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Welcome to the STM8 eForth Wiki!
A team of authors regularly updates the following topics:
- a gentle step-by-step introduction to STM8 eForth and technical docs (see sidebar)
- example code (demos, libraries and projects)
- supported boards, e.g. thermostats, breakout boards (see sidebar)
- STM8 programming tips with a focus on SDCC (assembler, C-compiler and simulator)
- comparison of STM8 Low Density device families
Most pages are directly listed in the sidebar, while other some topics can be accessed by clicking Pages. The issue tracker and the releases overview also contain a lot of information.
If you want to contribute a page or work on a topic, please create an issue.
TG9541/STM8EF is an improved version of Dr. C.H.Ting's STM8 eForth for the STM8S Discovery. With the kind permission of the original author it provides a permissive FOSS license.
Thanks to innovations and contributions from experienced and skilled members of the Forth community STM8 eForth has found its place as a tiny but very usable embedded Forth system. Thanks a lot :-)
STM8 eForth is a very lightweight interactive Forth for low-end STM8 µCs with a good "feature-to-binary-size" ratio:
The STM8 architecture is very well suited for interactive embedded Forth systems. STM8 eForth provides carefully designed embedded control features (e.g. Background and Idle Tasks, interrupts, RAM and Flash operation), e4thcom support, and a framework approach for board support. Even with STM8S Low Density devices interactive development is possible (e.g. W1209 data logging thermostat). STM8S Medium and High Density devices and most STM8L devices are also supported.
Experienced Forth practitioners found STM8 eForth very usable, even when compared with open-source µC Forth systems that have a richer feature set, or that target more powerful hardware. STM8 eForth favors a practical approach with respect to standardization: when gaps in the original eForth functionality have to be filled, inspiration is taken from Forth-79, Forth-83, FIG-Forth or ANS-Forth. Some solutions for embedded devices are cutting-edge (e.g. Manfred Marlow's VOC extensions).
This project has the following goals:
- provide an easy to use Forth kit for STM8 µCs
- engage with the Forth community on core, development environment, libraries, and applications,
- support projects that apply STM8 eForth for embedded control
- provide board support for common low-cost Chinese control boards
- maximize the product features * free space (for fun and profit)
The GitHub repository has a sister project eForth for Cheap STM8S Gadgets on Hack-a-Day. There are other projects HaD projects and GitHub repositories that use STM8 eForth code (some or listed in STM8 eForth Example Code).
eForth is a well documented implementation of a basic Forth by Bill Muench and Dr. C.H. Ting.
eForth is based on a set of about 30 Forth core words written in assembly or C instead of using meta-compilation from another Forth system. Higher level words, e.g. for interpreter and compiler, are written in Forth. eForth was designed with portability in mind there are implementations for many µCs and µPs.
Originally eForth was a DTC Forth (versions 1.x use an "inner interpreter"), some later implementation, like STM8 eForth, use the STC approach (versions 2.x use subroutine calls).
Some eForth loop idioms, like FOR .. AFT .. THEN .. NEXT are notoriously "under-documented" - the page eForth FOR .. NEXT provides the "missing docs".
Forth, the programming language that does things differently, is the work of Charles H. Moore and others.
Traditionally, Forth systems target PCs with mass storage, keyboard and display, which embedded Forth systems often don't have. Examples for other embedded Forth systems are AmForth for AVR8 and MSP430, noForth for MSP430, Fast Forth for MSP430, Mecrisp for MSP430, or Mecrisp-Stellaris for Cortex-M.
There are many on-line Forth resources. Some of the most notable are:
- Leo Brodie's books Starting Forth, and Thinking Forth
- scans of the magazine Forth Dimensions (indexed)
- some issues of Forthwrite, the FIG UK Magazine
- publications by the German Forth-Gesellschaft e.V. (mostly German, some in English).