Re: [stella] 2600onachip: sorry about the question of Cosmic Ark stars

Subject: Re: [stella] 2600onachip: sorry about the question of Cosmic Ark stars
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Thu, 29 Aug 2002 21:45:10 +0200
> I tested Gi Joe and it looks messed up like in the first picture John. But
> don't worry, thanks to an old post of Eckhard Stolberg
> ( I  was
> able to perform some tests in order to have a better comprehension of the
> motion registers operation. The problem is that I didn't implement the
> motion registers exactly as in the original TIA, because it isn't a fully
> synchronous design. I made some assumptions but now I am fixing the

A quick note on this message:
It was written at the very beginning of our experimentation with this
It still says that missile0 gets shifted 15 pixels in every scanline. Later
we found out that it is actually shifted 17 pixels per scanline, and that
every fourth line is empty, while the line before this has a double width
pixel. Also during some systematic tests John and I later found several
other occasions where this effect appears with other objects too. I think we
had posted the results to the list too. So, if you aren't copying the TIA
design exactly from the schematics, you should be very carefull to implement
at least the known wierdnesses properly.

Ciao, Eckhard Stolberg

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