4x3 matrix keypad interfacing with micrcontroller and Mikro C

In this tutorial I am show you how to interface keypad with PIC16F877A microcontroller. In this project I am use 4x3 matrix keypad and LM16x2 Lcd display. 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

4x3 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

Pin Diagram

pin configuration of 4x3 matrix keypad

Circuit diagram of keypad circuit

circuit schematic

Mikro C Code:

	unsigned short kp; // kp short variable
	// keypad module connections
	char keypadPort at PORTD;
	// End keypad module connections

	// Lcd module connections
	sbit LCD_RS at RB0_bit;
	sbit LCD_EN at RB1_bit;
	sbit LCD_D4 at RB2_bit;
	sbit LCD_D5 at RB3_bit;
	sbit LCD_D6 at RB4_bit;
	sbit LCD_D7 at RB5_bit;

	sbit LCD_RS_Direction at TRISB0_bit;
	sbit LCD_EN_Direction at TRISB1_bit;
	sbit LCD_D4_Direction at TRISB2_bit;
	sbit LCD_D5_Direction at TRISB3_bit;
	sbit LCD_D6_Direction at TRISB4_bit;
	sbit LCD_D7_Direction at TRISB5_bit;
	// End Lcd module connections
	void main() {
	Lcd_Init(); // initialize Lcd module
	Keypad_Init(); // initilize keypad module
	Lcd_Cmd(_LCD_CLEAR); // Lcd clear
	Lcd_Out(1,3,"DEVELOPED BY");
	Lcd_Out(2,1,"MINA TECHNOLOGY");
	delay_ms(2000);
	Lcd_Cmd(_LCD_CLEAR);
	while(1){
	kp = 0 ; // Reset the key code variable
	// wait for key to be pressed and relised
	do
	kp = Keypad_Key_Click(); // Store key code in kp varible
	while(!kp);
	switch(kp){
	case 1 : kp = 49 ; break ; // 1
	case 2 : kp = 50 ; break ; // 2
	case 3 : kp = 51 ; break ; // 3
	case 5 : kp = 52 ; break ; // 4
	case 6 : kp = 53 ; break ; // 5
	case 7 : kp = 54 ; break ; // 6
	case 9 : kp = 55 ; break ; // 7
	case 10 : kp = 56 ; break ; // 8
	case 11 : kp = 57 ; break ; // 9
	case 13 : kp = 42 ; break ; // *
	case 14 : kp = 48 ; break ; // 0
	case 15 : Lcd_Cmd(_LCD_CLEAR) ; break ; // Clear Lcd display
	}
	Lcd_Chr_Cp(kp);
	}

	}