Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!usc!ucselx!crash!jcs
From: jcs@crash.cts.com (John Schultz)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Paddles from assembly
Summary: Same thing as analog joysticks, man
Message-ID: <3057@crash.cts.com>
Date: 9 Jun 90 01:33:00 GMT
References: <3338.AA3338@ufweed.UUCP>
Distribution: na
Organization: Crash TimeSharing, El Cajon, CA
Lines: 22

In article <3338.AA3338@ufweed.UUCP> fweed@ufweed.UUCP (Frank P. Weed II) writes:
>   How exactly does a person read standard Atari paddles from assembly?  The
>following fragment would seem to be correct, but Intuition doesn't like the
>"move.w  d0,$dff034" - it thinks it has RMB events.
>
>         move.l   _GfxBase,a6          ; C has this variable
>         jsr      WaitTOF(a6)
>         moveq.l  #1,d0
>         move.w   d0,$dff034           ; start paddle timing
>         jsr      WaitTOF(a6)          ; data ready next vblank
>         move.w   $dff012,_Pot0Dat
>         move.w   $dff014,_Pot1Dat

  You should allocate the pot bits from misc.resource, and use WritePOTGO.
Furthermore, you should do your writes from a vertical blanking interrupt,
as it will be more more efficient than waiting around with WaitTOF().
You'll need to throw a couple of .22uf caps between pins 5-8 and 9-8 to
get full range readings, assuming the paddles are wired correcly for the
Amiga. The caps also tend to suppress jitter.


  John