void setup() {
  pinMode(A0, INPUT);
  pinMode(6, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  int a = analogRead(A0); // Read analog value
  int pwm = map(a, 0, 1023, 0, 255); // Map analog value to PWM range
  analogWrite(6, pwm); // Write PWM value to pin 3

  Serial.print("Value Analog = ");
  Serial.println(a);
  Serial.print("Value PWM = ");
  Serial.println(pwm);

  delay(250);
}