How to create tasks on FreeRTOS

Image from the FreeRTOS website

FreeRTOS is a great tool for those of you who want to get the most out of their microcontrollers and do something more than blink a LED. It enables you to run several tasks concurrently (i.e. simultaneously, but no in parallel) and do things like, while one process is waiting for your I²C interface to finish (the task is blocked) let different process take advantage of the waiting time to do work.

In this post we will take a look at how to create two simple FreeRTOS tasks that run concurrently on Arduino, although this is perfectly applicable to any other microcontroller you have lying around.

Run FreeRTOS on Arduino UNO (ATMega328P)

On one hand we have FreeRTOS, an awesome tiny operating system you can run on almost any microcontroller in order to run concurrent processes. It is also great to learn how more complex operating systems, say Linux, work under the hood. And on the other hand we have Arduino, a small, low-cost and user-friendly microcontroller development board.

So, why not combine both? Let's have a look at it.

How to program Arduino with Atmel Studio

Arduino is a fun entry point for those of you who want to program microcontrollers. It comes in two parts: the Arduino development board itself, and the Arduino IDE, a very easy to use notepad-like environment where you can write your code.The Arduino board itself is nothing more than a development board for an ATmega328P microcontroller with some nice extras, while the Arduino IDE takes care of making programming a microcontroller a kid's game.

However, the IDE can sometimes get in the way of a more advanced programmer, as it ads a lot of extra code we sometimes do not want (o prefer to do our self). The remedy is to program the ATmega328P with Ateml Studio 7, just as if it were a regular microcontroller. But for that, we first need to tell it how to "talk" to the Arduino to program it.