[SOLVED] 4x3 matrix key pad interfacing with 8051

[johnpaularul]

This is john..
Hi guys... Here I tried 4x3 matrix key pad interfacing with 8051 and its working... I have used port 3 and connected row 0, 1, 2, 3 in P3.4, P3.5, P3.6, P3.7 and column 0, 1, 2 in P3.2, P3.1, P3.0 respectively.

#include <REGX51.H>
sfr keypad = 0xB0; //port 3
sfr lcd_output = 0x90; //port 1
sbit RS = 0xA0; //port 2.0
sbit RW = 0xA1; //port 2.1
sbit EN = 0xA2; //port 2.2

void delay(unsigned int value){
unsigned int i, j;
for(i=0;i<=value;i++){
for(j=0;j<=1000;j++){
}
}
}

void lcd_cmd(unsigned char value){
lcd_output = value;
RS = 0;
RW = 0;
EN = 1;
delay(1);
EN = 0;
return;
}

void lcd_data(unsigned char value){
static int a =1;
a++;
if(a==17){
a=1;
lcd_cmd(0x01);
}
lcd_output = value;
RS = 1;
RW = 0;
EN = 1;
delay(1);
EN = 0;
return;
}

void lcd_init(){
lcd_cmd(0x38);
lcd_cmd(0x0C);
lcd_cmd(0x80);
}

void main(){
unsigned char arr[4][3] = {'1','2','3',
'4','5','6',
'7','8','9',
'*','0','#'};
unsigned int row, col;
lcd_init();
while(1){
keypad=0xF0;
while(keypad != 0xF0); //check for key not pressed
while(keypad==0xF0); //check for key pressed
if(keypad==0xE0){ //check for row 0
row = 0;
keypad=0xFF;
keypad=0xEF;
if(keypad==0xEB)
col = 0;
if(keypad==0xED)
col = 1;
if(keypad==0xEE)
col = 2;
lcd_data(arr[row][col]);
}
else if(keypad==0xD0){ //check for row 1
row = 1;
keypad=0xFF;
keypad=0xDF;
if(keypad==0xDB)
col = 0;
if(keypad==0xDD)
col = 1;
if(keypad==0xDE)
col = 2;
lcd_data(arr[row][col]);
}
else if(keypad==0xB0){ //check for row 2
row = 2;
keypad=0xFF;
keypad=0xBF;
if(keypad==0xBB)
col = 0;
if(keypad==0xBD)
col = 1;
if(keypad==0xBE)
col = 2;
lcd_data(arr[row][col]);
}
else if(keypad==0x70){ //check for row 3
row = 3;
keypad=0xFF;
keypad=0x7F;
if(keypad==0x7B)
col = 0;
if(keypad==0x7D)
col = 1;
if(keypad==0x7E)
col = 2;
lcd_data(arr[row][col]);
}
}
}