Heart Beat Monitor with microcontroller 8051 include keil(c and hex) and Proteus

Design circuit diagram in Proteus as bellow :-

put all component as shown in figure.

program

#include<at89x52.h>          //reg51.h 
sbit lcd_d7 = P2^3;              //LCD interface in 4 bit mode



sbit lcd_d6 = P2^2;
sbit lcd_d5 = P2^1;
sbit lcd_d4 = P2^0;
sbit lcd_en = P2^4;
sbit lcd_rs = P2^5;
unsigned char bt,sec,sec100,min,r,t1,t2;
void initializelcd();
void delay(n);
void lcd_send_byte(unsigned char godata,bit w);
void gotoxy(unsigned char x, unsigned char y);
void printlcd(unsigned char *ch);
void send(void);
void extrint (void) interrupt 0
{
bt++;

}
void timer0 (void) interrupt 1 using 1
{
TH0 = 0xdc;
sec100++;
if(sec100>=10)
{
sec++;
sec100=0;
if(sec>=6)
{
min++;
sec=0;
}
}
}

main()
{ EA = 1;
TMOD = 0x21;
IT0 = 1;
EX0 = 1;
ET0 = 1;
TR0 = 1;

delay(1000);
initializelcd();
delay(1000);
gotoxy(0,0);
delay(1500);
printlcd("Welcome to H.R.M. ");
delay(500);
t1=0;t2=0;
                                              //delay(15000);

while(1)
{

if(min>=1)
{
gotoxy(0,1);
delay(500);
bt=t1;
lcd_send_byte((bt/100)+48,1);
r=bt%100;
lcd_send_byte((r/10)+48,1);
lcd_send_byte((r%10)+48,1);
delay(500);
min=0;
}
}
}
void initializelcd(void)
{
delay(16000);
lcd_en = 1;
lcd_send_byte(0x30,0);
delay(1000);
lcd_en = 0;
delay(1000);
lcd_en = 1;
lcd_send_byte(0x30,0);
delay(1000);
lcd_en = 0;
delay(1000);
lcd_en = 1;
lcd_send_byte(0x30,0);
delay(1000);
lcd_en = 0;
delay(1000);
lcd_en = 1;
lcd_send_byte(0x20,0);
delay(1000);
lcd_en = 0;
delay(1000);
lcd_en = 1;
lcd_send_byte(0x28,0);
delay(500);
lcd_send_byte(0x10,0);
delay(500);
lcd_send_byte(0x01,0);
delay(500);
lcd_send_byte(0x06,0);
delay(500);
lcd_send_byte(0x0c,0);
delay(500);
lcd_send_byte(0x1c,0);
delay(500);
lcd_send_byte(0x01,0);
delay(500);
}

void delay(ndelay)
int ndelay;
{
int idelay;

for (idelay=0;idelay <=ndelay;idelay++){;}
}