#include "mbed.h"
#include "mbed_debug.h"
#include "SDFileSystem.h"

/* Serial debug port. */
Serial pc(P1_13, P1_14); // tx, rx

FILE *fp;
SDFileSystem sd(P1_22, P1_21, P1_20, P1_19, "sd"); 
DigitalOut led22(P0_22);
 
int main() {
    pc.printf("Hello World!\r\n");   

    fp = fopen("/sd/sdtest.txt", "w");
    pc.printf("fopen\r\n"); 
    
    if(fp == NULL) {
        pc.printf("Could not open file for write\r\n");
    }
    fprintf(fp, "Hello fun SD Card World!");
    fclose(fp); 
 
    pc.printf("Goodbye World!\r\n");

}

I've trying to get my SD card working with a 11U24 based board. I have been able to create a directory on the SD card. At least sometimes. This gives a good feeling that the hardware is working. I'm trying to write a file to the card. The code below never gets past the fopen call. Everything stops. I've turned on debugging in the SDFileSystem code. I've been able to see the code progress till it gets to the disk_read() function in diskio.cpp. The card apparently initializes, based on the debug messages. Anybody using SDFileSystem with this processor? <<info title=debug output>> Hello World!\\ open(sdtest.txt) on filesystem [sd], drv [0]\\ disk_initialize on drv [0]\\ Init: SDCARD_V2\\ init card = 2\\ SDHC Card\\ hc_c_size: 15199\\ capacity: 7969177600\\ sectors: 15564800\\ disk_read(sector 0, count 1) on drv [0]\\ disk_read(sector 0)\\ <</info>> <<code>> #include "mbed.h" #include "mbed_debug.h" #include "SDFileSystem.h" /* Serial debug port. */ Serial pc(P1_13, P1_14); // tx, rx FILE *fp; SDFileSystem sd(P1_22, P1_21, P1_20, P1_19, "sd"); DigitalOut led22(P0_22); int main() { pc.printf("Hello World!\r\n"); fp = fopen("/sd/sdtest.txt", "w"); pc.printf("fopen\r\n"); if(fp == NULL) { pc.printf("Could not open file for write\r\n"); } fprintf(fp, "Hello fun SD Card World!"); fclose(fp); pc.printf("Goodbye World!\r\n"); } <</code>>