Path: utzoo!utgpu!attcan!uunet!cbmvax!rutgers!ucsd!sdcc6!sdcc10!cs161agc
From: cs161agc@sdcc10.ucsd.EDU (John Schultz)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Analog Joysticks
Keywords: Analog, Joystick, Full-range
Message-ID: <7@sdcc10.ucsd.EDU>
Date: 7 Nov 88 05:42:38 GMT
References: <1384@fbog.UUCP>
Reply-To: cs161agc@sdcc10.ucsd.edu.UUCP (John Schultz)
Distribution: na
Organization: University of California, San Diego
Lines: 83



               ANALOG JOYSTICK SOLUTION/PROPOSALS

  We have built simple adapters and written the necessary software
to support Intuition Compatible analog joysticks.  The necessary
hardware:

          1 DB-9 female connector
          1 DB-15 female "      "
          2 .22 Micro Farad capacitors
          6 Strips of wire and solder

          1 IBM Analog Joystick (I used a Gravis Mk VI)

  Wiring:

      Amiga DB-9                       IBM DB-15

Button 1     3                              2 
Button 2     4                              7
PotX         5                              6
+5 Volts     7                              1
Ground       8                              4
PotY         9                              3
Button 3     2                              10

  Capacitors: (Both on the Amiga DB-9)

    Solder one from pin 5 to pin 8, and the
other from pin 9 to pin 8.  (Each pot to ground, putting the
capacitor in parallel with the RC circuit). 
NOTE:  On my Gravis the range was 0..223, on my Hayes Mach III
(Apple) the range was 0..255.  I wired another .1 uF in parallel on
the Gravis and brought the range up to 255, so a higher value cap
may be needed for IBM joysticks.  I'll check on this...

  Software:

    You can use any software that drives analog joysticks as
outlined in the Hardware Manual (Examples have been posted and are
on the Developer's Conference Disks).  For Example, SubLOGIC's Jet
(early versions that supported analog joysticks) works fantastic
(Type "J" to switch to analog).  My latest game SpaceSpuds will
support analog joysticks in the Release version (any day now), and
also my next two player over-the-modem version.  I have heard from
Dave Albrecht (sp?) who is now supporting analog joysticks in his
game (Air Battle?).  Thanks Dave for the clues to the correct cap
values.


  Proposal:

  C-A:  Why were pins 3 and 4 chosen for the fire buttons?  We are
going to support three fire buttons and pins 1,2, and 3 would be the
most logical for buttons 1-3 (or even 1-4).  Currently we are using
pin 2 as button 3.

    Analog Joystick Library:

  We are writing an Analog Joystick Library, to be called from any
language.  C-A: Do you have any input?  Any reason to handle it as a
device?  If a C-A version is in the works, what should we do to make
ours functionally compatible?


  As soon as completed, we'll make the ajoystick.lib available to
everyone.  If enough developers are willing to support analog
joysticks, we'll look into mass-marketing the adaptor.  Many people
already have PC joysticks, they are cheap $20-$50, and can be used
on both computers.  We also wired up an Apple // joystick, but the
button polarity is reversed (or maybe we hosed it up taking it apart
so many times; it'll probably work).

  All parties interested, send email.


  Thanks,

    John