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

#define SCK   7          //PB7
#define MISO  6          //PB6
#define PL    4          //PB4

void portinitial(void)
{
   PORTA=0XFF;
  DDRA=0XFF;                            //OUT
  PORTB=0XFF;
  DDRB=(1<<SCK)|(1<<PL);               //PB7,PB4 OUT
  PORTC=0XFF;                           //PULL-UP
  PORTD=0XFF;                           //PULL-UP
}

void spiinit(void)
{
 SPCR=(1<<SPE)|(1<<MSTR)|(1<<SPR1)|(1<<SPR0);     //enable spi,Master Mode
                                                 }

int main(void)
{
 portinitial();
 spiinit();
 while(1)
 {
  PORTB&=~(1<<PL);
  _delay_us(10);
  PORTB|=(1<<PL);
  SPDR=0XAA;
  while(!(SPSR&(1<<SPIF)));        //wait until spi receive succeed
  PORTA=~SPDR;                       //light led  to the corresponding bit
 }
}