//#include <reg51.h>

#define uint unsigned int
#define uchar unsigned char
sbit scl=P0^4;  //24c02 SCL
sbit sda=P3^7;  //24c02 SDA
void delay1(uchar x)
{  
	uint i;
	for(i=0;i<x;i++);
}
void flash()
{  ;  ; }
void x24c02_init()  //24c02初始化子程序
{
	scl=1; 
	flash(); 
	sda=1; 
	flash();
}
void start()        //啟動I2C總線
{
	sda=1; 
	flash(); 
	scl=1; 
	flash(); 
	sda=0; 
	flash(); 
	scl=0; 
	flash();
}
void stop()         //停止I2C總線
{
	sda=0; 
	flash(); 
	scl=1; 
	flash(); 
	sda=1; 
	flash();
}
void writex(uchar j)  //寫一個字節
{  
	uchar i,temp;
    temp=j;
    for (i=0;i<8;i++)
		{
			temp=temp<<1; 
			scl=0; 
			flash(); 
			sda=CY; 
			flash(); 
			scl=1; 
			flash();
		}

	scl=0; 
	flash(); 
	sda=1; 
	flash();
}
uchar readx()   //讀一個字節
{
	uchar i,j,k=0;
	scl=0; 
	flash(); 
	sda=1;
    for (i=0;i<8;i++)
		{  
			flash(); 
			scl=1; 
			flash();
			if (sda==1) j=1;
			else j=0;
			k=(k<<1)|j;
			scl=0;
		}
	flash(); 
	return(k);
}
void clock()         //I2C總線時鐘
{
	uchar i=0;
	scl=1; 
	flash();
	while ((sda==1)&&(i<255))i++;
	scl=0; 
	flash();
}

////////從24c02的地址address中讀取一個字節數據/////

uchar x24c02_read(uchar address)
{
	uchar i;
	start(); 
	writex(0xa0);
	clock(); 
	writex(address);
	clock(); 
	start();
	writex(0xa1); 
	clock();
	i=readx(); 
	stop();
	delay1(10);
	return(i);
}

//////向24c02的address地址中寫入一字節數據info/////

void x24c02_write(uchar address,uchar info)
{
	EA=0;
	start(); 
	writex(0xa0);
	clock(); 
	writex(address);
	clock(); 
	writex(info);
	clock(); 
	stop(); 
	EA=1;
	delay1(50);
}