sdcard.c

Explains how to read and write from/to sdcard.

/*
 * This example shows how to read and write a file on the sdcard.
 */

#include <stm32f4xx.h>
#include <carme.h>
#include <rtc.h>
#include <ff.h>

FATFS main_fs;

int main(void) {

    FIL f;
    char buff[20];
    UINT totalwrite = 0, totalread = 0, tmpwrite, tmpread;
    UINT size;

    /* initialize the rtc */
    CARME_RTC_Init();
    /* mount the sdcard */
    if (f_mount(&main_fs, "0:", 1) != FR_OK) {
        while (1);
    }

    /* open the read.txt file to get the size */
    if (!f_open(&f, "read.txt", FA_OPEN_ALWAYS | FA_READ)) {
        /* get the size of the file */
        size = f_size(&f);
        f_close(&f);
    }

    while (1) {

        /* open the read.txt file to read the next string */
        if (!f_open(&f, "read.txt", FA_OPEN_ALWAYS | FA_READ)) {
            /* set the cursor next position to read */
            f_lseek(&f, totalread);
            f_read(&f, buff, sizeof(buff), &tmpread);
            f_close(&f);
            totalread += tmpread;
        }

        /* open the write.txt file to write this string */
        if (!f_open(&f, "write.txt", FA_OPEN_ALWAYS | FA_WRITE)) {
            /* set the cursor next position to read */
            f_lseek(&f, f_size(&f));
            f_write(&f, buff, tmpread, &tmpwrite);
            f_close(&f);
            totalwrite += tmpwrite;
        }

        if (!tmpwrite) {
            /* there are no bytes written, so there is a error */
            break;
        }

        if (totalwrite == size) {
            /* there is the full file copied */
            break;
        }
    }

    for (;;) {
    }
    return 0;
}