/* Program 1-1: Toggling LED on an Arduino board    */

void setup() {
    pinMode(13, OUTPUT);    /* set pin 13 as output */
}
void loop() {
    digitalWrite(13,HIGH);  /* turn on the LED */
    delay(750);             /* delay 750 ms */
    digitalWrite(13,LOW);   /* turn off the LED */
    delay(750);             /* delay 750 ms */
}