SDD
3fd1e13b2e
Distils public docs into reference/keyboard-mouse/PROTOCOL.md for the level-1 Keyboard (27) / Mouse (26) device tests: - keyboard: 4800 8N1 RS-423, self-test via FD -> 01 00 00 00 (errors 3D/3E) - mouse: 4800 8O1 RS-232, self-test via 'T' -> 4-byte report (errors 3D/3E, >=0x20 fatal) - separate ports: DUART2 A=keyboard, B=mouse (NOT daisy-chained) MAME already has an LK201 device (src/mame/dec/lk201.cpp/.h) but no DEC mouse.
Linux host setup
elkay sends the LK401's F13–F20 as the standard USB keys F13–F20. The kernel reports them as
KEY_F13–KEY_F20, but xkb's default symbols then turn them into other keys:
| LK401 key | Default keysym | GNOME does |
|---|---|---|
| F13 | XF86Tools | opens Settings |
| F14 | XF86Launch5 | |
| Help (F15) | XF86Launch6 | |
| Do (F16) | XF86Launch7 | |
| F17 | XF86Launch8 | |
| F18 | XF86Launch9 | |
| F19 | none | |
| F20 | XF86AudioMicMute | mutes the microphone |
GNOME acts on F13 and F20 before any application sees them, so veetee can't fix this on its
own. The xkb option elkay:fkeys gives all eight keys the keysyms F13–F20, and veetee's default
keymap already binds those.
Install
host/linux/install-xkb.sh
This copies xkb/ to ~/.config/xkb/, where libxkbcommon looks for user rules, and adds
elkay:fkeys to GNOME's xkb-options, keeping any options already set. On other desktops, run
it and then enable the option in the keyboard settings.
The option applies to every keyboard. That's harmless: few PC keyboards have F13–F20, and the ones that do then send F13–F20 too.
Remove
gsettings reset org.gnome.desktop.input-sources xkb-options # or remove just elkay:fkeys
rm ~/.config/xkb/symbols/elkay ~/.config/xkb/rules/evdev
Testing without the keyboard
xkb/ was checked by compiling evdev / pc105 / us keymaps with libxkbcommon, with and
without the option. Keycodes FK13–FK20 resolve to F13–F20 only with it. The rules file includes
the system rules first: rules apply in file order, and the option has to come after
inet(evdev) to override it.