text: #include "mbed.h"
  #include "rtos.h"
  #include "SDFileSystem.h"
  
  #define FILE_LOC "/sd/test.txt"
  
  Serial pc(USBTX, USBRX);
  Serial gps(p28, p27);
  Serial test(p9,p10);
  
  SDFileSystem sd(p11, p12, p13, p14, "sd");
  
  DigitalOut myled(LED1);
  DigitalOut sdled(LED2);
  
  void sd_thread(void const *argument) {
      while (true) {
          sdled = !sdled;
          FILE *fp = NULL;
          fp = fopen(FILE_LOC, "w");
          if( fp != NULL ) fclose(fp);
          Thread::wait(1000);
      }
  }
  
  int main() {
      Thread sdTask(sd_thread, NULL, osPriorityNormal, DEFAULT_STACK_SIZE * 2.25);
      while (true) {
          myled = !myled;
          Thread::wait(1000);
      }
  }
  