#define  led_PWM 16

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(led_PWM, OUTPUT);
}

void loop() {
  for(int i = 1; i <= 255; i++){
    analogWrite(led_PWM, i);
    delay(100);
    Serial.println(i);
  }
  // put your main code here, to run repeatedly:
   // this speeds up the simulation

  for(int j = 255; j >= 0; j--){
    analogWrite(led_PWM, j);
    delay(100);
    Serial.println(j);
  }
}