4x4 Keypad(calculator keypad) interfacing with microcontroller and Mikro C

In this tutorial I am show you how to interface keypad with PIC16F877A microcontroller. In this project I am use 4x4 matrix keypad. In this project I am use Mikro C Pro For Pic Compiler for source code editing. Mikro c provide a keypad library working with 4x4 matrix keypad. You can watch this video or read the written tutorial below.

MATRIX KEYPAD

Before I interface the keypad with PIC16F877A microcontroller , frist we need to understand how to working matrix keypad.
Keypad is set of button. It contain digits,symbols&alphabetical letters. It can be (4x4),(4x3) & (3x2). 4x3 it means 3 column and 4 row. Matrix keypads are commonly used in calculator , digital scale, security systems ,electronic device etc. Matrix keypad is array of push switch. Push button switch leg are connected to columns and rows. 4x4 matrix keypad contain (4*4)=16 push button switch. If we are use 3x4 matrix there are (3*4)=12 push button switch. 4x4 matrix keypad has (4+4)=8 pin connection and 3x4 matrix keypad (3+4)=7 pin connection.

4X4 MATRIX KEYPAD STRUCTURE

When press the any key than any column & row are connected each other at a time. Than current flowing column to row.

3x4 matrix keypad

CIRCUIT DIAGRAM OF KEYPAD INTERFACING

Keypad Library

The mikroC PRO for PIC provides a library for working with 4x4 keypad. The library routines can also be used with 4x1, 4x2, or 4x3 keypad. For connections explanation see schematic at the bottom of this page.