Millis Delay Example

MillisDelay.c

const int ledPin =  13;
int ledState = LOW;             
long previousTime = 0;        
long interval = 1000;           

void setup() {
  pinMode(ledPin, OUTPUT);      
}

void loop()
{

  unsigned long currentTime = millis();
 
  if(currentTime - previousTime > interval) {

    previousTime = currentTime;   

    if (ledState == LOW)
      ledState = HIGH;
    else
      ledState = LOW;

    digitalWrite(ledPin, ledState);
  }
}