iar14-1slave.c

手把手教你学AVR单片机C程序设计实验程序

#include<iom16.h>
#define uchar unsigned char	//变量类型的宏定义
#define uint  unsigned int	
#define CLR_BIT(x,y) (x&=~(1<<y))
#define CPL_BIT(x,y) (x^=(1<<y))
#define SPIF 7
/*******************************/
void port_init(void)
{
 PORTB = 0x01; 
 DDRB  = 0x41;
}
/*******************************/
void spi_init(void)
{
 SPCR = 0x41; //setup SPI
}
/*******************************/
uchar SPI_slavereceive(void)
{
 while(!(SPSR&(1<<SPIF)));
   return SPDR;
}
/*********************************************/
void main(void)
{
  uchar temp;
  port_init();
  spi_init();
  while(1)
  { 
    temp=SPI_slavereceive();
    CLR_BIT(SPSR,SPIF);
    if(temp==0x55)
    {CPL_BIT(PORTB,0);temp=0;}
  }
}