Thanks to DirtyHairy, Stella's TIA emulation has greatly improved over the last two years. It is now able to emulate a standard TIA almost completely with perfection. But "TIA is a beast" and on top of that Atari used numerous slightly different TIA versions in their consoles. Some of these TIAs cause problems with original games and homebrews. To help homebrewers avoiding such problems in the future, we want to analyze these TIA differences and then add some developer options to Stella.
This website describes a lot TIA chips in detail, together with the potentially affected games.
Note: Most INFO links are broken, you have to change the path into "www.ataricompendium.com/game_library/easter_eggs/vcs/" to make them work.
So if you own a console with an odd TIA which exhibits one of these problems and maybe also own a flash cart (e.g. Harmony, Krokodile, CC, Supercharger, Uno-Cart), you can help us.
For now we are mostly interested into consoles which
- display stray dots in Ebivision's Pesco/Pac Man (we suppose Atari Video Cube, QuickStep, Thrust and Ixion might be affected on these too)
- display extra pixels in Masters of the Universe - The Power of He-Man; note that there are two different variations of the problem (here e.g. Obelix, Octopus, Room of Doom, Ski Hunt, Space Treat Deluxe, Squeeze Box and SW-Ewok Adventure might be affected too)
- have problems with Kool Aid Man and Thunderground (probably Spider Fighter too)
- have problems with G.I. Joe - Cobra Strike
(see pictures attached)
There are more bugs listed (especially with the Cosmic Ark stars), these may follow once we unterstand the other ones.
If you want to help us, please tell us (here or via PM)
- which of the bugs listed above your console exhibits
- if you own a flashcart (for executing test ROMs) or any of the ROMs related to your console glitch listed above
We will then ask you to verify other games (as listed above) and try some test programs. With your help we hope to be able to adapt Stella to as many TIA variations as possible. Fingers crossed!
Edited by Thomas Jentzsch, Mon Jan 7, 2019 11:41 AM.