#include <REGX51.H>
unsigned char code table[]={0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};
 bit d_05s=0;
unsigned char num=0;
unsigned char   sec=0,minuter=0,hour=0;
void delay(unsigned char);
display(unsigned char a,unsigned b,unsigned char shi,unsigned char ge);
void main()
{ 
  EA=1;
  ET1=1;
  TMOD=0x10;
  TH1=0x3C;
  TL1=0xAF;
  TR1=1;
  
 while(1)
  {	
    if(num<=10)
	  d_05s=0;
	  else
	   
	   	 d_05s=1;
		 
	   
				  
   	if(num==20)
	{
	  num=0;
	 
	   if(sec>=59)
	   {
	      sec=0;
		  minuter++;
	      if(minuter>=59)
	     {
	       minuter=0;
		   if(hour>=23) 
		   hour=0;
		   
		   else
		   hour++;
		   }
       } 
	           
        else
	     sec++;
     }
    display(hour/10,hour%10, minuter/10, minuter%10);
   }
 }

void delay(unsigned char x)
{
  unsigned char m,n;
  for(m=x;m>0;m--)
   for(n=500;n>0;n--);
}

 display(unsigned char a,unsigned b,unsigned char shi,unsigned char ge)
{
  P1=0xfb;
  P0=table[shi];
  delay(10);
  P1=0xf7;
  P0=table[ge];
  delay(10);
  P1=0xfe;
  P0=table[a];
  delay(10);
  P1=0xfd;
  P0=table[b];
  delay(10);
  
	   	if( d_05s==1)
		 {if(P1_2==0Xfd)
		   P0_7=0;
		   else
		   	 P0_7=1;	 
	    }
		 delay(10);
 }
 void  tim1(void) interrupt 3   
{
  TH1=0x3C;
  TL1=0xAF;
  num++;
}