Subject: Re: IIGS ADB keyboard fix
From: [email-masked] (David Empson)
Date: 21 Jun 1996 21:02:04 +1200
Newsgroups: comp.sys.apple2

In article <[email-masked]>, MAC <[email-masked]> wrote:
> In article <[email-masked]>, [email-masked] (Robert Lee_Kwen)
> wrote:
> 
> > Also does a apple //e mouse card work on a Rom 03 apple //gs?
> > 
> 
> The Mouse card will not work in a GS of any ROM version.

Wrong.  The original IIgs mouse support (ROM 00 and ROM 01) was
specifically designed to allow the use of a IIe mouse card, so that a
IIe user upgrading to a IIgs could plug in their mouse card and
continue to use their mouse, rather than having to fork out money for
an ADB mouse.

In the ROM 00 and ROM 01, the ADB mouse is controlled by the slot 4
mouse firmware.  If you disable this, then you lose all access to the
mouse, from GS/OS and ProDOS-8.  However, if you install a IIe mouse
card (in any slot, as long as it is set to "Your Card"), then that
mouse can be used in all ProDOS-8 and GS/OS applications.  (There may
be some programs which assume the IIgs mouse is always in slot 4, or
bypass the firmware and try to use the ADB mouse directly.  These
programs would not work with a IIe mouse card.)

If the ROM 03 IIgs, Apple rewrote the mouse firmware.  The ADB mouse
is controlled directly by the IIgs toolbox (Miscellaneous Toolset),
and the slot 4 mouse firmware uses the toolbox code.  (The ROM 00/01
is the other way around - the toolbox calls use the slot firmware.)

This means that for a ROM 3, if you set slot 4 to "Your Card", you can
still use the mouse in GS/OS programs, but you cannot use it in
ProDOS-8 programs.  I have my system set up this way.

If you install a IIe mouse card into a ROM 3, then that mouse will be
available to ProDOS-8 applications, provided they use the standard
firmware entry points (which are the same for the IIe card, the IIc
and IIgs).  You should set slot 4 to "Your Card" to avoid confusion
with the ADB mouse.

GS/OS programs will not use the IIe mouse on a ROM 3, but they will
continue to work with an ADB mouse.

Summary of mouse used in each situation:

Slot 4          IIe mouse card     ROM 00/01      ROM 03
Setting                            P8   GS/OS     P8   GS/OS

Mouse Port      Not installed      ADB  ADB       ADB  ADB
                In slot 1-3        ADB? ADB?      ADB? ADB
                In slot 4          ADB  ADB       ADB  ADB
                In slot 5-7        IIe? IIe?      IIe? ADB

Your Card       Not installed      None None      None ADB
                In any slot        IIe  IIe       IIe  ADB

I'm not sure which order the slots are supposed to be scanned when
searching for the mouse.  In the table, I've assumed that the scan is
supposed to start at slot 7.

As I mentioned earlier, there may be some programs which differ from
this behaviour, but this is how things should work for any programs
which use the standard methods to access the mouse.
-- 
David Empson
[email-masked]
Snail mail: P.O. Box 27-103, Wellington, New Zealand