Re: [stella] Hacking the Supercharger ROM

Subject: Re: [stella] Hacking the Supercharger ROM
From: Chad Schell <gamer@xxxxxxxxxxx>
Date: Thu, 15 Mar 2001 22:54:32 -0800
At 10:20 PM 3/15/2001, you wrote:
At 09:20 PM 3/15/2001 +0100, you wrote:
No it's all done in the software. The SC constandly polls address
$fff9 and decides whether it has read a one or a zero bit depending
on how quickly it changes.

It writes all the memory byte by byte into RAM too?

Yes, it does. Using the same method to access RAM that you would in a Supercharger game.

I should clarify something about what I said above. It doesn't just sit there and poll 1FF9 constantly, it sets a timer and then checks the state of 1FF9 at the end of that timer. That way it can do other things like assemble the byte and write it to ram, increment the address, compute the checksum, adjust the playfield and audio, etc.

Keep in mind that it doesn't actually draw a proper screen during this time. Thus the bars are kind of unstable.


Wow. I never thought the 2600 had that much processing time available for that.

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