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- Alternative Controller for HHKB pro
- ===================================
- I want to add vi cursor and mouse keys to HHKB. Original HHKB controller is not programmable and
- firmware source code is not open. So, customizing HHKB needs to replace original controller with programmable one.
- I used Teensy++ as alternative controller. Though a Teensy has enough ports to drive HHKB,
- Teensy++ has clean pinout and it makes programing and wiring easier.
-
- This is just a proof of concept for replacing controller of HHKB, not a complete firmware.
-
- My prototype firmware source tree is here:
- github(http://github.com/tmk/tmk_keyboard)
- This firmware is a port of my previous project:
- HHKB style Mod(http://geekhack.org/showwiki.php?title=Island:11930)
- PJRC:
- Teensy++/Teensy(http://www.pjrc.com/teensy/)
-
-
- Pros:
- * without pattern cutting, case mod and soldering
- * can keep original controller intact
- * can change HHKB behaviour as you like(by C programming)
-
- Cons:
- * void your warranty
- * unavailability of Teensy++/Teensy(because of PS3 cracking boom?)
-
- Features:
- * customized keymap
- * more keymap layers
- * mouse keys for minimum mouse operation(never comfortable for normal use)
- * and more...(in the future)
-
- Any suggestions or ideas are welcome.
-
-
- NOTE:
- My HHKB is just "Professional". This means followings may not be applied to "Professional2".
-
- DISCLAIMER:
- I'm not a professional for electronics and MCU programming. This may damage your HHKB.
- And my English writing is poor, I'm not sure I can convey my notions accurately.
-
-
- Teensy++ installation
- ---------------------
- Angled USB mini B adapter is used to install Teensy++ laterally.
- (teensy_install.jpg)
-
- Bread baord wires are used to connect Teensy++.
- (teensy_wiring.jpg)
- (connector_contact.jpg)
-
-
- HHKB internal
- -------------
- HHKB pro has 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.alldatasheet.com/datasheet-pdf/pdf/203989/KODENSHI/KK74HC4051A.html
- LS145 BCD Decoder: select a column line.
- http://www.alldatasheet.com/datasheet-pdf/pdf/27373/TI/SN74LS145D.html
- BU9831 Non-volatile electronic potentiometer: for calibration?
- http://www.alldatasheet.com/datasheet-pdf/pdf/36387/ROHM/BU9831.html
- TP1684 Capacitive Sensing controller: no datasheet available.
-
- (HHKB_keyswitch.jpg)
-
- Topre original chip?
- (HHKB_TP1684.jpg)
-
-
- Two PCBs are connected by 15 lines. Vcc and GND use 3 lines each, other 9 lines are for keyboard signaling.
-
- Keyswitch PCB connector Teensy++ pins
- -------------------------------------------------------------------------------
- 1 Vcc(5V) 5V
- 2 Vcc(5V)
- 3 Vcc(5V)
- 4 TP1684 KEY: Low(0) when key pressed PE6 input(with pullup)
- 5 TP1684 KEY_PREV: assert previous key state??? PE7 output
- 6 HC4051 A(bit0) select 8 rows(0 to 7) PB0 output
- 7 HC4051 B(bit1) PB1 output
- 8 HC4051 C(bit2) PB2 output
- 9 LS145 A(bit0) select 8 columns(0 to 7) PB3 output
- 10 LS145 B(bit1) PB4 output
- 11 LS145 C(bit2) PB5 output
- 12 LS145 D(enable) Low(0) enable selected column PB6 output
- 13 GND
- 14 GND
- 15 GND GND
-
- (HHKB_connector.jpg)
-
-
- Keyswitch matrix
- ----------------
- 60 keyswitches in 8*8 matrix. It is ghost-free and bounce-free.
-
- 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_
-
-
- Matrix diagram:
- +-------------------------+-+-+-+-+-+-+-+ Vcc
- |bias control? - - - - - - - - ---
- | 3.9K*8 R R R R R R R R |
- +--------^+ +--------+ - - - - - - - - |
- | TP 1684 | | HC4051 <0-------|-|-|-|-|-|-|-|--|R|-+
- | |capa. | <1-------|-|-|-|-|-|-|-|--|R|-+
- | |sense | <2-------|-|-|-|-|-|-|-|--|R|-+
- | <------| <3-------|-|-|-|-|-|-|-|--|R|-+
- | | | <4-------|-|-|-|-|-|-|-|--|R|-+
- | | | <5-------|-|-|-|-|-|-|-|--|R|-+
- | |calib.| <6-------|-|-|-|-|-|-|-|--|R|-+
- | <-+? | <7-------|-|-|-|-|-|-|-|--|R|-+
- +---V-----+ | +-^-^-^--+ 0 1 2 3 4 5 6 7 33K*8
- KEY ??? | 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
-
-
- Signals charts:
- While pressing space bar, watched HHKB 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).
-
- 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
-
- _delay_us(10);
-
- if (KEY == 0) { // read TP1684(KEY)
- // key pressed
- } else {
- // not pressed
- }
-
- KEY_PREV_OFF;
- UNALBLE_COL(); // set LS145(D) to high
-
- _delay_us(150);
- }
- }
-
-
- Keymap layers
- -------------
- Followings are added layers with additional Fn keys.
-
- see keymap.c
-
- EOF
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