int pinR = 11;
int lvl = 0;
int fadeAmount = 5;   // how much to change each step
int wait = 30;        // delay between steps (ms)

void setup() {
  Serial.begin(115200);
  pinMode(pinR, OUTPUT);
}

void loop() {
  analogWrite(pinR, lvl);     // set LED brightness
  Serial.println(lvl);        // optional: monitor brightness level

  lvl = lvl + fadeAmount;     // change brightness

  // reverse direction at limits
  if (lvl <= 0 || lvl >= 255) {
    fadeAmount = -fadeAmount;
  }

  delay(wait);
}