void setup() {
  // put your setup code here, to run once:
  volatile char *dir = 0x30;
  *dir = 0b00000001;
  volatile char *out = 0x31;
  while(1){
    *out = 1;
    for(volatile long i = 0; i < 476225; i++);
    *out = 0;
    for(volatile long i = 0; i < 476225; i++);
  }
}

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

}