Re: [stella] Dumping ROM images

Subject: Re: [stella] Dumping ROM images
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Fri, 11 Mar 2005 08:47:02 -0500
> Is this possible?  If it is, then someone like AtariAge could sell
> ROM dumping kits with the RomDumper cart, the cable, and software.
> No soldering required.
> Unanswered questions: Will inserting and removing carts cause any noise
> on the bus lines?  Can the reader code be made to fit into 128 bytes?

The transfer code is small enough to fit into 128 bytes, and
infact it sometimes is used in RIOT RAM when a game can't
be read reliably at 7800 speed. But the code to autodetect
the bankswitching type would be too big to run in RIOT RAM,
so you would have to manually set the bankswitching type
for each game that you want to read.

But as Dusty has pointed out bus noise would be a problem when
changing carts. So it would be better to use some sort of
pass-though dumper cart, where the cart to read could be plugged
in. If you physically disconnect the cart port on the dumper cart
with a switch, you might be able to change the carts to read
without having to turn the console off.

If anyone is going to design a pass-though dumper cart, it might
be better to do one for the 7800 though, because it could be much
more flexible. And you might want to use serial transfer instead
of my parallel port protocol, because directly accessing the PC
parallel port only works nicely on older DOS and Windows versions.

BTW, since you are studying the TIA schematics, did you already
have a look at the setup logic for the movable-object output?
I'm wondering if there might be something in there that could
be messed up by a HMOVE pulse happening during this setup
procedure, because there is some pixel doubling and deleting
in some scanlines during the Cosmic Ark starfield effect that
I can't explain.

Ciao, Eckhard Stolberg

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