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From: phco@ecsvax.UUCP (John Miller)
Newsgroups: net.micro.pc
Subject: Re: What Does MS Serial Mouse Send?
Message-ID: <2075@ecsvax.UUCP>
Date: Mon, 29-Sep-86 13:57:40 EDT
Article-I.D.: ecsvax.2075
Posted: Mon Sep 29 13:57:40 1986
Date-Received: Fri, 3-Oct-86 08:31:59 EDT
References: <411@twitch.UUCP>
Reply-To: phco@ecsvax.UUCP (John Miller)
Distribution: net
Organization: Univ. of North Carolina at Chapel Hill
Lines: 28

In article <411@twitch.UUCP> dud@twitch.UUCP ( W.F.Dudley) writes:
>I need to know what the Microsoft Serial Mouse puts out.
>What baud rate, stop bits, parity, bits per character,
>and of course, what characters does it send?

The Microsoft and Mouse Systems Mice have the following RS-232C settings:
	1200 baud, 8 data bits, 1 stop bit, no parity

The Mouse Systems Mouse is a superset of the Microsoft Mouse, since
it has 3 buttons instead of 2.  The 3 button mouse sends data in five-
byte blocks whenever a change of state occurs (i.e., when the mouse moves
or a button is pressed or released).  The data format is as follows:

1st byte (syncbyte):  Upper five bits are 10000.
                      Lower three bits give the button states 
                            (0 = depressed).

Next four bytes are 2's-complement signed 8-bit binary numbers. Positive
is to the right and up.  The 2nd and 4th bytes report changes in the x,
or horizontal, direction, and the 3rd and 5th bytes report changes in the
y, or vertical, direction.  The resolution is 100/inch.


-- 

                        John Miller  (ecsvax!phco)
                        Dept. of Pharmacology, Univ. of N.C.-Chapel Hill
                        Chapel Hill, NC 27514       (919) 966-4628