SPI模拟编程《51例子》

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

模块名称： spi.h

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

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

模块名称： spi.c

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;

}

再一个SPI模拟

＃i nclude "COMMON.h"

＃i nclude "SPI.H"

＃i nclude "INTRINS.H"

/*------------------------------------------------------------------------*/

void SPIReset(void)

{

SPICLK = 0;

}

/*------------------------------------------------------------------------*/

void SPISendByte(unsigned char UC)

{

unsigned chari = 0;

CloseInt(); //要关中断

for(i=0;i<8;i++)

{

SPICLK = LOW;

SPIDI= (bit)(UC&0x80);UC<<=1;//Delay(0);

SPICLK = HIGH;//4个nop 8us

_nop_();

_nop_();

_nop_();

_nop_();

}

SPICLK = LOW;

OpenInt();//开中断

//开中断

/*

#pragma ASM

PUSH ACC;

PUSH 01H;

MOV 01H,#08H

LOOP:

SETB SPICLK

MOV A,R7;

RLC A;

MOV SPIDI,C;

DJNZ 01,LOOP

POP 01H;

popACC;

#pragma ENDASM

*/

}

/*-------------------------------------------------------------------------*/

void SPIInit(void)

{

SPICLK = LOW;

SPIDI= LOW;

SPIDO= HIGH;

}

/*------------------------------------------------------------------------*/

unsigned char SPIReadByte(void)

{

unsigned char i = 0,SPIData = 0;

CloseInt();

//要关中断

for(i=0;i<8;i++)

{

SPICLK = LOW;Delay8us();

SPICLK = HIGH;//Delay(10);//这个时间真还不太好控制

SPIData=(SPIData<<1)|SPIDO;

}

SPICLK = LOW;

// #pragma ASM

// #pragma ENDASM

OpenInt();//开中断

return SPIData;

}

/*------------------------------------------------------------------------*/

unsigned long SPIRead24Bit(void)

{

unsigned long SPIData = 0;

unsigned char Data[3] = {0,0,0};

unsigned char i;

CloseInt();//要关中断

/*

for(i=0;i<3*8;i++)

{

SPICLK = LOW;Delay8us();Delay8us();Delay8us();Delay8us();Delay8us();Delay8us();

SPICLK = HIGH;//Delay(8);//这个时间真还不太好控制

if(SPIDO)

{

SPIData=SPIData<<1;

SPIData|=0x01;

}

else

{

SPIData=(SPIData<<1);

SPIData|=0x00;

}

}

*/

for(i=0;i<8;i++)

{

SPICLK = LOW;Delay8us();Delay8us();Delay6us();

SPICLK = HIGH;

Data[0]=(Data[0]<<1)|SPIDO;

}

for(i=0;i<8;i++)

{

SPICLK = LOW;Delay8us();Delay8us();Delay6us();

SPICLK = HIGH;

Data[1]=(Data[1]<<1)|SPIDO;

}

for(i=0;i<8;i++)

{

SPICLK = LOW;Delay8us();Delay8us();Delay6us();

SPICLK = HIGH;

Data[2]=(Data[2]<<1)|SPIDO;

}

SPICLK = LOW;

SPIData = Data[0]*65536+Data[1]*256+Data[2];

OpenInt();//开中断

return SPIData;

}