File content as of revision 0:d96c133bf9d2:

#include "mbed.h"
#include "SDFileSystem.h"
#include "stdio.h"
#include "string.h"

DigitalOut myled(LED1); //initialize on board LED 
DigitalIn toggle(p7);   //initialize toggle switch
Serial GPS(p9, p10);    //initialize gps board
Serial pc(USBTX, USBRX);//initialize serial pc connection
SDFileSystem sd(p11,p12,p13,p14,"sd"); //Initializes filesystem (DI, D0, CLK, CS)
int hasbeenopened = 1;
int haslooped = 0;

int main() {
    char cc;
    toggle.mode(PullUp);
    FILE *fp = fopen("/sd/gpsdata.txt", "a");
    while(1){
        while(toggle==1){
            if (hasbeenopened==0){
                FILE *fp = fopen("/sd/gpsdata.txt", "a");
                hasbeenopened=1;
            }
            myled=1;
            cc = GPS.getc();
            fprintf(fp,"%c", cc);
            haslooped=1;
        }
        myled=0;
        if (haslooped==1){
            fclose(fp);
            hasbeenopened=0;
            haslooped=1;
        }
    }
}