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

功能:11:32 2008-6-27

作者:SG

時間:2004-03-15

版本:V1.0

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

#include "INTRINS.H"

#include "reg52.h"

#define WriteDeviceAddress 0xa0 //寫驅(qū)動地址指令

#define ReadDeviceAddress 0xa1 //讀驅(qū)動地址指令

sbit AT24C02_SCL = 0xa4;

sbit AT24C02_SDA = 0xa5;

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

功能：發(fā)起始信號

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

void Start_Cond()

{

AT24C02_SCL = 0;

_nop_();

AT24C02_SDA = 1;

_nop_();

AT24C02_SCL = 1;

_nop_();

AT24C02_SDA = 0;

_nop_();

}

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

功能：發(fā)停止信號

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

void Stop_Cond()

{

AT24C02_SCL = 0;

_nop_();

AT24C02_SDA = 0;

_nop_();

AT24C02_SCL = 1;

_nop_();

AT24C02_SDA = 1;

_nop_();

}

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

功能：發(fā)確認信號

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

void Ack()

{

AT24C02_SCL = 0;

_nop_();

AT24C02_SDA = 0;

AT24C02_SCL = 1;

_nop_();

AT24C02_SCL = 0;

_nop_();

AT24C02_SDA = 1;

}

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

功能：發(fā)無確認信號

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

void NoAck()

{

AT24C02_SCL = 0;

_nop_();

AT24C02_SDA = 1;

_nop_();

AT24C02_SCL = 1;

_nop_();

AT24C02_SCL = 0;

_nop_();

}

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

功能：寫一個字節(jié)數(shù)據(jù)

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

bit Write8Bit(unsigned char input)

{

unsigned char i;

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

{

AT24C02_SCL = 0;

input <<= 1;

AT24C02_SDA = CY;

AT24C02_SCL = 1;

}

AT24C02_SCL = 0;

_nop_();

AT24C02_SDA = 1;

AT24C02_SCL = 1;

_nop_();

CY = AT24C02_SDA;

return(CY) ;

}

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

功能：讀一個字節(jié)數(shù)據(jù)

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

unsigned char Read8Bit()

{

unsigned char temp,rbyte=0;

for (temp = 8;temp != 0;temp--)

{

AT24C02_SCL = 0;

_nop_();

rbyte = (rbyte << 1) | AT24C02_SDA;

AT24C02_SCL = 1;

_nop_();

}

return rbyte;

}

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

功能：從EEPROM中給定一個地址連續(xù)讀NLEN個字節(jié)數(shù)據(jù)存放在以指針

nContent開頭的往下內(nèi)容。

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

bit Read_Flash ( unsigned char *nContent, unsigned char nAddr, unsigned char nLen )

{

unsigned char Addr;

Addr = nAddr;

Start_Cond(); //寫開始信號

Write8Bit(WriteDeviceAddress); //寫驅(qū)動地址

Write8Bit(Addr); //寫從EEPROM中讀的開始地址

Start_Cond(); //寫開始信號

Write8Bit(ReadDeviceAddress); //寫讀數(shù)據(jù)指令

while(--nLen)

{

*nContent=Read8Bit(); //讀出內(nèi)容

nContent++; //指針加1

Ack(); //發(fā)確認信號

}

*nContent=Read8Bit(); //讀一字節(jié)

NoAck(); //沒有確認信號

Stop_Cond(); //發(fā)停止信號

return(0); //返回

}

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

功能：初始化EEPROM子程序內(nèi)容為FF

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

bit Init_Flash ( unsigned int nPage ) // 8 Byte/1Page init 0xFF

{

unsigned char nLen;

unsigned char Addr;

nLen=8;

Addr=8 *nPage;

Start_Cond();

Write8Bit(WriteDeviceAddress);

Write8Bit(Addr);

for(;nLen!=0;nLen--)

{

if(Write8Bit(0xff)) break; //if Write8Bit() Return 1 Write Flase

}

Stop_Cond();

return(CY);

}

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

功能：從EEPROM中給定一個地址連續(xù)寫NLEN個字節(jié)數(shù)據(jù)存放在以指針

nContent開頭的往下內(nèi)容。

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

bit Write_Flash ( unsigned char *nContent, unsigned char nAddr,unsigned char nLen)

{

unsigned char i,temp;

unsigned char Addr;

Addr = nAddr;

Start_Cond(); //寫開始信號

Write8Bit(WriteDeviceAddress); //寫驅(qū)動地址

Write8Bit(Addr); //寫從EEPROM中寫的開始地址

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

{

if(Addr%8==0) //每頁8字節(jié) //換頁

{

Stop_Cond();

_nop_();

Start_Cond();

Write8Bit(WriteDeviceAddress);

Write8Bit(Addr);

}

temp = *nContent;

if(Write8Bit(temp)) break; //CY

nContent++;

Addr++;

}

Stop_Cond(); //發(fā)停止信號

return(CY);

}

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

主程序

功能：實現(xiàn)存儲器EEPROM AT24C02的數(shù)據(jù)讀寫操作

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

void main()

{

unsigned char dat[16],i;

Read_Flash(dat,0,16); //讀出AT24C02中從地址0開始依次往后16個字節(jié)放入dat數(shù)組中

Init_Flash(0); //將AT24C02的第0頁初始化為FF

Read_Flash(dat,0,16); //讀出AT24C02中從地址0開始依次往后16個字節(jié)放入dat數(shù)組中

for(i = 0;i < 16;i++ )

{

dat[i] = i; //對數(shù)組dat初始化為0---F

}

Write_Flash(dat,0,16); //將dat數(shù)組中的數(shù)據(jù)寫入AT24C02中地址從0開始

Read_Flash(dat,1,16); //讀出AT24C02中從地址1開始依次往后16個字節(jié)放入dat數(shù)組中

while(1)

{

i = 9;

}

}