Xref: utzoo comp.sys.atari.8bit:2183 comp.sys.cbm:1997
Path: utzoo!utgpu!watmath!clyde!ima!bbn!bbn.com!slackey
From: slackey@bbn.com (Stan Lackey)
Newsgroups: comp.sys.atari.8bit,comp.sys.cbm
Subject: Re: commodore mouse
Message-ID: <34436@bbn.COM>
Date: 11 Jan 89 21:06:22 GMT
References: <33889@bbn.COM> <5644@cbmvax.UUCP> <13398@cup.portal.com>
Sender: news@bbn.COM
Reply-To: slackey@BBN.COM (Stan Lackey)
Organization: Bolt Beranek and Newman Inc., Cambridge MA
Lines: 39

In article <13398@cup.portal.com> Bob_BobR_Retelle@cup.portal.com writes:
>Fred Bowen writes about how the C-64 reads the 1351 Commodore mouse..
>The 8-bit Atari uses a somewhat similar way of reading the A/D ports through
>hardware, although the scaling seems to be a little different.  The Atari
>paddles on a C-64 give a slightly different range than the Commodore paddles
 
>As far as the proportional mode of the 1351 mouse, does the resultant data
>get stored in the same locations as the paddle values..?  If so, it just might
>be possible that the mouse could be read on an 8-bit Atari...  

I started this - I got a cbm mouse to use with the Atari.
The first problem was that it didn't even plug in due to differing mechanics
(on my XE - I know nothing of 400/800 or XL), so I had to go to Radio Shack
and get connectors.  Their joystick extension cable might work - I didn't
think of it at the time.

The mouse runs in two modes: joystick simulator and analog proportional.
I use joystick simulator - the mouse puts out a 20ms pulse on the appropriate
lines when moved.  I have an assem language routine that I invoke with a timer
that polls the lines, and updates memory locations accordingly.  Like the
ST mouse/trakball routine I posted sometime back.

The reason I am going to all this trouble is for that second mouse button -
my religion does not accept one-button mouses.  Also, I got the cbm mouse for
$40, and I don't even know how to get an ST mouse.  And my trakball is 
beginning to stick.

In joystick mode, the second
button can actually be read through the pot input; when pushed, it reads like
3, and when released, it reads like 230? or so.

Anyway, it looked to me like the Commodore and the Atari read the pot lines
in a similar way; but trust me, it doesn't work.  In proportional mode,
the Atari pot registers read 230? or whatever the max value is, regardless
of mouse position. 

I would love to get a curcuit to allow the Atari to read the analog output.
Joystick mode [insert obscene expression], but I can live with it for now...
-Stan