drivers/input/sermouse/sermouse.txt

   1  Following information obtained from Tomi Engdahl (then@delta.hut.fi),
   2  http://www.hut.fi/~then/mytexts/mouse.html
   3
   4  Microsoft serial mouse
   5
   6    Serial data parameters:
   7      1200bps, 7 databits, 1 stop-bit
   8
   9    Data packet format:
  10      Data packet is 3 byte packet. It is send to the computer every time mouse
  11      state changes (mouse moves or keys are pressed/released).
  12          D7      D6      D5      D4      D3      D2      D1      D0
  13      1.  X       1       LB      RB      Y7      Y6      X7      X6
  14      2.  X       0       X5      X4      X3      X2      X1      X0
  15      3.  X       0       Y5      Y4      Y3      Y2      Y1      Y0
  16
  17      Note: The bit marked with X is 0 if the mouse received with 7 databits
  18      and 2 stop bits format. It is also possible to use 8 databits and 1 stop
  19      bit format for receiving. In this case X gets value 1. The safest thing
  20      to get everything working is to use 7 databits and 1 stopbit when
  21      receiving mouse information (and if you are making mouse then send out
  22      7 databits and 2 stop bits).
  23      The byte marked with 1. is send first, then the others. The bit D6 in
  24      the first byte is used for syncronizing the software to mouse packets
  25      if it goes out of sync.
  26
  27       LB is the state of the left button (1 means pressed down)
  28       RB is the state of the right button (1 means pressed down)
  29       X7-X0 movement in X direction since last packet (signed byte)
  30       Y7-Y0 movement in Y direction since last packet (signed byte)
  31
  32     Mouse identification
  33       When DTR line is toggled, mouse should send one data byte containing
  34       letter 'M' (ascii 77).
  35
  36
  37  Logitech serial mouse
  38
  39    Logitech uses the Microsoft serial mouse protocol in their mouses (for
  40    example Logitech Pilot mouse and others). The origianal protocol supports
  41    only two buttons, but logitech as added third button to some of their
  42    mouse models. To make this possible logitech has made one extension to
  43    the protocol.
  44    I have not seen any documentation about the exact documents, but here is
  45    what I have found out: The information of the third button state is sent
  46    using one extra byte which is send after the normal packet when needed.
  47    Value 32 (dec) is sent every time when the center button is pressed down.
  48    It is also sent every time with the data packet when center button is kept
  49    down and the mouse data packet is sent for other reasons. When center
  50    button is released, the mouse sends the normal data packet followed by
  51    data bythe which has value 0 (dec). As you can see the extra data byte
  52    is sent only when you mess with the center button.
  53
  54
  55  Mouse systems mouse
  56
  57    Serial data parameters:
  58      1200bps, 8 databits, 1 stop-bit
  59
  60    Data packet format:
  61           D7      D6      D5      D4      D3      D2      D1      D0
  62      1.   1       0       0       0       0       LB      CB      RB
  63      2.   X7      X6      X5      X4      X3      X2      X1      X0
  64      3.   Y7      Y6      Y5      Y4      Y3      Y4      Y1      Y0
  65      4.   X7'     X6'     X5'     X4'     X3'     X2'     X1'     X0'
  66      5.   Y7'     Y6'     Y5'     Y4'     Y3'     Y4'     Y1'     Y0'
  67
  68      LB is left button state (0 = pressed, 1 = released)
  69      CB is center button state (0 = pressed, 1 = released)
  70      RB is right button state (0 = pressed, 1 = released)
  71      X7-X0 movement in X direction since last packet in signed byte
  72            format (-128..+127), positive direction right
  73      Y7-Y0 movement in Y direction since last packet in signed byte
  74            format (-128..+127), positive direction up
  75      X7'-X0' movement in X direction since sending of X7-X0 packet in
  76              signed byte format (-128..+127), positive direction right
  77      Y7'-Y0' movement in Y direction since sending of Y7-Y0 packet in
  78              signed byte format (-128..+127), positive direction up
  79
  80      The last two bytes in the packet (bytes 4 and 5) contains information
  81      about movement data changes which have occured after data bytes 2 and 3
  82      have been sent.