Re: a USB for the Apple II smoke test

[Roger Johnstone <rojaws@orcon.net.nz>]

In <r4udnaM8NNswz3TfRVn-2w@comcast.com> Michael J. Mahon wrote:
> Scott Alfter wrote:
>> Theoretically, you could've written a mouse driver that would talk to 
>> a serial mouse through a serial card.  Given information on the 
>> protocols used (the two main protocols used were from Microsoft and 
>> Mouse Systems, with many mice supporting both), it should've been 
>> doable.  It wouldn't have been compatible with existing software, 
>> though.
> 
> As long as the card(s) support the Apple mouse firmware interface
> it should be compatible.  Surely Apple created an abstract mouse
> interface...?

They did. In fact it has a clean interface with proper defined entry 
points and everything. The main things the Apple mouse card does is 
provide a way of tracking the mouse movement without assistance from the 
Apple's CPU (the card has its own CPU), and generating interrupts on 
mouse movement and vetical blanking. A simple timer could have done all 
that, and of course the IIc does it without using a second CPU and a 
bunch of support chips.

Here's a good story: the first mouse card for the Apple II, complete 
with a simple GUI. It was made in 1981 and it used just two chips.

http://folklore.org/StoryView.py?story=Apple_II_Mouse_Card.txt

-- 
Roger Johnstone, Invercargill, New Zealand
http://vintageware.orcon.net.nz/
________________________________________________________________________
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