0001 Elantech Touchpad Driver
0002 ========================
0003
0004 Copyright (C) 2007-2008 Arjan Opmeer <arjan@opmeer.net>
0005
0006 Extra information for hardware version 1 found and
0007 provided by Steve Havelka
0008
0009 Version 2 (EeePC) hardware support based on patches
0010 received from Woody at Xandros and forwarded to me
0011 by user StewieGriffin at the eeeuser.com forum
0012
0013 .. Contents
0014
0015 1. Introduction
0016 2. Extra knobs
0017 3. Differentiating hardware versions
0018 4. Hardware version 1
0019 4.1 Registers
0020 4.2 Native relative mode 4 byte packet format
0021 4.3 Native absolute mode 4 byte packet format
0022 5. Hardware version 2
0023 5.1 Registers
0024 5.2 Native absolute mode 6 byte packet format
0025 5.2.1 Parity checking and packet re-synchronization
0026 5.2.2 One/Three finger touch
0027 5.2.3 Two finger touch
0028 6. Hardware version 3
0029 6.1 Registers
0030 6.2 Native absolute mode 6 byte packet format
0031 6.2.1 One/Three finger touch
0032 6.2.2 Two finger touch
0033 7. Hardware version 4
0034 7.1 Registers
0035 7.2 Native absolute mode 6 byte packet format
0036 7.2.1 Status packet
0037 7.2.2 Head packet
0038 7.2.3 Motion packet
0039 8. Trackpoint (for Hardware version 3 and 4)
0040 8.1 Registers
0041 8.2 Native relative mode 6 byte packet format
0042 8.2.1 Status Packet
0043
0044
0045
0046 Introduction
0047 ~~~~~~~~~~~~
0048
0049 Currently the Linux Elantech touchpad driver is aware of four different
0050 hardware versions unimaginatively called version 1,version 2, version 3
0051 and version 4. Version 1 is found in "older" laptops and uses 4 bytes per
0052 packet. Version 2 seems to be introduced with the EeePC and uses 6 bytes
0053 per packet, and provides additional features such as position of two fingers,
0054 and width of the touch. Hardware version 3 uses 6 bytes per packet (and
0055 for 2 fingers the concatenation of two 6 bytes packets) and allows tracking
0056 of up to 3 fingers. Hardware version 4 uses 6 bytes per packet, and can
0057 combine a status packet with multiple head or motion packets. Hardware version
0058 4 allows tracking up to 5 fingers.
0059
0060 Some Hardware version 3 and version 4 also have a trackpoint which uses a
0061 separate packet format. It is also 6 bytes per packet.
0062
0063 The driver tries to support both hardware versions and should be compatible
0064 with the Xorg Synaptics touchpad driver and its graphical configuration
0065 utilities.
0066
0067 Note that a mouse button is also associated with either the touchpad or the
0068 trackpoint when a trackpoint is available. Disabling the Touchpad in xorg
0069 (TouchPadOff=0) will also disable the buttons associated with the touchpad.
0070
0071 Additionally the operation of the touchpad can be altered by adjusting the
0072 contents of some of its internal registers. These registers are represented
0073 by the driver as sysfs entries under /sys/bus/serio/drivers/psmouse/serio?
0074 that can be read from and written to.
0075
0076 Currently only the registers for hardware version 1 are somewhat understood.
0077 Hardware version 2 seems to use some of the same registers but it is not
0078 known whether the bits in the registers represent the same thing or might
0079 have changed their meaning.
0080
0081 On top of that, some register settings have effect only when the touchpad is
0082 in relative mode and not in absolute mode. As the Linux Elantech touchpad
0083 driver always puts the hardware into absolute mode not all information
0084 mentioned below can be used immediately. But because there is no freely
0085 available Elantech documentation the information is provided here anyway for
0086 completeness sake.
0087
0088
0089 Extra knobs
0090 ~~~~~~~~~~~
0091
0092 Currently the Linux Elantech touchpad driver provides three extra knobs under
0093 /sys/bus/serio/drivers/psmouse/serio? for the user.
0094
0095 * debug
0096
0097 Turn different levels of debugging ON or OFF.
0098
0099 By echoing "0" to this file all debugging will be turned OFF.
0100
0101 Currently a value of "1" will turn on some basic debugging and a value of
0102 "2" will turn on packet debugging. For hardware version 1 the default is
0103 OFF. For version 2 the default is "1".
0104
0105 Turning packet debugging on will make the driver dump every packet
0106 received to the syslog before processing it. Be warned that this can
0107 generate quite a lot of data!
0108
0109 * paritycheck
0110
0111 Turns parity checking ON or OFF.
0112
0113 By echoing "0" to this file parity checking will be turned OFF. Any
0114 non-zero value will turn it ON. For hardware version 1 the default is ON.
0115 For version 2 the default it is OFF.
0116
0117 Hardware version 1 provides basic data integrity verification by
0118 calculating a parity bit for the last 3 bytes of each packet. The driver
0119 can check these bits and reject any packet that appears corrupted. Using
0120 this knob you can bypass that check.
0121
0122 Hardware version 2 does not provide the same parity bits. Only some basic
0123 data consistency checking can be done. For now checking is disabled by
0124 default. Currently even turning it on will do nothing.
0125
0126 * crc_enabled
0127
0128 Sets crc_enabled to 0/1. The name "crc_enabled" is the official name of
0129 this integrity check, even though it is not an actual cyclic redundancy
0130 check.
0131
0132 Depending on the state of crc_enabled, certain basic data integrity
0133 verification is done by the driver on hardware version 3 and 4. The
0134 driver will reject any packet that appears corrupted. Using this knob,
0135 The state of crc_enabled can be altered with this knob.
0136
0137 Reading the crc_enabled value will show the active value. Echoing
0138 "0" or "1" to this file will set the state to "0" or "1".
0139
0140 Differentiating hardware versions
0141 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0142
0143 To detect the hardware version, read the version number as param[0].param[1].param[2]::
0144
0145 4 bytes version: (after the arrow is the name given in the Dell-provided driver)
0146 02.00.22 => EF013
0147 02.06.00 => EF019
0148
0149 In the wild, there appear to be more versions, such as 00.01.64, 01.00.21,
0150 02.00.00, 02.00.04, 02.00.06::
0151
0152 6 bytes:
0153 02.00.30 => EF113
0154 02.08.00 => EF023
0155 02.08.XX => EF123
0156 02.0B.00 => EF215
0157 04.01.XX => Scroll_EF051
0158 04.02.XX => EF051
0159
0160 In the wild, there appear to be more versions, such as 04.03.01, 04.04.11. There
0161 appears to be almost no difference, except for EF113, which does not report
0162 pressure/width and has different data consistency checks.
0163
0164 Probably all the versions with param[0] <= 01 can be considered as
0165 4 bytes/firmware 1. The versions < 02.08.00, with the exception of 02.00.30, as
0166 4 bytes/firmware 2. Everything >= 02.08.00 can be considered as 6 bytes.
0167
0168
0169 Hardware version 1
0170 ~~~~~~~~~~~~~~~~~~
0171
0172 Registers
0173 ---------
0174
0175 By echoing a hexadecimal value to a register it contents can be altered.
0176
0177 For example::
0178
0179 echo -n 0x16 > reg_10
0180
0181 * reg_10::
0182
0183 bit 7 6 5 4 3 2 1 0
0184 B C T D L A S E
0185
0186 E: 1 = enable smart edges unconditionally
0187 S: 1 = enable smart edges only when dragging
0188 A: 1 = absolute mode (needs 4 byte packets, see reg_11)
0189 L: 1 = enable drag lock (see reg_22)
0190 D: 1 = disable dynamic resolution
0191 T: 1 = disable tapping
0192 C: 1 = enable corner tap
0193 B: 1 = swap left and right button
0194
0195 * reg_11::
0196
0197 bit 7 6 5 4 3 2 1 0
0198 1 0 0 H V 1 F P
0199
0200 P: 1 = enable parity checking for relative mode
0201 F: 1 = enable native 4 byte packet mode
0202 V: 1 = enable vertical scroll area
0203 H: 1 = enable horizontal scroll area
0204
0205 * reg_20::
0206
0207 single finger width?
0208
0209 * reg_21::
0210
0211 scroll area width (small: 0x40 ... wide: 0xff)
0212
0213 * reg_22::
0214
0215 drag lock time out (short: 0x14 ... long: 0xfe;
0216 0xff = tap again to release)
0217
0218 * reg_23::
0219
0220 tap make timeout?
0221
0222 * reg_24::
0223
0224 tap release timeout?
0225
0226 * reg_25::
0227
0228 smart edge cursor speed (0x02 = slow, 0x03 = medium, 0x04 = fast)
0229
0230 * reg_26::
0231
0232 smart edge activation area width?
0233
0234
0235 Native relative mode 4 byte packet format
0236 -----------------------------------------
0237
0238 byte 0::
0239
0240 bit 7 6 5 4 3 2 1 0
0241 c c p2 p1 1 M R L
0242
0243 L, R, M = 1 when Left, Right, Middle mouse button pressed
0244 some models have M as byte 3 odd parity bit
0245 when parity checking is enabled (reg_11, P = 1):
0246 p1..p2 = byte 1 and 2 odd parity bit
0247 c = 1 when corner tap detected
0248
0249 byte 1::
0250
0251 bit 7 6 5 4 3 2 1 0
0252 dx7 dx6 dx5 dx4 dx3 dx2 dx1 dx0
0253
0254 dx7..dx0 = x movement; positive = right, negative = left
0255 byte 1 = 0xf0 when corner tap detected
0256
0257 byte 2::
0258
0259 bit 7 6 5 4 3 2 1 0
0260 dy7 dy6 dy5 dy4 dy3 dy2 dy1 dy0
0261
0262 dy7..dy0 = y movement; positive = up, negative = down
0263
0264 byte 3::
0265
0266 parity checking enabled (reg_11, P = 1):
0267
0268 bit 7 6 5 4 3 2 1 0
0269 w h n1 n0 ds3 ds2 ds1 ds0
0270
0271 normally:
0272 ds3..ds0 = scroll wheel amount and direction
0273 positive = down or left
0274 negative = up or right
0275 when corner tap detected:
0276 ds0 = 1 when top right corner tapped
0277 ds1 = 1 when bottom right corner tapped
0278 ds2 = 1 when bottom left corner tapped
0279 ds3 = 1 when top left corner tapped
0280 n1..n0 = number of fingers on touchpad
0281 only models with firmware 2.x report this, models with
0282 firmware 1.x seem to map one, two and three finger taps
0283 directly to L, M and R mouse buttons
0284 h = 1 when horizontal scroll action
0285 w = 1 when wide finger touch?
0286
0287 otherwise (reg_11, P = 0):
0288
0289 bit 7 6 5 4 3 2 1 0
0290 ds7 ds6 ds5 ds4 ds3 ds2 ds1 ds0
0291
0292 ds7..ds0 = vertical scroll amount and direction
0293 negative = up
0294 positive = down
0295
0296
0297 Native absolute mode 4 byte packet format
0298 -----------------------------------------
0299
0300 EF013 and EF019 have a special behaviour (due to a bug in the firmware?), and
0301 when 1 finger is touching, the first 2 position reports must be discarded.
0302 This counting is reset whenever a different number of fingers is reported.
0303
0304 byte 0::
0305
0306 firmware version 1.x:
0307
0308 bit 7 6 5 4 3 2 1 0
0309 D U p1 p2 1 p3 R L
0310
0311 L, R = 1 when Left, Right mouse button pressed
0312 p1..p3 = byte 1..3 odd parity bit
0313 D, U = 1 when rocker switch pressed Up, Down
0314
0315 firmware version 2.x:
0316
0317 bit 7 6 5 4 3 2 1 0
0318 n1 n0 p2 p1 1 p3 R L
0319
0320 L, R = 1 when Left, Right mouse button pressed
0321 p1..p3 = byte 1..3 odd parity bit
0322 n1..n0 = number of fingers on touchpad
0323
0324 byte 1::
0325
0326 firmware version 1.x:
0327
0328 bit 7 6 5 4 3 2 1 0
0329 f 0 th tw x9 x8 y9 y8
0330
0331 tw = 1 when two finger touch
0332 th = 1 when three finger touch
0333 f = 1 when finger touch
0334
0335 firmware version 2.x:
0336
0337 bit 7 6 5 4 3 2 1 0
0338 . . . . x9 x8 y9 y8
0339
0340 byte 2::
0341
0342 bit 7 6 5 4 3 2 1 0
0343 x7 x6 x5 x4 x3 x2 x1 x0
0344
0345 x9..x0 = absolute x value (horizontal)
0346
0347 byte 3::
0348
0349 bit 7 6 5 4 3 2 1 0
0350 y7 y6 y5 y4 y3 y2 y1 y0
0351
0352 y9..y0 = absolute y value (vertical)
0353
0354
0355 Hardware version 2
0356 ~~~~~~~~~~~~~~~~~~
0357
0358
0359 Registers
0360 ---------
0361
0362 By echoing a hexadecimal value to a register it contents can be altered.
0363
0364 For example::
0365
0366 echo -n 0x56 > reg_10
0367
0368 * reg_10::
0369
0370 bit 7 6 5 4 3 2 1 0
0371 0 1 0 1 0 1 D 0
0372
0373 D: 1 = enable drag and drop
0374
0375 * reg_11::
0376
0377 bit 7 6 5 4 3 2 1 0
0378 1 0 0 0 S 0 1 0
0379
0380 S: 1 = enable vertical scroll
0381
0382 * reg_21::
0383
0384 unknown (0x00)
0385
0386 * reg_22::
0387
0388 drag and drop release time out (short: 0x70 ... long 0x7e;
0389 0x7f = never i.e. tap again to release)
0390
0391
0392 Native absolute mode 6 byte packet format
0393 -----------------------------------------
0394
0395 Parity checking and packet re-synchronization
0396 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
0397
0398 There is no parity checking, however some consistency checks can be performed.
0399
0400 For instance for EF113::
0401
0402 SA1= packet[0];
0403 A1 = packet[1];
0404 B1 = packet[2];
0405 SB1= packet[3];
0406 C1 = packet[4];
0407 D1 = packet[5];
0408 if( (((SA1 & 0x3C) != 0x3C) && ((SA1 & 0xC0) != 0x80)) || // check Byte 1
0409 (((SA1 & 0x0C) != 0x0C) && ((SA1 & 0xC0) == 0x80)) || // check Byte 1 (one finger pressed)
0410 (((SA1 & 0xC0) != 0x80) && (( A1 & 0xF0) != 0x00)) || // check Byte 2
0411 (((SB1 & 0x3E) != 0x38) && ((SA1 & 0xC0) != 0x80)) || // check Byte 4
0412 (((SB1 & 0x0E) != 0x08) && ((SA1 & 0xC0) == 0x80)) || // check Byte 4 (one finger pressed)
0413 (((SA1 & 0xC0) != 0x80) && (( C1 & 0xF0) != 0x00)) ) // check Byte 5
0414 // error detected
0415
0416 For all the other ones, there are just a few constant bits::
0417
0418 if( ((packet[0] & 0x0C) != 0x04) ||
0419 ((packet[3] & 0x0f) != 0x02) )
0420 // error detected
0421
0422
0423 In case an error is detected, all the packets are shifted by one (and packet[0] is discarded).
0424
0425 One/Three finger touch
0426 ^^^^^^^^^^^^^^^^^^^^^^
0427
0428 byte 0::
0429
0430 bit 7 6 5 4 3 2 1 0
0431 n1 n0 w3 w2 . . R L
0432
0433 L, R = 1 when Left, Right mouse button pressed
0434 n1..n0 = number of fingers on touchpad
0435
0436 byte 1::
0437
0438 bit 7 6 5 4 3 2 1 0
0439 p7 p6 p5 p4 x11 x10 x9 x8
0440
0441 byte 2::
0442
0443 bit 7 6 5 4 3 2 1 0
0444 x7 x6 x5 x4 x3 x2 x1 x0
0445
0446 x11..x0 = absolute x value (horizontal)
0447
0448 byte 3::
0449
0450 bit 7 6 5 4 3 2 1 0
0451 n4 vf w1 w0 . . . b2
0452
0453 n4 = set if more than 3 fingers (only in 3 fingers mode)
0454 vf = a kind of flag ? (only on EF123, 0 when finger is over one
0455 of the buttons, 1 otherwise)
0456 w3..w0 = width of the finger touch (not EF113)
0457 b2 (on EF113 only, 0 otherwise), b2.R.L indicates one button pressed:
0458 0 = none
0459 1 = Left
0460 2 = Right
0461 3 = Middle (Left and Right)
0462 4 = Forward
0463 5 = Back
0464 6 = Another one
0465 7 = Another one
0466
0467 byte 4::
0468
0469 bit 7 6 5 4 3 2 1 0
0470 p3 p1 p2 p0 y11 y10 y9 y8
0471
0472 p7..p0 = pressure (not EF113)
0473
0474 byte 5::
0475
0476 bit 7 6 5 4 3 2 1 0
0477 y7 y6 y5 y4 y3 y2 y1 y0
0478
0479 y11..y0 = absolute y value (vertical)
0480
0481
0482 Two finger touch
0483 ^^^^^^^^^^^^^^^^
0484
0485 Note that the two pairs of coordinates are not exactly the coordinates of the
0486 two fingers, but only the pair of the lower-left and upper-right coordinates.
0487 So the actual fingers might be situated on the other diagonal of the square
0488 defined by these two points.
0489
0490 byte 0::
0491
0492 bit 7 6 5 4 3 2 1 0
0493 n1 n0 ay8 ax8 . . R L
0494
0495 L, R = 1 when Left, Right mouse button pressed
0496 n1..n0 = number of fingers on touchpad
0497
0498 byte 1::
0499
0500 bit 7 6 5 4 3 2 1 0
0501 ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0
0502
0503 ax8..ax0 = lower-left finger absolute x value
0504
0505 byte 2::
0506
0507 bit 7 6 5 4 3 2 1 0
0508 ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0
0509
0510 ay8..ay0 = lower-left finger absolute y value
0511
0512 byte 3::
0513
0514 bit 7 6 5 4 3 2 1 0
0515 . . by8 bx8 . . . .
0516
0517 byte 4::
0518
0519 bit 7 6 5 4 3 2 1 0
0520 bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0
0521
0522 bx8..bx0 = upper-right finger absolute x value
0523
0524 byte 5::
0525
0526 bit 7 6 5 4 3 2 1 0
0527 by7 by8 by5 by4 by3 by2 by1 by0
0528
0529 by8..by0 = upper-right finger absolute y value
0530
0531 Hardware version 3
0532 ~~~~~~~~~~~~~~~~~~
0533
0534 Registers
0535 ---------
0536
0537 * reg_10::
0538
0539 bit 7 6 5 4 3 2 1 0
0540 0 0 0 0 R F T A
0541
0542 A: 1 = enable absolute tracking
0543 T: 1 = enable two finger mode auto correct
0544 F: 1 = disable ABS Position Filter
0545 R: 1 = enable real hardware resolution
0546
0547 Native absolute mode 6 byte packet format
0548 -----------------------------------------
0549
0550 1 and 3 finger touch shares the same 6-byte packet format, except that
0551 3 finger touch only reports the position of the center of all three fingers.
0552
0553 Firmware would send 12 bytes of data for 2 finger touch.
0554
0555 Note on debounce:
0556 In case the box has unstable power supply or other electricity issues, or
0557 when number of finger changes, F/W would send "debounce packet" to inform
0558 driver that the hardware is in debounce status.
0559 The debouce packet has the following signature::
0560
0561 byte 0: 0xc4
0562 byte 1: 0xff
0563 byte 2: 0xff
0564 byte 3: 0x02
0565 byte 4: 0xff
0566 byte 5: 0xff
0567
0568 When we encounter this kind of packet, we just ignore it.
0569
0570 One/Three finger touch
0571 ^^^^^^^^^^^^^^^^^^^^^^
0572
0573 byte 0::
0574
0575 bit 7 6 5 4 3 2 1 0
0576 n1 n0 w3 w2 0 1 R L
0577
0578 L, R = 1 when Left, Right mouse button pressed
0579 n1..n0 = number of fingers on touchpad
0580
0581 byte 1::
0582
0583 bit 7 6 5 4 3 2 1 0
0584 p7 p6 p5 p4 x11 x10 x9 x8
0585
0586 byte 2::
0587
0588 bit 7 6 5 4 3 2 1 0
0589 x7 x6 x5 x4 x3 x2 x1 x0
0590
0591 x11..x0 = absolute x value (horizontal)
0592
0593 byte 3::
0594
0595 bit 7 6 5 4 3 2 1 0
0596 0 0 w1 w0 0 0 1 0
0597
0598 w3..w0 = width of the finger touch
0599
0600 byte 4::
0601
0602 bit 7 6 5 4 3 2 1 0
0603 p3 p1 p2 p0 y11 y10 y9 y8
0604
0605 p7..p0 = pressure
0606
0607 byte 5::
0608
0609 bit 7 6 5 4 3 2 1 0
0610 y7 y6 y5 y4 y3 y2 y1 y0
0611
0612 y11..y0 = absolute y value (vertical)
0613
0614 Two finger touch
0615 ^^^^^^^^^^^^^^^^
0616
0617 The packet format is exactly the same for two finger touch, except the hardware
0618 sends two 6 byte packets. The first packet contains data for the first finger,
0619 the second packet has data for the second finger. So for two finger touch a
0620 total of 12 bytes are sent.
0621
0622 Hardware version 4
0623 ~~~~~~~~~~~~~~~~~~
0624
0625 Registers
0626 ---------
0627
0628 * reg_07::
0629
0630 bit 7 6 5 4 3 2 1 0
0631 0 0 0 0 0 0 0 A
0632
0633 A: 1 = enable absolute tracking
0634
0635 Native absolute mode 6 byte packet format
0636 -----------------------------------------
0637
0638 v4 hardware is a true multitouch touchpad, capable of tracking up to 5 fingers.
0639 Unfortunately, due to PS/2's limited bandwidth, its packet format is rather
0640 complex.
0641
0642 Whenever the numbers or identities of the fingers changes, the hardware sends a
0643 status packet to indicate how many and which fingers is on touchpad, followed by
0644 head packets or motion packets. A head packet contains data of finger id, finger
0645 position (absolute x, y values), width, and pressure. A motion packet contains
0646 two fingers' position delta.
0647
0648 For example, when status packet tells there are 2 fingers on touchpad, then we
0649 can expect two following head packets. If the finger status doesn't change,
0650 the following packets would be motion packets, only sending delta of finger
0651 position, until we receive a status packet.
0652
0653 One exception is one finger touch. when a status packet tells us there is only
0654 one finger, the hardware would just send head packets afterwards.
0655
0656 Status packet
0657 ^^^^^^^^^^^^^
0658
0659 byte 0::
0660
0661 bit 7 6 5 4 3 2 1 0
0662 . . . . 0 1 R L
0663
0664 L, R = 1 when Left, Right mouse button pressed
0665
0666 byte 1::
0667
0668 bit 7 6 5 4 3 2 1 0
0669 . . . ft4 ft3 ft2 ft1 ft0
0670
0671 ft4 ft3 ft2 ft1 ft0 ftn = 1 when finger n is on touchpad
0672
0673 byte 2::
0674
0675 not used
0676
0677 byte 3::
0678
0679 bit 7 6 5 4 3 2 1 0
0680 . . . 1 0 0 0 0
0681
0682 constant bits
0683
0684 byte 4::
0685
0686 bit 7 6 5 4 3 2 1 0
0687 p . . . . . . .
0688
0689 p = 1 for palm
0690
0691 byte 5::
0692
0693 not used
0694
0695 Head packet
0696 ^^^^^^^^^^^
0697
0698 byte 0::
0699
0700 bit 7 6 5 4 3 2 1 0
0701 w3 w2 w1 w0 0 1 R L
0702
0703 L, R = 1 when Left, Right mouse button pressed
0704 w3..w0 = finger width (spans how many trace lines)
0705
0706 byte 1::
0707
0708 bit 7 6 5 4 3 2 1 0
0709 p7 p6 p5 p4 x11 x10 x9 x8
0710
0711 byte 2::
0712
0713 bit 7 6 5 4 3 2 1 0
0714 x7 x6 x5 x4 x3 x2 x1 x0
0715
0716 x11..x0 = absolute x value (horizontal)
0717
0718 byte 3::
0719
0720 bit 7 6 5 4 3 2 1 0
0721 id2 id1 id0 1 0 0 0 1
0722
0723 id2..id0 = finger id
0724
0725 byte 4::
0726
0727 bit 7 6 5 4 3 2 1 0
0728 p3 p1 p2 p0 y11 y10 y9 y8
0729
0730 p7..p0 = pressure
0731
0732 byte 5::
0733
0734 bit 7 6 5 4 3 2 1 0
0735 y7 y6 y5 y4 y3 y2 y1 y0
0736
0737 y11..y0 = absolute y value (vertical)
0738
0739 Motion packet
0740 ^^^^^^^^^^^^^
0741
0742 byte 0::
0743
0744 bit 7 6 5 4 3 2 1 0
0745 id2 id1 id0 w 0 1 R L
0746
0747 L, R = 1 when Left, Right mouse button pressed
0748 id2..id0 = finger id
0749 w = 1 when delta overflows (> 127 or < -128), in this case
0750 firmware sends us (delta x / 5) and (delta y / 5)
0751
0752 byte 1::
0753
0754 bit 7 6 5 4 3 2 1 0
0755 x7 x6 x5 x4 x3 x2 x1 x0
0756
0757 x7..x0 = delta x (two's complement)
0758
0759 byte 2::
0760
0761 bit 7 6 5 4 3 2 1 0
0762 y7 y6 y5 y4 y3 y2 y1 y0
0763
0764 y7..y0 = delta y (two's complement)
0765
0766 byte 3::
0767
0768 bit 7 6 5 4 3 2 1 0
0769 id2 id1 id0 1 0 0 1 0
0770
0771 id2..id0 = finger id
0772
0773 byte 4::
0774
0775 bit 7 6 5 4 3 2 1 0
0776 x7 x6 x5 x4 x3 x2 x1 x0
0777
0778 x7..x0 = delta x (two's complement)
0779
0780 byte 5::
0781
0782 bit 7 6 5 4 3 2 1 0
0783 y7 y6 y5 y4 y3 y2 y1 y0
0784
0785 y7..y0 = delta y (two's complement)
0786
0787 byte 0 ~ 2 for one finger
0788 byte 3 ~ 5 for another
0789
0790
0791 Trackpoint (for Hardware version 3 and 4)
0792 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0793
0794 Registers
0795 ---------
0796
0797 No special registers have been identified.
0798
0799 Native relative mode 6 byte packet format
0800 -----------------------------------------
0801
0802 Status Packet
0803 ^^^^^^^^^^^^^
0804
0805 byte 0::
0806
0807 bit 7 6 5 4 3 2 1 0
0808 0 0 sx sy 0 M R L
0809
0810 byte 1::
0811
0812 bit 7 6 5 4 3 2 1 0
0813 ~sx 0 0 0 0 0 0 0
0814
0815 byte 2::
0816
0817 bit 7 6 5 4 3 2 1 0
0818 ~sy 0 0 0 0 0 0 0
0819
0820 byte 3::
0821
0822 bit 7 6 5 4 3 2 1 0
0823 0 0 ~sy ~sx 0 1 1 0
0824
0825 byte 4::
0826
0827 bit 7 6 5 4 3 2 1 0
0828 x7 x6 x5 x4 x3 x2 x1 x0
0829
0830 byte 5::
0831
0832 bit 7 6 5 4 3 2 1 0
0833 y7 y6 y5 y4 y3 y2 y1 y0
0834
0835
0836 x and y are written in two's complement spread
0837 over 9 bits with sx/sy the relative top bit and
0838 x7..x0 and y7..y0 the lower bits.
0839 ~sx is the inverse of sx, ~sy is the inverse of sy.
0840 The sign of y is opposite to what the input driver
0841 expects for a relative movement
