sd_i2s.c

#include <string.h>
#include <sys/unistd.h>
#include <sys/stat.h>
#include "esp_vfs_fat.h"
#include "sdmmc_cmd.h"
#include "driver/sdmmc_host.h"
#include <driver/i2s.h>

static const char *TAG = "example";

#define MOUNT_POINT "/sdcard"

#define SAMP_RATE (325000 * 2)
#define BITS_PER_SAMPLE 16
#define BLCK 20800000

//#define SAMP_RATE 44100
//#define BITS_PER_SAMPLE 32

#define DMA_CHUNK_SIZE 1024
#define BUFFER_SIZE 32768
//#define BUFFER_SIZE DMA_CHUNK_SIZE

uint8_t buffer[BUFFER_SIZE];

void configure_port(i2s_port_t port) {
    //Set up I2S
    i2s_config_t i2s_config = {
        .mode = (i2s_mode_t)(I2S_MODE_SLAVE | I2S_MODE_RX),
        .sample_rate = SAMP_RATE,
        .bits_per_sample = BITS_PER_SAMPLE,
        .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
        .communication_format = I2S_COMM_FORMAT_STAND_I2S,
        .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,  // Interrupt level 1, default 0
        .dma_buf_count = 32,
        .dma_buf_len = DMA_CHUNK_SIZE,
        .use_apll = true,
        .tx_desc_auto_clear = false,
        .fixed_mclk = BLCK,
        .mclk_multiple = I2S_MCLK_MULTIPLE_DEFAULT,
        //.bits_per_chan = 0    
    };
    i2s_driver_install(port, &i2s_config, 0, NULL);

    //Set up pins
    i2s_pin_config_t pin_config = {
        .bck_io_num = 18,
        .ws_io_num = 5,
        .data_out_num = I2S_PIN_NO_CHANGE,
        .data_in_num = 23
    };
    i2s_set_pin(port, &pin_config);
}

void print_status(const char* text, int64_t start, int total) {
    //int target = 16*1024*1024;//(SAMP_RATE * (BITS_PER_SAMPLE / 8)) * 10;
    int target = 2600000 * 10;//(SAMP_RATE * (BITS_PER_SAMPLE / 8)) * 10;
    int64_t end = esp_timer_get_time();
    double speed = target / ((end - start) / 1000000.0);
    double target_speed = 2600000;
    ESP_LOGI(TAG, "%s (written %i bytes; %f bytes/sec, %f%% of target)", text, total, (float)speed, (float)((speed / target_speed) * 100.0));
}

void app_main(void)
{
    esp_err_t ret;

    // Options for mounting the filesystem.
    // If format_if_mount_failed is set to true, SD card will be partitioned and
    // formatted in case when mounting fails.
    esp_vfs_fat_sdmmc_mount_config_t mount_config = {
        .format_if_mount_failed = true,
        .max_files = 5,
        .allocation_unit_size = BUFFER_SIZE
    };
    sdmmc_card_t *card;
    const char mount_point[] = MOUNT_POINT;
    ESP_LOGI(TAG, "Initializing SD card");

    // Use settings defined above to initialize SD card and mount FAT filesystem.
    // Note: esp_vfs_fat_sdmmc/sdspi_mount is all-in-one convenience functions.
    // Please check its source code and implement error recovery when developing
    // production applications.

    ESP_LOGI(TAG, "Using SDMMC peripheral");
    sdmmc_host_t host = SDMMC_HOST_DEFAULT();
    host.max_freq_khz = SDMMC_FREQ_HIGHSPEED;

    // This initializes the slot without card detect (CD) and write protect (WP) signals.
    // Modify slot_config.gpio_cd and slot_config.gpio_wp if your board has these signals.
    sdmmc_slot_config_t slot_config = SDMMC_SLOT_CONFIG_DEFAULT();

    // To use 1-line SD mode, change this to 1:
    slot_config.width = 4;

    // Enable internal pullups on enabled pins. The internal pullups
    // are insufficient however, please make sure 10k external pullups are
    // connected on the bus. This is for debug / example purpose only.
    slot_config.flags |= SDMMC_SLOT_FLAG_INTERNAL_PULLUP;

    ESP_LOGI(TAG, "Mounting filesystem");
    ret = esp_vfs_fat_sdmmc_mount(mount_point, &host, &slot_config, &mount_config, &card);

    if (ret != ESP_OK) {
        if (ret == ESP_FAIL) {
            ESP_LOGE(TAG, "Failed to mount filesystem. "
                     "If you want the card to be formatted, set the EXAMPLE_FORMAT_IF_MOUNT_FAILED menuconfig option.");
            vTaskDelay(1000 / portTICK_PERIOD_MS);
            esp_restart();
        } else {
            ESP_LOGE(TAG, "Failed to initialize the card (%s). "
                     "Make sure SD card lines have pull-up resistors in place.", esp_err_to_name(ret));
            vTaskDelay(1000 / portTICK_PERIOD_MS);
            esp_restart();
        }
        return;
    }
    ESP_LOGI(TAG, "Filesystem mounted");

    // Card has been initialized, print its properties
    sdmmc_card_print_info(stdout, card);

    //Set up ports
    configure_port(I2S_NUM_0);

    //Open output file
    FILE* output = fopen("/sdcard/out.bin", "wb");
    if (output == 0) {
        ESP_LOGE(TAG, "Failed to open output file.");
        vTaskDelay(1000 / portTICK_PERIOD_MS);
        esp_restart();
    }
    
    //Enter read loop
    size_t read;
    int total = 0;
    int target = 2600000 * 10;
    int64_t start = esp_timer_get_time();
    int64_t last_log = start;
    while (total < target) {
        //Read
        i2s_read(I2S_NUM_0, buffer, sizeof(buffer), &read, /*portMAX_DELAY*/100);
        //read = sizeof(buffer);
        if (read == 0)
            printf("WARN: Read nothing!\n");

        //Write
        fwrite(buffer, 1, read, output);

        //Log once a second
        if (esp_timer_get_time() - last_log > 1000000) {
            print_status("READING IN PROGRESS...", start, total);
            last_log = esp_timer_get_time();
        }

        //Set
        total += read;
    }
    print_status("DONE READING.", start, total);
    fclose(output);
    

    // All done, unmount partition and disable SDMMC peripheral
    esp_vfs_fat_sdcard_unmount(mount_point, card);
    ESP_LOGI(TAG, "Card unmounted");
}