#include <avr/io.h>
#define	F_CPU 1000000
#include <util/delay.h>
int main(void)
{
	DDRB=0xff;   // Declaration of port(whether i/p or o/p)
	while(1)   // Follows an infinite loop
	{
		PORTB=0x00;   // Condition of PORTB is 0(All led's are off)
		_delay_ms(500);
		for(unsigned char i=0;i<8;i++)
		{
			PORTB=0x01<<i;   // Only one led is on at a time
			_delay_ms(500);   // Led's are on for 500ms
		}
	}
}