AWCTTYPA@UIAMVS.BITNET ("David A. Lyons") (01/12/88)
>Date: Sun, 11 Jan 87 13:02:00 MEZ >Sender: INFO-APP Info-Apple List <INFO-APP@NDSUVM1> >From: Matthias Kapffer <KAPFFER%DMZRZU71.BITNET@CUNYVM.CUNY.EDU> >Subject: Re: Reading the Button with PDL() command > >I/O addresses from $C060 thru $C067 (cassette in/button 0-2/paddle 0-3) are >repeated immediatly after them. Therefore a PDL(n), n= 4..7, will access the >four one-bit inputs mentioned above. I recommend NOT counting on this sort of thing. If Apple hasn't documented it, it might not work on future machines. --David A. Lyons a.k.a. DAL Systems PO Box 287 | North Liberty, IA 52317 BITNET: AWCTTYPA@UIAMVS CI$: 72177,3233
estell@uiucdcsm.cs.uiuc.edu (01/13/88)
This trick will definitely not work on the GS. John K. Estell estell@m.cs.uiuc.edu
KAPFFER@DMZRZU71.BITNET (Matthias Kapffer) (01/19/88)
I didn't ment my contribution as a programming tip but wanted to complete the
statement that PDL() has nothing to do with the buttons.
It *does* work as described by me on an Apple ][+ and was documented by Apple
in the Apple ][ Reference Manual which tries to explain the hardware as it is.
Nowadays Apple has a stronger feeling for ensuring upward compatiblity and
includes in its manuals the concepts of what the various features are supposed
to fullfill.
I should have stated that in my original message to avoid this confusion and
agree that there is realy too much software unnecessarily losing with each
hard/firmware upgrade.
Matthias Kapffer
<KAPFFER@DMZRZU71.BITNET>