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

All software (steckOS, BIOS, libraries, tools, games, stuff):

Hardware (Schematics, PCB Layouts):

Steckschwein Emulator:


We almost exclusively use Open Source-Software to design and code for the Steckschwein.

  • 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 - Powerful eda suite once you get the hang of it. We use it for all things hardware.
  • 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 - We use it’s 6502-emulator/simulator for automated testing using unit tests.
  • Acme - 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.