Program to interface external interrupt to switches [Embedded systems Lab]

/*Program to interface external interrupt to switches// 

/*programed by hiq test equipment***/

#include<reg51.h> //include at89c51 microcontoller header file

//#define led P0 //connect lower nibble of p0 to leds

sbit rs  = P1^0;

sbit en  = P1^1;

sbit db7 = P1^5;

sbit db6 = P1^4;

sbit db5 = P1^3;

sbit db4 = P1^2;

void init_lcd(void);

void cmd_lcd(unsigned char);

void write_lcd(unsigned char);

void display_lcd(unsigned char *);

void delay_ms(unsigned int);

sbit sw1=P3^7;

sbit sw2=P3^6;

sbit sw3=P3^5;

sbit sw4=P3^4;

sbit led1=P0^0;

sbit led2=P0^1;

sbit led3=P0^2;

sbit led4=P0^3;

fun0();

fun1();

fun2();

fun3();

fun4();

//sbit led1=P0^0;

//sbit led2=P0^1;

void delay_ms(unsigned int);

void external_intruppet0(void) interrupt 0;

int flag=0;

void main(void)

{

init_lcd();

delay_ms(500);

init_lcd();

init_lcd();

display_lcd("hi");

delay_ms(1000);

cmd_lcd(0x01);

IE=0x81; 

IT0=1;  

while(1) 

{  

                   

  if(flag==1)

{

flag=0;

init_lcd();

if(sw1==1&&sw2==1&&sw3==1&&sw4==1)

{

cmd_lcd(0x01);

fun0();

}

else if(sw1==0&&sw2==1&&sw3==1&&sw4==1)

{

fun1();

}

else if(sw1==1&&sw2==0&&sw3==1&&sw4==1)

{

    

  fun2();

 }  

   

   else if(sw1==1&&sw2==1&&sw3==0&&sw4==1)

   {

  fun3();

   cmd_lcd(0x01);

   display_lcd("HI to ALL");

   }

   else if(sw1==1&&sw2==1&&sw3==1&&sw4==0)

   {

   fun4();

  }

}

}

}

void init_lcd(void)

{

delay_ms(10);

cmd_lcd(0x28);

cmd_lcd(0x0c);

cmd_lcd(0x06);

cmd_lcd(0x01);

}

void cmd_lcd(unsigned char c)

{

unsigned char temp;

temp = c & 0xf0;

rs = 0;

en = 1;

db7 = temp & 0x80;

db6 = temp & 0x40;

db5 = temp & 0x20;

db4 = temp & 0x10;

en = 0;

temp = ( c & 0x0f ) << 4;

rs = 0;

en = 1;

db7 = temp & 0x80;

db6 = temp & 0x40;

db5 = temp & 0x20;

db4 = temp & 0x10;

en = 0;

delay_ms(2);

}

void write_lcd(unsigned char c)

{

unsigned char temp;

temp = c & 0xf0;

rs = 1;

en = 1;

db7 = temp & 0x80;

db6 = temp & 0x40;

db5 = temp & 0x20;

db4 = temp & 0x10;

en = 0;

temp = ( c & 0x0f ) << 4;

rs = 1;

en = 1;

db7 = temp & 0x80;

db6 = temp & 0x40;

db5 = temp & 0x20;

db4 = temp & 0x10;

en = 0;

delay_ms(2);

}

void display_lcd(unsigned char *s)

{

while(*s)

write_lcd(*s++);

}

void delay_ms(unsigned int i)

{

unsigned int j;

while(i-->0)

{

for(j=0;j<500;j++);

}

}

void external_interrupt0(void) interrupt 0 

{  

EX0=0;    

flag=1;   

 delay_ms(200);

EX0=1;    

}

  fun0()

 {

 //while((sw1==1)&&(sw2==1)&&(sw3==1)&&(sw4==1))

 {

 led1=1;

 led2=1;

 led3=1;

 led4=1;

 delay_ms(500);

 led1=0;

 led2=0;

 led3=0;

 led4=0;

 delay_ms(500);

 }

 }

 fun1()

 {

// while((sw1==1)&&(sw2==1)&&(sw3==1)&&(sw4==1))

 {

cmd_lcd(0x01); 

display_lcd("Good Morning");

 led1=0;

 led2=1;

 led3=1;

 led4=1;

 delay_ms(500);

 led1=0;

 led2=0;

 led3=0;

 led4=0;

 delay_ms(500);

 }

 }

 fun2()

  {

// while((sw1==1)&&(sw2==1)&&(sw3==1)&&(sw4==1))

  {

  cmd_lcd(0x01); 

  display_lcd("Hello Everybody");

   led1=1;

 led2=0;

 led3=1;

 led4=1;

 delay_ms(500);

 led1=0;

 led2=0;

 led3=0;

 led4=0;

 delay_ms(500);

 }

}

 fun3()

   {

  //while((sw1==1)&&(sw2==1)&&(sw3==1)&&(sw4==1))

  {

   cmd_lcd(0x01);

   display_lcd("HI to ALL");

   led1=1;

 led2=1;

 led3=0;

 led4=1;

 delay_ms(500);

 led1=0;

 led2=0;

 led3=0;

 led4=0;

 delay_ms(500);

  }

 }

 fun4()

  {

//while((sw1==1)&&(sw2==1)&&(sw3==1)&&(sw4==1))

  {

   cmd_lcd(0x01);

   display_lcd("HELLO to ALL");

   led1=1;

led2=1;

led3=1;

  led4=0;

  delay_ms(500);

  led1=0;

  led2=0;

  led3=0;

  led4=0;

  delay_ms(500);

  }

 } 

save it as LCD & INT.c