Write display data

main.cpp

#include <stdio.h>
#include "esp_err.h"
#include "esp_log.h"
#include "esp_vfs_fat.h"
#include "driver/sdspi_host.h"
#include "driver/spi_common.h"
#include "sdmmc_cmd.h"
#include "M5Unified.h"

static const char *TAG = "main";
#define MOUNT_POINT "/sdcard"

#define PIN_NUM_CS 4

void write_data(void)
{
    esp_err_t ret;

    const char mount_point[] = MOUNT_POINT;
    esp_vfs_fat_sdmmc_mount_config_t mount_config = {
        .format_if_mount_failed = false,
        .max_files = 5,
        .allocation_unit_size = 16 * 1024,
    };
    sdmmc_card_t *card;

    sdmmc_host_t host = SDSPI_HOST_DEFAULT();
    host.slot = VSPI_HOST;

    sdspi_device_config_t slot_config = SDSPI_DEVICE_CONFIG_DEFAULT();
    slot_config.gpio_cs = static_cast<gpio_num_t>(PIN_NUM_CS);
    slot_config.host_id = static_cast<spi_host_device_t>(host.slot);

    ret = esp_vfs_fat_sdspi_mount(mount_point, &host, &slot_config, &mount_config, &card);

    if (ret != ESP_OK)
    {
        ESP_LOGE(TAG, "Failed to initialize the card (%s). ", esp_err_to_name(ret));
        return;
    }
    ESP_LOGI(TAG, "Filesystem mounted");

    sdmmc_card_print_info(stdout, card);

    FILE *f = fopen(MOUNT_POINT "/tmp1.bin", "wb");
    if (f == NULL)
    {
        ESP_LOGE(TAG, "Failed to open file for writing");
        return;
    }

    uint16_t *buf = reinterpret_cast<uint16_t *>(malloc(sizeof(uint16_t) * M5.Display.width()));
    for (int16_t y = M5.Display.height() - 1; y >= 0; y--)
    {
#if 1
        M5.Display.readRect(0, y, M5.Display.width(), 1, buf);
#endif
        fwrite(buf, sizeof(uint16_t), M5.Display.width(), f);
    }
    fclose(f);
    free(buf);
    ESP_LOGI(TAG, "Binary data written");

    esp_vfs_fat_sdcard_unmount(mount_point, card);
    ESP_LOGI(TAG, "Card unmounted");
}

extern "C"
{
    void app_main()
    {
        M5.begin();
        M5.Display.clear();
        write_data();
        while (true)
        {
            vTaskDelay(1000 / portTICK_RATE_MS);
        }
    }
}