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From: gwyn@smoke.brl.mil (Doug Gwyn)
Newsgroups: comp.sys.apple2
Subject: Re: Help with joystick (a clarification)
Message-ID: <14954@smoke.brl.mil>
Date: 24 Jan 91 00:04:31 GMT
References: <72832@bu.edu.bu.edu> <1991Jan22.002513.8357@uwovax.uwo.ca> <36056@netnews.upenn.edu>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 13

In article <36056@netnews.upenn.edu> tyler@eniac.seas.upenn.edu (Tyler W Phillips) writes:
>On my friends IIe, the joystick works fine, centering at about 127 and
>maxing at 255.  Put it on my IIgs, and it centers at about 40 and maxes
>at 80.  Oddly enough, it seems to work perfectly within that 0 to 80 range.

One possibility is that the program you're using relies on the CPU running
at 1 MHz.  Another, more interesting possibility is that the joystick
manufacturer had trouble finding the specific potentiometer values that
Apple specifies, and decided instead to fake out the 555 timer by making
an equivalent RC time constant by using a capacitor in addition to the
potentiometer.  I think the IIGS has a different internal arrangement for
the joystick port, such that the proper potentiometer value works okay but
"equivalent" RC combinations no longer have equivalent behavior.