/***************************************************************
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;
}
}
