stm32f103单片机用fatfs读写sd卡测试代码

您好，我能够为您提供以下的代码作为参考：

#include <stdio.h>
#include "ff.h"
#include "diskio.h"

#define BUFFER_SIZE 512

FATFS fs;
FIL fil;
FRESULT fr;
BYTE buffer[BUFFER_SIZE];

int main(void) {
    // Mount SD card
    fr = f_mount(&fs, "", 0);
    if (fr != FR_OK) {
        printf("Could not mount SD card!\n");
        return 1;
    }
    // Open file for writing
    fr = f_open(&fil, "example.txt", FA_WRITE | FA_CREATE_ALWAYS);
    if (fr != FR_OK) {
        printf("Could not open file!\n");
        return 1;
    }
    // Write data to file
    UINT bytes_written;
    fr = f_write(&fil, buffer, BUFFER_SIZE, &bytes_written);
    if (fr != FR_OK) {
        printf("Could not write to file!\n");
        return 1;
    }
    // Close file
    fr = f_close(&fil);
    if (fr != FR_OK) {
        printf("Could not close file!\n");
        return 1;
    }
    // Open file for reading
    fr = f_open(&fil, "example.txt", FA_READ);
    if (fr != FR_OK) {
        printf("Could not open file!\n");
        return 1;
    }
    // Read data from file
    UINT bytes_read;
    fr = f_read(&fil, buffer, BUFFER_SIZE, &bytes_read);
    if (fr != FR_OK) {
        printf("Could not read from file!\n");
        return 1;
    }
    // Close file
    fr = f_close(&fil);
    if (fr != FR_OK) {
        printf("Could not close file!\n");
        return 1;
    }
    // Unmount SD card
    fr = f_mount(NULL, "", 0);
    if (fr != FR_OK) {
        printf("Could not unmount SD card!\n");
        return 1;
    }
    return 0;
}

这是一个简单的测试代码，可以用于读写SD卡。可根据实际情况进行代码修改。