#define F_CPU 16000000UL
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>

int main (void) {

 DDRB |= (1 << DDB1);
 TCCR1A |= (1 << COM1A1) | (1 << WGM10);
 TCCR1B |= (1 << CS12) | (1 << CS10) | (1 << WGM12);

 while(1) {
 for (unsigned int pwm = 0; pwm < 256; pwm++) {
 OCR1A = pwm;
 _delay_ms(10);
 }
 }
}