Based on kernel version 4.10.8. Page generated on 2017-04-01 14:43 EST.
1 Elantech Touchpad Driver 2 ======================== 3 4 Copyright (C) 2007-2008 Arjan Opmeer <arjan@opmeer.net> 5 6 Extra information for hardware version 1 found and 7 provided by Steve Havelka 8 9 Version 2 (EeePC) hardware support based on patches 10 received from Woody at Xandros and forwarded to me 11 by user StewieGriffin at the eeeuser.com forum 12 13 14 Contents 15 ~~~~~~~~ 16 17 1. Introduction 18 2. Extra knobs 19 3. Differentiating hardware versions 20 4. Hardware version 1 21 4.1 Registers 22 4.2 Native relative mode 4 byte packet format 23 4.3 Native absolute mode 4 byte packet format 24 5. Hardware version 2 25 5.1 Registers 26 5.2 Native absolute mode 6 byte packet format 27 5.2.1 Parity checking and packet re-synchronization 28 5.2.2 One/Three finger touch 29 5.2.3 Two finger touch 30 6. Hardware version 3 31 6.1 Registers 32 6.2 Native absolute mode 6 byte packet format 33 6.2.1 One/Three finger touch 34 6.2.2 Two finger touch 35 7. Hardware version 4 36 7.1 Registers 37 7.2 Native absolute mode 6 byte packet format 38 7.2.1 Status packet 39 7.2.2 Head packet 40 7.2.3 Motion packet 41 8. Trackpoint (for Hardware version 3 and 4) 42 8.1 Registers 43 8.2 Native relative mode 6 byte packet format 44 8.2.1 Status Packet 45 46 47 48 1. Introduction 49 ~~~~~~~~~~~~ 50 51 Currently the Linux Elantech touchpad driver is aware of four different 52 hardware versions unimaginatively called version 1,version 2, version 3 53 and version 4. Version 1 is found in "older" laptops and uses 4 bytes per 54 packet. Version 2 seems to be introduced with the EeePC and uses 6 bytes 55 per packet, and provides additional features such as position of two fingers, 56 and width of the touch. Hardware version 3 uses 6 bytes per packet (and 57 for 2 fingers the concatenation of two 6 bytes packets) and allows tracking 58 of up to 3 fingers. Hardware version 4 uses 6 bytes per packet, and can 59 combine a status packet with multiple head or motion packets. Hardware version 60 4 allows tracking up to 5 fingers. 61 62 Some Hardware version 3 and version 4 also have a trackpoint which uses a 63 separate packet format. It is also 6 bytes per packet. 64 65 The driver tries to support both hardware versions and should be compatible 66 with the Xorg Synaptics touchpad driver and its graphical configuration 67 utilities. 68 69 Note that a mouse button is also associated with either the touchpad or the 70 trackpoint when a trackpoint is available. Disabling the Touchpad in xorg 71 (TouchPadOff=0) will also disable the buttons associated with the touchpad. 72 73 Additionally the operation of the touchpad can be altered by adjusting the 74 contents of some of its internal registers. These registers are represented 75 by the driver as sysfs entries under /sys/bus/serio/drivers/psmouse/serio? 76 that can be read from and written to. 77 78 Currently only the registers for hardware version 1 are somewhat understood. 79 Hardware version 2 seems to use some of the same registers but it is not 80 known whether the bits in the registers represent the same thing or might 81 have changed their meaning. 82 83 On top of that, some register settings have effect only when the touchpad is 84 in relative mode and not in absolute mode. As the Linux Elantech touchpad 85 driver always puts the hardware into absolute mode not all information 86 mentioned below can be used immediately. But because there is no freely 87 available Elantech documentation the information is provided here anyway for 88 completeness sake. 89 90 91 ///////////////////////////////////////////////////////////////////////////// 92 93 94 2. Extra knobs 95 ~~~~~~~~~~~ 96 97 Currently the Linux Elantech touchpad driver provides three extra knobs under 98 /sys/bus/serio/drivers/psmouse/serio? for the user. 99 100 * debug 101 102 Turn different levels of debugging ON or OFF. 103 104 By echoing "0" to this file all debugging will be turned OFF. 105 106 Currently a value of "1" will turn on some basic debugging and a value of 107 "2" will turn on packet debugging. For hardware version 1 the default is 108 OFF. For version 2 the default is "1". 109 110 Turning packet debugging on will make the driver dump every packet 111 received to the syslog before processing it. Be warned that this can 112 generate quite a lot of data! 113 114 * paritycheck 115 116 Turns parity checking ON or OFF. 117 118 By echoing "0" to this file parity checking will be turned OFF. Any 119 non-zero value will turn it ON. For hardware version 1 the default is ON. 120 For version 2 the default it is OFF. 121 122 Hardware version 1 provides basic data integrity verification by 123 calculating a parity bit for the last 3 bytes of each packet. The driver 124 can check these bits and reject any packet that appears corrupted. Using 125 this knob you can bypass that check. 126 127 Hardware version 2 does not provide the same parity bits. Only some basic 128 data consistency checking can be done. For now checking is disabled by 129 default. Currently even turning it on will do nothing. 130 131 * crc_enabled 132 133 Sets crc_enabled to 0/1. The name "crc_enabled" is the official name of 134 this integrity check, even though it is not an actual cyclic redundancy 135 check. 136 137 Depending on the state of crc_enabled, certain basic data integrity 138 verification is done by the driver on hardware version 3 and 4. The 139 driver will reject any packet that appears corrupted. Using this knob, 140 The state of crc_enabled can be altered with this knob. 141 142 Reading the crc_enabled value will show the active value. Echoing 143 "0" or "1" to this file will set the state to "0" or "1". 144 145 ///////////////////////////////////////////////////////////////////////////// 146 147 3. Differentiating hardware versions 148 ================================= 149 150 To detect the hardware version, read the version number as param[0].param[1].param[2] 151 152 4 bytes version: (after the arrow is the name given in the Dell-provided driver) 153 02.00.22 => EF013 154 02.06.00 => EF019 155 In the wild, there appear to be more versions, such as 00.01.64, 01.00.21, 156 02.00.00, 02.00.04, 02.00.06. 157 158 6 bytes: 159 02.00.30 => EF113 160 02.08.00 => EF023 161 02.08.XX => EF123 162 02.0B.00 => EF215 163 04.01.XX => Scroll_EF051 164 04.02.XX => EF051 165 In the wild, there appear to be more versions, such as 04.03.01, 04.04.11. There 166 appears to be almost no difference, except for EF113, which does not report 167 pressure/width and has different data consistency checks. 168 169 Probably all the versions with param[0] <= 01 can be considered as 170 4 bytes/firmware 1. The versions < 02.08.00, with the exception of 02.00.30, as 171 4 bytes/firmware 2. Everything >= 02.08.00 can be considered as 6 bytes. 172 173 ///////////////////////////////////////////////////////////////////////////// 174 175 4. Hardware version 1 176 ================== 177 178 4.1 Registers 179 ~~~~~~~~~ 180 181 By echoing a hexadecimal value to a register it contents can be altered. 182 183 For example: 184 185 echo -n 0x16 > reg_10 186 187 * reg_10 188 189 bit 7 6 5 4 3 2 1 0 190 B C T D L A S E 191 192 E: 1 = enable smart edges unconditionally 193 S: 1 = enable smart edges only when dragging 194 A: 1 = absolute mode (needs 4 byte packets, see reg_11) 195 L: 1 = enable drag lock (see reg_22) 196 D: 1 = disable dynamic resolution 197 T: 1 = disable tapping 198 C: 1 = enable corner tap 199 B: 1 = swap left and right button 200 201 * reg_11 202 203 bit 7 6 5 4 3 2 1 0 204 1 0 0 H V 1 F P 205 206 P: 1 = enable parity checking for relative mode 207 F: 1 = enable native 4 byte packet mode 208 V: 1 = enable vertical scroll area 209 H: 1 = enable horizontal scroll area 210 211 * reg_20 212 213 single finger width? 214 215 * reg_21 216 217 scroll area width (small: 0x40 ... wide: 0xff) 218 219 * reg_22 220 221 drag lock time out (short: 0x14 ... long: 0xfe; 222 0xff = tap again to release) 223 224 * reg_23 225 226 tap make timeout? 227 228 * reg_24 229 230 tap release timeout? 231 232 * reg_25 233 234 smart edge cursor speed (0x02 = slow, 0x03 = medium, 0x04 = fast) 235 236 * reg_26 237 238 smart edge activation area width? 239 240 241 4.2 Native relative mode 4 byte packet format 242 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 243 244 byte 0: 245 bit 7 6 5 4 3 2 1 0 246 c c p2 p1 1 M R L 247 248 L, R, M = 1 when Left, Right, Middle mouse button pressed 249 some models have M as byte 3 odd parity bit 250 when parity checking is enabled (reg_11, P = 1): 251 p1..p2 = byte 1 and 2 odd parity bit 252 c = 1 when corner tap detected 253 254 byte 1: 255 bit 7 6 5 4 3 2 1 0 256 dx7 dx6 dx5 dx4 dx3 dx2 dx1 dx0 257 258 dx7..dx0 = x movement; positive = right, negative = left 259 byte 1 = 0xf0 when corner tap detected 260 261 byte 2: 262 bit 7 6 5 4 3 2 1 0 263 dy7 dy6 dy5 dy4 dy3 dy2 dy1 dy0 264 265 dy7..dy0 = y movement; positive = up, negative = down 266 267 byte 3: 268 parity checking enabled (reg_11, P = 1): 269 270 bit 7 6 5 4 3 2 1 0 271 w h n1 n0 ds3 ds2 ds1 ds0 272 273 normally: 274 ds3..ds0 = scroll wheel amount and direction 275 positive = down or left 276 negative = up or right 277 when corner tap detected: 278 ds0 = 1 when top right corner tapped 279 ds1 = 1 when bottom right corner tapped 280 ds2 = 1 when bottom left corner tapped 281 ds3 = 1 when top left corner tapped 282 n1..n0 = number of fingers on touchpad 283 only models with firmware 2.x report this, models with 284 firmware 1.x seem to map one, two and three finger taps 285 directly to L, M and R mouse buttons 286 h = 1 when horizontal scroll action 287 w = 1 when wide finger touch? 288 289 otherwise (reg_11, P = 0): 290 291 bit 7 6 5 4 3 2 1 0 292 ds7 ds6 ds5 ds4 ds3 ds2 ds1 ds0 293 294 ds7..ds0 = vertical scroll amount and direction 295 negative = up 296 positive = down 297 298 299 4.3 Native absolute mode 4 byte packet format 300 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 301 302 EF013 and EF019 have a special behaviour (due to a bug in the firmware?), and 303 when 1 finger is touching, the first 2 position reports must be discarded. 304 This counting is reset whenever a different number of fingers is reported. 305 306 byte 0: 307 firmware version 1.x: 308 309 bit 7 6 5 4 3 2 1 0 310 D U p1 p2 1 p3 R L 311 312 L, R = 1 when Left, Right mouse button pressed 313 p1..p3 = byte 1..3 odd parity bit 314 D, U = 1 when rocker switch pressed Up, Down 315 316 firmware version 2.x: 317 318 bit 7 6 5 4 3 2 1 0 319 n1 n0 p2 p1 1 p3 R L 320 321 L, R = 1 when Left, Right mouse button pressed 322 p1..p3 = byte 1..3 odd parity bit 323 n1..n0 = number of fingers on touchpad 324 325 byte 1: 326 firmware version 1.x: 327 328 bit 7 6 5 4 3 2 1 0 329 f 0 th tw x9 x8 y9 y8 330 331 tw = 1 when two finger touch 332 th = 1 when three finger touch 333 f = 1 when finger touch 334 335 firmware version 2.x: 336 337 bit 7 6 5 4 3 2 1 0 338 . . . . x9 x8 y9 y8 339 340 byte 2: 341 bit 7 6 5 4 3 2 1 0 342 x7 x6 x5 x4 x3 x2 x1 x0 343 344 x9..x0 = absolute x value (horizontal) 345 346 byte 3: 347 bit 7 6 5 4 3 2 1 0 348 y7 y6 y5 y4 y3 y2 y1 y0 349 350 y9..y0 = absolute y value (vertical) 351 352 353 ///////////////////////////////////////////////////////////////////////////// 354 355 356 5. Hardware version 2 357 ================== 358 359 360 5.1 Registers 361 ~~~~~~~~~ 362 363 By echoing a hexadecimal value to a register it contents can be altered. 364 365 For example: 366 367 echo -n 0x56 > reg_10 368 369 * reg_10 370 371 bit 7 6 5 4 3 2 1 0 372 0 1 0 1 0 1 D 0 373 374 D: 1 = enable drag and drop 375 376 * reg_11 377 378 bit 7 6 5 4 3 2 1 0 379 1 0 0 0 S 0 1 0 380 381 S: 1 = enable vertical scroll 382 383 * reg_21 384 385 unknown (0x00) 386 387 * reg_22 388 389 drag and drop release time out (short: 0x70 ... long 0x7e; 390 0x7f = never i.e. tap again to release) 391 392 393 5.2 Native absolute mode 6 byte packet format 394 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 395 5.2.1 Parity checking and packet re-synchronization 396 There is no parity checking, however some consistency checks can be performed. 397 398 For instance for EF113: 399 SA1= packet[0]; 400 A1 = packet[1]; 401 B1 = packet[2]; 402 SB1= packet[3]; 403 C1 = packet[4]; 404 D1 = packet[5]; 405 if( (((SA1 & 0x3C) != 0x3C) && ((SA1 & 0xC0) != 0x80)) || // check Byte 1 406 (((SA1 & 0x0C) != 0x0C) && ((SA1 & 0xC0) == 0x80)) || // check Byte 1 (one finger pressed) 407 (((SA1 & 0xC0) != 0x80) && (( A1 & 0xF0) != 0x00)) || // check Byte 2 408 (((SB1 & 0x3E) != 0x38) && ((SA1 & 0xC0) != 0x80)) || // check Byte 4 409 (((SB1 & 0x0E) != 0x08) && ((SA1 & 0xC0) == 0x80)) || // check Byte 4 (one finger pressed) 410 (((SA1 & 0xC0) != 0x80) && (( C1 & 0xF0) != 0x00)) ) // check Byte 5 411 // error detected 412 413 For all the other ones, there are just a few constant bits: 414 if( ((packet[0] & 0x0C) != 0x04) || 415 ((packet[3] & 0x0f) != 0x02) ) 416 // error detected 417 418 419 In case an error is detected, all the packets are shifted by one (and packet[0] is discarded). 420 421 5.2.2 One/Three finger touch 422 ~~~~~~~~~~~~~~~~ 423 424 byte 0: 425 426 bit 7 6 5 4 3 2 1 0 427 n1 n0 w3 w2 . . R L 428 429 L, R = 1 when Left, Right mouse button pressed 430 n1..n0 = number of fingers on touchpad 431 432 byte 1: 433 434 bit 7 6 5 4 3 2 1 0 435 p7 p6 p5 p4 x11 x10 x9 x8 436 437 byte 2: 438 439 bit 7 6 5 4 3 2 1 0 440 x7 x6 x5 x4 x3 x2 x1 x0 441 442 x11..x0 = absolute x value (horizontal) 443 444 byte 3: 445 446 bit 7 6 5 4 3 2 1 0 447 n4 vf w1 w0 . . . b2 448 449 n4 = set if more than 3 fingers (only in 3 fingers mode) 450 vf = a kind of flag ? (only on EF123, 0 when finger is over one 451 of the buttons, 1 otherwise) 452 w3..w0 = width of the finger touch (not EF113) 453 b2 (on EF113 only, 0 otherwise), b2.R.L indicates one button pressed: 454 0 = none 455 1 = Left 456 2 = Right 457 3 = Middle (Left and Right) 458 4 = Forward 459 5 = Back 460 6 = Another one 461 7 = Another one 462 463 byte 4: 464 465 bit 7 6 5 4 3 2 1 0 466 p3 p1 p2 p0 y11 y10 y9 y8 467 468 p7..p0 = pressure (not EF113) 469 470 byte 5: 471 472 bit 7 6 5 4 3 2 1 0 473 y7 y6 y5 y4 y3 y2 y1 y0 474 475 y11..y0 = absolute y value (vertical) 476 477 478 5.2.3 Two finger touch 479 ~~~~~~~~~~~~~~~~ 480 481 Note that the two pairs of coordinates are not exactly the coordinates of the 482 two fingers, but only the pair of the lower-left and upper-right coordinates. 483 So the actual fingers might be situated on the other diagonal of the square 484 defined by these two points. 485 486 byte 0: 487 488 bit 7 6 5 4 3 2 1 0 489 n1 n0 ay8 ax8 . . R L 490 491 L, R = 1 when Left, Right mouse button pressed 492 n1..n0 = number of fingers on touchpad 493 494 byte 1: 495 496 bit 7 6 5 4 3 2 1 0 497 ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0 498 499 ax8..ax0 = lower-left finger absolute x value 500 501 byte 2: 502 503 bit 7 6 5 4 3 2 1 0 504 ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0 505 506 ay8..ay0 = lower-left finger absolute y value 507 508 byte 3: 509 510 bit 7 6 5 4 3 2 1 0 511 . . by8 bx8 . . . . 512 513 byte 4: 514 515 bit 7 6 5 4 3 2 1 0 516 bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0 517 518 bx8..bx0 = upper-right finger absolute x value 519 520 byte 5: 521 522 bit 7 6 5 4 3 2 1 0 523 by7 by8 by5 by4 by3 by2 by1 by0 524 525 by8..by0 = upper-right finger absolute y value 526 527 ///////////////////////////////////////////////////////////////////////////// 528 529 6. Hardware version 3 530 ================== 531 532 6.1 Registers 533 ~~~~~~~~~ 534 * reg_10 535 536 bit 7 6 5 4 3 2 1 0 537 0 0 0 0 R F T A 538 539 A: 1 = enable absolute tracking 540 T: 1 = enable two finger mode auto correct 541 F: 1 = disable ABS Position Filter 542 R: 1 = enable real hardware resolution 543 544 6.2 Native absolute mode 6 byte packet format 545 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 546 1 and 3 finger touch shares the same 6-byte packet format, except that 547 3 finger touch only reports the position of the center of all three fingers. 548 549 Firmware would send 12 bytes of data for 2 finger touch. 550 551 Note on debounce: 552 In case the box has unstable power supply or other electricity issues, or 553 when number of finger changes, F/W would send "debounce packet" to inform 554 driver that the hardware is in debounce status. 555 The debouce packet has the following signature: 556 byte 0: 0xc4 557 byte 1: 0xff 558 byte 2: 0xff 559 byte 3: 0x02 560 byte 4: 0xff 561 byte 5: 0xff 562 When we encounter this kind of packet, we just ignore it. 563 564 6.2.1 One/Three finger touch 565 ~~~~~~~~~~~~~~~~~~~~~~ 566 567 byte 0: 568 569 bit 7 6 5 4 3 2 1 0 570 n1 n0 w3 w2 0 1 R L 571 572 L, R = 1 when Left, Right mouse button pressed 573 n1..n0 = number of fingers on touchpad 574 575 byte 1: 576 577 bit 7 6 5 4 3 2 1 0 578 p7 p6 p5 p4 x11 x10 x9 x8 579 580 byte 2: 581 582 bit 7 6 5 4 3 2 1 0 583 x7 x6 x5 x4 x3 x2 x1 x0 584 585 x11..x0 = absolute x value (horizontal) 586 587 byte 3: 588 589 bit 7 6 5 4 3 2 1 0 590 0 0 w1 w0 0 0 1 0 591 592 w3..w0 = width of the finger touch 593 594 byte 4: 595 596 bit 7 6 5 4 3 2 1 0 597 p3 p1 p2 p0 y11 y10 y9 y8 598 599 p7..p0 = pressure 600 601 byte 5: 602 603 bit 7 6 5 4 3 2 1 0 604 y7 y6 y5 y4 y3 y2 y1 y0 605 606 y11..y0 = absolute y value (vertical) 607 608 6.2.2 Two finger touch 609 ~~~~~~~~~~~~~~~~ 610 611 The packet format is exactly the same for two finger touch, except the hardware 612 sends two 6 byte packets. The first packet contains data for the first finger, 613 the second packet has data for the second finger. So for two finger touch a 614 total of 12 bytes are sent. 615 616 ///////////////////////////////////////////////////////////////////////////// 617 618 7. Hardware version 4 619 ================== 620 621 7.1 Registers 622 ~~~~~~~~~ 623 * reg_07 624 625 bit 7 6 5 4 3 2 1 0 626 0 0 0 0 0 0 0 A 627 628 A: 1 = enable absolute tracking 629 630 7.2 Native absolute mode 6 byte packet format 631 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 632 v4 hardware is a true multitouch touchpad, capable of tracking up to 5 fingers. 633 Unfortunately, due to PS/2's limited bandwidth, its packet format is rather 634 complex. 635 636 Whenever the numbers or identities of the fingers changes, the hardware sends a 637 status packet to indicate how many and which fingers is on touchpad, followed by 638 head packets or motion packets. A head packet contains data of finger id, finger 639 position (absolute x, y values), width, and pressure. A motion packet contains 640 two fingers' position delta. 641 642 For example, when status packet tells there are 2 fingers on touchpad, then we 643 can expect two following head packets. If the finger status doesn't change, 644 the following packets would be motion packets, only sending delta of finger 645 position, until we receive a status packet. 646 647 One exception is one finger touch. when a status packet tells us there is only 648 one finger, the hardware would just send head packets afterwards. 649 650 7.2.1 Status packet 651 ~~~~~~~~~~~~~ 652 653 byte 0: 654 655 bit 7 6 5 4 3 2 1 0 656 . . . . 0 1 R L 657 658 L, R = 1 when Left, Right mouse button pressed 659 660 byte 1: 661 662 bit 7 6 5 4 3 2 1 0 663 . . . ft4 ft3 ft2 ft1 ft0 664 665 ft4 ft3 ft2 ft1 ft0 ftn = 1 when finger n is on touchpad 666 667 byte 2: not used 668 669 byte 3: 670 671 bit 7 6 5 4 3 2 1 0 672 . . . 1 0 0 0 0 673 674 constant bits 675 676 byte 4: 677 678 bit 7 6 5 4 3 2 1 0 679 p . . . . . . . 680 681 p = 1 for palm 682 683 byte 5: not used 684 685 7.2.2 Head packet 686 ~~~~~~~~~~~ 687 688 byte 0: 689 690 bit 7 6 5 4 3 2 1 0 691 w3 w2 w1 w0 0 1 R L 692 693 L, R = 1 when Left, Right mouse button pressed 694 w3..w0 = finger width (spans how many trace lines) 695 696 byte 1: 697 698 bit 7 6 5 4 3 2 1 0 699 p7 p6 p5 p4 x11 x10 x9 x8 700 701 byte 2: 702 703 bit 7 6 5 4 3 2 1 0 704 x7 x6 x5 x4 x3 x2 x1 x0 705 706 x11..x0 = absolute x value (horizontal) 707 708 byte 3: 709 710 bit 7 6 5 4 3 2 1 0 711 id2 id1 id0 1 0 0 0 1 712 713 id2..id0 = finger id 714 715 byte 4: 716 717 bit 7 6 5 4 3 2 1 0 718 p3 p1 p2 p0 y11 y10 y9 y8 719 720 p7..p0 = pressure 721 722 byte 5: 723 724 bit 7 6 5 4 3 2 1 0 725 y7 y6 y5 y4 y3 y2 y1 y0 726 727 y11..y0 = absolute y value (vertical) 728 729 7.2.3 Motion packet 730 ~~~~~~~~~~~~~ 731 732 byte 0: 733 734 bit 7 6 5 4 3 2 1 0 735 id2 id1 id0 w 0 1 R L 736 737 L, R = 1 when Left, Right mouse button pressed 738 id2..id0 = finger id 739 w = 1 when delta overflows (> 127 or < -128), in this case 740 firmware sends us (delta x / 5) and (delta y / 5) 741 742 byte 1: 743 744 bit 7 6 5 4 3 2 1 0 745 x7 x6 x5 x4 x3 x2 x1 x0 746 747 x7..x0 = delta x (two's complement) 748 749 byte 2: 750 751 bit 7 6 5 4 3 2 1 0 752 y7 y6 y5 y4 y3 y2 y1 y0 753 754 y7..y0 = delta y (two's complement) 755 756 byte 3: 757 758 bit 7 6 5 4 3 2 1 0 759 id2 id1 id0 1 0 0 1 0 760 761 id2..id0 = finger id 762 763 byte 4: 764 765 bit 7 6 5 4 3 2 1 0 766 x7 x6 x5 x4 x3 x2 x1 x0 767 768 x7..x0 = delta x (two's complement) 769 770 byte 5: 771 772 bit 7 6 5 4 3 2 1 0 773 y7 y6 y5 y4 y3 y2 y1 y0 774 775 y7..y0 = delta y (two's complement) 776 777 byte 0 ~ 2 for one finger 778 byte 3 ~ 5 for another 779 780 781 8. Trackpoint (for Hardware version 3 and 4) 782 ========================================= 783 8.1 Registers 784 ~~~~~~~~~ 785 No special registers have been identified. 786 787 8.2 Native relative mode 6 byte packet format 788 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 789 8.2.1 Status Packet 790 ~~~~~~~~~~~~~ 791 792 byte 0: 793 bit 7 6 5 4 3 2 1 0 794 0 0 sx sy 0 M R L 795 byte 1: 796 bit 7 6 5 4 3 2 1 0 797 ~sx 0 0 0 0 0 0 0 798 byte 2: 799 bit 7 6 5 4 3 2 1 0 800 ~sy 0 0 0 0 0 0 0 801 byte 3: 802 bit 7 6 5 4 3 2 1 0 803 0 0 ~sy ~sx 0 1 1 0 804 byte 4: 805 bit 7 6 5 4 3 2 1 0 806 x7 x6 x5 x4 x3 x2 x1 x0 807 byte 5: 808 bit 7 6 5 4 3 2 1 0 809 y7 y6 y5 y4 y3 y2 y1 y0 810 811 812 x and y are written in two's complement spread 813 over 9 bits with sx/sy the relative top bit and 814 x7..x0 and y7..y0 the lower bits. 815 ~sx is the inverse of sx, ~sy is the inverse of sy. 816 The sign of y is opposite to what the input driver 817 expects for a relative movement