thinkpad-ec/docs/table_matrix.txt

The basic design of the thinkpad keyboard is one of a 16 column matrix
with 8 rows.  While this layout is not specifically related to the
physical layout of the actual keys, some of it is dictated by that layout.

The mapping of logical-row+column into a EC scancode is done with a
table in the EC firmware.  This table is largely the same between all
the models investigated and served as the basis of the classic keyboard
modification.



ThinkPad x220 matrix:
---------------------

This table is arranged in an array of bytes that is 16 columns by 17 rows,
with the second half of each row being unused (except for one anomaly).

This corresponds to the physical hardware, which uses 16 "drive" lines
and 8 "sense" lines - with one extra row, probably for some software keys.

The hardware "drive" line forms the row number and the "sense" line forms
the column number.

             0  1  2  3  4  5  6  7    0    1    2    3    4    5    6    7

matrix[ 0]: 01 02 11 10 1f 6e 2e 83   `    1    Q    TAB  A    Esc  Z    ??
matrix[ 1]: 70 03 12 1e 20 2d 2f 00   F1   2    W    CpLk S    (|)  X
matrix[ 2]: 71 04 13 72 21 73 30 00   F2   3    E    F3   D    F4   C
matrix[ 3]: 06 05 14 15 22 23 31 32   5    4    R    T    F    G    V    B
matrix[ 4]: 07 08 17 16 25 24 34 33   6    7    U    Y    J    H    M    N
matrix[ 5]: 0d 09 18 1c 26 75 35 38   =    8    I    ]    K    F6   ,    (/)
matrix[ 6]: 77 0a 19 76 27 84 36 85   F8   9    O    F7   L    ??   .    ??
matrix[ 7]: 0c 0b 1a 1b 28 29 2a 37   -    0    P    [    ;    '    (#)  ?
matrix[ 8]: 78 79 0e 0f 1d 74 2b 3d   F9   F10  ??   BS   \    F5   Ent  Spc
matrix[ 9]: 4b 7b 00 9b 00 00 00 59   Ins  F12       WinL                Rgt
matrix[10]: 4c 7a 9a 99 98 97 a0 54   Del  F11  Vol+ Vol- Mute IBM  Mic  Down
matrix[11]: 55 56 00 00 9c 00 89 8a   PgUp PgDn           Menu      PgBk PgFd
matrix[12]: 50 51 00 00 00 53 7e 4f   Home End                 Up   Paus Left
matrix[13]: 00 7c 7d 00 00 3c 00 3e        PrSc ScLk           AltL      AltR
matrix[14]: 00 00 00 2c 00 00 39 00                  SftL           SftR
matrix[15]: 3a 00 00 00 00 00 40 00   CtlL                          CtlR

matrix[15][15] = 0x96                 ??
matrix[16]: 00 9d 00 9e 9f 4a 3a 00        WinR?     Pwr? Slp? Wak? CtlL

Unknown key codes: 0x0e 0x83 0x84 0x85 0x96

    (source: x220 EC firmware version 8DHT34WW, offset 0x1f080)

ThinkPad x230 matrix:
---------------------

The x230 uses the same basic table layout as the x220 and shares its
contents with all of the xx30 series laptops.  The basic classic keyboard
fix was made by updating the x230 table to look like the x220, combined
with updating the live/dead key table.

             0  1  2  3  4  5  6  7    0    1    2    3    4    5    6    7

matrix[ 0]: 01 02 11 10 1f 6e 2e 83   `    1    Q    TAB  A    Esc  Z    ??
matrix[ 1]: 70 03 12 1e 20 2d 2f 00   F1   2    W    CpLk S    (|)  X
matrix[ 2]: 71 04 13 72 21 73 30 00   F2   3    E    F3   D    F4   C
matrix[ 3]: 06 05 14 15 22 23 31 32   5    4    R    T    F    G    V    B
matrix[ 4]: 07 08 17 16 25 24 34 33   6    7    U    Y    J    H    M    N
matrix[ 5]: 0d 09 18 1c 26 75 35 38   =    8    I    ]    K    F6   ,    (/)
matrix[ 6]: 77 0a 19 76 27 84 36 85   F8   9    O    F7   L    ??   .    ??
matrix[ 7]: 0c 0b 1a 1b 28 29 2a 37   -    0    P    [    ;    '    (#)  ?
matrix[ 8]: 78 79 0e 0f 1d 74 2b 3d   F9   F10  ??   BS   \    F5   Ent  Spc
matrix[ 9]: 00 7b 00 9b 00 00 00 59        F12       WinL                Rgt
matrix[10]: 50 7a 9a 99 98 97 a0 54   Home F11  Vol+ Vol- Mute IBM  Mic  Down
matrix[11]: 4c 4b 00 00 7c 00 55 56   Del  Ins            PrSc      PgUp PgDn
matrix[12]: 00 51 00 00 00 53 00 4f        End                 Up        Left
matrix[13]: 00 00 00 00 00 3c 00 3e                            AltL      AltR
matrix[14]: 00 00 00 2c 00 00 39 00                  SftL           SftR
matrix[15]: 3a 00 00 00 00 00 40 00   CtlL                          CtlR

matrix[15][15] = 0x96                 ??
matrix[16]:   00 9d 00 9e 9f 4a 3a 9c      WinR?     Pwr? Slp? Wak? CtlL Menu
matrix[16][8] 7d 7e 00 00 00 00 00 00 ScLk Paus

Unknown key codes: 0x0e 0x83 0x84 0x85 0x96

    (source: x230 EC firmware version G2HT35WW, offset 0x218d8)

ThinkPad x230 live/dead bitmap:
-------------------------------

Again, this table is shared with all of the xx30 series laptops.  There is
a similar table in the x220 EC firmware, but with a different endianess (as
a result of the different embedded controller used in the x220)

The live/dead bitmap is an array of 16 words, each word being 16 bits long.
Each detected keypress is looked up in this array - the "drive" line is used
as the index into the array and the "sense" line is the bit number in that
word.  If the bit at that location is set, then the keypress is considered
a "live" key and the value from the matrix table is used as the embedded
controller scancode of the key pressed (Note that this scancode is internal
to the EC - it is not the same as the BIOS scancode)

    (source: x230 EC firmware version G2HT35WW, offset 0x219e8)


Other ThinkPad firmware matrix offsets:
---------------------------------------

While examining the firmware from other thinkpad models, the keyboard matrix
table has often been located.  To avoid needing to locate these tables
multiple times, they are recorded here.

p51.N1UHT24W.img.orig       02cbc8 and 02cd20 (both identical)
t470.N1QHT57W.img.orig      02d81c and 02d974 (both identical)
t470p.R0FHT16W.img.orig     02b430 and 02b588 (both identical)
t480.N24HT23W.img.orig      02efd0 and 02f128 (both identical)
t480s.N22HT22W.img.orig     02bd38 and 02be90 (both identical)
x240.GIHT32WW.img.enc.orig  023ec0 and 023ff4 (both identical)
x250.N10HT17W.img.enc.orig  025cd8 and 025e0c (both identical)
x260.R02HT29W.img.orig      0287b0 and 0288e4 (both identical)
x270.R0IHT50W.img.orig      02ce00 and 02cf34 (both identical)
x280.N20HT29W.img.orig      02b1c0 and 02b318 (both identical)

One think noted from this examination was that many of the matrix tables are
identical (thus the keyboards in those models are interchangable with no
firmware changes)

* the x240, x250 and x260 matrices are identical
* all the xx70 and xx80 matrices checked are identical - including t480s,
  t470p and additionally the p51