Keyswitch PCB
-------------
HC4051 Analog Multiplexer: select a row line.
- http://www.alldatasheet.com/datasheet-pdf/pdf/203989/KODENSHI/KK74HC4051A.html
+ http://www.ti.com/lit/ds/schs122j/schs122j.pdf
LS145 BCD Decoder: select a column line.
- http://www.alldatasheet.com/datasheet-pdf/pdf/27373/TI/SN74LS145D.html
+ http://www.ti.com/lit/ds/symlink/sn74ls145.pdf
BU9831 Non-volatile electronic potentiometer: for calibration?
- http://www.alldatasheet.com/datasheet-pdf/pdf/36387/ROHM/BU9831.html
+ https://www.spezial.com/doc/rohm-a/bu9831.pdf
TP1683/4 Capacitive Sensing controller: no datasheet available.
(HHKB_keyswitch.jpg)
Connector Cable
---------------
Two PCBs are connected by 15 lines(13 in case of Pro2).
-Vcc and GND use 3(2) lines each, other 9 lines are for keyboard signaling.
+Vcc and GND use 3(2) lines each, other lines are for keyboard signaling.
- Keyswitch connector
- pro pro2 Description Teensy++ pins
+ HHKB connector lines:
+ JP Pro2 Pro Function Description Teensy++ pins
--------------------------------------------------------------------------------------------
- 1 Vcc(5V) Not exist on Pro2 5V
- 2 1 Vcc(5V) 5V
- 3 2 Vcc(5V) 5V
- 4 3 TP1684 KEY: Low(0) when key pressed PE6 input(with pullup)
- 5 4 TP1684 KEY_PREV: make threshold PE7 output
- 6 5 HC4051 A(bit0)\ PB0 output
- 7 6 HC4051 B(bit1) > select row(0 to 7) PB1 output
- 8 7 HC4051 C(bit2)/ PB2 output
- 9 8 LS145 A(bit0)\ PB3 output
- 10 9 LS145 B(bit1) > select column(0 to 7) PB4 output
- 11 10 LS145 C(bit2)/ PB5 output
- 12 11 LS145 D(enable) Low(0) enables selected column PB6 output
- 13 12 GND GND
- 14 13 GND GND
- 15 GND Not exist on Pro2 GND
+ 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
----------------
-60 keyswitches in 8*8 matrix. It is ghost-free and bounce-free.
+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
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 |
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 |
- +--------------------------------------------------+ |
- | connector | ---
- +--------------------------------------------------+ GND
- to controller
+ --- | | +------+ | | | 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 original controller signals by logic analyzer.
+ 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.
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).
- Usage of TP1684(5) is not clear. Controller seemed to output previous key state on this line.
- However key state can be read without using this signal.
-
(HHKB_chart2.jpg)
-Matrix scan pseudo code
------------------------
- for (row: 0-7) {
- SELECT_ROW(row); // set HC4051(A,B,C)
-
- for (col: 0-7) {
- SELECT_COL(col); // set LS145(A,B,C)
-
- _delay_us(40);
-
- if (prev_key_state(row, col)) {
- KEY_PREV_ON;
- }
-
- _delay_us(7);
-
- ENALBLE_COL(); // set LS145(D) to low
+ Signal of JP:
- _delay_us(10);
+ 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)
- if (KEY == 0) { // read TP1684(KEY)
- // key pressed
- } else {
- // not pressed
- }
+ 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
- KEY_PREV_OFF;
- UNALBLE_COL(); // set LS145(D) to high
+ 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
- _delay_us(150);
- }
- }
+ 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.
projects / tmk_firmware.git / blobdiff