const int buttonPin = 32;   // the pin that the button is connected to
const int ledPin = 4;      // the pin that the LED is connected to
const int freq = 5000;
const int resol = 8;
const int ledCh = 0;

int buttonState = 0;       // variable for storing the button state
int ledState = LOW;        // variable for storing the LED state
int counter = 0;

void IRAM_ATTR Ext_INT1_ISR() {
  counter++;
  if (counter > 2) {
    counter = 0;
  }
}

void setup() {
  ledcSetup(ledCh, freq, resol);
  ledcAttachPin(ledPin, ledCh);
  pinMode(buttonPin, INPUT);  // set the button pin as input with pullup resistor
  pinMode(ledPin, OUTPUT);           // set the LED pin as output
  digitalWrite(ledPin, HIGH); 
  attachInterrupt(buttonPin,Ext_INT1_ISR,RISING);
  Serial.begin(9600);   // initialize the LED state
}

void loop() {
  buttonState = digitalRead(buttonPin);   // read the button state
  if (buttonState == HIGH) {   
    for(int dutyCycle = 0; dutyCycle <= 255; dutyCycle+=10){   // changing the LED brightness with PWM
    ledcWrite(ledCh, dutyCycle);
    delay(500);              // debounce delay to prevent false positives
  }
}
}