#include <Servo.h> // include the servo library

const int ServoPin = 11;

Servo myServo; //initialize the servo object
// we will control our servo with
volatile int angle = 0;

ISR(TIMER2_COMPA_vect) { 
  angle++;
  if (angle > 180) { 
    angle = 0;
  }

}
void setup() { 
  myServo.attach(ServoPin); // Attach servo pin to servo object 
  cli(); // Disable global interrupts 

  TCCR2A = 0; // Clear TCCR2A register 
  TCCR2B = 0; // Clear TCCR2B register 

  // Set CTC mode (Clear Timer on Compare Match)
  TCCR2A |= (1 << WGM21);
  TCCR2B |= (1 << CS22) | (1 << CS21); // Prescaler 256

  TCNT2 = 0; 
  OCR2A = 1506;

  // Enable compare interrupt
  TIMSK2 |= (1 << OCIE2A); 

  sei(); // Enable global interrupts

}

void loop() {
  myServo.write(angle);
  delay(50);
}