keychron_qmk_firmware/converter/adb_usb

ADB to USB keyboard converter

This firmware converts ADB keyboard protocol to USB. You can use PJRC Teensy for this converter, though, other USB AVR(ATMega32U4, AT90USB64/128 or etc) should work. But binary size is about 10KB or more it doesn't fit into 8K flash like ATMega8U2.

Discuss: http://geekhack.org/showwiki.php?title=Island:14290

README FIRST

https://github.com/tmk/tmk_keyboard https://github.com/tmk/tmk_keyboard/tree/master/converter/adb_usb

Also check these when you are in trouble.

https://github.com/tmk/tmk_keyboard/wiki https://github.com/tmk/tmk_keyboard/labels/NOTE

Wiring

Connect ADB pins to controller just by 3 lines(Vcc, GND, Data). By default Data line uses port PD0.

ADB female socket from the front:

  ,--_--.
 / o4 3o \      1: DATA
| o2   1o |     2: Power SW
 -  ===  -      3: VCC
  `-___-'       4: GND

This converter uses AVR's internal pull-up, but it seems to be too weak, in particular when you want to use a long or coiled cable. The external pull-up resistor(1K-10K Ohm) on Data is strongly recommended.(It is almost must!) https://github.com/tmk/tmk_keyboard/wiki/FAQ#pull-up-resistor

Pull-up resister:

Keyboard       Conveter
               ,------.
5V------+------|VCC   |
        |      |      |
       [R]     |      |
        |      |      |
Signal--+------|PD0   |
               |      |
GND------------|GND   |
               `------'
R: 1K Ohm resistor

Define following macros for ADB connection in config.h if you use other than port PD0.

ADB_PORT, ADB_PIN, ADB_DDR, ADB_DATA_BIT

Build

See doc/build.md. In short,

$ make clean
$ make

You can select keymap(ansi is default) like this:

$ make KEYMAP=[ansi|iso|hasu]

Keymap

You can change a keymap by editing code of keymap_[ansi|iso|hasu|yours].c. How to define the keymap is probably obvious. You can find key symbols in common/keycode.h. And see doc/keymap.md for more detail.

Magic command

To get help press h holding Magic key. Magic key is Power key.

Locking CapsLock

Many of old ADB keyboards have mechanical push-lock switch for Capslock key and this converter supports the locking Capslock key by default. See README in top directory for more detail about this feature. https://github.com/tmk/tmk_keyboard/blob/master/README.md#mechanical-locking-support

Also you may want to remove locking pin from the push-lock switch to use capslock as a normal momentary switch.

Notes

Not-extended ADB keyboards have no discrimination between right modifier and left one, you will always see left control even if you press right control key. Apple Extended Keyboard and Apple Extended Keyboard II can discriminate both side modifiers except for GUI key(Windows/Command).

And most ADB keyboard has no diodes in its matrix so they are not NKRO, though ADB protocol itself supports it. See protocol/adb.c for more info.

If keyboard has ISO layout you need to use ISO keymap with make KEYMAP=iso. With ANSI keymap you will suffer from swapped keys problem.

https://github.com/tmk/tmk_keyboard/issues/35

EOF