#include<reg51.h>
#define display_port P2 
sbit output=P2^0; 
sbit rs=P3^2;
sbit rw=P3^3;
sbit e=P3^4;
sbit C4=P1^0;
sbit C3=P1^1;
sbit C2=P1^2;
sbit C1=P1^3;
sbit R4=P1^4;
sbit R3=P1^5;
sbit R2=P1^6;
sbit R1=P1^7;
void msdelay(unsigned int time) 
{
   unsigned i,j;
   for(i=0;i<time;i++)
   {
       for(j=0;j<1275;j++)
       {
       }
   }
}
void lcd_cmd(unsigned char command)
{
   display_port=command;
   rs=0;
   rw=0;
   e=1; 
   msdelay(1); 
   e=0;
}
void lcd_data(unsigned char disp_data)
{
   display_port=disp_data; 
   rs=1;
   rw=0;
   e=1; 
   msdelay(1); 
   e=0;
}
void lcd_init() //Function to prepare the LCD and get it ready 
{
   lcd_cmd(0x38); //for 2 lines and 5X7 matrix of LCD
   msdelay(10); 
   lcd_cmd(0x0F); //turn display ON, cursor blinking 
   msdelay(10); 
   lcd_cmd(0x01); //clear screen 
   msdelay(10); 
   lcd_cmd(0x81); //bring cursor to position 1 of line 1 
   msdelay(10); 
}
void row_finder1() //Function for finding the row for column 1
{
   R1=R2=R3=R4=1; 
   C1=C2=C3=C4=0;
   if(R1==0)
       lcd_data('1');
   if(R2==0)
       lcd_data('4');
   if(R3==0)
       lcd_data('7');
   if(R4==0)
       lcd_data('*');
}
void row_finder2() //Function for finding the row for column 2
{
   R1=R2=R3=R4=1; 
   C1=C2=C3=C4=0;
   if(R1==0)
       lcd_data('2');
   if(R2==0)
       lcd_data('5');
   if(R3==0)
       lcd_data('8');
   if(R4==0)
       lcd_data('0');
}
void row_finder3() //Function for finding the row for column 3
{
   R1=R2=R3=R4=1; 
   C1=C2=C3=C4=0;
   if(R1==0)
       lcd_data('3');
   if(R2==0)
       lcd_data('6');
   if(R3==0)
       lcd_data('9');
   if(R4==0)
       lcd_data('#');
}
void row_finder4() //Function for finding the row for column 4
{
   R1=R2=R3=R4=1; 
   C1=C2=C3=C4=0;
   if(R1==0)
       lcd_data('A');
   if(R2==0)
       lcd_data('B');
   if(R3==0)
       lcd_data('C');
   if(R4==0)
       lcd_data('D');
}
void main()
{
   lcd_init(); 
   while(1) 
   {
       msdelay(30);
       C1=C2=C3=C4=1;
       R1=R2=R3=R4=0; 
       if(C1==0)
           row_finder1();
       if(C2==0)
           row_finder2();
       if(C3==0)
           row_finder3();
       if(C4==0)
           row_finder4();
   }
}