#include <reg51.h>  
#include <absacc.h>
void bcdconv(unsigned x);
void serial(unsigned x);
void main(void)
  {
	unsigned char hr,min,sec; 
	TMOD=0x20;
	TH1=0xFD;    		
	SCON=0x50;
	TR1=1;
	while(1)				
		{
		serial('2'); 	
		serial('0'); 	
  		yr=XBYTE[9];  	
   		bcdconv(yr); 	
		serial(':'); 	
		month=XBYTE[8];	
   		bcdconv(month);	
		serial(':'); 	
		day=XBYTE[7]; 	
   		bcdconv(sec);	
   		serial(0x0D);	
   		serial(0x0A);	
   		}
  }
  void bcdconv(unsigned mybyte)    
  {
   	unsigned char x,y,z;
   	x=mybyte&0x0F;
   	x=x|0x30;
   	y=mybyte&0xF0;
   	y=y>>4;
   	y=y|0x30;
   	serial(y);
   	serial (x);
  }
  void serial(unsigned x)
  {
   	SBUF=x;
   	while(TI==0);
   	TI=0;
  }