#include <reg52.h>
#include<intrins.h>
#define uchar unsigned char
#define uint unsigned int
#define IIC_READ  0XA1   //定義讀指令
#define IIC_WRITE 0XA0   //定義寫指令
#define NOP _nop_(); _nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_()

//==============================

sbit 	SDA=P0^6;		
sbit 	SCL=P0^7;		

//===============================
//define a bit_operation byte to use in shift operation
//use this mode can achieve high operation speed 
uchar bdata bbyte;//定義位操作用數組，采用此方法可提高位操作速度
sbit a0=bbyte^0;
sbit a1=bbyte^1;
sbit a2=bbyte^2;
sbit a3=bbyte^3;
sbit a4=bbyte^4;
sbit a5=bbyte^5;
sbit a6=bbyte^6;
sbit a7=bbyte^7;
//========================================
bit IFACK;	//record the SDA state to confirn if ACK has happened 
bit NO_ACK;	//no ack flag
bit BUS_FAULT;	//bus fault flag
//========================================
//FUNCTION:ROUTES TO PROVIDE A START SIGNAL
void start(void)
{
	SCL=0;SDA=1; NOP;SCL=1;SDA=0;NOP;SCL=0;
}
//=======================================
//FUNCTION:ROUTES TO PROVIDE A STOP SIGNAL
void stop(void)
{
	SCL=0;SDA=0;NOP;SCL=1;SDA=1;NOP;SCL=0;
}
//=====================================
//FUNCTION:ROUTES TO PROVIDE ACK SINGAL
void ack(void)
{
	SCL=0;SDA=0;NOP;SCL=1;NOP;SCL=0;
}
//=====================================
//FUNCTION:ROUTES TO RELEASE THE SDA TO RECEIVE A ACK SIGNAL 
//	             OR TO PROVIDE A NO_ACK SIGNAL
//type=1等待應答信號
//type=0 產生無應答信號
void nack(uchar type)
{
	SCL=0;SDA=1;NOP;SCL=1;IFACK=SDA; NOP;SCL=0;
	if(type)
	{
		if(IFACK)//如果無應答信號，則置標志位NO_ACK,程序中止
		{	
			NO_ACK=1;//用戶可以加入自己的異常處理程序
			//while(1);
		}
		else NO_ACK=0;
	}
}
//=======================================================
//FUNCTION:THE IIC DEVICE SHIFT OUT A BYTE  TO THE MASTER
uchar  inbyte(void) 
{//從IIC器件中讀出數據
	SDA=1;
	SCL=1;a7=SDA;NOP;SCL=0;
	SCL=1;a6=SDA;NOP;SCL=0;
	SCL=1;a5=SDA;NOP;SCL=0;
	SCL=1;a4=SDA;NOP;SCL=0;
	SCL=1;a3=SDA;NOP;SCL=0;
	SCL=1;a2=SDA;NOP;SCL=0;
	SCL=1;a1=SDA;NOP;SCL=0;
	SCL=1;a0=SDA;NOP;SCL=0;
	return(bbyte);
}
//=======================================================
//FUNCTION:THE IIC DEVICE SHIFT IN A BYTE FROM THE MASTER 
void outbyte(uchar outdata)
 {//將數據寫放IIC器件
	bbyte=outdata;
	SDA=a7;SCL=1;NOP;SCL=0;
	SDA=a6;SCL=1;NOP;SCL=0;
	SDA=a5;SCL=1;NOP;SCL=0;
	SDA=a4;SCL=1;NOP;SCL=0;
	SDA=a3;SCL=1;NOP;SCL=0;
	SDA=a2;SCL=1;NOP;SCL=0;
	SDA=a1;SCL=1;NOP;SCL=0;
	SDA=a0;SCL=1;NOP;SCL=0;
}

/**********************寫函數****************************************
**   函數名稱:  寫數據 
**   入口參數：add為讀起始地址，ptr數據保存指針,writelen為寫出數據長度
********************************************************************/
void writebyteseq(unsigned char page_addr, unsigned char byte_address,uchar *ptr,uchar writelen)
{
	uchar temph;
	uchar i;
//	unsigned char x;
	  temph = (page_addr<<1);                         
       
	start(); 		
	outbyte(IIC_WRITE);		
	nack(1);		
	outbyte(temph);
	nack(1);
	outbyte(byte_address);
	nack(1);
	for(i=0;i<writelen;i++)
	{
		outbyte(*(ptr+i));
		nack(1);
	}
	stop();	
}
/**********************讀函數***************************************
**   函數名稱:  連續讀數據 
**   入口參數：add為讀起始地址，ptr數據保存指針,readlen為讀出數據長度
********************************************************************/
void readbyteseq(unsigned char page_addr, unsigned char byte_address,uchar *ptr,uchar readlen)
{

	uchar temph;
	uchar i;
    temph = (page_addr<<1);                          // 2 address bytes.    
	start();
	outbyte(IIC_WRITE);
	nack(1);
	outbyte(temph);
	nack(1);
	outbyte(byte_address);
	nack(1);
	start();
	outbyte(IIC_READ);
	nack(1);
	for(i=0;i<readlen-1;i++)
	{
		*(ptr+i)=inbyte();
		ack();		
	}
	*(ptr+readlen-1)=inbyte();
	nack(0);
	stop();
}