实现存储器EEPROM AT24C02的数据读写操作 采用IIC总线读写 C程序
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/*************************************************************** 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++)
{
A T24C02_SCL = 0;
input <<= 1;
A T24C02_SDA = CY;
A T24C02_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--)
{
A T24C02_SCL = 0;
_nop_();
rbyte = (rbyte << 1) | AT24C02_SDA;
A T24C02_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)
{