#define F_CPU 1000000UL
#include <avr/io.h>
#include <util/delay.h>
int main(void)
{
DDRB = 0xff ;

TCCR1A |= 1<<WGM11 | 1<<COM1A1 ;
TCCR1B |= 1<<WGM13 | 1<<WGM12 | 1<<CS10 ;
ICR1 = 19999;
			while (1)
	{

			OCR1A =1000;
			_delay_ms(1000);



			OCR1A =1400;
			_delay_ms(1000);

			OCR1A =1800;
			_delay_ms(1000);





	}
}