//program to set,read time and send it serially
#include<reg51.h>
#include<absacc.h>//to use XBYTE

unsigned char hr,min,sec,UIP;

void bcdconvert(unsigned char);
void serialsend(unsigned char);
void Delay(unsigned char);

void main(void){
	Delay(200);

	//55SEC 48 MIN 3 HR 15-02-08

	XBYTE[10]=0X20;//TURN ON OSC

	XBYTE[11]=0X83;//TURN OFF TIME UPDATE

	XBYTE[0]=0X55;
	XBYTE[2]=0X48;	
	XBYTE[4]=0X15;	
	XBYTE[7]=0X15;
	XBYTE[8]=0X02;
	XBYTE[9]=0X08;

	XBYTE[11]=0X03;//start updating time
	
	TMOD=0x20;
	TH1=0xfd;
	SCON=0x50;
	TR1=1;
	
	
	while(1){
	UIP=XBYTE[10];// update in progress, UIP IS A VARIABLE DECLARED AS CHAR
	UIP=UIP&0X80; // TO GET UIP BIT
	while(UIP);	  // AS LONG AS UIP IS HIGH THERE IS NO READING OF TIME
   //WHEN UIP IS LOW USER HAS 244uSEC....BEFORE THE NEXT UPDATE
	hr=XBYTE[4];
	min=XBYTE[2];
	sec=XBYTE[0];

	bcdconvert(hr);
	serialsend(':');
	
	bcdconvert(min);
	serialsend(':');
	
	bcdconvert(sec);

	serialsend(0x0d); //CARRIAGE RETURN
	serialsend(0x0a); //NEWLINE
	}
}
//To covert bcd to hex code	
void bcdconvert(unsigned char mybyte){
	unsigned  char x,y;
	x=mybyte&0x0f;
	x=x|0x30;
	y=mybyte&0xf0;
	y=y>>4;
	y=y|0x30;
	serialsend(y);
	serialsend(x);
	}
//send serially to pc
void serialsend(unsigned char x){
	SBUF=x;	
	while(TI==0);
	TI=0;
	}
//osc takes 200ms to power on. 
void Delay(unsigned char x){
unsigned char i,j;
for(i=0;i<x;i++)
	for(j=0;j<1000;j++);
	}