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cvload

Run Colecovision games on a Z180 retrocomputer:

  • SC203 Modular Z180 computer
  • Propeller graphics card that emulates a TMS9918A
  • Keyboard input via serial port to replace or in addition to game controller

Can it run Donkey Kong? Basically all these components are different from a real Colecovision, and only a limited number of games will be playable. See: games.txt

Loader steps

  1. Load game ROM file from disk
  2. Include Colecovision BIOS binary
  3. Include SCM 1.3 binary
  4. Include Colecovision patch program
  5. Move loaded/included binaries to destination RAM locations
  6. Apply system settings for speed and interrupts
  7. Start Colecovision patcher or SCM

CP/M is only used to load the binaries.
The Coleco rom file and scm binary must be added to compile the program.

Colecovision BIOS patches

  • Replace VDP video i/o routines
  • Extend game controller input routines
  • Emulate TMS9918A vsync interrupt with 60Hz timer
  • Apply system patches
  • Boot Colecovision BIOS

SCM for Colecovision

Start game from scm prompt with: g 5000

I did some hacks in the scm source code to make it work for this purpose. Modified sources and config files are in the scm folder.

Keyboard control

Default key assignment:
A = Left
D = Right
W = Up
X = Down
, = Left fire
. = Right fire
P = Invoke SCM monitor

Other keys:
0..9,*,#

Todo

  • Emulate SN76489A with an YM2149
  • Load/save game state on disk(?)

References

Colecovision Coding Guide: https://archive.org/details/manualzilla-id-5667325

SCM V1.3: https://smallcomputercentral.com/small-computer-monitor/

SC203 Modular Z180 Computer: https://smallcomputercentral.com/sc203-modular-z180-computer/

Propeller Graphics Card: https://github.com/maccasoft/propeller-graphics-card

Game controller card: https://github.com/jblang/GameController Part of the loader code is based on examples/z180load.asm

SN76489 Sound card: https://github.com/jblang/SN76489

YM2149 card: https://github.com/electrified/rc2014-ym2149

Example code to emulate SN76489: http://www.ricbit.com/mundobizarro/sic.php