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From: jmalahtinen@cc.helsinki.fi
Newsgroups: comp.os.msdos.programmer
Subject: Re: Reading MS Serial Mouse Directly.  How?
Message-ID: <1991Feb2.232807.4751@cc.helsinki.fi>
Date: 2 Feb 91 23:28:07 GMT
References: <11609@ucrmath.ucr.edu>
Followup-To: comp.os.msdos.programmer
Organization: University of Helsinki
Lines: 47

In article <11609@ucrmath.ucr.edu>, lulu@ucrmath.ucr.edu (david lu) writes:
> Here at UCR we are in the process of revamping a CS hardware
> class.  One of the labs that we thought would be fun to do is
> to have the students write an assembly program that reads the
> mouse directly from the serial port, bypassing the device
> drivers.  So ... does anyone know Microsoft's encoding scheme
> for their serial mouse?  This information is not in the docs.
> 
> Also, what are the parameters of the serial port?  Baud rate?
> Stop bits?  Parity bits?  If someone can at least provide the
> parameters, I suppose that I can write some code to read from
> the port, and try to figure out the return codes myself.  But
> if anyone already has that information already available, I'd
> be _very_ grateful if you could let me know.
> 
> I guess that I can always try looking at MS's device drivers
> with DEBUG, but I'd rather not do that ... :-)
> 
> Thank you for any help you can provide.
> 
> ---==lulu@ucrmath==---  just another bewildered college student.
> David T Lu, Amateur Thinker: lulu@ucrmath.ucr.edu, {ucsd, uci}!ucrmath!lulu
> "I seem to be having tremendous difficulty with my lifestyle."
> 					- Arthur Dent, Hitchhiker's

Microsoft format :

bit number	7    6    5    4    3    2    1    0
byte 1		1    1    L    R    Y7   Y6   X7   X6
byte 2		0    0    X5   X4   X3   X2   X1   X0
byte 3		0    0    Y5   Y4   Y3   Y2   Y1   Y0

Where	L for left key status	1 for pressed.	X0-X7 is X-axis movement data.
	R for right key status	0 for released.	Y0-Y7 is Y-axis movement data.

Data is shifted from byte 1 bit 0 to byte 3 bit 7 at speed of 1200 bps, no
parity, 2 stop bits. Data is reported upon key status change and X, Y data
change. No change will not cause report.

Source : MIGHTY MOUSE user's manual.

                              
Jussi Lahtinen         E-mail jmalahtinen@cc.Helsinki.FI (Internet)
                              JMALAHTI@FINUH.BITNET      (EARN/BITNET)
                              jmalahti@cs.Helsinki.FI    (in UNIX word)
                              HYLK::JMALAHTINEN          (DECNET)