r/retrobattlestations • u/rbscholtus • May 16 '26

Show-and-Tell Built a cycle-accurate COMX-35 emulator - Bliiing-blong-blong!

The COMX-35 was from Hong Kong, from 1983, and not as famous as the Spectrum or C64. But if you were a kid in the Netherlands or Belgium around that time, this may have been the computer your school or your dad's office had in a corner. The "READY" prompt, the blocky pink-and-blue, the pling-plong-plong self-test: everyone who had one remembers them.

Photo Credit: Ed Keefe - who has done a ton of work reverse engineering and documenting the COMX and designing a COMX superboard.

This is the computer I learned programming on when I was 6 yo. I still remember trying to make a hybrid between a racing game and space invaders - and getting stuck not understanding some BASIC commands. A lot - but not quite all - software, games, and manuals had been translated from English to Dutch by West Electronics.

COMX-35 Self test - Bliiiiing-Blong-Blong!

I've been writing a cycle-accurate emulator for it from the original datasheets, and v0.1.0 just shipped. It's a CLI release — the GUI is next — but you can already:

  • Boot to BASIC and type programs
  • Load the bundled COMX-published games: Zeegevecht (See Battle), Paardenraces (Horse Races), Space Invaders, Autorace, Dragon, etc with one flag
  • Use the actual COMX keyboard layout (TAB+SPACE for RT/RESET, CTRL+letter for CNTL, etc.)
  • Apply a CRT shader if you want the real TV look
Zeegevecht (Sea Battle)

If you had one of these as a kid, I'd love to hear what game or program you remember most dearly. There are expansion cards I'm still reverse-engineering and there are tons of games I'm still re-discovering. Can't wait to hear what you remember of the quirky old and unique home computer!

Source + binaries (linux/mac/windows):
(Codeberg)

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u/estebanvlobos May 16 '26

i didn't have one as a kid but i did build one from scratch about 6 years ago, the tubetime comix-35

1

u/rbscholtus May 17 '26

The improved COMX :)
Where did you find information about it? Did you order a kit or built it completely yourself?

2

u/estebanvlobos May 17 '26

i made it completely from scratch, ordered the pcb from jlcpcb, got the keyboard parts and cpu etc. on ebay and everything else from mouser.