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From: gnome@oliven.UUCP
Newsgroups: net.micro,net.games.video
Subject: Update on Vectrex hardware...
Message-ID: <118@oliven.UUCP>
Date: Tue, 27-Mar-84 14:22:29 EST
Article-I.D.: oliven.118
Posted: Tue Mar 27 14:22:29 1984
Date-Received: Fri, 30-Mar-84 01:33:35 EST
Organization: Olivetti ATC., Cupertino, Ca
Lines: 55

B U L L E T I N      on cartridge modifications !!!

Well, after looking into some of the new cartridges
(namely Web Wars and animaction) I have found that
GCE has thrown me a few curves!

Curve #1
	The Web Wars Cart (and possibly others) has
an 8k x 8 ROM in it.  The pinouts are only slightly
different than the older 4K  carts.  But this will
be a bit of a problem with the EPROM mod that I just
published on the net.  Basically, the new 8K rom is
also in a 24 pin package (same number of pins as a 2732),
but the equivalently large EPROM (a 2764) has 28 pins.
There are a couple of solutons -
                    1) treat all carts like 8k ROMS
		       and use i2764's as the standard
		       EPROM for the present time.

		    2) Just wait until there is a solid
		       hacking standard that everyone likes.
		       (this is especially true because of
		        Curve #2 !  )

Curve #2
	The Animaction cartridge was even more of a
surprise!  First off, it had no screw holding it together.
Instead, it was glued around the edges.  Upon opening it
up, there was an evident difference!

It contains -
	1) an 8K ROM (like WebWars)
	2) an HM6116 CMOS Static ram
	3) a 74LS139 dual 2-4 decoder (address decode)

Basically the low order address bits of the RAM and ROM
(A0 through A10) are tied together as are the data lines.
The 74LS139 uses A12-A14 to select between RAM and ROM
address areas.


********************************************************

Maybe a more universal cartridge would be one that can
use both 2732's, 2764's (8Kx8) and RAM?

When I get more information, I'll pass it along.
Please send me your ideas on the subject.

                   Gary
	(hplabs,allegra)oliveb!oliven!gnome

PS- Werner (ARPA), I am receiving your messages, but can't
    get  through the local ARPANET gateways... I'm stuck!