Easy led blink

// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin 13 as an output.
  pinMode(13, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(13, HIGH);
  delay(1000);                      
  digitalWrite(13, LOW);   
  delay(500);                       
}