RE: [stella] 2600 rpg

Subject: RE: [stella] 2600 rpg
From: Matt Pritchard <MPritchard@xxxxxxxxxxxx>
Date: Mon, 24 Mar 1997 16:47:13 -0600
	At 03:07 PM 3/24/97 -0600, you wrote:
	>I'm curious if anyone here does any 7800 programming also?
We've got a

	More to the point, has anyone EVER done 7800-exclusive
programming?  I
	don't even think there is any good reference material on the
Maria chip.

	The manual with the Monitor cart is fairly complete, and Bruce
has filled in some of the registers that were not documented.   You may
have seen his post about the 7800 cart dumper. (dumps 2600 carts,
determines bank switch method, sends ASCII dump out the joystick port
where it is converted into 2400 baud RS-232 data)

	>workaround for the encryption, and a 7800 cart can hold up to
144K of
	>ROM and 32K of RAM -- Enough to make something comparable to
8-bit games
	>of the era anyway.  would it be ok to include 7800 programming
topics on
	>this newslist?

	I was assuming that 7800 programming was only useful insofar as
using the
	monitor cartridge in 2600 mode.  Why don't you let us know what
	encryption workaround is?  It's unfortunate that the encryption
key seems
	to be lost to the ages, gone even from the vaults of Atari
itself it seems.

	Is there any confirmation to that?

	The workaround is pretty simple.  Not all of the cartridge is
used to generate the enctryption key.  As little as 4K can be used.
Some games uses only a tiny amount, and have the 6502 vector tables set
up to jump out of the encrypted area right away to a place where can set
up the vectors as you like.

	I see no reason why we shouldn't discuss 7800 programming as
well, if it's
	possible to write for it.

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