Re: apple II roms and eproms

["Bill Garber" <willy46pa@comcast DOT net>]

"David Wilson" <david@uow.edu.au> wrote in message
news:40d4ca0d$1@news.uow.edu.au...
: David Wilson <david@uow.edu.au> writes:
: >Apple IIgs
: >ROM00/01/03 1 megabit ??? none 28
:
: >The IIgs uses a 28 pin 1 MegaBit (128KB) ROM but the
: >equivalent EPROM has 32 pins...
:
: I just double checked the ROM03 schematics, my memory data book
: and my ROM03 PCB.
:
: 1) The PCB is laid out for 32 pin sockets (but my IIgs
: has only got 28 pin sockets soldered to it).

Mine also.

: 2) There are two versions of 128Kx8 EPROMs. One has /OE on
: pin 24 and is not usable in the IIgs. The other has A16 on
: pin 24 and /OE is on pin 2. Compatible EPROMs are:
:
: Hitachi HN27C301G
: Toshiba TC571001D
:
: So if your ROM03 has 32 pin sockets you can use EPROMs.

So, if I replace my 28 pin sockets with 32 pin, or just
add the other 4 pins with the suggested extensions, then
I can expand my ROMs? What can I add to it? I'd like to
have some extra features, but I don't know much about the
firmware yet. BTW, David, I picked up a hard-bound version
of the IIgs hardware reference.  :o)

Bill @ GarberStreet Enterprizez };-)
Web Site - http://garberstreet.netfirms.com
Email - willy46pa @ comcast DOT net
Change DOT to a dot to contact me



---
This email ain't infected, dude!

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.699 / Virus Database: 456 - Release Date: 6/5/04