4x4 Keypad Interfacing Using AT89V51 Microcontroller

 In this Tutorial we Interface 4x4 keypad using AT89V51 Microcontroller and display the result on LCD screen.

Connections:

Program: 

#include<reg51.h>

#include<lcd2.h>

sbit LED1 = P1^0;

sbit LED2 = P1^1;

sbit LED3 = P1^2;

sbit LED4 = P1^3;

sbit r1 = P3^0;

sbit r2 = P3^1;

sbit r3 = P3^2;

sbit r4 = P3^3;

sbit c1 = P3^4;

sbit c2 = P3^5;

sbit c3 = P3^6;

sbit c4 = P3^7;

void main ()

{

while (1)

{

lcd_init();

r2=r3=r4=1;

c1=c2=c3=c4=1;

r1=0;

if(c1==0)

{

lcd_cmd(0x01);

display("Hello");

delay(1);

}

if(c2==0)

{

lcd_cmd(0x01);

display("Hi");

delay(1);

}

r1=r3=r4=1;

c1=c2=c3=c4=1;

r2=0;

if(c1==0)

{

lcd_cmd(0x01);

display("Yes");

}

if(c2==0)

{

LED2 = 1;

}

r1=r2=r4=1;

c1=c2=c3=c4=1;

r3=0;

if(c1==0)

{

lcd_cmd(0x01);

display("No");

}

if(c2==0)

{

LED3 = 1;

}

r1=r2=r3=1;

c1=c2=c3=c4=1;

r4=0;

if(c1==0)

{

//LED4 = 0;

//while(c2==0);

lcd_cmd(0x01);

display("No");

}

if(c2==0)

{

LED4 = 1;

}

}

}

Output: