text: #include <Arduino.h>
  
  /*
    Blink
    Turns on an LED on for one second, then off for one second, repeatedly.
  
    This example code is in the public domain.
   */
  
  /* Pin 13 has an LED connected on most Arduino boards.
  Pin 11 has the LED on Teensy 2.0
  Pin 6  has the LED on Teensy++ 2.0
  Pin 13 has the LED on Teensy 3.0
  give it a name: */
  
  const uint8_t led = 13;     //unsigned integer 8 bit data type- designating pin, no negative pins, limited number of pins
  //#define led 13                //alternate way of setting 13 to LED- uses less memory, pin number cannot be changed iin code
  
  // the setup routine runs once when you press reset:
  void setup() {
    // initialize the digital pin as an output.
    pinMode(led, OUTPUT);
  }
  
  // the loop routine runs over and over again forever:
  void loop() {
    digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
    delay(500);               // wait for a second
    digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
    delay(1000);               // wait for a second
  }