求教：关于Arduino官网的小例子-blinking without delay
// constants won't change. Used here to// set pin numbers:
const int ledPin =13; // the number of the LED pin
// Variables will change:
int ledState = LOW; // ledState used to set the LED
long previousMillis = 0; // will store last time LED was updated
// the follow variables is a long because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
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);
}
}
小弟一直不懂为什么digitalWrite的亮灯周期与interval一致。按道理说digitalWrite应该写在 if 外面才对啊
因为currentMillis - previousMillis 总有 小于interval的时候啊，那digitalWrite就不可能一直持续发亮啊，而且周期与interval一样
有没有大侠懂的？求教啊
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