uint16_t analogPin = A0; 
uint16_t val = 0;  // variable to store the value read
uint16_t pwm = 0;
char str[16];

void setup() {
  //pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  Serial.begin(9600);           //  setup serial

  //analogWrite(5, 25);
  analogWrite(6, 0);
}

void loop() {
  val = analogRead(analogPin);  // 0<= val <= 1023  10 bits
  //pwm = map(val,0,1023,0,255);  //map(value, fromLow, fromHigh, toLow, toHigh)
  //pwm = val*255/1023;
  pwm = val/4;
  analogWrite(6,pwm);
  
  sprintf(str, "val = %u ->  pwm = %u", val, pwm);
  Serial.println(str); 
  delay(200);
}