![Arjan Opmeer](/assets/img/avatar_default.png)
This is version 5 of the driver. Relative mode support has been dropped (users wishing to use touchpad in relative mode can use standard PS/2 protocol emulation done in hardware). The driver supports both original version of Elantech protocol and the newer one used by touchpads installed in EeePC. Signed-off-by: Arjan Opmeer <arjan@opmeer.net> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
406 lines
10 KiB
Text
406 lines
10 KiB
Text
Elantech Touchpad Driver
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========================
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Copyright (C) 2007-2008 Arjan Opmeer <arjan@opmeer.net>
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Extra information for hardware version 1 found and
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provided by Steve Havelka
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Version 2 (EeePC) hardware support based on patches
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received from Woody at Xandros and forwarded to me
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by user StewieGriffin at the eeeuser.com forum
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Contents
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~~~~~~~~
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1. Introduction
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2. Extra knobs
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3. Hardware version 1
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3.1 Registers
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3.2 Native relative mode 4 byte packet format
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3.3 Native absolute mode 4 byte packet format
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4. Hardware version 2
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4.1 Registers
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4.2 Native absolute mode 6 byte packet format
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4.2.1 One finger touch
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4.2.2 Two finger touch
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1. Introduction
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~~~~~~~~~~~~
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Currently the Linux Elantech touchpad driver is aware of two different
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hardware versions unimaginatively called version 1 and version 2. Version 1
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is found in "older" laptops and uses 4 bytes per packet. Version 2 seems to
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be introduced with the EeePC and uses 6 bytes per packet.
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The driver tries to support both hardware versions and should be compatible
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with the Xorg Synaptics touchpad driver and its graphical configuration
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utilities.
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Additionally the operation of the touchpad can be altered by adjusting the
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contents of some of its internal registers. These registers are represented
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by the driver as sysfs entries under /sys/bus/serio/drivers/psmouse/serio?
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that can be read from and written to.
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Currently only the registers for hardware version 1 are somewhat understood.
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Hardware version 2 seems to use some of the same registers but it is not
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known whether the bits in the registers represent the same thing or might
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have changed their meaning.
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On top of that, some register settings have effect only when the touchpad is
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in relative mode and not in absolute mode. As the Linux Elantech touchpad
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driver always puts the hardware into absolute mode not all information
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mentioned below can be used immediately. But because there is no freely
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available Elantech documentation the information is provided here anyway for
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completeness sake.
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/////////////////////////////////////////////////////////////////////////////
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2. Extra knobs
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~~~~~~~~~~~
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Currently the Linux Elantech touchpad driver provides two extra knobs under
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/sys/bus/serio/drivers/psmouse/serio? for the user.
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* debug
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Turn different levels of debugging ON or OFF.
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By echoing "0" to this file all debugging will be turned OFF.
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Currently a value of "1" will turn on some basic debugging and a value of
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"2" will turn on packet debugging. For hardware version 1 the default is
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OFF. For version 2 the default is "1".
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Turning packet debugging on will make the driver dump every packet
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received to the syslog before processing it. Be warned that this can
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generate quite a lot of data!
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* paritycheck
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Turns parity checking ON or OFF.
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By echoing "0" to this file parity checking will be turned OFF. Any
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non-zero value will turn it ON. For hardware version 1 the default is ON.
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For version 2 the default it is OFF.
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Hardware version 1 provides basic data integrity verification by
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calculating a parity bit for the last 3 bytes of each packet. The driver
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can check these bits and reject any packet that appears corrupted. Using
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this knob you can bypass that check.
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It is not known yet whether hardware version 2 provides the same parity
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bits. Hence checking is disabled by default. Currently even turning it on
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will do nothing.
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/////////////////////////////////////////////////////////////////////////////
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3. Hardware version 1
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==================
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3.1 Registers
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~~~~~~~~~
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By echoing a hexadecimal value to a register it contents can be altered.
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For example:
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echo -n 0x16 > reg_10
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* reg_10
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bit 7 6 5 4 3 2 1 0
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B C T D L A S E
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E: 1 = enable smart edges unconditionally
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S: 1 = enable smart edges only when dragging
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A: 1 = absolute mode (needs 4 byte packets, see reg_11)
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L: 1 = enable drag lock (see reg_22)
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D: 1 = disable dynamic resolution
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T: 1 = disable tapping
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C: 1 = enable corner tap
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B: 1 = swap left and right button
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* reg_11
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bit 7 6 5 4 3 2 1 0
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1 0 0 H V 1 F P
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P: 1 = enable parity checking for relative mode
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F: 1 = enable native 4 byte packet mode
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V: 1 = enable vertical scroll area
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H: 1 = enable horizontal scroll area
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* reg_20
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single finger width?
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* reg_21
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scroll area width (small: 0x40 ... wide: 0xff)
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* reg_22
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drag lock time out (short: 0x14 ... long: 0xfe;
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0xff = tap again to release)
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* reg_23
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tap make timeout?
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* reg_24
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tap release timeout?
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* reg_25
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smart edge cursor speed (0x02 = slow, 0x03 = medium, 0x04 = fast)
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* reg_26
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smart edge activation area width?
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3.2 Native relative mode 4 byte packet format
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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byte 0:
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bit 7 6 5 4 3 2 1 0
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c c p2 p1 1 M R L
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L, R, M = 1 when Left, Right, Middle mouse button pressed
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some models have M as byte 3 odd parity bit
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when parity checking is enabled (reg_11, P = 1):
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p1..p2 = byte 1 and 2 odd parity bit
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c = 1 when corner tap detected
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byte 1:
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bit 7 6 5 4 3 2 1 0
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dx7 dx6 dx5 dx4 dx3 dx2 dx1 dx0
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dx7..dx0 = x movement; positive = right, negative = left
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byte 1 = 0xf0 when corner tap detected
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byte 2:
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bit 7 6 5 4 3 2 1 0
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dy7 dy6 dy5 dy4 dy3 dy2 dy1 dy0
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dy7..dy0 = y movement; positive = up, negative = down
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byte 3:
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parity checking enabled (reg_11, P = 1):
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bit 7 6 5 4 3 2 1 0
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w h n1 n0 ds3 ds2 ds1 ds0
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normally:
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ds3..ds0 = scroll wheel amount and direction
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positive = down or left
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negative = up or right
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when corner tap detected:
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ds0 = 1 when top right corner tapped
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ds1 = 1 when bottom right corner tapped
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ds2 = 1 when bottom left corner tapped
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ds3 = 1 when top left corner tapped
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n1..n0 = number of fingers on touchpad
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only models with firmware 2.x report this, models with
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firmware 1.x seem to map one, two and three finger taps
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directly to L, M and R mouse buttons
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h = 1 when horizontal scroll action
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w = 1 when wide finger touch?
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otherwise (reg_11, P = 0):
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bit 7 6 5 4 3 2 1 0
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ds7 ds6 ds5 ds4 ds3 ds2 ds1 ds0
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ds7..ds0 = vertical scroll amount and direction
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negative = up
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positive = down
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3.3 Native absolute mode 4 byte packet format
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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byte 0:
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firmware version 1.x:
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bit 7 6 5 4 3 2 1 0
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D U p1 p2 1 p3 R L
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L, R = 1 when Left, Right mouse button pressed
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p1..p3 = byte 1..3 odd parity bit
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D, U = 1 when rocker switch pressed Up, Down
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firmware version 2.x:
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bit 7 6 5 4 3 2 1 0
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n1 n0 p2 p1 1 p3 R L
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L, R = 1 when Left, Right mouse button pressed
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p1..p3 = byte 1..3 odd parity bit
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n1..n0 = number of fingers on touchpad
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byte 1:
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firmware version 1.x:
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bit 7 6 5 4 3 2 1 0
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f 0 th tw x9 x8 y9 y8
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tw = 1 when two finger touch
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th = 1 when three finger touch
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f = 1 when finger touch
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firmware version 2.x:
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bit 7 6 5 4 3 2 1 0
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. . . . x9 x8 y9 y8
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byte 2:
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bit 7 6 5 4 3 2 1 0
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x7 x6 x5 x4 x3 x2 x1 x0
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x9..x0 = absolute x value (horizontal)
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byte 3:
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bit 7 6 5 4 3 2 1 0
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y7 y6 y5 y4 y3 y2 y1 y0
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y9..y0 = absolute y value (vertical)
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/////////////////////////////////////////////////////////////////////////////
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4. Hardware version 2
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==================
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4.1 Registers
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~~~~~~~~~
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By echoing a hexadecimal value to a register it contents can be altered.
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For example:
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echo -n 0x56 > reg_10
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* reg_10
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bit 7 6 5 4 3 2 1 0
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0 1 0 1 0 1 D 0
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D: 1 = enable drag and drop
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* reg_11
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bit 7 6 5 4 3 2 1 0
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1 0 0 0 S 0 1 0
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S: 1 = enable vertical scroll
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* reg_21
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unknown (0x00)
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* reg_22
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drag and drop release time out (short: 0x70 ... long 0x7e;
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0x7f = never i.e. tap again to release)
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4.2 Native absolute mode 6 byte packet format
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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4.2.1 One finger touch
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~~~~~~~~~~~~~~~~
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byte 0:
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bit 7 6 5 4 3 2 1 0
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n1 n0 . . . . R L
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L, R = 1 when Left, Right mouse button pressed
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n1..n0 = numbers of fingers on touchpad
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byte 1:
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bit 7 6 5 4 3 2 1 0
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x15 x14 x13 x12 x11 x10 x9 x8
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byte 2:
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bit 7 6 5 4 3 2 1 0
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x7 x6 x5 x4 x4 x2 x1 x0
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x15..x0 = absolute x value (horizontal)
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byte 3:
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bit 7 6 5 4 3 2 1 0
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. . . . . . . .
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byte 4:
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bit 7 6 5 4 3 2 1 0
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y15 y14 y13 y12 y11 y10 y8 y8
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byte 5:
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bit 7 6 5 4 3 2 1 0
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y7 y6 y5 y4 y3 y2 y1 y0
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y15..y0 = absolute y value (vertical)
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4.2.2 Two finger touch
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~~~~~~~~~~~~~~~~
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byte 0:
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bit 7 6 5 4 3 2 1 0
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n1 n0 ay8 ax8 . . R L
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L, R = 1 when Left, Right mouse button pressed
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n1..n0 = numbers of fingers on touchpad
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byte 1:
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bit 7 6 5 4 3 2 1 0
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ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0
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ax8..ax0 = first finger absolute x value
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byte 2:
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bit 7 6 5 4 3 2 1 0
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ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0
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ay8..ay0 = first finger absolute y value
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byte 3:
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bit 7 6 5 4 3 2 1 0
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. . by8 bx8 . . . .
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byte 4:
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bit 7 6 5 4 3 2 1 0
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bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0
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bx8..bx0 = second finger absolute x value
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byte 5:
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bit 7 6 5 4 3 2 1 0
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by7 by8 by5 by4 by3 by2 by1 by0
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by8..by0 = second finger absolute y value
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