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Welcome to the STM8 eForth Wiki!
Here you'll find information on the following topics:
- A gentle step-by-step introduction to STM8 eForth
- Example Code (demos, libraries and projects)
- STM8S Value Line Gadgets documents supported boards (e.g. thermostats, breakout boards)
- Technical documentation, e.g. start-up code, interrupts or programming tools (see sidebar)
- STM8 Programming tips with the focus on SDCC (assembler, C-compiler and simulator)
Some topics, mainly community contributions, can be accessed by clicking Pages in the sidebar. The Issue tracker and the Release notes also contain a lot of additional information.
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. Interactive development is possible even with STM8S Low Density devices (for an example see W1209 data logging thermostat), but STM8S Medium and High Density devices, as well as most devices of the STM8L family, are also supported.
STM8 eForth favors a practical approach with respect to standardization: when gaps in the original eForth functionality have to be filled, Forth-79, Forth-83, FIG-Forth, ANS-Forth or later standardization attempts are taken for inspiration.
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.
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).
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).