keypad interfacing with 8051

how interface keypad with 8051........?

---------- Post added at 12:59 ---------- Previous post was at 12:56 ----------

//P2=keypad connected
//P1=lcd connected
#include <REGX51.H>
#include"lcd.c"
sbit r1=P2^0;
sbit r2=P2^1;
sbit r3=P2^2;
sbit r4=P2^3;
sbit c1=P2^4;
sbit c2=P2^5;
sbit c3=P2^6;
sbit c4=P2^7;
sbit rs=P3^5;
sbit rw=P3^6;
sbit en=P3^7;
delay(unsigned int i)
{
while(i--);
}
lcd_cmd(unsigned char c)
{
P1=c;
rs=0;
rw=0;
en=1;
delay(150);
en=0;
}
lcd_data(unsigned char c)
{
P1=c;
rs=1;
rw=0;
en=1;
delay(150);
en=0;
}
lcd_init()
{
lcd_cmd(0x38);
lcd_cmd(0x0c);
lcd_cmd(0x01);
lcd_cmd(0x80);

}
void main()
{
lcd_init();
lcd_data('a');
while(1)
{

P2=0xf0; //column=1111 rows=0000
while(P2==0xf0);

P2=0xfe;//c=1111 r=1110
if(!r1)
{

if(!c1)
{
lcd_data('1');while(!c1);
}
if(!c2)
{
lcd_data('2');while(!c2);
}
if(!c3)
{
lcd_data('3');while(!c3);
}
if(!c4)
{
lcd_data('4');while(!c4);
}
}

P2=0xfd;//c=1111 r=1101
if(!r2)
{

if(!c1)
{
lcd_data('5');while(!c1);
}
if(!c2)
{
lcd_data('6');while(!c2);
}
if(!c3)
{
lcd_data('7');while(!c3);
}
if(!c4)
{
lcd_data('8');while(!c4);
}
}

P2=0xfb;//c=1111 r=1011
if(!r3)
{
if(!c1)
{
lcd_data('9');while(!c1);
}
if(!c2)
{
lcd_data('a');while(!c2);
}
if(!c3)
{
lcd_data('b');while(!c3);
}
if(!c4)
{
lcd_data('c');while(!c4);
}
}

P2=0xf7;//c=1111 r=0111
if(!r4)
{
if(!c1)
{
lcd_data('d');while(!c1);
}
if(!c2)
{
lcd_data('e');while(!c2);
}
if(!c3)
{
lcd_data('f');while(!c3);
}
if(!c4)
{
lcd_data('0');while(!c4);
}
}
}
}

What information you need exactly? I can see that, you just checked IO status to display a character on LCD. But you may see lot many characters on display for a single key press.