Interfacing Switches with ATmega2560 Development Board

Introduction

This guide will demonstrate how to interface switches with the ATmega2560 development board. The board has six built-in switches connected to pins on ports "D" and "E" of the ATmega2560 microcontroller. By following the steps outlined in this guide, you will be able to read the state of the switches and incorporate them into your projects.

Problem Statement

The goal is to read the state of the switches connected to pins on ports "D" and "E" of the ATmega2560 and perform actions based on their states. This will allow you to take user input from the switches and utilize it in your embedded systems projects.

Requirements

To successfully complete this project, you will need the following components:

1. ATmega2560 development board.

2. Micro USB cable

3. Push button switches  (built-in)

Working

• Six switches are connected to the development board as follows:

• When you press, the logic “LOW” appears on the respective pin; otherwise, the PIN will be “HIGH”. 

• 8 LED are connected to development board as follows:

• When the push button "S1" is pressed, the corresponding LED on port "C" is turned on.

Circuit Connections

Code

1. Open VS Code and paste the code into the file named switch_led.c

2. To compile and convert the source code into hex, run the following command in your terminal- 

avr-gcc -Wall -g -Os -mmcu=atmega2560 -o switch_led.hex switch_led.c

You can download the code from here.

#ifndef F_CPU

#define F_CPU 16000000UL // set the CPU clock

#endif

#include <avr/io.h>

#include <util/delay.h>

int main(void)

{

    DDRC = DDRC | (1 << 0); // Makes PORTC0 as Output

    DDRE = DDRE & (~1 << 4); // Makes of PORTE4 as Input

    while (1) // infinite loop

    {

        if (bit_is_clear(PINE, 4))

        {

            PORTC = PORTC & (~1 << 0); // HIGH ON PORTC.0

        }

        else if (bit_is_set(PINE, 4))

        {

            PORTC = PORTC | (1 << 0); // LOW ON PORTC.0

        }

    }

}

3. Now open AVRDUDES and from the Programmer (-c) dropdown select Any usbasp clone with the correct VID/PID

4. In the Flash section, click on three dots and navigate to the desired hex file, and select it. Finally, click on Program to burn the hex file in the microcontroller

Output

Upon successful upload and execution of the code, pressing each switch on the development board will turn on the corresponding LED, and releasing the switch will turn off the LED. You can verify this by observing the LEDs connected to the switches on the circuit.

Conclusion

Interfacing switches with the ATmega2560 development board allows you to control LEDs based on switch inputs. By following the steps outlined in this guide and using the provided code, you should be able to successfully interface switches with the ATmega2560 board and control LEDs accordingly. Feel free to modify the code and circuit to suit your specific requirements and explore further possibilities with switch and LED interfacing.