#include <avr/io.h>
#include <avr/delay.h>

static void avr_init(void);


int main(void)
{
 	avr_init();

    unsigned char tmp;

	PORTB=0b00000100;
	_delay_ms(100);
	PORTB=0b00000000;
	_delay_ms(100);
	PORTB=0b00000100;
	_delay_ms(100);
	PORTB=0b00000100;

    for(;;)
    {
		tmp=PINB&0b00011000;

		switch (tmp)
		{
		case 0b00011000:
		
			PORTB=0b00000100;
			break;

		case 0b00010000:

			PORTB=0b00000110;
			break;

		case 0b00001000:

			PORTB=0b00000101;
			break;

		case 0b00000000:

			PORTB=0b00000100;
			break;
		}
    }
    return(0);
}


static void avr_init(void)
{
	DDRB=0b00000111;
	PORTB=0b00000000;
    return;
}