24c02.c

通用51系列单片机读写24C02程序,可以移植到其他型号的MCU中.

/******************************************************
//file    name  :  24c02.c
//creat   by    :  squall45
//date          :  2008/10/20
*******************************************************/
#include <reg52.h>
#include <intrins.h>
// 对24C02的读、写
// extern void read24c02(unsigned char *RamAddress,unsigned char RomAddress,unsigned char bytes);
// extern void write24c02(unsigned char *RamAddress,unsigned char RomAddress,unsigned char bytes);
/***************for 24c02************************************************************/
#define	WriteDeviceAddress 0xa0
#define	ReadDviceAddress 0xa1
#define NOP() _nop_();_nop_();_nop_();_nop_();_nop_()/***************************************************************************/
sbit	SCL=P1^6;
sbit	SDA=P1^7;
/***************************************************************************/
void delay_ms(unsigned char number);	
/***************************************************************************/
void Start() 
{
	SDA=1;
	NOP();	
        SCL=1;
	NOP();
	SDA=0;
	NOP();
	SCL=0;
	NOP();
}
/***************************************************************************/
void Stop() 
{
	SDA=0;
	NOP();
	SCL=1;
	NOP();
	SDA=1;
	NOP();
	SCL=0;
	NOP();
}
/***************************************************************************/
void Ack() 
{
	SDA=0;
	NOP();
	SCL=1;
	NOP();
	SCL=0;
	NOP();
	SDA=1;
}
/***************************************************************************/
void NoAck()
{
	SDA=1;
	NOP();
	SCL=1;
	NOP();
	SCL=0;
	NOP();
}
/***************************************************************************/
bit TestAck(void) 
{
	bit ErrorBit;
	SDA=1;
	NOP();
	SCL=1;
	NOP();
	ErrorBit=SDA;
	NOP();
	SCL=0;
	return(ErrorBit);
}
/***************************************************************************/
void Write8Bit(unsigned char input) 
{
	unsigned char temp;
	for(temp=8;temp!=0;temp--) 
        {
	    SDA=(bit)(input&0x80);
	    NOP();
	    SCL=1;
	    NOP();
	    SCL=0;
	    NOP();
	    input=input<<1;
	}
}
/***************************************************************************/
void write24c02(unsigned char *Wdata,unsigned char RomAddress,unsigned char number) 
{
	Start();
	Write8Bit(WriteDeviceAddress);
	TestAck();
	Write8Bit(RomAddress);
	TestAck();
	for(;number!=0;number--) 
        {
		Write8Bit(*Wdata);
		TestAck();
		Wdata++;
	}
	Stop();
	delay_ms(10);
}
/***************************************************************************/
unsigned char Read8Bit() 
{
	unsigned char temp,rbyte=0;
	for(temp=8;temp!=0;temp--) 
        {
		SCL=1;
		rbyte=rbyte<<1;
		rbyte=rbyte|((unsigned char)(SDA));
		SCL=0;
	}
	return(rbyte);
}
/***************************************************************************/
void read24c02(unsigned char *RamAddress,unsigned char RomAddress,unsigned char bytes) 
{
	Start();
	Write8Bit(WriteDeviceAddress);
	TestAck();
	Write8Bit(RomAddress);
	TestAck();
	Start();
	Write8Bit(ReadDviceAddress);
	TestAck();
	while(bytes!=1) 
        {
	    *RamAddress=Read8Bit();
	    Ack();
	    RamAddress++;
	    bytes--;
	}
	*RamAddress=Read8Bit();
	NoAck();
	Stop();
}