The 3 Button Serial Mouse mini-HOWTO
Geoff Short (geoff@kipper.york.ac.uk)
v1.26 11th July 1997
_________________________________________________________________
0. Disclaimer
1. Introduction
2. Serial ports
3. Switched Mice
4. Normal Mice
5. Switching a Mouse to 3-Button Mode
6. Using gpm to Change Mouse Modes
7. Using two mice
8. XF86Config and Xconfig file examples
9. Cables, extensions and adaptors
10. Miscellaneous Problems and Setup
11. Models Tested
12. Further Information
13. Mouse Tail
__________________________________________________________________
0. Disclaimer
The following document is offered in good faith as comprising only
safe programming and procedures. No responsibility is accepted by the
author for any loss or damage caused in any way to any person or
equipment, as a direct or indirect consequence of following these
instructions.
1. Introduction
The most recent version of this document can always be found at
http://kipper.york.ac.uk/mouse.html
There is a japanese translation at
http://jf.gee.kyoto-u.ac.jp/JF/JF-ftp/euc/3-Button-Mouse.euc
Most X applications are written with the assumption that the user will
be working with a 3 button mouse. Serial mice are commonly used on
computers and are cheap to buy. Many of these mice have 3 buttons and
claim to use the Microsoft protocol, which in theory means they are
ideal for the X windows setup. (The record for the cheapest working 3
button mouse currently stands at $1.89!)
Most dual-protocol mice will work in two modes:
* 2-button Microsoft mode.
* 3-button MouseSystems mode.
This document leads you through the different steps needed to
configure your mouse in these two different modes, especially the
steps needed to use the more useful 3-button mode.
2. Serial Ports
The first thing to do is to make sure the software can find the mouse.
Work out which serial port your mouse is connected to - usually this
will be /dev/ttyS0 (COM1 under DOS) or /dev/ttyS1 (COM2). (ttyS0 is
usually the 9 pin socket, ttyS1 the 25 pin socket, but of course there
is no hard and fast rule about these things.) There are also an
equivalent number of /dev/cua devices, which are almost the same as
the ttyS ones, for instance /dev/cua0 should do the same as
/dev/ttyS0. In some cases one might work better than the other. For
convenience make a new link /dev/mouse pointing at this port. For
instance, for ttyS0:
* ln -s /dev/ttyS0 /dev/mouse
3. Switched Mice
Some mice, not usually the cheapest ones, have a switch on the bottom
marked `2/3'. Sometimes this may be `PC/MS'. In this case the `2'
setting is for 2 button Microsoft mode, and the `3' for 3 button
MouseSystems mode. The `PC/MS' switch is a bit more complicated. You
will probably find the `MS' setting is for Microsoft, and the `PC' is
for MouseSystems. You may find the `PC' setting described as ps/2
mode, but it should do MouseSystems as well. If you have such a mouse,
you can switch the switch to `3' or `PC', put the MouseSystems
settings in your XConfigs (see below) and the mouse should work
perfectly in 3-button mode.
4. Normal Mice
If you don't have any switches, and no instructions, then a little bit
of experimentation is needed. The first thing to try is to assume the
mouse maker is telling the truth, and the mouse is full Microsoft. Set
up your Xconfigs to expect a Microsoft mouse (see the Xconfig section)
and give it try.
If the mouse didn't work at all, then you don't have a Microsoft
mouse, or there is some other problem. Try the other protocols in the
configs, the man page for the config file is the best place to start
looking. Also look in the Miscellaneous Problems section below.
What you will probably find is that when you run X, the mouse works
fine but only the outer two buttons do anything. You can of course
accept this, and emulate the third button (press both buttons at once
to click the middle one) like you do with a two button mouse. To do
this, change your Xconfig file as shown in the Xconfig example section
below. This may mean you have bought a 3 button mouse for no good
reason, and you are certainly no further forward. So, now you need to
look at your hardware.
5. Switching a Mouse to 3-Button Mode
Even cheap mice can also work under the Mouse Systems protocol, with
all three buttons working. The trick is to get the mouse to think it's
a Mouse Systems one, something you rarely see in your instructions.
* Before you power up your computer, hold down the left mouse button
(and keep it held down until it has booted to be on the safe
side).
When the mouse first gets power, if the left button is held down it
switches into Mouse Systems mode. A simple fact, but not always
publicised. Note that a soft reboot of your computer may not cut the
mouse power and therefore may not work. There are a number of other
ways of switching the mode, which may or may not work with your
particular mouse. Some of these are less drastic than rebooting your
computer, two are more so!
* If your computer is get-at-able you can unplug the mouse and plug
it back in with the button held down (although you shouldn't
normally plug things in to a live computer, the RS232 spec says it
is OK).
* You may be able to reset the mouse by typing echo "*n" >
/dev/mouse, which should have the same effect as unplugging it.
Hold the left button down for Mouse Systems mode, not for
Microsoft. You could put this in whatever script you use to start
X up.
* Bob Nichols (rnichols@interaccess.com) has written a small c
program to do the same thing, which may work if echo "*n" does not
(and vice versa). You can find a copy of his source code at
http://kipper.york.ac.uk/src/fix-mouse.c
* Someone has reported that the `ClearDTR' line in the Xconfig is
enough to switch their mouse into Mouse Systems mode.
* If you are brave enough, open the mouse up (remember that this
will invalidate your warranty) and have a look inside. In some
cases, the mouse may have a switch inside, for some strange reason
known only to the manufacturer. More likely on the cheap mice is a
jumper which you can move. The switch or jumper may have the same
effect as a `MS/PC' switch described in the Switched Mice section
above. You may find that the circuit board is designed for a
switch between 2 & 3 buttons, but it hasn't been fitted. It will
look something like:
-----------
| o | o | o | SW1
-----------
1 2 3
Try linking pins 1-2 or 2-3, and see if it changes the behaviour of
the mouse. If it does, you can either fit a small switch, or
solder across the contacts for a quick and permenant solution.
* Another soldering solution which might be a last-resort for mice
which don't understand MouseSystems at all, from Peter Benie (
pjb1008@chiark.chu.cam.ac.uk). If the middle button's switch is
double-pole, connect one side of the switch to the left button's
switch, and the other side to right button's switch. If it's not a
double pole switch then use diodes rather than wire. Now, the
middle button pushes the left and right buttons down together.
Select "chordmiddle" in the XF86Config and you have a working
middle button.
* The ultimate recourse with the soldering iron was first described
to me by Brian Craft (bcboy@pyramid.bio.brandeis.edu ). Two common
generic mouse chips are the 16 pin Z8350, and the 18 pin HM8350A.
On each of these chips, one pin controls the mode of the chip, as
follows.
Pin 3 Mode
----- ----
Open Default Microsoft. Mouse Systems if a button is
held on power-up.
GND Always Mouse Systems.
Vdd Always Microsoft.
(Pins are usually numbered as follows:)
____
pin1 -| \/ |-
pin2 -| |-
pin3 -| |-
-| |-
-| |-
-| |-
-| |-
pin8 -|____|-
(This info comes courtesy of Hans-Christoph Wirth, and Juergen Exner,
who posted it to de.comp.os.linux.hardware) You can solder a link
between pin 3 and gnd, which will fix the mouse into MouseSystems
mode.
+ Peter Fredriksson (peterf@lysator.liu.se) has tried the
SYSGRATION SYS2005 chip, and found that linking Pin 3 to Gnd
forced Mouse System mode.
+ Urban Widmark (ubbe@ts.umu.se) says the same applies to the
EC3567A1 chip, where Pin 8 is ground. I've tried it as well
and it works fine.
+ Timo T Metsala (metsala@cc.helsinki.fi) has found that on the
HT6510A chip pin 3 is mode select, pin 9 is Gnd. The same
works for the HT6513A chip. Holtek also make HT6513B and
HT6513F chips - on these, pin 8 is Gnd.
+ Robert Romanowski (robin@cs.tu-berlin.de) says pin 3 - pin 8
(Gnd) works on an EM83701BP chip too.
+ Robert Kaiser (rkaiser@sysgo.de) confirms that pin 3 - Gnd
works on a EC3576A1 chip too.
* As an alternative to the above soldering methods, you can get the
mouse to hold it's own button down when booting: this circuit from
Mathias Katzer.
-----
--- R ---------O------ + Supply
| ----- | | C = 100nF capacitor
| | E | R = 100kOhm
| __ / | T = BC557 transistor
| / \ O
| B | #V | T /
|-----|-# | / Left button switch of the mouse
| | #\ | O
| \__/ |
--- \ C |
--- C ------O----------> (to somewhere deep inside the mouse)
|
### Ground
The test mouse was a no-name model MUS2S - whether this works in other
mice depends on the circuit of the mouse; if the switch is
connected to ground and not to +Supply, an npn-transistor like the
BC547 should work; R and C have to be swapped then, too.
So there you have it, the choice is yours. Stick with the default
Microsoft two buttons, or work out how to switch the mode and set X up
to take advantage of this.
6. Using gpm to Switch Mouse Modes
gpm is the program that lets you use the mouse in console mode. It is
usually included in linux distributions, and can be started from the
command line or in the startup script /etc/rc.d/rc.local. gpm is the
cause of much problem to people using bus mice, since it locks the
mouse and stops X from using it - those of us using serial mice don't
have this problem.
The two main modes for serial mice under gpm are:
* gpm -t ms for Microsoft mode;
* gpm -t msc for MouseSystems mode.
To run gpm in MouseSystems mode, you may need a -3 flag, and possibly
a DTR option, using the -o dtr flag:
* gpm -3 -o dtr -t msc
You may also be able to use gpm to probe the mouse for you and tell
you what protocol the mouse is currently using:
* gpm -t help
However, gpm is often able to recognise all three buttons of the mouse
even in Microsoft mode. And newer versions (Version 1.0 and later (?))
can then make this information available to other programs. For this
to work, you need to run gpm with the -R tag, like this:
* gpm -R -t ms
This will make gpm re-export the mouse data to a new device, called
/dev/gpmdata, which looks like a mouse to any other program. Note that
this device _always_ uses the MouseSystems protocol. You can then set
your Xconfig to use this instead of /dev/mouse as shown below, but of
course you must ensure gpm is always running when you use X. Some
people have reported that some middle-button events are not correctly
interpreted by X using this technique, this may be down to an
individual mouse setup.
Changing button mapping for gpm and X (gustafso@math.utah.edu)
You may find that gpm uses different default button mappings to X, so
using both systems on the same machine can be confusing. To make X use
the same buttons for select and paste operations as gpm, use the X
command
* xmodmap -e "pointer = 1 3 2"
which causes the left button to select and the right button to paste,
for either 2-button or 3-button mice. To force gpm to use the X
standard button mapping, start it with a -B command, eg:
* gpm -t msc -B 132
7. Using two mice
In some cases, for instance a laptop with a built-in pointing device,
you may wish to use a serial mouse as a second device. In most cases
the built-in device uses the ps/2 protocol, and can be ignored if you
don't wish to use it. Simply configure gpm or X to use /dev/ttyS0 (or
whatever) as usual.
To use both at once, you might be able to use gpm to re-export one or
both devices. One person who has done this is Patrick Canupp
(canupp@leland.Stanford.EDU) - you can check out his web pages at
http://www-leland.stanford.edu/~canupp/install_index.html for details.
8. XF86Config and Xconfig file examples
The location of your configuration file for X depends on the
particular release and distribution you have. It will probably be
either /etc/Xconfig /etc/XF86Config or /usr/X11/lib/X11/XF86Config.
You should see which one it is when you start X - it will be echoed to
the screen before all the options are displayed. The syntax is
slightly different between the XF86Config and Xconfig files, so both
are given.
Microsoft Serial Mouse
* XF86config:
Section "Pointer"
Protocol "microsoft"
Device "/dev/mouse"
EndSection
* Xconfig:
#
# Mouse definition and related parameters
#
Microsoft "/dev/mouse"
Microsoft Serial Mouse (2 or 3 button) with Three Button Emulation
* XF86config:
Section "Pointer"
Protocol "microsoft"
Device "/dev/mouse"
Emulate3Buttons
EndSection
* Xconfig:
#
# Mouse definition and related parameters
#
Microsoft "/dev/mouse"
Emulate3Buttons
MouseSystems Three Button Serial Mouse
* XF86config:
Section "Pointer"
Protocol "mousesystems"
Device "/dev/mouse"
ClearDTR # These two lines probably won't be needed,
ClearRTS # try without first and then just the DTR
EndSection
* Xconfig:
#
# Mouse definition and related parameters
#
MouseSystems "/dev/mouse"
ClearDTR # These two lines probably won't be needed,
ClearRTS # try without first and then just the DTR
Microsoft Serial Mouse with gpm -R
* XF86config:
Section "Pointer"
Protocol "MouseSystems"
Device "/dev/gpmdata"
EndSection
* Xconfig:
#
# Mouse definition and related parameters
#
MouseSystems "/dev/gpmdata"
9. Cables, extensions and adaptors
The only wires needed in a mouse cable are as follows: TxD and RxD for
data transfer, RTS and/or DTR for power sources, and ground.
Translated into pin numbers, they are:
9-pin port 25-pin port
TxD 3 2
RxD 2 3
RTS 7 4
DTR 4 20
Gnd 5 7
The above table may be of use if you wish to make adaptors between 9-
and 25-pin plugs, or extension cables.
10. Miscellaneous Problems and Setups
* If you have trouble with your mouse in X or console mode, check
you are not running a getty on the serial line, or anything else
such as a modem for that matter. Also check for IRQ conflicts.
* It is possible that you need to hold down the left button when
booting X windows. Some systems may send some sort of signal or
spike to the mouse when X starts.
* Problems with serial devices may be due to the serial port not
being initialised correctly at boot. This is done by the setseral
command, run from the start-up script /etc/rc.d/rc.serial. Check
the man page for setserial and the Serial-HOWTO for more details.
It may be worth a little experimentation with types, for instance
try setserial /dev/mouse uart 16550 or 16550a regardless of what
port you actually have. (For instance, mice don't like the
16c550AF).
* The ClearDTR flag may not work properly on some systems, unless
you disable the RTS/CTS handshaking with the command:
+ stty -crtscts < /dev/mouse
(Tested on UART 16450/Pentium by Vladimir Geogjaev
geogjaev@wave.sio.rssi.ru)
* Logitech mice may require the line ChordMiddle to enable the
middle of the three buttons to work. This line replaces
Emulate3Buttons or goes after the /dev/mouse line in the config
file. You may well need the ClearDTR and ClearRTS lines in your
Xconfig. Some Logitech mice positively do not need the ChordMiddle
line - one symptom of this problem is that menus seem to move with
the mouse instead of scrolling down. (From: chang@platform.com)
* Swapping buttons: use the xmodmap command to change which physical
button registers as each mouse click. eg: xmodmap -e "pointer = 3
2 1" will turn round the buttons for use in the left hand. If you
only have a two-button mouse then it's just numbers 1 & 2.
* Acceleration: use the xset m command to change the mouse settings.
eg xset m 2 will set the acceleration to 2. Look at the manpage
for full details.
* Pointer offset: If the click action appears to be coming from the
left or right of where the cursor is, it may be that your screen
is not aligned. This is a problem with the S3 driver, which you
may be able to fix using xvidtune. Try Invert_VCLK/InvertVCLK, or
EarlySC. This info from Bill Lavender ( lavender@MCS.COM) and
Simon Hargrave. In the XF86Config, it might look like this:
+ XF86Config:
Subsection "Display"
Modes "1024x768" "800x600" "640x480" "1280x1024"
Invert_VCLK "*" 1
* If you are getting `bouncing' of the mouse buttons, ie two clicks
when you only wanted one, there may be something wrong with the
mouse. This problem has been solved for logitech mice by Bob
Nichols ( rnichols@interaccess.com) and involves soldering some
resistors and a chip in the mouse to debounce the microswitches.
* If some users cannot get the mouse to work but some (eg root) can,
it is possible that the users are not running exactly the same
thing - for instance a different version of X or a different
Xconfig. Check the X start-up messages carefully to make sure.
* If you find the mouse pointer is erasing things from your screen,
you have a server config problem. Try adding the option linear, or
maybe nolinear to the graphics card section, or if it is a PCI
board, the options tgui_pci_write_off and tgui_pci_read_off. (This
seems to be a Trident Card problem.)
* If your mouse stops working when its sunny or when you turn a
light on, it may be that the sensors are being swamped by light
getting through the case. You could try painting the inside of the
case black, or putting some card in the top.
11. Models Tested
There are a lot of different mice out there, and I cannot honestly say
that you should go out and buy one rather than the other. What I can
do is give a list of what I think these mice do, based on experience
and heresay. Even with this information you should be a little
cautious - we have two identical mice in our office on two computers,
some things work on one and not t'other! Any additions to this list
would be welcome.
Mouse Systems optical mouse, serial version
Works well (as you might expect from the name!) without
ClearDTR or ClearRTS in the config.
WiN mouse, as sold by Office World for eight quid.
Standard dual-mode Microsoft/MouseSystems.
Agiler Mouse 2900
Standard dual-mode Microsoft/MouseSystems. SYSGRATION
SYS2005 chip is solderable.
Sicos mouse,
Works ok, needs ClearDTR & Clear RTS in config.
Index sell a mouse for 10 quid,
Doesn't work in 3 button mode, but does have nice
instructions :-)
Artec,
Usual dual-protocol mouse, needs `ClearDTR' set in config,
NOT `ClearRTS'
DynaPoint 3 button serial mouse.
Usual dual-protocol mouse, needs `ClearDTR' AND `ClearRTS'
in Xconfig.
Genius Easymouse 3 button mouse
Works fine with Mouseman protocol without the ChordMiddle
parameter set. From Roderick Johnstone (
rmj@ast.cam.ac.uk)
Truemouse, made in Taiwan
Works OK, needs `ClearDTR' in config. (From Tim
MacEachern)
Champ brand mouse
Needs to have switch in PC mode, which enables
MouseSystems protocol also. (From
tnugent@gucis.cit.gu.edu.au)
MicroSpeed mouse
Usual dual-protocol mouse.
Venus brand ($7)
Has a jumper inside to switch between 2 and 3 button mode.
(From mhoward@mth.com )
Saturn
Switched mouse, works OK as MouseSystems in 3-button
position. (From grant@oj.rsmas.miami.edu .)
Manhattan mouse.
Switch for `MS AM' / `PC AT' modes, MS mode works fine
with the gpm -R method. (From komanec@umel.fee.vutbr.cz).
Inland mouse.
Switch for `PC/MS' modes, works fine. (From
http://ptsg.eecs.berkeley.edu/~venkates).
qMouse (3-button), FCC ID E6qmouse X31.
Sells in the USA for about $10. Works with `gpm -t msc -r
20'. No jumpers or switches for MouseSystems 3-button
mode. Unreliable in X. Does not respond to echo "*n" >
/dev/mouse.
Mitsumi Mouse (2-button), FCC ID EW4ECM-S3101.
Sells in the USA for about $12. Reliable in X and under
gpm, smooth double-button. (These two from
gustafso@math.utah.edu)
PC Accessories mouse that i got from CompUSA for under $10.
Has PC/MS switch on bottom. Works OK. (From
steveb@communique.net)
First Mouse - seriously cheap at 7.79 pounds at Tempo.
Dual Microsoft/MouseSystems, mode set by button depress at
power-up. No switches, no links. Four wire connection,
echo '*n' doesn't work. `gpm -R' works a treat. (From
peterk@henhouse.demon.co.uk)
Trust 3-button mouse.
Dual-mode with switch, works OK as MouseSystems in `PC'
mode. gpm doesn't like the Microsoft mode though.
Chic 410
Works perfectly when kept in ms mode and used with the gpm
-R command. From Stephen M. Weiss
(steve@esc.ie.lehigh.edu)
KeyMouse 3-button mouse.
No switch, works OK with ClearDTR and ClearRTS in Xconfig;
`-o dtr needed with gpm. (From EZ4PHIL@aol.com)
Qtronix keyboard `Scorpio 60'
All three buttons work in MouseSystems protocol. (From
hwe@uebemc.siemens.de)
Tecra 720 laptop
The glidepoint is on /dev/cua0; the stick is on
/dev/psaux. (From apollo@anl.gov)
Anubis mouse
Works fine, need to hold down left button whenever
switching to the X virtual console. (From Joel Crisp)
Yakumo No.1900 mouse
Works with gpm -R -t ms exporting to X. (From Oliver
Schwank)
Genius `Easy Trak' Trackball
Is _not_ Microsoft compatible, use Mouseman in the Xconfig
and it will work fine. (From VTanger@aol.com.)
Highscreen Mouse Pro
`Works fine' says alfonso@univaq.it.
Logitech CA series
Works in X using MMseries protocol, at 2400 Baud, 150
SampleRate. (Should also apply to Logitech CC, CE, C7 & C9
mice). From vkochend@nyx.net.
A4-Tech mouse
Works OK, needs DTR line under both X and gpm. (From
deane@gooroos.com)
12. Further Information
* Mouse Systems has a web site at http://www.mousesystems.com/. They
have a Windows driver if you need one.
* The Linux Serial HOWTO is available from mirrors of sunsite around
the world. If you don't know where your nearest mirror is, start
at http://sunsite.unc.edu/mdw/linux.html
* There is a very good explanation of how mice work at
http://box.argonet.co.uk/users/4qd/meece.html.
* Fuller details of the Xconfig and XF86Config files are found on
the relevant man pages, and in the documentation about installing
X windows such as the Xfree86 HOWTO. Also, see the XFree86 FAQ at
a mirror of http://www.XFree86.org/.
* Information about gpm can be found on the man page, also try the
web page of Darin Ernst at
http://www.castle.net/X-notebook/mouse.txt.
* Lots of information on mice hardware and software can be found at
http://www.hut.fi/~then/electronics/pc.html#pc_mouse
13. Mouse Tail
Much of the information for this document has been trawled from the
various linux newsgroups. I am sorry I did not keep a record of
everyone who has indirectly contributed by this route, thank you all
very much.
So, to sum up:
* Even cheap 3 button Microsoft mice can be made to work.
* Configure your copy of X to expect a Mouse Systems mouse.
* Hold down the left button at power-on to switch the mouse to
MouseSystems mode.
* You might need to hold the left button down when starting X.
* Mice are more intelligent than you think.