Re: [stella] Resend: My Latest Project: the Super Atari

Subject: Re: [stella] Resend: My Latest Project: the Super Atari
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Sun, 4 Jan 2004 15:08:02 +0100
> Can a 7800 in 2600 mode access the extra cart pins that were added to
> it?  I guess it can if that's the trick behind getting Superchip games
> Klax to work on it without any extra circuitry.

Yes it can. But in 2600 mode the TIA/RIOT are mapped into every even 4K
segment of the 6502 address space. So you can only use the area at
$1xxx, $3xxx, ... , $Fxxx for your cartridge.

> But at least internally the 7800 has only 4K extra RAM over a 2600 and I
> don't think any of it is accessible in 2600 mode..

That correct too. In 2600 mode the 7800 only has the 128 bytes of RIOT
RAM internally. But other than on the 2600, you have all the nessessary
lines on the cartridge port to easily access RAM on the cartridge.
Therefore you can have a simple 32K RAM cart (in 4K steps) without
making any changes to the console itself.

Ciao, Eckhard Stolberg

Archives (includes files) at
Unsub & more at

Current Thread