Hi,

I'm new to microcontroller programming and am trying to get a Mega2560 
running at 16Mhz to move a servo back and forth.  I'm trying to 
controller the servo by letting the timer do all the work and for some 
reason I am having problems. I am curious as to whether or not this can 
be done without using interrupt handeling. My understanding is that when 
I set the Port to output, OC1A should be updated automatically.  The 
idea is to clear OC1A when upcounting and set it again when 
downcounting.  By changing the value of OCR1A, I should be able to 
change the pulse width. Unfortunately, it doesn't work in the simulator, 
which doesn't suprise me since the winavr simulator seems to have a 
number of bugs in it, but it doesn't work on my 2560 properly either. 
I'd appreciate any help.


#include<avr/io.h>
#ifndef F_CPU
#warning "F_CPU war noch nicht definiert!"
#define F_CPU 16000000UL
#endif
#include <util/delay.h>


void main (void) {
  //Set testFactor to 1 for real life or to a higher value
  //to speed up the simulation
  int testFactor=1; //ICR1 and OCR1A are divided by this value


  //Initialize PORTB

  PORTB=0b00100000;  //start with OC1A high
  DDRB= 0xFF;  //set OC1A to output (among others)

  //Initialize Timer/Counter 1
  //System Clock as source
  //Mode 8: Phase and Freq. Correct PWM top=ICR1
  //OC1A output: Non-inverted
  //OC1B output: currently disabled
  //OC1C output: currently disabled

  ICR1=20000/testFactor;
  OCR1A=1000/testFactor; //set 1ms pulse  1000=1ms  2000=2ms
  TCCR1A=(1<<COM1A1);//COM1A1 Clear OCnA when match counting up,Set on 
down
  TCCR1B=(1<<WGM13)|(1<<CS11);// Phase and Freq correct ICR1=Top

while (1)
      {

      OCR1A = 1000; //leave servo at min rotation
      _delay_ms(1000);
      OCR1A = 2000; //leave serve at max rotation
    _delay_ms(1000);

      };


}