199 lines
7.2 KiB
Text
199 lines
7.2 KiB
Text
Alternative Controller for HHKB pro
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===================================
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I want to add vi cursor and mouse keys to HHKB. Original HHKB controller is not programmable and
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firmware source code is not open. So, customizing HHKB needs to replace original controller with programmable one.
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I used Teensy++ as alternative controller. Though a Teensy has enough ports to drive HHKB,
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Teensy++ has clean pinout and it makes programing and wiring easier.
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This is just a proof of concept for replacing controller of HHKB, not a complete firmware.
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My prototype firmware source tree is here:
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github(http://github.com/tmk/tmk_keyboard)
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This firmware is a port of my previous project:
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HHKB style Mod(http://geekhack.org/showwiki.php?title=Island:11930)
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PJRC:
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Teensy++/Teensy(http://www.pjrc.com/teensy/)
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Pros:
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* without pattern cutting, case mod and soldering
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* can keep original controller intact
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* can change HHKB behaviour as you like(by C programming)
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Cons:
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* void your warranty
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* unavailability of Teensy++/Teensy(because of PS3 cracking boom?)
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Features:
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* customized keymap
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* more keymap layers
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* mouse keys for minimum mouse operation(never comfortable for normal use)
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* and more...(in the future)
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Any suggestions or ideas are welcome.
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NOTE:
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My HHKB is just "Professional". This means followings may not be applied to "Professional2".
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DISCLAIMER:
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I'm not a professional for electronics and MCU programming. This may damage your HHKB.
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And my English writing is poor, I'm not sure I can convey my notions accurately.
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Teensy++ installation
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---------------------
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Angled USB mini B adapter is used to install Teensy++ laterally.
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(teensy_install.jpg)
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Bread baord wires are used to connect Teensy++.
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(teensy_wiring.jpg)
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(connector_contact.jpg)
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HHKB internal
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-------------
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HHKB pro has some chips on separate two PCBs.
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Controller PCB:
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M38K07M4 Renesas MCU with USB function
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http://documentation.renesas.com/eng/products/mpumcu/rej03b0192_38k0ds.pdf
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(HHKB_controller.jpg)
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Keyswitch PCB:
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HC4051 Analog Multiplexer: select a row line.
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http://www.alldatasheet.com/datasheet-pdf/pdf/203989/KODENSHI/KK74HC4051A.html
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LS145 BCD Decoder: select a column line.
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http://www.alldatasheet.com/datasheet-pdf/pdf/27373/TI/SN74LS145D.html
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BU9831 Non-volatile electronic potentiometer: for calibration?
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http://www.alldatasheet.com/datasheet-pdf/pdf/36387/ROHM/BU9831.html
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TP1684 Capacitive Sensing controller: no datasheet available.
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(HHKB_keyswitch.jpg)
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Topre original chip?
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(HHKB_TP1684.jpg)
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Two PCBs are connected by 15 lines. Vcc and GND use 3 lines each, other 9 lines are for keyboard signaling.
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Keyswitch PCB connector Teensy++ pins
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-------------------------------------------------------------------------------
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1 Vcc(5V) 5V
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2 Vcc(5V)
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3 Vcc(5V)
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4 TP1684 KEY: Low(0) when key pressed PE6 input(with pullup)
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5 TP1684 KEY_PREV: assert previous key state??? PE7 output
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6 HC4051 A(bit0) select 8 rows(0 to 7) PB0 output
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7 HC4051 B(bit1) PB1 output
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8 HC4051 C(bit2) PB2 output
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9 LS145 A(bit0) select 8 columns(0 to 7) PB3 output
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10 LS145 B(bit1) PB4 output
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11 LS145 C(bit2) PB5 output
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12 LS145 D(enable) Low(0) enable selected column PB6 output
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13 GND
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14 GND
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15 GND GND
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(HHKB_connector.jpg)
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Keyswitch matrix
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----------------
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60 keyswitches in 8*8 matrix. It is ghost-free and bounce-free.
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COL 0 1 2 3 4 5 6 7
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ROW ---------------------------------------------------------------
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0| 2 q w s a z x c
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1| 3 4 r e d f v b
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2| 5 6 y t g h n _NONE_
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3| 1 Esc Tab Control LShift LAlt LMeta Space
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4| 7 8 u i k j m _NONE_
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5| \ ` Delete Return Fn RShift RAlt RMeta
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6| 9 0 o p ; l , _NONE_
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7| - + ] [ ' / . _NONE_
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Matrix diagram:
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+-------------------------+-+-+-+-+-+-+-+ Vcc
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|bias control? - - - - - - - - ---
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| 3.9K*8 R R R R R R R R |
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+--------^+ +--------+ - - - - - - - - |
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| TP 1684 | | HC4051 <0-------|-|-|-|-|-|-|-|--|R|-+
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| |capa. | <1-------|-|-|-|-|-|-|-|--|R|-+
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| |sense | <2-------|-|-|-|-|-|-|-|--|R|-+
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| <------| <3-------|-|-|-|-|-|-|-|--|R|-+
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| | | <4-------|-|-|-|-|-|-|-|--|R|-+
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| | | <5-------|-|-|-|-|-|-|-|--|R|-+
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| |calib.| <6-------|-|-|-|-|-|-|-|--|R|-+
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| <-+? | <7-------|-|-|-|-|-|-|-|--|R|-+
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+---V-----+ | +-^-^-^--+ 0 1 2 3 4 5 6 7 33K*8
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KEY ??? | A B C +-----------------+
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| | +-^----+ | | | | LS145 |
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Vcc | | |BU9831| | | | +-^--^--^--^------+
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--- | | +------+ | | | A B C D +------+
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| | | | | | | | | | | |
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1-3 4 5 6 7 8 9 10 11 12 13-15 |
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+--------------------------------------------------+ |
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| connector | ---
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+--------------------------------------------------+ GND
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to controller
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Signals charts:
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While pressing space bar, watched HHKB original controller signals by logic analyzer.
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Row and column is looping between 0-7 each for selecting a key.
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A key is scaned every about 15ms, so scan rate is 66Hz.
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(HHKB_chart1.jpg)
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Space bar locate at ROW:3 COL:7. A key is selected by HC4051(C,B,A) and LS145(C,B,A).
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Key state can be read on TP1684(4/KEY) while asserting low on LS145(D).
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Usage of TP1684(5) is not clear. Controller seemed to output previous key state on this line.
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However key state can be read without using this signal.
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(HHKB_chart2.jpg)
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Matrix scan pseudo code:
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for (row: 0-7) {
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SELECT_ROW(row); // set HC4051(A,B,C)
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for (col: 0-7) {
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SELECT_COL(col); // set LS145(A,B,C)
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_delay_us(40);
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if (prev_key_state(row, col)) {
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KEY_PREV_ON;
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}
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_delay_us(7);
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ENALBLE_COL(); // set LS145(D) to low
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_delay_us(10);
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if (KEY == 0) { // read TP1684(KEY)
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// key pressed
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} else {
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// not pressed
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}
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KEY_PREV_OFF;
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UNALBLE_COL(); // set LS145(D) to high
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_delay_us(150);
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}
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}
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Keymap layers
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-------------
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Followings are added layers with additional Fn keys.
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see keymap.c
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EOF
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