[tmk_keyboard.git] / keyboard / hhkb / doc / HHKB.txt

Internal of HHKB pro
=====================
HHKB pro has MCU and some chips on separate two PCBs.

Controller PCB
--------------
    M38K07M4    Renesas MCU with USB function
                http://documentation.renesas.com/eng/products/mpumcu/rej03b0192_38k0ds.pdf

    (HHKB_controller.jpg)

Keyswitch PCB
-------------
    HC4051      Analog Multiplexer: select a row line.
                http://www.ti.com/lit/ds/schs122j/schs122j.pdf
    LS145       BCD Decoder: select a column line.
                http://www.ti.com/lit/ds/symlink/sn74ls145.pdf
    BU9831      Non-volatile electronic potentiometer: for calibration?
                https://www.spezial.com/doc/rohm-a/bu9831.pdf
    TP1683/4    Capacitive Sensing controller: no datasheet available.

    (HHKB_keyswitch.jpg)

    Topre original chip?
    (HHKB_TP1684.jpg)


Connector Cable
---------------
Two PCBs are connected by 15 lines(13 in case of Pro2).
Vcc and GND use 3(2) lines each, other lines are for keyboard signaling.

    HHKB connector lines:
    JP   Pro2   Pro     Function    Description                               TMK pin usage
    --------------------------------------------------------------------------------------------
                 1      Vcc(5V)                                               5V
     1    1      2      Vcc(5V)                                               5V
     2    2      3      Vcc(5V)                                               5V
     3    3      4      TP1684      ~KEY: Low(0) when key is pressed          PD7 input(with pullup)
     4    4      5      TP1684      HYS: High(1) when key is pressed          PB7 output
     5    5      6      HC4051      A(bit0)\                                  PB0 output
     6    6      7      HC4051      B(bit1) > select row 0-7                  PB1 output
     7    7      8      HC4051      C(bit2)/                                  PB2 output
     8    8      9      LS145       A(bit0)\                                  PB3 output
     9    9     10      LS145       B(bit1) > select column 0-7               PB4 output
    10   10     11      LS145       C(bit2)/                                  PB5 output
    11   11     12      LS145       ~D(enable) Low(0) enables selected column PB6 output
    12   12     13      GND                                                   GND
    13   13     14      GND                                                   GND
                15      GND
    14                  HC4051(Z2)  ~Enable of Z2   row0-7                    PC6
    15                  HC4051(Z3)  ~Enable of Z3   row8-15                   PC7

    NOTE: Probably HYS changes threshold for upstroke and makes hysteresis in the result.
    NOTE: HYS should be given High(1) when previous KEY state is Low(0).
    NOTE: 1KOhm didn't work as pullup resistor on KEY. AVR internal pullup or 10KOhm resistor was OK.
    NOTE: JP has two HC4051(Z2,Z3) and line 5, 6 and 7 are connected to both of them.

    (HHKB_connector.jpg)


Keyswitch matrix
----------------
HHKB switch matrix is ghost-free and bounce-free.

    Pro/Pro2(8x8):
      COL 0     1       2       3       4       5       6       7
    ROW ---------------------------------------------------------------
      0|  2     q       w       s       a       z       x       c
      1|  3     4       r       e       d       f       v       b
      2|  5     6       y       t       g       h       n       _NONE_
      3|  1     Esc     Tab     Control LShift  LAlt    LMeta   Space
      4|  7     8       u       i       k       j       m       _NONE_
      5|  \     `       Delete  Return  Fn      RShift  RAlt    RMeta
      6|  9     0       o       p       ;       l       ,       _NONE_
      7|  -     +       ]       [       '       /       .       _NONE_


    JP(16x8):
      COL 0     1       2       3       4       5       6       7
    ROW ---------------------------------------------------------------
      0|                ESC     TAB     LFn     LShift  LCtrl
      1|                4       E       MuHKN   C       D
      2|                3       W       LAlt    X       S
      3|                1               HHK
      4|  
      5|                5       R               V       F
      6|                2       Q       LGui    Z       A
      7|                6       T       Space   B       G
      8|                9       I       Kana    ,       K
      9|                8       U       Henkan  M       J
      A|                7       Y               N       H
      B|                0       O       RAlt    .       L
      C|                BS              Right   RShift  Enter
      D|                \       [       Down    Up      ]
      E|                -       P       RFn     /       ;
      F|                ~       @       Left    Ro      :


Matrix diagram:

    Pro/Pro2:
             +-------------------------+-+-+-+-+-+-+-+     Vcc
             |bias control?            - - - - - - - -     ---
             |                  3.9K*8 R R R R R R R R      |
    +--------^+      +--------+        - - - - - - - -      |  
    |        3|      | HC4051 <0-------|-|-|-|-|-|-|-|--|R|-+
    | DIL-20  |capa. |        <1-------|-|-|-|-|-|-|-|--|R|-+
    | TP1684  |sense |        <2-------|-|-|-|-|-|-|-|--|R|-+
    |       20<------|        <3-------|-|-|-|-|-|-|-|--|R|-+
    |         |      |        <4-------|-|-|-|-|-|-|-|--|R|-+
    |         |      |        <5-------|-|-|-|-|-|-|-|--|R|-+
    >5~EN     <-+    |        <6-------|-|-|-|-|-|-|-|--|R|-+
    |   2   4 | |    |        <7-------|-|-|-|-|-|-|-|--|R|-+
    +---V---^-+ |    +-^-^-^--+        0 1 2 3 4 5 6 7  33K*8
       KEY HYS  |      A B C         +-----------------+
        |   | +-^----+ | | |         |      LS145      |
    Vcc |   | |BU9831| | | |         +-^--^--^--^------+
    --- |   | +------+ | | |           A  B  C  D   +-------+
     |  |   |          | | |           |  |  |  |   |       |
    1-3 4   5          6 7 8           9 10 11 12 13-15 Pro |
    1-2 3   4          5 6 7           8  9 10 11 12-13 Pro2|
    +--------------------------------------------------+    |
    |                connector                         |   ---
    +--------------------------------------------------+   GND


    JP:
             +-----------------------------+-+-+-+-+       Vcc
             |bias control?                - - - - -       ---
             |                  3.9K*5     R R R R R        |
    +--------^+      +--------+            - - - - -        |  
    |        3|      | HC4051 <0-----------|-|-|-|-|----|R|-+
    |         |capa. |    Z2  <1-----------|-|-|-|-|----|R|-+
    | TP1684  |sense |        <2-----------|-|-|-|-|----|R|-+
    |       20<---+--|        <3-----------|-|-|-|-|----|R|-+
    |         |   |  |        <4-----------|-|-|-|-|----|R|-+
    |         |   ~En|        <5-----------|-|-|-|-|----|R|-+
    >5~EN     | +---->        <6-----------|-|-|-|-|----|R|-+
    |   2   4 | | |  | A B C  <7-----------|-|-|-|-|----|R|-+
    +---V---^-+ | |  +-^-^-^--+            | | | | |        |
       KEY HYS  | |    | | |               | | | | |        |
        |   |   | |  +--------+            | | | | |        |
        |   |   | |  | HC4051 <8-----------|-|-|-|-|----|R|-+
        |   |   | |  |    Z3  <9-----------|-|-|-|-|----|R|-+
        |   |   | +--|        <A-----------|-|-|-|-|----|R|-+
        |   |   |    |        <B-----------|-|-|-|-|----|R|-+
        |   |   |    |        <C-----------|-|-|-|-|----|R|-+
        |   |   | ~En|        <D-----------|-|-|-|-|----|R|-+
        |   |   |  +->        <E-----------|-|-|-|-|----|R|-+
        |   |   |  | | A B C  <F-----------|-|-|-|-|----|R|-+
        |   |   |  | +-^-^-^--+        0 1 2 3 4 5 6 7  33K*8
        |   |   |  |   | | |         +-----------------+
        |   |   |  |   | | |         |      LS145      |
    Vcc |   |   |  |   | | |         +-^--^--^--^------+
    --- |   |   |  |   | | |           A  B  C  D   +-------+
     |  |   |   |  |   | | |           |  |  |  |   |       |
    1-2 3   4  14 15   5 6 7           8  9 10 11 12-13     |
    +--------------------------------------------------+    |
    |                connector                         |   ---
    +--------------------------------------------------+   GND

TP1684-5(~EN) pin is connected with LS145-D/Connector-11.
                                    

Signals charts
--------------
    While pressing space bar, watched HHKB Pro original controller signals by logic analyzer.
    Row and column is looping between 0-7 each for selecting a key.
    A key is scaned every about 15ms, so scan rate is 66Hz.

    (HHKB_chart1.jpg)

    Space bar locate at ROW:3 COL:7. A key is selected by HC4051(C,B,A) and LS145(C,B,A).
    Key state can be read on TP1684(4) while asserting low on LS145(D).

    (HHKB_chart2.jpg)


    Signal of JP:

    1) Select row
    rowC    ____~~~~____~~~~    3.8/3.8ms(JP) 7.7/7.7ms(Pro)   S2 of HC4051
    rowB    __~~__~~__~~__~~    1.9/1.9ms(JP) 3.8/3.8ms(Pro)   S1 of HC4051
    rowA    _~_~_~_~_~_~_~_~    1.0/1.0ms(JP) 1.9/1.9ms(Pro)   S0 of HC4051
            0123456701234567    selected row(Pro)
            0123456789ABCDEF    selected row(JP)
    rowEn0  ________~~~~~~~~    7.7/7.7ms(JP only)              ~Enable of Z2 HC4051(JP only)
    rowEn1  ~~~~~~~~________    7.7/7.7ms(JP only)              ~Enable of Z3 HC4051(JP only)

    2) Select column
    colC    ____~~~~____~~~~    550/410us(JP)      /   us(Pro)
    colB    __~~__~~__~~__~~    200/210us(JP)   450/460us(Pro)
    colA    _~_~_~_~_~_~_~_~    100/110us(JP)   220/230us(Pro)
            0123456701234567    selected column

    3) Wait 5us after column select, then set prev, strobe colD to spit out key status and read it.
    hys     _~~~~_____          20us if previous key state is low
    colD    ~~~__~~~~~          10us strobe
    key     ~~~____~~~          22us indicates current state of the key

    NOTE: JP scans twice fast as Pro/Pro2 does. So Pro/Pro2 scans 8x8 matrix in 15.4ms while JP scans 16x8 in that time.


EOF
Commit	Line	Data
208f6d7f	1	Internal of HHKB pro
	2	=====================
	3	HHKB pro has MCU and some chips on separate two PCBs.
99bba8d9	4
208f6d7f	5	Controller PCB
208f6d7f	6	--------------
99bba8d9	7	M38K07M4 Renesas MCU with USB function
99bba8d9	8	http://documentation.renesas.com/eng/products/mpumcu/rej03b0192_38k0ds.pdf
c8e1ad8c	9
99bba8d9	10	(HHKB_controller.jpg)
99bba8d9	11
208f6d7f	12	Keyswitch PCB
208f6d7f	13	-------------
99bba8d9	14	HC4051 Analog Multiplexer: select a row line.
60134830	15	http://www.ti.com/lit/ds/schs122j/schs122j.pdf
99bba8d9	16	LS145 BCD Decoder: select a column line.
60134830	17	http://www.ti.com/lit/ds/symlink/sn74ls145.pdf
99bba8d9	18	BU9831 Non-volatile electronic potentiometer: for calibration?
60134830	19	https://www.spezial.com/doc/rohm-a/bu9831.pdf
13e4662b	20	TP1683/4 Capacitive Sensing controller: no datasheet available.
c8e1ad8c	21
99bba8d9	22	(HHKB_keyswitch.jpg)
c8e1ad8c	23
99bba8d9	24	Topre original chip?
	25	(HHKB_TP1684.jpg)
	26
	27
208f6d7f	28	Connector Cable
	29	---------------
	30	Two PCBs are connected by 15 lines(13 in case of Pro2).
60134830	31	Vcc and GND use 3(2) lines each, other lines are for keyboard signaling.
99bba8d9	32
60134830	33	HHKB connector lines:
8e7153d1	34	JP Pro2 Pro Function Description TMK pin usage
d2ea9e80	35	--------------------------------------------------------------------------------------------
60134830	36	1 Vcc(5V) 5V
	37	1 1 2 Vcc(5V) 5V
	38	2 2 3 Vcc(5V) 5V
8e7153d1	39	3 3 4 TP1684 ~KEY: Low(0) when key is pressed PD7 input(with pullup)
8e7153d1	40	4 4 5 TP1684 HYS: High(1) when key is pressed PB7 output
60134830	41	5 5 6 HC4051 A(bit0)\ PB0 output
	42	6 6 7 HC4051 B(bit1) > select row 0-7 PB1 output
	43	7 7 8 HC4051 C(bit2)/ PB2 output
	44	8 8 9 LS145 A(bit0)\ PB3 output
	45	9 9 10 LS145 B(bit1) > select column 0-7 PB4 output
	46	10 10 11 LS145 C(bit2)/ PB5 output
8e7153d1	47	11 11 12 LS145 ~D(enable) Low(0) enables selected column PB6 output
60134830	48	12 12 13 GND GND
	49	13 13 14 GND GND
	50	15 GND
8e7153d1	51	14 HC4051(Z2) ~Enable of Z2 row0-7 PC6
8e7153d1	52	15 HC4051(Z3) ~Enable of Z3 row8-15 PC7
208f6d7f	53
8e7153d1	54	NOTE: Probably HYS changes threshold for upstroke and makes hysteresis in the result.
8e7153d1	55	NOTE: HYS should be given High(1) when previous KEY state is Low(0).
d2ea9e80	56	NOTE: 1KOhm didn't work as pullup resistor on KEY. AVR internal pullup or 10KOhm resistor was OK.
60134830	57	NOTE: JP has two HC4051(Z2,Z3) and line 5, 6 and 7 are connected to both of them.
c8e1ad8c	58
99bba8d9	59	(HHKB_connector.jpg)
	60
	61
	62	Keyswitch matrix
	63	----------------
60134830	64	HHKB switch matrix is ghost-free and bounce-free.
99bba8d9	65
60134830	66	Pro/Pro2(8x8):
208f6d7f	67	COL 0 1 2 3 4 5 6 7
	68	ROW ---------------------------------------------------------------
	69	0\| 2 q w s a z x c
	70	1\| 3 4 r e d f v b
	71	2\| 5 6 y t g h n _NONE_
	72	3\| 1 Esc Tab Control LShift LAlt LMeta Space
	73	4\| 7 8 u i k j m _NONE_
	74	5\| \ ` Delete Return Fn RShift RAlt RMeta
	75	6\| 9 0 o p ; l , _NONE_
	76	7\| - + ] [ ' / . _NONE_
99bba8d9	77
99bba8d9	78
60134830	79	JP(16x8):
	80	COL 0 1 2 3 4 5 6 7
	81	ROW ---------------------------------------------------------------
	82	0\| ESC TAB LFn LShift LCtrl
	83	1\| 4 E MuHKN C D
	84	2\| 3 W LAlt X S
	85	3\| 1 HHK
	86	4\|
	87	5\| 5 R V F
	88	6\| 2 Q LGui Z A
	89	7\| 6 T Space B G
	90	8\| 9 I Kana , K
	91	9\| 8 U Henkan M J
	92	A\| 7 Y N H
	93	B\| 0 O RAlt . L
	94	C\| BS Right RShift Enter
	95	D\| \ [ Down Up ]
	96	E\| - P RFn / ;
	97	F\| ~ @ Left Ro :
	98
	99
99bba8d9	100	Matrix diagram:
208f6d7f	101
60134830	102	Pro/Pro2:
99bba8d9	103	+-------------------------+-+-+-+-+-+-+-+ Vcc
	104	\|bias control? - - - - - - - - ---
	105	\| 3.9K*8 R R R R R R R R \|
	106	+--------^+ +--------+ - - - - - - - - \|
e109b550	107	\| 3\| \| HC4051 <0-------\|-\|-\|-\|-\|-\|-\|-\|--\|R\|-+
e109b550	108	\| DIL-20 \|capa. \| <1-------\|-\|-\|-\|-\|-\|-\|-\|--\|R\|-+
13e4662b	109	\| TP1684 \|sense \| <2-------\|-\|-\|-\|-\|-\|-\|-\|--\|R\|-+
e109b550	110	\| 20<------\| <3-------\|-\|-\|-\|-\|-\|-\|-\|--\|R\|-+
99bba8d9	111	\| \| \| <4-------\|-\|-\|-\|-\|-\|-\|-\|--\|R\|-+
99bba8d9	112	\| \| \| <5-------\|-\|-\|-\|-\|-\|-\|-\|--\|R\|-+
e109b550	113	>5~EN <-+ \| <6-------\|-\|-\|-\|-\|-\|-\|-\|--\|R\|-+
e109b550	114	\| 2 4 \| \| \| <7-------\|-\|-\|-\|-\|-\|-\|-\|--\|R\|-+
13e4662b	115	+---V---^-+ \| +-^-^-^--+ 0 1 2 3 4 5 6 7 33K*8
8e7153d1	116	KEY HYS \| A B C +-----------------+
99bba8d9	117	\| \| +-^----+ \| \| \| \| LS145 \|
99bba8d9	118	Vcc \| \| \|BU9831\| \| \| \| +-^--^--^--^------+
60134830	119	--- \| \| +------+ \| \| \| A B C D +-------+
	120	\| \| \| \| \| \| \| \| \| \| \| \|
	121	1-3 4 5 6 7 8 9 10 11 12 13-15 Pro \|
	122	1-2 3 4 5 6 7 8 9 10 11 12-13 Pro2\|
	123	+--------------------------------------------------+ \|
	124	\| connector \| ---
	125	+--------------------------------------------------+ GND
	126
	127
	128	JP:
	129	+-----------------------------+-+-+-+-+ Vcc
	130	\|bias control? - - - - - ---
	131	\| 3.9K*5 R R R R R \|
	132	+--------^+ +--------+ - - - - - \|
e109b550	133	\| 3\| \| HC4051 <0-----------\|-\|-\|-\|-\|----\|R\|-+
60134830	134	\| \|capa. \| Z2 <1-----------\|-\|-\|-\|-\|----\|R\|-+
60134830	135	\| TP1684 \|sense \| <2-----------\|-\|-\|-\|-\|----\|R\|-+
e109b550	136	\| 20<---+--\| <3-----------\|-\|-\|-\|-\|----\|R\|-+
60134830	137	\| \| \| \| <4-----------\|-\|-\|-\|-\|----\|R\|-+
60134830	138	\| \| ~En\| <5-----------\|-\|-\|-\|-\|----\|R\|-+
e109b550	139	>5~EN \| +----> <6-----------\|-\|-\|-\|-\|----\|R\|-+
e109b550	140	\| 2 4 \| \| \| \| A B C <7-----------\|-\|-\|-\|-\|----\|R\|-+
60134830	141	+---V---^-+ \| \| +-^-^-^--+ \| \| \| \| \| \|
8e7153d1	142	KEY HYS \| \| \| \| \| \| \| \| \| \| \|
60134830	143	\| \| \| \| +--------+ \| \| \| \| \| \|
	144	\| \| \| \| \| HC4051 <8-----------\|-\|-\|-\|-\|----\|R\|-+
	145	\| \| \| \| \| Z3 <9-----------\|-\|-\|-\|-\|----\|R\|-+
	146	\| \| \| +--\| <A-----------\|-\|-\|-\|-\|----\|R\|-+
	147	\| \| \| \| <B-----------\|-\|-\|-\|-\|----\|R\|-+
	148	\| \| \| \| <C-----------\|-\|-\|-\|-\|----\|R\|-+
	149	\| \| \| ~En\| <D-----------\|-\|-\|-\|-\|----\|R\|-+
	150	\| \| \| +-> <E-----------\|-\|-\|-\|-\|----\|R\|-+
	151	\| \| \| \| \| A B C <F-----------\|-\|-\|-\|-\|----\|R\|-+
	152	\| \| \| \| +-^-^-^--+ 0 1 2 3 4 5 6 7 33K*8
	153	\| \| \| \| \| \| \| +-----------------+
	154	\| \| \| \| \| \| \| \| LS145 \|
	155	Vcc \| \| \| \| \| \| \| +-^--^--^--^------+
	156	--- \| \| \| \| \| \| \| A B C D +-------+
	157	\| \| \| \| \| \| \| \| \| \| \| \| \| \|
	158	1-2 3 4 14 15 5 6 7 8 9 10 11 12-13 \|
	159	+--------------------------------------------------+ \|
	160	\| connector \| ---
	161	+--------------------------------------------------+ GND
e109b550	162
e109b550	163	TP1684-5(~EN) pin is connected with LS145-D/Connector-11.
99bba8d9	164
99bba8d9	165
208f6d7f	166	Signals charts
208f6d7f	167	--------------
92004d67	168	While pressing space bar, watched HHKB Pro original controller signals by logic analyzer.
99bba8d9	169	Row and column is looping between 0-7 each for selecting a key.
99bba8d9	170	A key is scaned every about 15ms, so scan rate is 66Hz.
c8e1ad8c	171
99bba8d9	172	(HHKB_chart1.jpg)
99bba8d9	173
2ca3ab18	174	Space bar locate at ROW:3 COL:7. A key is selected by HC4051(C,B,A) and LS145(C,B,A).
e109b550	175	Key state can be read on TP1684(4) while asserting low on LS145(D).
2ca3ab18	176
99bba8d9	177	(HHKB_chart2.jpg)
99bba8d9	178
99bba8d9	179
92004d67	180	Signal of JP:
99bba8d9	181
92004d67	182	1) Select row
	183	rowC ____~~~~____~~~~ 3.8/3.8ms(JP) 7.7/7.7ms(Pro) S2 of HC4051
	184	rowB __~~__~~__~~__~~ 1.9/1.9ms(JP) 3.8/3.8ms(Pro) S1 of HC4051
	185	rowA _~_~_~_~_~_~_~_~ 1.0/1.0ms(JP) 1.9/1.9ms(Pro) S0 of HC4051
	186	0123456701234567 selected row(Pro)
	187	0123456789ABCDEF selected row(JP)
	188	rowEn0 ________~~~~~~~~ 7.7/7.7ms(JP only) ~Enable of Z2 HC4051(JP only)
	189	rowEn1 ~~~~~~~~________ 7.7/7.7ms(JP only) ~Enable of Z3 HC4051(JP only)
99bba8d9	190
92004d67	191	2) Select column
	192	colC ____~~~~____~~~~ 550/410us(JP) / us(Pro)
	193	colB __~~__~~__~~__~~ 200/210us(JP) 450/460us(Pro)
	194	colA _~_~_~_~_~_~_~_~ 100/110us(JP) 220/230us(Pro)
	195	0123456701234567 selected column
6c3b9a2d	196
92004d67	197	3) Wait 5us after column select, then set prev, strobe colD to spit out key status and read it.
8e7153d1	198	hys _~~~~_____ 20us if previous key state is low
92004d67	199	colD ~~~__~~~~~ 10us strobe
92004d67	200	key ~~~____~~~ 22us indicates current state of the key
6c3b9a2d	201
92004d67	202	NOTE: JP scans twice fast as Pro/Pro2 does. So Pro/Pro2 scans 8x8 matrix in 15.4ms while JP scans 16x8 in that time.
99bba8d9	203
99bba8d9	204
99bba8d9	205
99bba8d9	206	EOF