#include <avr/io.h>


void init_PWM(void)
{
    TCCR0A|=(1<<WGM00)|(1<<WGM01)|(1<<COM0A1)|(1<<CS00);
   

    //Set OC0 PIN as output. It is  PB3 on ATmega16 ATmega32

    DDRB|=(1<<PB7);
}

void setPWM(uint8_t duty)
{
   OCR0A = duty;
}


void main (void)
{
   uint8_t brightness = 0;
   init_PWM();
   
   for (brightness=0; brightness<=255; brightness++)
   {
      setPWM(brightness);
      _delay_ms(100);
   }
}