#define F_CPU 1000000UL /* 1 MHz CLK */

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

// blinks leds connected to portd  

int main(){                      

DDRD = 0b11111111;   // output

while (1) {         

   PORTD = 0b10000000; 
   _delay_ms(50);      
   PORTD = 0b01000000; 
   _delay_ms(50);      
   PORTD = 0b00100000;
   _delay_ms(50);
   PORTD = 0b00010000;
   _delay_ms(50);
   PORTD = 0b00001000;
   _delay_ms(50);
   PORTD = 0b00000100;
   _delay_ms(50);
   PORTD = 0b00000010;
   _delay_ms(50);
   PORTD = 0b00000001;
   _delay_ms(50);
}
   
}