1/*-----------------------------------------------
  ???ƣ?IICЭ?? PCF8591ADDAת??
  ??˾???Ϻ???????ӿƼ????޹?˾
  ??д??ʦ??
  ???ڣ?2009.5
  ?޸ģ???
  ???ݣ??˳???ͨ??IICЭ???DAADоƬ????????ȡ??λ???ĵ?ѹ???????ģ????????LED???Ƚ???ָʾ
------------------------------------------------*/
 #include<reg52.h>    //????ͷ?ļ???һ?????????Ҫ?Ķ???ͷ?ļ????????⹦?ܼĴ????Ķ???
 #include <intrins.h> //????NOP??ָ???_nop_();

 #define AddWr 0x90   //д???ݵ?ַ 
 #define AddRd 0x91   //?????ݵ?ַ

 
 sbit Sda=P1^2;       //???????????Ӷ˿?
 sbit Scl=P1^1;

 bit ADFlag;          //????AD??????־λ
unsigned char code Datatab[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f};//7??????????ܶ????
data unsigned char  Display[8];//??????ʱ??????????ֵ
/*------------------------------------------------
                    ??ʱ????
------------------------------------------------*/
 void mDelay(unsigned char j)
 {
  unsigned int i;
  for(;j>0;j--)
     {
	  for(i=0;i<125;i++)
	     {;}
	  }
  }
/*------------------------------------------------
                    ??ʼ????ʱ??1
------------------------------------------------*/
void Init_Timer1(void)
{
 TMOD |= 0x10;			     
 TH1=0xff;	              	/* Init value */
 TL1=0x00;
 //PT1=1;                   /* ???ȼ?    */
 EA=1;                      /* interupt enable */
 ET1=1;                     /* enable timer1 interrupt */
 TR1=1;  
}
/*------------------------------------------------
                    ????IIC????
------------------------------------------------*/
  void Start(void)
  {
   Sda=1;
   _nop_();
   Scl=1;
   _nop_();
   Sda=0;
   _nop_();
   Scl=0;
  }


/*------------------------------------------------
                    ֹͣIIC????
------------------------------------------------*/
  void Stop(void)
  {
   Sda=0;
   _nop_();
   Scl=1;
   _nop_();
   Sda=1;
   _nop_();
   Scl=0;
   }


/*------------------------------------------------
                   Ӧ??IIC????
------------------------------------------------*/
   void Ack(void)
   {
    Sda=0;
	_nop_();
	Scl=1;
	_nop_();
	Scl=0;
	_nop_();
	}


/*------------------------------------------------
                 ??Ӧ??IIC????
------------------------------------------------*/
	void NoAck(void)
	{
	 Sda=1;
	 _nop_();
	 Scl=1;
	 _nop_();
	 Scl=0;
	 _nop_();
	 }


/*------------------------------------------------
              ????һ???ֽ?
------------------------------------------------*/
	 void Send(unsigned char Data)
	 { 
	  unsigned char BitCounter=8;
	  unsigned char temp;

	  do
	    {
		 temp=Data;
		 Scl=0;
		 _nop_();
		 if((temp&0x80)==0x80)
		    Sda=1;
		 else
		    Sda=0;

			Scl=1;
			temp=Data<<1;
			Data=temp;
			BitCounter--;
		  }
	  while(BitCounter);
	      Scl=0;
	  }


/*------------------------------------------------
               ????һ???ֽڲ?????
------------------------------------------------*/
	  unsigned char Read(void)
	  {
	   unsigned char temp=0;
	   unsigned char temp1=0;
	   unsigned char BitCounter=8;

	   Sda=1;
	   do
	     {
		  Scl=0;
          _nop_();
		  Scl=1;
		  _nop_();
		  if(Sda)
		     temp=temp|0x01;
		  else
		     temp=temp&0xfe;

		  if(BitCounter-1)
		     {
			  temp1=temp<<1;
			  temp=temp1;
			  }
			  BitCounter--;
			 }
		while(BitCounter);
		return(temp);
	  }
 
/*------------------------------------------------
                    д??DA??ģת??ֵ
------------------------------------------------*/
	  void DAC(unsigned char Data)
	  {
		   Start();
		   Send(AddWr); //д??оƬ??ַ
		   Ack();
		   Send(0x40);  //д?????λ??ʹ??DAC???
		   Ack();
		   Send(Data);  //д????
		   Ack();
		   Stop();
		 
	   }

/*------------------------------------------------
                 ??ȡADģ??ת????ֵ???з???ֵ
------------------------------------------------*/
	  unsigned char ReadADC(unsigned char Chl)
	  {
       unsigned char Data;
		   Start();        //д??оƬ??ַ
		   Send(AddWr);
		   Ack();
 		   Send(0x40|Chl);//д??ѡ???ͨ??????????ֻ?õ??????룬??ֲ?????Ҫ????????
		                  //Chl??ֵ?ֱ?Ϊ0??1??2??3???ֱ????1-4ͨ??
		   Ack();
		   Start();
		   Send(AddRd);    //?????ַ
		   Ack();
		   Data=Read();    //??????
		   Scl=0;
		   NoAck();
		   Stop();
		   return Data;   //????ֵ
	  }

/*------------------------------------------------
                   ??????
------------------------------------------------*/
	void main()
	{
	 unsigned char num;                   //DA??ģ???????
    unsigned char ADtemp;                //?????м????
     Init_Timer1();

	 while(1)
	      { 
           DAC(num);       //DA???????????LEDģ???ѹ?&#20207;
		   num++;          //?ۼӣ???256???????Ϊ0??????ѭ??????ʾ??LED???????𽥱&#20207;
		   mDelay(20);     //??ʱ?????????????&#20207;
		   if(ADFlag)      //??ʱ?ɼ?????ģ????
           {
   		ADFlag=0;

   		ADtemp=ReadADC(0);
		Display[0]=Datatab[(ReadADC(0))/50]|0x80;//????0ͨ????ѹ??ʾ
  		Display[1]=Datatab[((ReadADC(0))%50)/10];
  	
        ADtemp=ReadADC(1);
		Display[2]=Datatab[((ReadADC(1))/50)]|0x80;//????1ͨ????ѹ??ʾ ??ͨ????ʱ???Σ?????????????
  		Display[3]=Datatab[((ReadADC(1))%50)/10];
  		
        ADtemp=ReadADC(2);
		Display[4]=Datatab[((ReadADC(2))/50)]|0x80;//????1ͨ????ѹ??ʾ ??ͨ????ʱ???Σ?????????????
  		Display[5]=Datatab[((ReadADC(2))%50)/10];
  		
        ADtemp=ReadADC(3);
		Display[6]=Datatab[((ReadADC(3))/50)]|0x80;//????1ͨ????ѹ??ʾ ??ͨ????ʱ???Σ?????????????
  		Display[7]=Datatab[((ReadADC(3))%50)/10];
  		

		   }
	   }
	}

/*------------------------------------------------
                   ??ʱ???жϳ???
------------------------------------------------*/
void Timer1_isr(void) interrupt 3 using 1//??ʱ??1ִ??????ܶ?̬ɨ??
{

 static unsigned int count,j;
 TH1=0xfb;		//???¸?ֵ
 TL1=0x00;
 j++;
 if(j==300) 
    {j=0;ADFlag=1;} //??ʱ??λAD??????־λ
	 
    P0=Display[count];//???ڶ?̬ɨ???????
    P2=count;
    count++;
   if(count==8)     //??ʾɨ??8???????
      count=0;

 
}