void setup() {
  // put your setup code here, to run once:
  volatile char *direction;
  volatile char *data;
  volatile long i;
  data = 0x31;
  direction = 0x30;
  *direction = 0xFF;
  while(1){
    *data = 1;
    for(i=0;i<100000;i++);
    *data = 0;
    for(i=0;i<100000;i++);
  }
}

void loop() {
  // put your main code here, to run repeatedly:

}