I2S Input DMA setup

[dawime]

Hello - I am trying to interface a mems I2C microphone to I2S0 - I have verified that the device is clocking and outputing data - The idea is to setup DMA buffers, to trigger an interrupt when DMA is complete, from the DMA ISR signal a task that will read out the last buffer, process it and notify other consumers for that data.

My problem seems to be that the DMA ISR is not getting set. I checked that the semaphores are setup properly, but I can't quite figure it out. Here is the code:

Code: mic.c Select all

static int16_t dma_buf[DMA_BUF_COUNT][DMA_BUF_LEN];

static int buf_ptr = 0;

SemaphoreHandle_t i2s_dma_sem;

static intr_handle_t i2s_isr_ret_handle;



void IRAM_ATTR i2s_isr_handler(void *arg)

{

    BaseType_t xHigherPriorityTaskWoken = pdFALSE;



    xSemaphoreGiveFromISR(i2s_dma_sem, &xHigherPriorityTaskWoken);

    if (xHigherPriorityTaskWoken) {

        portYIELD_FROM_ISR();

    }

}





void mic_task(void *arg)

{

    size_t bytesRead;

    color_t sample_colors[6] = { red, green, blue, yellow, purple, silver };

    printf("mic_task enabled\n\r");

    while (1)

    {

        if (xSemaphoreTake(i2s_dma_sem, portMAX_DELAY) == pdTRUE) {

            // Process the data in dma_buf[buf_ptr]

            // ...

            i2s_read(I2S_NUM, (void *)&dma_buf[buf_ptr], DMA_BUF_LEN * sizeof(int16_t), &bytesRead, 0);

            buf_ptr = (buf_ptr + 1) % DMA_BUF_COUNT;

            printf("Read %d bytes",bytesRead);

           

            // Signal the main application that new data is available

            // ...

        }

    }

}



void mic_init()

{

    i2s_config_t i2s_config = {

        .mode = I2S_MODE_MASTER | I2S_MODE_RX,

        .sample_rate = 44100,

        .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,

        .channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,

        .communication_format = I2S_COMM_FORMAT_I2S_MSB,

        .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,

        .dma_buf_count = DMA_BUF_COUNT,

        .dma_buf_len = DMA_BUF_LEN,

        .use_apll = false,

        .tx_desc_auto_clear = false,

        .fixed_mclk = 0,

        

  

    };

    i2s_driver_install(I2S_NUM, &i2s_config, 0, NULL);

    i2s_set_clk(I2S_NUM, 44100, I2S_BITS_PER_SAMPLE_16BIT, I2S_CHANNEL_MONO);

    i2s_pin_config_t pin_config = {

        .mck_io_num = I2S_PIN_NO_CHANGE,

        .bck_io_num = 3,

        .ws_io_num = I2S_PIN_NO_CHANGE,

        .data_out_num = I2S_PIN_NO_CHANGE,

        .data_in_num = 8

    };

    i2s_set_pin(I2S_NUM, &pin_config);

    i2s_zero_dma_buffer(I2S_NUM);

    

    i2s_dma_sem = xSemaphoreCreateBinary();

    esp_err_t err =esp_intr_alloc(ETS_I2S0_INTR_SOURCE, ESP_INTR_FLAG_LEVEL1 | ESP_INTR_FLAG_IRAM, i2s_isr_handler, NULL, &i2s_isr_ret_handle);

	if (err != ESP_OK)

		ESP_LOGE(TAG, "Error esp_intr_alloc %s", esp_err_to_name(err));



    

    err = esp_intr_enable(i2s_isr_ret_handle);

    ESP_LOGI(TAG, "INTERRUPT Enable:      %d ", err);

    xTaskCreate(mic_task, "mic_task", 4096, NULL, 5, NULL);



}

Any ideas why i2s_isr_handler does not get called? Both esp_intr_alloc() and esp_intr_enable() return ESP_OK.

Thank you

[Sprite]

You cannot use both the driver as well as install your own ISR, and in your particular case, you don't need to. i2s_read() already suspends the calling task until the i2s peripheral has data available (that's why the driver needs the interrupt, it uses that to unblock the task calling i2s_read).

[dawime]

Thank you - I couldn't locate any documentation on it, but it makes sense. If the read will be blocking already, then I can forgo my interrupt and just running it on my thread directly.