const int buttonPin = 2;  // Button connected to pin 2
const int ledPin = 13;    // LED connected to pin 13

volatile bool interruptOccurred = false;
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 10;  // Adjust as needed

bool ledState = LOW;
bool lastButtonState = HIGH;  // Assuming INPUT_PULLUP

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);
  
  // Attach an interrupt to the button pin
  attachInterrupt(digitalPinToInterrupt(buttonPin), buttonInterrupt, FALLING);
}

void loop() {
  if (interruptOccurred) {
    interruptOccurred = false;
    
    if ((millis() - lastDebounceTime) > debounceDelay) {
      bool reading = digitalRead(buttonPin);
      
      if (reading != lastButtonState) {
        lastDebounceTime = millis();
        
        if (reading == LOW) {  // Button is pressed (LOW due to INPUT_PULLUP)
          ledState = !ledState;
          digitalWrite(ledPin, ledState);
        }
        
        lastButtonState = reading;
      }
    }
  }
}

// Interrupt Service Routine
void buttonInterrupt() {
  interruptOccurred = true;
}