ATMega32 LCD and Keypad Interfacing Example

In previous example I showed a simple keypad programming example using C in Atmel Studio 7. It displays key value on a typical single seven segments display. We can add a character LCD as an output device.

In this programming example we use a 4x4 keypad matrix as a digital input, and a character LCD bases on HD44780 as an output device. A 20x4 character LCD is used to show information a key value.

Program starts up

Port C is 8-bit wide, connects to a 4x4 matrix keypad as shown in the picture above. Port D connects to a character LCD in 8-bit mode. Read/Write pin is ignored, and it's connects to ground as the LCD just accept the data/command from micro-controller.

Atmega32 operates at 16MHz supplies at +5V DC supply voltage.

C main program shows below. It requires LCD and Keypad driver files that I don't show them here.

/*

 * m32LcdKeyPad.c

 *

 * Created: 5/18/2021 10:15:15 PM

 * Author : aki-technical

 */ 

#include <avr/io.h>

#define F_CPU 16000000UL

#include <util/delay.h>

#include "keypad4x4.h"

#include "m32Lcd.h"

void writeTitle(void);

unsigned char getKey=0;

int main(void)

{

unsigned char pressCount=0,newLine=0,lineCount=1;

DDRD=0xFF;

PORTD=0x00;

keyInit();

lcdInit();

setXy(0,0);

writeString("Atmega32 LCD KeyPad");

setXy(0,1);

writeString("Interfacing Example");

setXy(0,2);

writeString("Programing in C ");

setXy(0,3);

writeString("in Atmel Studio 7");

_delay_ms(2500);

writeTitle();

while(1)

{

getKey=scan();

if (getKey!=0)

{

writeChararacter(getKey);

_delay_ms(250);

pressCount+=1;

getKey=0;

}

if (pressCount==20)

{

newLine=1;

lineCount++;

pressCount=0;

}

if (newLine)

{ 

newLine=0;

setXy(0,lineCount);

}

if (lineCount==4)

{

lineCount=1;

writeTitle();

}

}

}

void writeTitle(void){

/*Clear LCD*/

writeCommand(LCD_CLEAR);

setXy(0,0);

writeString("Enter Key Value: ");

writeCommand(CURSOR_ON);

setXy(0,1);

}

Click here to download this example in zip file. I additionally add its schematic diagram below.

Schematic

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See Also,

• PIC16F887 KeyPad and Character LCD Example using XC8
• ATMega32 interfaces to keypad and display