学习，控制LED灯，亮2秒，灭1秒

int led=13;

void setup() {
  // put your setup code here, to run once:
  pinMode(led,OUTPUT);

}

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

  digitalWrite(led,HIGH);
  delay(2000);
  digitalWrite(led,LOW);
  delay(1000);
}