#include <avr/io.h>
#include <util/delay.h>
#define RCK 0  //STCP
#define SCK 1  //SHCP	
#define DS 2
#define OE 3
#define MR 4
#define setbit(p,n) p|=_BV(n)
#define clearbit(p,n) p&=~_BV(n)
#define time 100

void writebyte(char b);



int main(void)
{char i;
 DDRA=0;
 PORTA=0x00;
 DDRB=0xff;
 DDRD=0xff;
 UCSRA=0x00;
 PORTD=0x00;
 setbit(PORTD,MR);
 clearbit(PORTD,OE);
 for (i=240;1;i++){ 
   writebyte(i); 
   PORTB=PINA;
   _delay_ms(200);
   PORTB=PINA;
   _delay_ms(800);
   }
 while (1) asm("nop");
}

void writebyte(char b)
{
 for (char i=0;i<=7;i++){
   if (_BV(i)&b) {setbit(PORTD,DS);}
   else {clearbit(PORTD,DS);}
   _delay_us(12);
   setbit(PORTD,SCK);
   clearbit(PORTD,SCK);
   }
 setbit(PORTD,RCK);
 clearbit(PORTD,RCK);
 
 }