Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!lll-winken!uunet!skivs!dr
From: dr@skivs.UUCP (David Robins)
Newsgroups: comp.sys.apple
Subject: Re: Trouble with Applesoft's DEF FN
Message-ID: <2817@skivs.UUCP>
Date: 3 Apr 89 16:41:37 GMT
References: <3038@m2-net.UUCP>
Reply-To: dr@skivs.UUCP (David Robins)
Organization: Smith-Kettlewell Eye Research Institute, San Francisco, CA
Lines: 25

In article <3038@m2-net.UUCP> muaddib@m-net.UUCP (David Pieczkiewicz) writes:
...
>From what I know about them, the Apple
>keys are simply hardwires of the paddle buttons, and their condition
>can be read by PEEK(49249), or PEEK(-16287) in the case of pre-IIe's, for
>button #0 (AKA the Open-Apple key), and PEEK(49250) (PEEK(-16286) for 
>early Apples) for button #1, also known as the Closed-Apple on the IIe/IIc
>and the Option key on the GS. If the returned value is > 127, the key
>is being pressed. (Curiously, the source of this info, Beagle Bros.' 
>indispensable Peeks, Pokes and Pointers chart, lists a third button (#2)
>under 49251 (-16285). Anyone know anything about this?)

SW 2 is a third switch input.  The Apple //e Tech manual states that
"some software for the older models of the Apple II uses the third
switch, switch 2, as a way of detecting the shift key." (mentions the
single-wire shift-key modification).

SW 2 is available on the //e gameport, as well as the internal 16-pin
gameport on the motherboard.  It is no connected to any keyboard buttons.
It is detected the same as SW 0 and SW 1.
-- 
David Robins, M.D.  (ophthalmologist / electronics engineer)
The Smith-Kettlewell Institute of Visual Science,  ***  net:  uunet!skivs!dr
2232 Webster St, San Francisco CA 94115            ***  415/561-1705 (voice) 
The opinions expressed herein do not reflect the opinion of the Institute!