const byte ledPin = 14;

void setup() {
  Serial.begin ( 112500);
  pinMode(ledPin, OUTPUT);
}

void loop() {
  // increase the LED brightness
  for (int dutyCycle = 0; dutyCycle <=255; dutyCycle++) {
     Serial.print("dutyCycle++  : "); Serial.println(dutyCycle);
    analogWrite(ledPin, dutyCycle);
    delay(10);
  }

  // decrease the LED brightness
  for (int dutyCycle = 255; dutyCycle >= 0; dutyCycle--) {
     Serial.print("dutyCycle--: "); Serial.println(dutyCycle);
    analogWrite(ledPin, dutyCycle);
    delay(10);
  }
}