Re: [stella] that supercharger thingy

Subject: Re: [stella] that supercharger thingy
From: Erik Mooney <emooney@xxxxxxxxxxxxxxxx>
Date: Tue, 1 Jun 1999 12:56:51 -0400 (EDT)
> > banking since the 2600 can only read 4K at a time (though I heard once that
> > some weird custom addressing scheme could allow for 6K without banks).
> 
> As soon as I get a chance to pull out my schematics, I'll look into this.
> But in the meantime, do you remember where you heard this?  Try, if you can,
> to get more details.

At one point, we were trying to figure out if there was any way to reclaim
any part of the lower 4k address space of the CPU.  Turned out that there
wasn't really, since the TIA and RIOT only decode as much address as they
need - the RIOT RAM occupies $80 through $FF on pages 0, 1, 4, 5, 8, 9,
etc (and the RIOT I/O on the other pages)... and the TIA registers occupy
the $00 through $2C and $40 through $6c addresses on every page.  There
are a couple 'holes' like $30 to $3F on every page that could
theoretically be used for RAM or ROM on the cart, but that's about it.
You're pretty much stuck with a 4k address space.


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