int led =3;
int fade=0;

void setup() {
  pinMode(led, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  for(fade=0;fade<=225;fade+=3){
    analogWrite(led,fade);
    delay(0.07);
  Serial.print("fade=");
  Serial.println(fade);
  }
  for(fade=225;fade>=225;fade-=3){
    analogWrite(led,fade);
    delay(0.07);
  Serial.print("fade=");
  Serial.println(fade);
  }

}