模块说明： c51单片机的i/o模拟spi操作

创建时间： 2005/03/09

创建者： xichen

********************************************************************************/

#ifndef SPI_H

#define SPI_H

sbit SPIS_N = P2^1;

sbit SPIC = P2^3;

sbit SPID = P2^2;

sbit SPIQ = P2^4;

extern void spi_reset();

extern void spi_write(unsigned char spi_bValue);

extern unsigned char spi_read();

#endif

/*******************************************************************************

模块说明： c51单片机的i/o模拟spi操作

创建时间： 2005/03/09

创建者： xichen

********************************************************************************/

#include "includes.h"

#define set_spi_cs() SPIS_N =1

#define clr_spi_cs() SPIS_N =0

#define set_spi_clk() SPIC =1

#define clr_spi_clk() SPIC =0

#define set_spi_di() SPID =1

#define clr_spi_di() SPID =0

#define read_spi_do() SPIQ

void spi_reset()

{

set_spi_cs();

}

//-----------------------------------------

void spi_write(unsigned char spi_bValue)

{

unsigned char no;

clr_spi_cs();

for (no=0;no<8;no++)

{

clr_spi_clk();

if ((spi_bValue &0x80)==0x80)

set_spi_di();

else

clr_spi_di();

set_spi_clk();

spi_bValue = (spi_bValue <<1);

}

}

//----------------------------------------------

unsigned char spi_read()

{

unsigned char no,spi_bValue;

clr_spi_cs();

for (no=0;no<8;no++)

{

clr_spi_clk();

spi_bValue = (spi_bValue <<1);

set_spi_clk();

if (read_spi_do() ==1)

spi_bValue |=0x01;

else

spi_bValue &=~0x01;

}

return spi_bValue;

}