Forth (Mecrisp Stellaris 2.5.6) for Raspberry Pi Pico

Matthias Koch has released Mecrisp Forth for the Raspberry Pi Pico - Stellaris 2.5.6

You can download it from here:


This interpreter has quite the learning curve. It’s an amazing effort from Matthias, but needs clearer documentation and examples to get more people using it.

Terry Porter has written a very comprehensive “unofficial” documentation for Mecrisp Stellaris, and I see that Terry has been named as assisting Matthias with the latest Stellaris port to the RP Pico.

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Ooh, a bootable Mandelbrot in only 287 bytes! Hurrah!

Comprehensive it certainly is. There are a lot of words in there.

Sadly, the project maintainers appear to be rabidly opposed to any form of abstraction library. Wanna do a “Hello, World!” blinky test on your new board in Mecrisp Stellaris? Write entirely new code, hitting hardware registers, different for every board. Maybe I’ve been spoiled by the excellent user documentation and hardware libraries from the Wiring/Arduino and Raspberry Pi communities, but it’s hard to create users without them.

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Forth users tend to see it as a replacement or competitor for C where you would be configuring hardware registers anyway.

Mecrisp Forth started with the MSP430 and evolved to support ARM Cortex M microcontrollers.

Modern microcontrollers are complex systems characterised by multiple peripherals controlled by numerous 32 bit registers.

The Mecrisp unofficial documentation summarises the complexity of some of these parts with the following table

Forth evolved during the 1960s, establishing itself with the IBM 1130 in 1968.

To port Forth to a new architecture is a significant task, hampered by the fact that the chosen microcontroller may have approaching 2000 peripheral control registers.

Mecrisp is a 1 man, non profit organisation with voluntary assistance, Arduino is a multi-developer organisation.

Perhaps we should be less critical when it becomes apparent of the magnitude of these projects.

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