Re: 128 K RAM Card for ][ Plus

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <3vb36u$phb@freenet.vancouver.bc.ca>,
Gareth Jones <gareth@freenet.vancouver.bc.ca> wrote:
> Can anyone tell me about a Slot 0 memory card for the Apple ][Plus that 
> has 128K of RAM? It doesn't have a cable that connects to the 
> motherboard, the way some slot 0 cards did. It is a full-size card. There 
> are 4 red LEDs on the top (for banks of RAM?). There's no manufacturer's 
> name on it. The largest chip on it is by Motorola, and it has the 
> following identification "MC3242AP" then "QQ8327" on a separate line.

The 8327 sounds like a date code (27th week of 1983), but a dubious
one for a card intended for use in a II+.  I can't tell you what the
chip is just now.  It might be listed in one of the Motorola databooks
I have at work.

My best guess is that the card is a multi-bank language card, i.e. it
provides 8 banks of 16K.  It probably uses three more softswitches to
select the active bank.  The standard language card uses $C080-$C083
and $C088-$C08B, so it might use $C084-C087 and $C08C-$C08F (these are
echoes on the Apple language card).

The name "Saturn" comes to mind as a multi-bank language card, but I
don't know anything about it other than its name.  I don't know
whether this is that card.

The LEDs might be used as you describe.  The original Apple language
card also had three or four LEDs to indicate the state of its
softswitches.

> I'd like to emphasize that it's working fine as a 16K language card, but 
> I'd like to find out how to access the rest of the RAM for a ProDOS 
> RAMdisk. Any ideas?

Could be tricky.  ProDOS and the RAM disk driver run in the language
card, so you would lose access to the code if you switched in another
bank.  The best method would probably be to duplicate the driver code
(or the relevant parts of it) in each bank, resulting in about 1 page
of wasted space in each bank.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand