rtc ds1307 with p89v51rd2

 #ifndef __vrtc_h__
#define __vrtc_h__
#include<reg51.h>
#include<Vdelay.h>

sbit sda=P1^0;
sbit scl=P1^1;	
 
void start_bit()
      {
    	sda=1;
 		scl=1;
		sda=0;
		scl=0;
  	  }
void stop_bit()
      {
    	scl=0;
		sda=0;
		scl=1;
		sda=1;
	  }

void write_mem(unsigned char m )
{
   	unsigned char i;
		unsigned char b;
		b=m;
		for(i=0;i<8;i++)
	  	  {	
        	b=(b & 0x80);
			if(b!=0)
			sda=1;
		  	else
			sda=0;
			b=m<<1;
			m=b;
			scl=1;
			scl=0;
		   }
			scl=1;
			scl=0;
	  }
unsigned char read_mem()
{
	unsigned char i,a1,b1=0;
	sda=1;
	for(i=0;i<8;i++)
	{
 		scl=0;
		delay();
		scl=1;
		delay();
		if(sda==1)
		  	b1=(b1 | 0x01);
		a1=b1;
		b1=b1<<1;
	}
	scl=1;
	scl=0;	   
//	val = a1;
	return a1;
}

unsigned char read_eprom(unsigned char addr)
{	
	 unsigned char a1=0xd0,a2=0xd1,dat;
     start_bit();
	 write_mem(a1);
	 write_mem(addr);
	 start_bit();
	 write_mem(a2);
	 dat = read_mem();
	 stop_bit();
     delay1();
	 return dat;
}				  
	  
 void write_eprom(unsigned char addr,unsigned char b)
 {
 	unsigned char ad=0xd0;
 	start_bit();
 	write_mem(ad);
 	write_mem(addr);
 	write_mem(b);
	 stop_bit();
	 delay1();
 }
 	 
#endif

#ifndef __Vdelay_H__
#define __Vdelay_H__



 
void delay_ms(int a)
{
	int i;
	while(a)
		for(i = 0;i < 36;i++)//25micro * 40 = 1 ms,but due to overhead of for loop,we use 36
		{
			TMOD = 0x02;//timer 0,mode 2
			TH0 = -23;//for getting 25 micro seconds
			TR0 = 1;
			TF0 = 0;
			while(!TF0);
			TR0 = 0;
			TF0 = 0;
		}
}



void delay1()
	  {	
		int x=900;
		while(x--);
	  }
void delay()
      {	int x=40;
		while(x--);
	  }
 

#endif

//#include<reg51.h>
#include<vrtc.h>  

void main()			  
 {	
  // 	int j;
	unsigned char i;
    P0 = 0;
	P1 = 0;	
//	dat = 0x1e;
	for(i = 0;i < 10;i++) 	
		write_eprom(i,i+10);
	P0 = read_eprom(3);		
/*	{	
		
		for(j=0;j<20000;j++);
	}  */
	while(1);			
 }