[Coco] [Bulk] AT306 Mouse Question

[Gene Heskett]

On Saturday 08 September 2007, Joel Ewy wrote:

>Paul Fitch wrote:

>> There is a 3-pin header on the AT306 motherboard that says MOUSE.  How do

>> I use that?

>

>My assumption, from the era in which the AT306 was produced, would be

>that that is a serial port.  So you should have a ground wire, a

>Transmit Data pin, and uh, er...  That's not enough pins.  I don't know

>enough about the serial mouse protocol.  Does the mouse ever need to

>receive data from the host?  E.g., some kind of configuration packet?


The serial mice that were popular back about that time were transmit only, at 
1200 baud, 8n1, and either a 3 byte or 5 byte packet depending on how many 
buttons it had.  I used one such for quite some time on my coco.  It sent an 
x/y position move, and a switch status for any motion activity at all, or was 
quiet when just laying there.  The one I had did use the +-12 volts for a 
true rs232 interface, but I believe there was also some of the 'ps2' stuff 
that ran on straight 5 volts using a ttl version of the protocol, possibly at 
a higher baud rate, but I've no experience there.  I'd open it up and 
ascertain the supply connections, power it with 5 volts, and monitor the 
third line with a scope, which could tell you everything else you'd need to 
know.


>If not, then I suppose all you would need is power and data from the

>mouse to the host.  Power is probably supplied by a ground wire and one

>of the RS-232 handshaking lines (it would have to be one that's present

>in the 9-pin AT serial port).  Maybe CTS?  But on something like this,

>it's entirely possible that it's just connected to a +5 or +12 volt

>supply line.

>

>You can pretty quickly determine if this is anywhere close to correct if

>you have an ohm meter (nice if it has a continuity beeper).  See if one

>of the pins hooks up to ground, (either an obvious ground plane or a

>ground wire on the power supply connector), and then try to trace one of

>the other two to the +5 or +12V supply.  Failing that, turn the beast on

>and see if you get 5-12 volts on one of the pins with a volt meter.

>

>Probably somebody on this list has better information about the '306

>mouse port than I.

>

>JCE

>

>> --

>> Coco mailing list

>> Coco at maltedmedia.com

>> http://five.pairlist.net/mailman/listinfo/coco

>

>--

>Coco mailing list

>Coco at maltedmedia.com

>http://five.pairlist.net/mailman/listinfo/coco




-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Detroit is Cleveland without the glitter.