#define LED 9
int i;

void setup()
{
  pinMode(LED, OUTPUT);
}

void loop()
{
  for (i = 0; i <= 255; i += 25)
  {
    int v;
    Serial.print("v=");
Serial.print(v);
    analogWrite(LED, i);
    delay(1000);
  }
  for (i = 255; i >= 0; i -= 51)
  {
    analogWrite(LED, i);
    delay(2000);
  }
}