megaAVR + Arduino + FreeRTOS + C++ = Teaching Real-Time Software Development

So this is the latest idea that I've gotten all obsessive-compulsive over: using Arduino, FreeRTOS, and C++ to teach real-time software design and embedded software development. I like the combination as a platform to teach both introductory students (using the Arduino Uno, SW and IDE), and to advanced students (using Arduino Mega or clone, FreeRTOS, C++, Eclipse, make, etc.). I really like the progression of starting out on the Uno with Arduino 1.0 and progressing to a multitasking RTOS, interrupt driven device drivers, etc. I like FreeRTOS because it's small, understandable, and it works. I like C++ because having spent many years in commercial product development (after having spent part of graduate school teaching real-time software design) I believe you need to climb as high on the abstraction ladder as you can to control costs, yet you need to see what's going on under the hood. The combination of Arduino and FreeRTOS hits a sweet spot of "just complex enough to be worth learning about".

So I started out doing exactly that: learning the AVR architecture on the Uno using Arduino 1.0, got FreeRTOS running on a Freetronics EtherMega (a Mega clone that incorporates the equivalent of an Ethernet Shield on the same board), wrote C++ OO wrappers around the FreeRTOS facilities (Task, MutexSemaphore, PeriodicTimer, etc.), wrote interrupt-driven device drivers in C++ (Serial, SPI), and a main program using a simple unit test framework that exercises all of it and demonstrates how it works. And there's plenty of room for student projects to write software for various applications, shields, hardware control, etc.

Recent blog articles I've written on this project:



Link to tarball can be found on project page:


For years I've futzed around with stuff like an Atmel AT91 evaluation board, a couple of BeagleBoards, etc. But even though I've spent years doing commercial development with Linux on ARM and PowerPC targets, I think when you throw in a memory management unit and the machinations that Linux goes through to be platform-independent, the result is too complicated for anything other than an advanced course. An RTOS like VxWorks, for which I've done a lot of commercial development, is too big, complex, and expensive, to use in anything except an advanced class. But once students got though Arduino, and then FreeRTOS, I think they could easily progress to VxWorks, and even to Linux, without much problems. The progression of Arduino and FreeRTOS would give them the confidence that they could figure out the more complex stuff.

I know this is my thing and I don't necessarily expect anyone else to be interested in it. But here it is.

-- Chip


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