One can find the complete sources for BIOS, SteckOS, Firmware for the keyboard controller, decoder sources of the GAL’s and full schematics and board layouts as KiCad-projects at bitbucket.org
All software (steckOS, BIOS, libraries, tools, games, stuff): https://bitbucket.org/steckschwein/steckschwein-code
Hardware (Schematics, PCB Layouts): https://bitbucket.org/steckschwein/steckschwein-hardware
Steckschwein Emulator: https://github.com/Steckschwein/steckschwein-emulator
We almost exclusively use Open Source-Software to design and code for the Steckschwein.
- cc65 - http://cc65.github.io/cc65/ Extensive suite of cross development tools for almost every 6502 based platform. We mostly use ca65 because of the linker. Also, we have a few tools written in C.
- KiCad - http://kicad-pcb.org/ Powerful eda suite once you get the hang of it. We use it for all things hardware.
- GALasm - https://github.com/daveho/GALasm Our GAL-based address decoding logic and our wait state generator logic are defined using GALasm, which is an ancient tool, but still very useful.
- py65mon - https://github.com/mnaberez/py65 We use it’s 6502-emulator/simulator for automated testing using unit tests.
- Acme - https://sourceforge.net/projects/acme-crossass/ Very nice 65xx crossassembler for almost every platform. We used ACME in the beginning, but moved on to ca65 from the cc65 suite. We still use it for quick-and dirty stuff.