
    .dma_buf_len = I2S_DMA_BUF_LEN,
    .use_apll = false,
    .tx_desc_auto_clear = false,
    .fixed_mclk = 0
  };

  i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);
  i2s_set_adc_mode(ADC_UNIT_1, ADC_INPUT);
  i2s_adc_enable(I2S_NUM_0);
  adc1_config_channel_atten(ADC_INPUT, ADC_ATTEN_DB_11);
}

void setup(void) {
  i2sInit();
}

void loop() {
  
  i2s_read(I2S_NUM_0, &buffer, sizeof(buffer), &bytes_read, 0);
  
  //at this point the buffer is full and it was filled at 1250000Hz rate
  //according to the constant I2S_SAMPLE_RATE
  //Under certain circustances I want to change the sample rate to other
  //values. I have tryied to define uint32_t newrate and replace
  //.sample_rate = I2S_SAMPLE_RATE by .sample_rate = newrate, on i2sInit()
  //under this change all I get are successives reset loop like this:
    
  //rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
  //configsip: 0, SPIWP:0xee
  //clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
  //mode:DIO, clock div:1
  //load:0x3fff0030,len:1344
  //load:0x40078000,len:13864
  //load:0x40080400,len:3608
  //entry 0x400805f0
  //ets Jun  8 2016 00:22:57
  //
}
7

What compile error do you get?

And, if you get a compile error, how can you be getting "successives reset loop" as that's a run time problem?

8

Oooops... Sorry. There is no compile error. It was a mistake when I wrote that post. I have already edit and fixed it.

9

Please post the exact code that causes the problem rather than just saying what you tried.

10

Bellow the exactly code that results in successives resets.
Recall that if I defined samplerate as a constant like
#define samplerate (1250000) the program works well !!!
Thanks

#include <driver/i2s.h>

#define ADC_INPUT (ADC1_CHANNEL_4)    //pin 32
#define I2S_DMA_BUF_LEN (720)

size_t bytes_read;
uint16_t buffer[I2S_DMA_BUF_LEN] = {0};
uint32_t samplerate=1250000;

void i2sInit() {
  i2s_config_t i2s_config = {
    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX | I2S_MODE_ADC_BUILT_IN),
    .sample_rate =  samplerate,
    .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
    .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
    .communication_format = I2S_COMM_FORMAT_I2S_MSB,
    .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
    .dma_buf_count = 2,
    .dma_buf_len = I2S_DMA_BUF_LEN,
    .use_apll = false,
    .tx_desc_auto_clear = false,
    .fixed_mclk = 0
  };

  i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);
  i2s_set_adc_mode(ADC_UNIT_1, ADC_INPUT);
  i2s_adc_enable(I2S_NUM_0);
  adc1_config_channel_atten(ADC_INPUT, ADC_ATTEN_DB_11);
}

void setup(void) {
  Serial.begin(115200);
  i2sInit();
}

void loop() {
  
  i2s_read(I2S_NUM_0, &buffer, sizeof(buffer), &bytes_read, 0);
  Serial.println("buffer full.. Ready to be processed...");
}
11

I did not get crashes / resets with that code. Using ESP32 Board Package 2.0.8 and board "ESP32 Dev Module".

12

This is a very good news. My board is a different clone. I will by the model you have tested. Thanks a lot

13

My Chinese is too bad to read the tons of documentation, kudos to you.

14

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