[51] 8051 based rtc circuit

#include<reg51.h>

sbit e1=P2^0;   //for display1
sbit e2=P2^1;   //for display2
sbit e3=P2^2;    //for display3
sbit e4=P2^3;   //for display4
                      // P3 is a data port.
void delay_ms(unsigned int ms_count);
void delay_us(unsigned int us_count);


void main()
	
{
P2=0x00;       //turning off all displays(common cathod)

 while(1)
 {
 
 P3=0x40;   
	e1=1; //enable display1
	 delay_ms(2);
e1=0;
	P3=0xf9;
	 e2=1;
	 delay_ms(2);
   e2=0;
	 
	P3=0x24;
	 e3=1;
	 delay_ms(2);
	 e3=0;

	P3=0x30;
	 e4=1;
	 delay_ms(2);
	 e4=0;
  }
  }


 void delay_ms(unsigned int ms_count)
 {
        while(ms_count!=0)
         {
            delay_us(112);   //delay_us is called to generate 1ms delay
             ms_count--;
            }
   }
 

  void delay_us(unsigned int us_count)
 {  
    while(us_count!=0)
      {
         us_count--;
       }												   
   }

[ATTACH=CONFIG]114651._xfImport[/ATTACH]#include<reg51.h>
unsigned char  DSPL_RAM[4]={1,2,3,4};//this is for rtc data like HH MM 
unsigned char code image[10]={0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};
void main()
{
	TMOD=0x01; //timer 0 in 16bit timer
	TH0=0xEF;//for 4ms so refresh rate 4x4=16ms==60Hz
	TL0=0xBA;
	ET0=1;//enable timer 0
	EA=1;//globle enable
	TR0=1;//timer run
	while(1)
	{
		//do your task for read rtc and update DSPL_RAM
	}
}
void ISR() interrupt 1
{
	static unsigned char i;//for digit counter
	TH0=0xEF; //reload timer for next segment
	TL0=0xBA;
	P2|=0x0F;//OFF ALL SEGMENT
	P0=image[DSPL_RAM[i]];
	P2&=~(1<<i); //ON CROSPOND SEMENT
	if(i++>=3)
		i=0;
}