esp32开发与应用（esp32的tf卡读写）-171主机测评

前面我们学习了esp32-s3的tf卡读写，今天想学习下esp32的tf卡读写。两者虽然功能差不多，但是前者比后者多一个usb口，所以成本上要贵一点的，所以我们有必要考虑下esp32是否也支持tf卡读写。答案是肯定的，不过有一些地方需要注意下。

1、确认模块电压

前面说过，电商网站买到的很多tf卡模块都是5v输入电压，并不是3.3v，这一点是需要注意的。

2、继续确认引脚连线

esp32和esp32-s3的引脚并不是完全一致的，所以直接用spi代替sdio配置tf卡的时候，一定要注意找到对应的spi引脚。不然就算代码是正确的，也有可能跑不起来。

3、调低spi速率

很多时候esp32-s3是ok的，但是esp32却不行。如果是5v也配置好了，连线也没有问题，tf卡本身也是大牌、并且小于32g，这个时候就要想办法降低spi的速率了，这样才可能读取到tf卡里面的内容。

4、通过ai生成代码

这一切都准备好之后，就可以让ai帮助我们生成代码了。可以这么说，用esp-idf生成一个esp32的tf卡读写demo。不出意外，就可以得到这样的代码。首先是CMakeLists.txt,

idf_component_register(SRCS "main.c" "sdcard_driver.c"
INCLUDE_DIRS "."
REQUIRES fatfs sdmmc driver )

接着是一个头文件sdcard_driver.h文件，

#ifndef SDCARD_DRIVER_H
#define SDCARD_DRIVER_H

#include "esp_err.h"
#include "driver/gpio.h"

// Pin definitions (modify according to your hardware connection)
#define SD_PIN_CS GPIO_NUM_15 // Chip select
#define SD_PIN_CLK GPIO_NUM_14 // Clock
#define SD_PIN_MOSI GPIO_NUM_13 // Master Out Slave In
#define SD_PIN_MISO GPIO_NUM_12 // Master In Slave Out

// Mount point path
#define SD_MOUNT_POINT "/sdcard"

// Initialize SD card
esp_err_t sdcard_init(void);

// Unmount SD card
void sdcard_unmount(void);

// Write data to a file
esp_err_t sdcard_write_file(const char* filename, const char* data);

// Read data from a file
esp_err_t sdcard_read_file(const char* filename, char* buffer, size_t buffer_size);

// Append data to a file
esp_err_t sdcard_append_file(const char* filename, const char* data);

// Delete a file
esp_err_t sdcard_delete_file(const char* filename);

// Check if a file exists
bool sdcard_file_exists(const char* filename);

// Print SD card capacity information
void sdcard_print_info(void);

// List directory contents
void sdcard_list_directory(const char* path);

#endif // SDCARD_DRIVER_H

然后是sdcard_driver.c文件，

#include <stdio.h>
#include <string.h>
#include <sys/unistd.h>
#include <sys/stat.h>
#include <dirent.h>
#include <errno.h>
#include "esp_err.h"
#include "esp_log.h"
#include "esp_vfs_fat.h"
#include "sdmmc_cmd.h"
#include "driver/sdspi_host.h"
#include "driver/spi_common.h"
#include "sdcard_driver.h"

static const char* TAG = "SDCARD";

static sdmmc_card_t* s_card = NULL;
static bool s_is_mounted = false;

esp_err_t sdcard_init(void)
{
esp_err_t ret;

if (s_is_mounted) {
ESP_LOGW(TAG, "SD card already mounted");
return ESP_OK;
}

ESP_LOGI(TAG, "Initializing SD card (SPI mode)");
ESP_LOGI(TAG, "Pin configuration: CS=%d, CLK=%d, MOSI=%d, MISO=%d",
SD_PIN_CS, SD_PIN_CLK, SD_PIN_MOSI, SD_PIN_MISO);

// Configure SPI bus
spi_bus_config_t bus_config = {
.mosi_io_num = SD_PIN_MOSI,
.miso_io_num = SD_PIN_MISO,
.sclk_io_num = SD_PIN_CLK,
.quadwp_io_num = -1,
.quadhd_io_num = -1,
.max_transfer_sz = 4000,
};

// Initialize SPI bus
ret = spi_bus_initialize(SPI2_HOST, &bus_config, SPI_DMA_CH_AUTO);
if (ret != ESP_OK) {
ESP_LOGE(TAG, "SPI bus initialization failed: %s", esp_err_to_name(ret));
return ret;
}

// Configure SD SPI device
sdspi_device_config_t slot_config = {
.host_id = SPI2_HOST,
.gpio_cs = SD_PIN_CS,
.gpio_cd = GPIO_NUM_NC,
.gpio_wp = GPIO_NUM_NC,
.gpio_int = GPIO_NUM_NC,
};

// Initialize SD SPI host driver
ret = sdspi_host_init();
if (ret != ESP_OK) {
ESP_LOGE(TAG, "SD SPI host initialization failed: %s", esp_err_to_name(ret));
spi_bus_free(SPI2_HOST);
return ret;
}

// Configure host parameters
sdmmc_host_t host = SDSPI_HOST_DEFAULT();
host.slot = SPI2_HOST;
host.max_freq_khz = 10000; // 10MHz

// Mount configuration
esp_vfs_fat_sdmmc_mount_config_t mount_config = {
.format_if_mount_failed = false,
.max_files = 5,
.allocation_unit_size = CONFIG_WL_SECTOR_SIZE
};

// Mount file system
ret = esp_vfs_fat_sdspi_mount(SD_MOUNT_POINT, &host, &slot_config, &mount_config, &s_card);

if (ret != ESP_OK) {
ESP_LOGE(TAG, "SD card mount failed: %s", esp_err_to_name(ret));

if (ret == ESP_FAIL) {
ESP_LOGE(TAG, "File system mount failed, please check:");
ESP_LOGE(TAG, " 1. Whether the SD card is properly inserted");
ESP_LOGE(TAG, " 2. Whether the SD card is formatted as FAT/FAT32");
ESP_LOGE(TAG, " 3. Whether pin connections are correct");
ESP_LOGE(TAG, " 4. Try reducing SPI frequency");
}

sdspi_host_deinit();
spi_bus_free(SPI2_HOST);
return ret;
}

s_is_mounted = true;

// Print SD card information
sdcard_print_info();

return ESP_OK;
}

void sdcard_unmount(void)
{
if (!s_is_mounted) {
ESP_LOGW(TAG, "SD card not mounted");
return;
}

esp_err_t ret = esp_vfs_fat_sdcard_unmount(SD_MOUNT_POINT, s_card);
if (ret != ESP_OK) {
ESP_LOGE(TAG, "Failed to unmount SD card: %s", esp_err_to_name(ret));
}

ret = sdspi_host_deinit();
if (ret != ESP_OK) {
ESP_LOGE(TAG, "Failed to deinitialize SD SPI host: %s", esp_err_to_name(ret));
}

ret = spi_bus_free(SPI2_HOST);
if (ret != ESP_OK) {
ESP_LOGE(TAG, "Failed to free SPI bus: %s", esp_err_to_name(ret));
}

s_is_mounted = false;
s_card = NULL;
ESP_LOGI(TAG, "SD card unmounted");
}

esp_err_t sdcard_write_file(const char* filename, const char* data)
{
if (!s_is_mounted) {
ESP_LOGE(TAG, "SD card not mounted");
return ESP_FAIL;
}