Arduino不使用Delay的定時（燈閃爍）

看到一篇關於Arduino不使用Delay的定時燈閃爍。主要是millis()方法，這個用法很是強大，不少時候須要使用，也不用擔憂溢出。

 

 

// constants won't change. Used here to set a pin number:

const int ledPin =  LED_BUILTIN;// the number of the LED pin

 

// Variables will change:

int ledState = LOW;             // ledState used to set the LED

 

// Generally, you should use "unsigned long" for variables that hold time

// The value will quickly become too large for an int to store

unsigned long previousMillis = 0;        // will store last time LED was updated

 

// constants won't change:

const long interval = 1000;           // interval at which to blink (milliseconds)

 

void setup() {

  // set the digital pin as output:

  pinMode(ledPin, OUTPUT);

}

 

void loop() {

  // here is where you'd put code that needs to be running all the time.

 

  // check to see if it's time to blink the LED; that is, if the difference

  // between the current time and last time you blinked the LED is bigger than

  // the interval at which you want to blink the LED.

  unsigned long currentMillis = millis();

 

  if (currentMillis - previousMillis >= interval) {

    // save the last time you blinked the LED

    previousMillis = currentMillis;

 

    // if the LED is off turn it on and vice-versa:

    if (ledState == LOW) {

      ledState = HIGH;

    } else {

      ledState = LOW;

    }

 

    // set the LED with the ledState of the variable:

    digitalWrite(ledPin, ledState);

  }

}