实现AT24C02的数据读写操作

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

功能:11:32 2008-6-27

作者:SG

时间:2004-03-15

版本:V1.0

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

#include "INTRINS.H"

#include "reg52.h"

#define WriteDeviceAddress 0xa0 //写驱动地址指令

#define ReadDeviceAddress 0xa1 //读驱动地址指令

sbit AT24C02_SCL = 0xa4;

sbit AT24C02_SDA = 0xa5;

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

功能：发起始信号

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

void Start_Cond()

{

AT24C02_SCL = 0;

_nop_();

AT24C02_SDA = 1;

_nop_();

AT24C02_SCL = 1;

_nop_();

AT24C02_SDA = 0;

_nop_();

}

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

功能：发停止信号

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

void Stop_Cond()

{

AT24C02_SCL = 0;

_nop_();

AT24C02_SDA = 0;

_nop_();

AT24C02_SCL = 1;

_nop_();

AT24C02_SDA = 1;

_nop_();

}

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

功能：发确认信号

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

void Ack()

{

AT24C02_SCL = 0;

_nop_();

AT24C02_SDA = 0;

AT24C02_SCL = 1;

_nop_();

AT24C02_SCL = 0;

_nop_();

AT24C02_SDA = 1;

}

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

功能：发无确认信号

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

void NoAck()

{

AT24C02_SCL = 0;

_nop_();

AT24C02_SDA = 1;

_nop_();

AT24C02_SCL = 1;

_nop_();

AT24C02_SCL = 0;

_nop_();

}

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

功能：写一个字节数据

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

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：读一个字节数据

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

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：从EEPROM中给定一个地址连续读NLEN个字节数据存放在以指针

nContent开头的往下内容。

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

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

{

unsigned char Addr;

Addr = nAddr;

Start_Cond(); //写开始信号

Write8Bit(WriteDeviceAddress); //写驱动地址

Write8Bit(Addr); //写从EEPROM中读的开始地址

Start_Cond(); //写开始信号

Write8Bit(ReadDeviceAddress); //写读数据指令

while(--nLen)

{

*nContent=Read8Bit(); //读出内容

nContent++; //指针加1

Ack(); //发确认信号

}

*nContent=Read8Bit(); //读一字节

NoAck(); //没有确认信号

Stop_Cond(); //发停止信号

return(0); //返回

}

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

功能：初始化EEPROM子程序内容为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：从EEPROM中给定一个地址连续写NLEN个字节数据存放在以指针

nContent开头的往下内容。

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

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

{

unsigned char i,temp;

unsigned char Addr;

Addr = nAddr;

Start_Cond(); //写开始信号

Write8Bit(WriteDeviceAddress); //写驱动地址

Write8Bit(Addr); //写从EEPROM中写的开始地址

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

{

if(Addr%8==0) //每页8字节 //换页

{

Stop_Cond();

_nop_();

Start_Cond();

Write8Bit(WriteDeviceAddress);

Write8Bit(Addr);

}

temp = *nContent;

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

nContent++;

Addr++;

}

Stop_Cond(); //发停止信号

return(CY);

}

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

主程序

功能：实现存储器EEPROM AT24C02的数据读写操作

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

void main()

{

unsigned char dat[16],i;

Read_Flash(dat,0,16); //读出AT24C02中从地址0开始依次往后16个字节放入dat数组中

Init_Flash(0); //将AT24C02的第0页初始化为FF

Read_Flash(dat,0,16); //读出AT24C02中从地址0开始依次往后16个字节放入dat数组中

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

{

dat[i] = i; //对数组dat初始化为0---F

}

Write_Flash(dat,0,16); //将dat数组中的数据写入AT24C02中地址从0开始

Read_Flash(dat,1,16); //读出AT24C02中从地址1开始依次往后16个字节放入dat数组中

while(1)

{

i = 9;

}

}