arduino ibox项目实战14－按键控制LED灯实验（二） - 九鼎创展论坛

// constants won't change. They're used here to
// set pin numbers:
const int buttonPin = KEY0; // the number of the pushbutton pin 24(KEY0)
const int ledPin = LED1; // the number of the LED pin 22(LED1)
// Variables will change:
int ledState = HIGH; // the current state of the output pin
int buttonState; // the current reading from the input pin
int lastButtonState = LOW; // the previous reading from the input pin
// the following variables are long's because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
long lastDebounceTime = 0; // the last time the output pin was toggled
long debounceDelay = 50; // the debounce time; increase if the output flickers
void setup() {
pinMode(buttonPin, INPUT);
pinMode(ledPin, OUTPUT);
// set initial LED state
digitalWrite(ledPin, ledState);
}
void loop() {
// read the state of the switch into a local variable:
int reading = digitalRead(buttonPin);
// check to see if you just pressed the button
// (i.e. the input went from LOW to HIGH), and you've waited
// long enough since the last press to ignore any noise:
// If the switch changed, due to noise or pressing:
if (reading != lastButtonState) {
// reset the debouncing timer
lastDebounceTime = millis();
}
if ((millis() - lastDebounceTime) > debounceDelay) {
// whatever the reading is at, it's been there for longer
// than the debounce delay, so take it as the actual current state:
// if the button state has changed:
if (reading != buttonState) {
buttonState = reading;
// only toggle the LED if the new button state is HIGH
if (buttonState == HIGH) {
ledState = !ledState;
}
}
}
// set the LED:
digitalWrite(ledPin, ledState);
// save the reading. Next time through the loop,
// it'll be the lastButtonState:
lastButtonState = reading;
}

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