const int ledPin12 = 12;

int pom = 0;

int rychlost = 40;

byte svited = 0;

void setup() {
  pinMode(ledPin12, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  while (pom <= 255){
    analogWrite(ledPin12, pom);
    pom = pom + 5;
    delay(rychlost);
    Serial.println(pom);
  }

  delay(500);

  while (pom >= 0){
    analogWrite(ledPin12, pom);
    pom = pom - 5;
    delay(rychlost);
    Serial.println(pom);
  }

  delay(500);

}