Example 1-1

example1-1.ino

int i = 1000;

void setup()
{                
  pinMode(3, OUTPUT);     // sets digital pin 3 to an output
  pinMode(6, OUTPUT);     // sets digital pin 6 to an output  
}

void loop() 
{
  digitalWrite(3, HIGH);   // turns on digital pin 3
  digitalWrite(6, LOW);    // turns off digital pin 6
  delay(i);              // wait one second
  digitalWrite(3, LOW);   // turns off digital pin 3
  digitalWrite(6, HIGH);    // turns on digital pin 6
  delay(i);             
}