eeprom_2402.c

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#include <at89x52.h>
sbit  SCL=P2^6;
sbit  SDA=P2^7;
#define	WriteDeviceAddress 0xa0  //写驱动的硬件地址  引脚A0，A1，A2全接地
#define	ReadDviceAddress 0xa1	 //读驱动的硬件地址  引脚A0，A1，A2全接地

/*************************************************/
void Delay5ms(void)
{
register int i;
for(i=0;i<1000;i++);
    
}

/*******************起始信号***********************/
void Start(void) 
{
	SDA=1;
	SCL=1;
	SDA=0;
	SCL=0;
}
/********************停止信号*************************/
void Stop(void)
{
	SCL=0;
	SDA=0;
	SCL=1;
	SDA=1;
}
/*******************应答信号*************************/
void Ack(void) 
{
	SDA=0;
	SCL=1;
	SCL=0;
	SDA=1;
}

/******************无应答***************************/
void NoAck(void) 
{
	SDA=1;
	SCL=1;
	SCL=0;
}

/***************测试应答信号***********************/
bit TestAck(void) 
{
	bit ErrorBit;
	SDA=1;
	SCL=1;
	ErrorBit=SDA;
	SCL=0;
	return(ErrorBit);
}

/******************写8位数据**************************/
void Write8Bit(unsigned char input) 
{
	unsigned char temp;
	for(temp=8;temp!=0;temp--) 
	{
		SDA=(bit)(input&0x80);
		SCL=1;
		SCL=0;
		input=input<<1;
	}
}
 /**************////////****************************/
void Write24c04(unsigned char RomAddress,unsigned char *Wdata,unsigned char number) {
	Start();
	Write8Bit(WriteDeviceAddress);
	TestAck();
	Write8Bit(RomAddress);
	TestAck();
	for(;number!=0;number--) {
		Write8Bit(*Wdata);
		TestAck();
		Wdata++;
	}
	Stop();
	Delay5ms();
	Delay5ms();
}

/**********************读8位操作******************/
unsigned char Read8Bit(void) 
{
	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 Read24c04(unsigned char RomAddress,unsigned char *RamAddress,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();
}