/*-----------------------------------------*/
//File:  	AT24C2.H
//Data:  	2008.6.9//3:06 PM
//Amend:	08-8-1 19:31
//Version: 	Ver0.2
//Thanks:  	Web
//Code:  	I love C51~



/*-----------------------------------------*/
#ifndef __AT24C02_H__
#define __AT24C02_H__



/*-----------------------------------------*/
#define unchar unsigned char 
#define unint  unsigned int
#define unlong unsigned long



/*-----------------------------------------*/
#define WriteDeviceAddress 0xa0 //寫
#define ReadDeviceAddress  0xa1 //讀
sbit SCL = P2^0;				//串行接口定義
sbit SDA = P2^1;



/*-----------------------------------------*/
//函數聲明
void delay1ms(void);				 //延時1ms 	
void Start(void);                    //開始總線
void Stop(void);                     //結束總線
void NoAck(void);                    //發送ACk0
bit TestAck(void);                   //測試ACk
void Write8Bit(unchar input);        //寫入8個Bit 到24C02
void Write24C02(unchar ch,unchar address);//寫入一個字到24C02中的指定地址中
unchar Read8Bit(void);               //從24C02中讀出8個Bit
unchar Read24C02(unchar address);    //從24C02指定地址位置中讀出1個字節



/*-----------------------------------------*/
//延時1000us
void delay1ms(void)
{
   	unsigned char i,j,k;
  	for(i=5;i>0;i--)
  	for(j=28;j>0;j--)
  	for(k=2;k>0;k--);
}



/*-----------------------------------------*/
//開始總線
void Start(void)
{
	SDA=1;
	SCL=1;
	SDA=0;
	SCL=0;
}



/*-----------------------------------------*/
//結束總線
void Stop(void)
{
	SCL=0;
	SDA=0;
	SCL=1;
	SDA=1;
}



/*-----------------------------------------*/
//發送ACk0
void NoAck(void)
{
	SDA=1;
	SCL=1;
	SCL=0;
}



/*-----------------------------------------*/
//測試ACk
bit TestAck(void)
{
	bit ErrorBit;
	SDA=1;
	SCL=1;
	ErrorBit=SDA;
	SCL=0;
	return (ErrorBit);
}



/*-----------------------------------------*/
//寫入8個Bit 到24C02
void Write8Bit(unchar input)
{
	unchar temp;
	for(temp=8;temp!=0;temp--)
	{
		SDA=(bit)(input&0x80);
		SCL=1;
		SCL=0;
		input<<=1;
	}
}



/*-----------------------------------------*/
//寫入一個字到24C02中的指定地址中
void Write24C02(unchar ch,unchar address)
{
	Start();
	Write8Bit(WriteDeviceAddress);
	TestAck();
	Write8Bit(address);
	TestAck();
	Write8Bit(ch);
	TestAck();
	Stop();
	delay1ms();		//延遲時間1ms!!!
}



/*-----------------------------------------*/
//從24C02中讀出8個Bit
unchar Read8Bit(void)
{
	unchar temp,rbyte=0;
	for(temp=8;temp!=0;temp--)
	{
		SCL=1;
		rbyte<<=1;
		rbyte|=((unchar)(SDA));
		SCL=0;
	}
	return (rbyte);
}



/*-----------------------------------------*/
//從24C02指定地址位置中讀出1個字節
unchar Read24C02(unchar address)
{
	unchar ch;
	Start();
	Write8Bit(WriteDeviceAddress);
	TestAck();
	Write8Bit(address);
	TestAck();
	Start();
	Write8Bit(ReadDeviceAddress);
	TestAck();
	ch=Read8Bit();
	NoAck();
	Stop();
	return (ch);
}



/*-----------------------------------------*/
/*
//應用舉例
void main(void)
{
	unsigned char i;
	for(i=0;i<256;i++)
	{
	   Write24C02(i,i);
	   P1=Read24C02(i);
	   delayms(1000);
	}
	while(1);
}
*/


/*-----------------------------------------*/
#endif