Re: a USB for the Apple II smoke test

[David Wilson <david@uow.edu.au>]

Mitchell Spector <mitch2gs@hotmail.com> writes:
>    It's important to remember that Apple expected persons purchasing
>the Apple IIe to IIGS upgrade would be migrating their mouse card
>and serial mouse. For that reason they made sure built-in firmware 
>support was provided. By the time the ROM 3 had been introduced, 
>the IIGS Upgrade kit had been long since phased out and that's 
>reflected in some ROM 3 motherboard/firmware changes.

The ROM00/01 toolbox mouse firmware called the slot 4 firmware to read the
mouse. This meant that a mouse card in slot 4 would work to replace the ADB
mouse. It also meant that you had to have slot 4 set to "Mouse Port" making
slot 4 unusable for cards (for most users).

The ROM03 IIGS reverses this. The Slot 4 mouse firmware calls the Toolbox
mouse code to read the mouse. This means that setting slot 4 to "Your Card"
does not disable the ADB mouse for GS/OS (but it does for ProDOS 8 programs)
meaning that you can put a non-mouse card in slot 4 and use both it and
the mouse in GS/OS.
-- 
David Wilson  School of IT & CS, Uni of Wollongong, Australia