OK64 : The OK 8-bit computer.

Do you know what the best part of creating our very own computer is? No nosy poignant ambitious pedantic opinionated brigands of cacophonic fellow nerds who constantly tell you what is possible or not, or the best way, or fastest, or what has been done before, or that this can’t be done, or this is stupid, or that you’re stupid, or change the processor, or it needs BASIC, or does it run “Far Cry”, more ram, less ram, bigger better smaller.

I therefore decided to start making my own “fantasy” computer, based on my experiences with the excellent Pico-8. I had just finished creating a blockbuster demo for the system (https://www.youtube.com/watch?v=_KIFP_j2cZo), but was somewhat still unsettled by the fact that the fantasy console.. doesn’t have a CPU. While it does have RAM – the program code isn’t stored anywhere on the system, and the LUA script is executed internally and with arbitrary speed and size constraints.

So after having experimented for a couple of days, I had a rudimentary emulator for a “fantasy” computer that uses an underpowered *real* CPU with *real* constraints (and a custom overpowered video chip) that can be programmed for using TRSE. Here’s the deal:

  • MOS 6502 processor clocked in at 0.985 mhz (PAL)
  • SID chip (registers at $FF20)
  • OKVC (OK Video chip) registers at $F000-$FFF0)
  • 64K of program memory (pram)
  • 1mb of video memory (vram), accessible through pram registers
  • 256×256 8-bit VGA output (custom palette of 24-bit RGB 256 colors)
  • The OKVC has several built-in methods for fast drawing of primitives
    • Draw lines
    • Pixels
    • Circles (filled)
    • Triangles
    • Blitting (copying) of image data within vram, acts as sprites
    • Clearing
  • Combining the 0.985 mhz MOS 6502 with a very fast video chip will probably yield unexpected results!
  • I’m no hardware wiz, but I’m hoping that this computer could potentially be built IRL

If you have questions / suggestions on topics regarding the OK64, please check out the TRSE facebook page and/or contact me! If you’d like to try out the OK64, then the emulator (version 1.01 for windows) is currently included with TRSE, and is bundled together with 3 example projects:

  • The KOS (OK Operating system)
  • Standard tutorials with 5 examples
  • The OK Computer – a demo for the OK64 released in the “Wild compo” at Revision 2020.
An example of the OK 64 in action. Here, several TRSE Pascal programs are being compiled to assembler before being executed.