Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!wuarchive!udel!mmdf
From: ccsoola@sacemnet.af.mil (CCSOOLA)
Newsgroups: comp.sys.amiga
Subject: New Atari Trackball hack
Message-ID: <37165@nigel.ee.udel.edu>
Date: 25 Nov 90 03:23:52 GMT
Sender: mmdf@ee.udel.edu
Lines: 50

Quoting from message <15998@cbmvax.commodore.com>
		by Bob Raible <raible@cbmvax.commodore.com>:

>  The following are directions for converting the Atari trakball that has
>  no testpoints and no socketed IC's as previously described.

		[Other identification info omitted...]
 
>  ...on left side of [the trackball's] PCB are 2 IC's....  Topmost IC I'll
>  label IC#1 (16 pins)....    

		[Other instructions omitted...]

>  	3) Connect port pin #1 to IC#1,pin #6.
>  	   Connect port pin #2 to IC#1,pin #10.
>  	   Connect port pin #3 to IC#2,pin #11.
>	   Connect port pin #4 to IC#2,pin #3.
> 
>  	   This serves to hook up mouse vertical and horizontal, and
>	   their quadratures(in that order).
 
		[Further instructions omitted...]

I followed the instructions to the letter, and the trackball conversion
_mostly_ worked.  I couldn't get any coherent movement in the horizontal axis,
though, so I had to fiddle with it.  I wound up making one change to the above
instructions:

Instead of 
  	   "Connect port pin #2 to IC#1,pin #10."
try
  	   "Connect port pin #2 to IC#1,pin #2."

When I did this, the x-axis worked.  (I'm not sure just what I've hooked into;
I don't have pinouts for IC#1, but I traced signals with a logic probe until I
found something likely-looking.  When I did, I tried the connection described
above, and it's hunky-dorey.)

					>JS<
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