Alternative Controller for HHKB Pro

I wanted to add some features like vi cursor and mouse keys to my HHKB but its controller is not programmable and firmware source code is not open, of course. This means customizing this keyboard needs to replace original controller with programmable one. This controller can work with HHKB Professional and Professional 2 model.

See this thread in geekhack.org.

Features

• Customizable keymap
• More keymap layers(more Fn keys)
• Mouse keys
• USB NKRO

See README of tmk_keyboard for more.

Pros

• No risks: Everything is all reversible
• No need for PCB trace patching, case cutting or any other destructive mod
• Can keep original controller intact
• Can change all HHKB behaviour as you like

Cons

• Void your warranty
• Lose USB hub function of Pro2

DISCLAIMER

I’m not a professional of electronics nor MCU programming. This may damage your HHKB. And my English writing is poor, I’m not sure I can convey my notions accurately.

Documents

See doc/HHKB.txt and files under doc/ for internal of HHKB and this controller.

Build Firmware & Program

See this document first.

Configuration

Set MCU, BOOTLOADER_SIZE and other build options in Makefile and config.h.

Build

Just run make after intall tools.

$ make

Use Makefile.pjrc if you want to use PJRC stack instead of LUFA.(LUFA is recommended.)

$ make -f Makefile.pjrc

Use Makefile.vusb for V-USB controller.(not supported actively any more.)

$ make -f Makefile.vusb

Program

First, push reset button on board to start bootloader.

This command programs the controller with dfu-programmer if the tool is intalled and configured properly.

$ make dfu

Or you can also use FLIP command to program. Also the tool should be intalled and configured properly. FLIP GUI app is also available.

$ make flip

Use Teensy Loader if your controller is Teensy/Teensy++.

How to Customize

See tmk_keyboard documents.

Hardware

You have some options for hardware. Development boards with USB AVR family(ATMega32U4, AT90USB1286) like Teensy will work while MegaAVR with V-USB library is also cheapear option for DIY.

1. TMK Alt Controller Board

TMK designed Keyboard Controller Board for HHKB Pro2(KiCad project). See this post.

2. PJRC Teensy++ 2.0 connection

+---------------+
|   Teensy++    |
|               |
|               |               HHKB pro    HHKB pro2
|               |               ~~~~~~~~    ~~~~~~~~~
|          PB0-2|------->ROW    (6-8)       (5-7)
|          PB3-5|------->COL    (9-11)      (8-10)
|            PB6|------->ENABLE (12)        (11)
|            PE6|<-------KEY    (4)         (3)
|            PE7|------->PREV   (5)         (4)
|               |
|               |   5V---       (1-3)       (1-2)
|               |  GND---       (13-14)     (12-13)
+---------------+

• NOTE: PJRC Teensy

3. V-USB connection

                +---+   +---------------+
USB            GND  |   |   ATmega328p  |
~~~                 C3  |               |
5V <-------+--------+---|Vcc,AVCC       |               HHKB pro    pro2
           R1           |               |               ~~~~~~~~    ~~~~
D- <----+--+-----R2-----|INT1      PB2-4|------->ROW    (6-8)       (5-7)
D+ <----|---+----R3-----|INT0      PC0-2|------->COL    (9-11)      (8-10)
        Z1  Z2          |            PC3|------->ENABLE (12)        (11)
GND<----+---+-----------|GND         PB0|<-------KEY    (4)         (3)
                        |            PB1|------->PREV   (5)         (4)
                        |               |
            GND+-C2--+--|XTAL1       RXD|------->Debug Console
                     X1 |            TXD|<-------Debug Console
            GND+-C3--+--|XTAL2       RST|---SW--+GND
                        +---------------+
R1:     1.5K Ohm
R2,R3:  68 Ohm
Z1,Z2:  Zener 3.6V
C1,C2:  22pF
C3:     0.1uF
X1:     Crystal 12MHz
SW:     Push Switch(for bootloader)

• NOTE: See V-USB documentation for more detail of hardware and the USB stack.
• NOTE: USBaspLoader is very useful for firmware update.