spi_test_slave._c

用ICC编写的程序包括SPI

#include <iom16v.h>
#include <macros.h>
#define SIZE 100  
#define MOSI 	  PORTB5
#define MISO	  PINB6
#define	SCK		  PORTB7
#define	SS		  PORTB4

unsigned char SPI_rx_buff[SIZE];  
unsigned char SPI_tx_buff[SIZE];  
unsigned char rx_wr_index,rx_rd_index,rx_counter,rx_buffer_overflow;  
unsigned char tx_wr_index,tx_rd_index,tx_counter,SPI_ok,SPI_datain;  

#pragma interrupt_handler spi_stc_isr:18  
void spi_stc_isr(void)  
{  
  SPI_rx_buff[rx_wr_index] = SPDR;    //从ISP口读出收到的字节  
  SPI_ok=1;
  SPI_datain=1;
  if (++rx_wr_index == SIZE) rx_wr_index = 0;    //放入接收缓冲区，并调整队列指针  
  if (++rx_counter == SIZE)  
  {  
    rx_counter = 0;  
    rx_buffer_overflow = 1;  
  }  
  if (tx_counter)        //如果发送缓冲区中有待发的数据  
  {  
     --tx_counter;  
     SPDR = SPI_tx_buff[tx_rd_index]; //发送一个字节数据，并调整指针  
     SPI_ok=0;
	 if (++tx_rd_index == SIZE) tx_rd_index = 0;  
  }  
}  

unsigned char getSPIchar(void)  
{  
  unsigned char data;  
  while (rx_counter == 0);     //无接收数据，等待  
  data = SPI_rx_buff[rx_rd_index];    //从接收缓冲区取出一个SPI收到的数据  
  if (++rx_rd_index == SIZE) rx_rd_index = 0;    //调整指针  
  CLI();  
  --rx_counter;  
  SEI();  
  return data;  
}  

void putSPIchar(char c)  
{  
  while (tx_counter == SIZE);//发送缓冲区满，等待  
  CLI();  
  if (tx_counter || (SPI_ok==0))//发送缓冲区已中有待发数据  
  {                //或SPI正在发送数据时  
    SPI_tx_buff[tx_wr_index] = c;    //将数据放入发送缓冲区排队  
    if (++tx_wr_index == SIZE) tx_wr_index = 0;    //调整指针  
    ++tx_counter;  
  }  
  else  
    SPDR = c;        //发送缓冲区中空且SPI口空闲，直接放入SPDR由SIP口发送  
  SPI_ok=0;
  SEI();  
}  
		 	  		
						//从机模式
void spi_init(void)  
{  
  unsigned char temp;  
  		   		    //MISO=ouput and MOSI,SCK,SS = input  
  DDRB |=BIT(MISO);
  PORTB |=BIT(MISO);    //MISO上拉电阻有效   
  SPCR = 0xC4;    //SPI允许，从机模式，MSB，允许SPI中断  极性方式01，1/4系统时钟速率  
  SPSR = 0x00;  
  temp = SPSR;  
  temp = SPDR;    //清空SPI，和中断标志，使SPI空闲
  SPI_ok=1;
  SPI_datain=0;  
} 

void main(void)  
{  
  unsigned char i=0;  
  unsigned char data[8]={1,2,3,4,5,6,7};
  CLI();        //关中断  
  spi_init();    //初始化SPI接口  
  SEI();        //开中断  
  while(1)  
  {  
  	 if(SPI_datain)
	 {
	  	for (i=0;i<7;i++)
		{
		  if(getSPIchar()==0xAA)
		  	putSPIchar(data[i]);
		  else
		  	putSPIchar(0xee);
		 }
		 SPI_datain=0;
	 }
	
  }  
}