stm8ef VS zeptoforth

Thanks, GitHub URL: https://github.com/TG9541/stm8ef

I'm a fan of the STM8 line, nice peripherals, and nice programming model if you are writing any assembler. Much cleaner than 8051. You can do debug with the STLink. There are free toolchains from ST as well as the open source SDCC compiler. There is even a nice Forth. Even if Forth does not interest you that set of pages has a lot of info about various STM8 devices.

This past week I've been on a mission to find the cheapest microcontroller that I can reasonably learn to program. I've gone down the STM8S 001 rabbit hole and found this https://github.com/TG9541/stm8ef/wiki/STM8-eForth-Example-Code

An example: eForth for the STM8 lets you fit an interactive development system including compiler onto an mcu with 8Kb flash and 1kB ram. Very useful for testing and exploratory development in systems that are otherwise far to small to support it.

Eventually you're going to need someone to help explain what on earth is going on here. Fortunately Thomas Göppel the maintainer of STM8 eForth has done that in a very readable explanation of FOR .. NEXT and how to use it.

It's always a multi dimensional spectrum of cost, performance, peripherals, development support, availability, family reach, etc. I personally really like STM8 microcontrollers for their simplicity and very low cost (can be less than 30 cents). There's actually another project that brings Forth to STM8: https://github.com/TG9541/stm8ef It has very good documentation and I recommend anyone to take a look

I used the discussions feature to express my thanks a few days ago. Might be better than opening an issue? https://github.com/TG9541/stm8ef/discussions/386

microcontroller options are interesting, also Forths (https://github.com/tabemann/zeptoforth)

Patch-level release 1.0.1 is out. This release improves the disassembler, particularly adding the ability to properly disassemble string literals.

This is a definite shameless plug, but I would recommend my zeptoforth - it has strong support for the RP2040 (e.g. the RPi Pico), including peripheral support and support for executing on both cores, and also has support for a number of STM32 platforms, and comes with a range of example code, documentation, and a wiki.

The release itself is at https://github.com/tabemann/zeptoforth/releases/tag/v0.45.0

Zeptoforth has this, but it’s for embedded systems. https://github.com/tabemann/zeptoforth

I initially implemented a rather Forth 2012-like wordlist system based on GET-ORDER, SET-ORDER, GET-CURRENT, SET-CURRENT, and WORDLIST for my Cortex-M Forth, zeptoforth. However, I ended up finding these quite cumbersome and error-prone to use in code that makes heavy use of wordlists to control the namespace, as is the case with zeptoforth. As a result I decided to completely remodel wordlists into a module system which, while internally based on those five words, is outwardly much more like the module systems found in other languages.

Multicore support for the RP2040 with zeptoforth has been in the works for a while but up until the last few days has not been mature enough for me to even consider including it in the devel branch of zeptoforth. However, now it has reached the point where I can run multiple tasks simultaneously on separate cores. I have a working test that blinks the LED on the Raspberry Pi Pico at two different rates in two different tasks, one on each core, while simultaneously writing an asterisk to the console once every second from the second core and having a usable REPL in the main task on the first core. It should be noted that even the Micropython does not do this, as it only allows two tasks, one per core, rather than allowing multiple tasks to run on each core separately.

I am the developer of zeptoforth, which is the main Forth I am using at the present. It supports the RP2040 (particularly the Raspberry Pi Pico, but it should work on other RP2040 boards), which I have been working with lately, and the STM32F407, STM32L476, and STM32F746 DISCOVERY boards. Note that it is not a desktop Forth; for that I would probably just recommend gforth.

zeptoforth 0.21.0 (https://github.com/tabemann/zeptoforth/releases/tag/v0.21.0) is now out, and introduces support for the RP2040 microcontroller (e.g. Raspberry Pi Pico, any RP2040 board with Winbond Quad SPI flash should work). Note that it comes in UF2 format, so one codes not need to solder pins for SWD onto one's Raspberry Pi Pico format to load it, and also the Makefile automatically generates UF2 files. Furthermore, when said UF2 file is first loaded, it erases flash above it up to the 1 MB mark, so one does not need to use OpenOCD (with SWD) or a special eraser UF2 file to clear old code out of flash.

The result of this is zeptoforth, which I have been developing for about a year and four months. One could say that it fits the same niche as Mecrisp-Stellaris, and it admittedly supports far fewer MCU's at the present. I could have just used that rather than bothered to implement my own Cortex-M Forth, but I wanted to create my own Forth environment which I could play with as I saw fit (e.g. adding preemptive multitasking and other multitasking supports such as locks and channels).