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- 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 Teensy++ pins
- --------------------------------------------------------------------------------------------
- 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 pressed PE6 input(with pullup)
- 4 4 5 TP1684 KEY_PREV: make threshold PE7 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
- 15 HC4051(Z3) ~Enable of Z3 row8-15
-
- NOTE: guessing pin5(KEY_PREV) may work for hysteresis of capacitive sensing.
- 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 |
- +--------^+ +--------+ - - - - - - - - |
- | 2| | HC4051 <0-------|-|-|-|-|-|-|-|--|R|-+
- | |capa. | <1-------|-|-|-|-|-|-|-|--|R|-+
- | TP1684 |sense | <2-------|-|-|-|-|-|-|-|--|R|-+
- | 11<------| <3-------|-|-|-|-|-|-|-|--|R|-+
- | | | <4-------|-|-|-|-|-|-|-|--|R|-+
- | | | <5-------|-|-|-|-|-|-|-|--|R|-+
- | <-+ | <6-------|-|-|-|-|-|-|-|--|R|-+
- | 1 4 | | | <7-------|-|-|-|-|-|-|-|--|R|-+
- +---V---^-+ | +-^-^-^--+ 0 1 2 3 4 5 6 7 33K*8
- KEY PREV | 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 |
- +--------^+ +--------+ - - - - - |
- | | | HC4051 <0-----------|-|-|-|-|----|R|-+
- | |capa. | Z2 <1-----------|-|-|-|-|----|R|-+
- | TP1684 |sense | <2-----------|-|-|-|-|----|R|-+
- | <---+--| <3-----------|-|-|-|-|----|R|-+
- | | | | <4-----------|-|-|-|-|----|R|-+
- | | ~En| <5-----------|-|-|-|-|----|R|-+
- | | +----> <6-----------|-|-|-|-|----|R|-+
- | | | | | A B C <7-----------|-|-|-|-|----|R|-+
- +---V---^-+ | | +-^-^-^--+ | | | | | |
- KEY PREV | | | | | | | | | | |
- | | | | +--------+ | | | | | |
- | | | | | 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
-
-
- 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/KEY) 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.
- prev _~~~~_____ 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
|
