EXTERNALINTERRUPT(PIC16F877A)-programming

PROGRAM

#include<pic.h>

#include<htc.h>

#define RS RC0

#define RW RC1

#define EN RC2

#define D0 RD0

#define D1 RD1

#define D2 RD2

#define D3 RD3

#define D4 RD4

#define D5 RD5

#define D6 RD6

#define D7 RD7 

#define _XTAL_FREQ 4000000

__CONFIG(WDTDIS & XT & UNPROTECT);

#include"lcd.h"

char a[10];

int count=0,i;

void interrupt isr()

{

if(INTF==1)

{

count++;

i=count;

a[1]=i%10+0x30;

i=i/10;

a[2]=i%10+0x30;

if(count<10)

{

Lcd8_Clear();

Lcd8_Set_Cursor(1,0);

Lcd8_Write_Char(a[1]);

}

if(count>9)

{

Lcd8_Clear();

Lcd8_Set_Cursor(1,0);

Lcd8_Write_Char(a[2]);

Lcd8_Set_Cursor(1,1);

Lcd8_Write_Char(a[1]);

}

INTF=0;

}

}

void main()

{

TXSTA=0X24;

RCSTA=0X90;

SPBRG=0X19;

TRISC=0x80;

TRISD=0x00;

TRISB=0x01;

TXIF=0;

RCIF=0;

GIE=1;

PEIE=1;

RCIE=1;

INTE=1;

INTEDG=1;

INTF=0;

Lcd8_Init();

Lcd8_Clear();

Lcd8_Set_Cursor(1,0);

Lcd8_Write_String("interrupt");

while(1);

}