22 KiB
Keymap framework - how to define your keymap
NOTE: This is not final version, may be inconsistent with source code and changed occasionally for a while.
0. Keymap and layers
Keymap is comprised of multiple layers of key layout, you can define 16 layers at most. Layer is an array of keycodes to define actions on each physical keys. respective layers can be validated simultaneously. Layers are indexed with 0 to 15 and higher layer has precedence.
Keymap with 16 Layers Layer: array of Keycodes
--------------------- ------------------------
stack of layers content of layer
____________ precedence _______________________
/ / | high / ESC / F1 / F2 / F3 ....
15 /___________// | /-----/-----/-----/-----
14 /___________// | / TAB / / / ....
13 /___________/_ | /-----/-----/-----/-----
: / : : : : : / | /LCtrl/ / / ....
3 /___________// | : / : : : :
2 /___________// | 2 `--------------------------
1 /___________// | 1 `--------------------------
0 /___________/ V low 0 `--------------------------
0.1 Keymap status
Keymap has its state in two parameters:
default_layer
indicates a base keymap layer(0-15) which is always valid and to be referred, keymap_stat
is 16bit variable which has current on/off status of layers on its each bit.
Keymap layer '0' is usually default_layer
and which is the only valid layer and other layers is initially off after boot up firmware, though, you can configured them in config.h
.
To change default_layer
will be useful when you want to switch key layout completely, say you use Colmak instead of Qwerty.
Initial state of Keymap Change base layout
----------------------- ------------------
15 15
14 14
13 13
: :
3 3 ____________
2 ____________ 2 / /
1 / / ,->1 /___________/
,->0 /___________/ | 0
| |
`--- default_layer = 0 `--- default_layer = 1
keymap_stat = 0x0001 keymap_stat = 0x0002
On the other hand, you shall change keymap_state
to overlay base layer with some layers for feature such as navigation keys, function key(F1-F12), media keys or special actions.
Overlay feature layer
--------------------- bit|status
____________ ---+------
15 / / 15 | 0
14 /___________// -----> 14 | 1
13 /___________/ -----> 13 | 1
: : |
3 ____________ 3 | 0
2 / / 2 | 0
,->1 /___________/ -----> 1 | 1
| 0 0 | 0
| |
`--- default_layer = 1 |
keymap_stat = 0x6002 <-----'
0.2 Layer Precedence and Transparency
Note that higher layer has higher priority on stack of layers, namely firmware falls down from top layer to bottom to look up keycode. Once it spots keycode other than KC_TRNS
(transparent) on a layer it stops searching and lower layers aren't referred.
You can place KC_TRNS
on overlay layer changes just part of layout to fall back on lower or base layer.
Key with KC_TRANS
doen't has its own keycode and refers to lower valid layers for keycode, instead.
See example below.
0.3 Keymap Example
Keymap is keymaps[]
C array in fact and you can define layers in it with KEYMAP()
C macro and keycodes. To use complex actions you need to define Fn
keycode in fn_actions[]
array.
This is a keymap example for HHKB keyboard. This example has three layers, 'Qwerty' as base layer, 'Cursor' and 'Mousekey'. In this example,
Fn0
is a momentary layer switching key, you can use keys on Cursor layer while holding the key.
Fn1
is a momentary layer switching key with tapping feature, you can get semicolon ';' with taping the key and switch layers while holding the key. The word 'tap' or 'tapping' mean to press and release a key quickly.
Fn2
is a toggle layer switch key, you can stay switched layer after releasing the key unlike momentary switching.
You can find other keymap definitions in file keymap.c
located on project directories.
static const uint8_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
/* 0: Qwerty
* ,-----------------------------------------------------------.
* |Esc| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| -| =| \| `|
* |-----------------------------------------------------------|
* |Tab | Q| W| E| R| T| Y| U| I| O| P| [| ]|Backs|
* |-----------------------------------------------------------|
* |Contro| A| S| D| F| G| H| J| K| L|Fn1| '|Enter |
* |-----------------------------------------------------------|
* |Shift | Z| X| C| V| B| N| M| ,| .| /|Shift |Fn0|
* `-----------------------------------------------------------'
* |Gui|Alt |Space |Alt |Fn2|
* `-------------------------------------------'
*/
KEYMAP(ESC, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, MINS,EQL, BSLS,GRV, \
TAB, Q, W, E, R, T, Y, U, I, O, P, LBRC,RBRC,BSPC, \
LCTL,A, S, D, F, G, H, J, K, L, FN1, QUOT,ENT, \
LSFT,Z, X, C, V, B, N, M, COMM,DOT, SLSH,RSFT,FN0, \
LGUI,LALT, SPC, RALT,FN2),
/* 1: Cursor(HHKB mode)
* ,-----------------------------------------------------------.
* |Pwr| F1| F2| F3| F4| F5| F6| F7| F8| F9|F10|F11|F12|Ins|Del|
* |-----------------------------------------------------------|
* |Caps | | | | | | | |Psc|Slk|Pus|Up | |Backs|
* |-----------------------------------------------------------|
* |Contro|VoD|VoU|Mut| | | *| /|Hom|PgU|Lef|Rig|Enter |
* |-----------------------------------------------------------|
* |Shift | | | | | | +| -|End|PgD|Dow|Shift | |
* `-----------------------------------------------------------'
* |Gui |Alt |Space |Alt |Gui|
* `--------------------------------------------'
*/
KEYMAP(PWR, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, INS, DEL, \
CAPS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,PSCR,SLCK,PAUS,UP, TRNS,BSPC, \
LCTL,VOLD,VOLU,MUTE,TRNS,TRNS,PAST,PSLS,HOME,PGUP,LEFT,RGHT,ENT, \
LSFT,TRNS,TRNS,TRNS,TRNS,TRNS,PPLS,PMNS,END, PGDN,DOWN,RSFT,TRNS, \
LGUI,LALT, SPC, RALT,RGUI),
/* 2: Mousekey
* ,-----------------------------------------------------------.
* |Esc| F1| F2| F3| F4| F5| F6| F7| F8| F9|F10|F11|F12|Ins|Del|
* |-----------------------------------------------------------|
* |Tab | | | | | |MwL|MwD|MwU|MwR| | | |Backs|
* |-----------------------------------------------------------|
* |Contro| | | | | |McL|McD|McU|McR| | |Return |
* |-----------------------------------------------------------|
* |Shift | | | | |Mb3|Mb2|Mb1|Mb4|Mb5| |Shift | |
* `-----------------------------------------------------------'
* |Gui |Alt |Mb1 |Alt | |
* `--------------------------------------------'
* Mc: Mouse Cursor / Mb: Mouse Button / Mw: Mouse Wheel
*/
KEYMAP(ESC, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, INS, DEL, \
TAB, TRNS,TRNS,TRNS,TRNS,TRNS,WH_L,WH_D,WH_U,WH_R,TRNS,TRNS,TRNS,BSPC, \
LCTL,TRNS,ACL0,ACL1,ACL2,TRNS,MS_L,MS_D,MS_U,MS_R,TRNS,QUOT,ENT, \
LSFT,TRNS,TRNS,TRNS,TRNS,BTN3,BTN2,BTN1,BTN4,BTN5,SLSH,RSFT,TRNS, \
LGUI,LALT, BTN1, RALT,TRNS),
};
static const uint16_t PROGMEM fn_actions[] = {
ACTION_KEYMAP_MOMENTARY(1), // FN0
ACTION_KEYMAP_TAP_KEY(2, KC_SCLN), // FN1
ACTION_KEYMAP_TOGGLE(2), // FN2
};
1. Keycode
See common/keycode.h
or keycode table below for the detail. Keycode is internal 8bit code to inidicate action performed on key in keymap. Keycode has KC_
prefixed symbol respectively. Most of keycodes like KC_A
have simple action registers key to host on press and unregister on release, while some of other keycodes has some special actions like Fn
keys, Media contorl keys, System control keys and Mousekeys.
In KEYMAP()
macro you should omit prefix part KC_
of keycode to keep keymap compact. For example, just use A
instead you place KC_A
in KEYMAP()
. Some keycodes has 4-letter short name in addition to descriptive name, you'll prefer short one in KEYMAP()
.
1.0 Other key
KC_NO
for no acitonKC_TRNS
for layer transparency (See above)
1.1 Normal key
KC_A
toKC_Z
,KC_1
toKC_0
for alpha numeric keyKC_MINS
,KC_EQL
,KC_GRV
,KC_RBRC
,KC_LBRC
,KC_COMM
,KC_DOT
,KC_BSLS
,KC_SLSH
,KC_SCLN
,KC_QUOT
KC_ESC
,KC_TAB
,KC_SPC
,KC_BSPC
,KC_ENT
,KC_DEL
,KC_INS
KC_UP
,KC_DOWN
,KC_RGHT
,KC_LEFT
,KC_PGUP
,KC_PGDN
,KC_HOME
,KC_END
KC_CAPS
,KC_NLCK
,KC_SLCK
,KC_PSCR
,KC_PAUS
,KC_APP
,KC_F1
toKC_F24
KC_P1
toKC_P0
,KC_PDOT
,KC_PCMM
,KC_PSLS
,KC_PAST
,KC_PMNS
,KC_PPLS
,KC_PEQL
,KC_PENT
for keypad.
1.2 Modifier
There are 8 modifiers which has discrimination between left and right.
KC_LCTL
andKC_RCTL
for ControlKC_LSFT
andKC_RSFT
for ShiftKC_LALT
andKC_RALT
for AltKC_LGUI
andKC_RGUI
for Windows key or Command key in Mac
1.3 Mousekey
KC_MS_U
,KC_MS_D
,KC_MS_L
,KC_MS_R
for mouse cursorKC_WH_U
,KC_WH_D
,KC_WH_L
,KC_WH_R
for mouse wheelKC_BTN1
,KC_BTN2
,KC_BTN3
,KC_BTN4
,KC_BTN5
for mouse buttons
1.4 System & Media key
KC_PWR
,KC_SLEP
,KC_WAKE
for Power, Sleep, WakeKC_MUTE
,KC_VOLU
,KC_VOLD
for audio volume controlKC_MNXT
,KC_MPRV
,KC_MSTP
,KC_MPLY
,KC_MSEL
for media controlKC_MAIL
,KC_CALC
,KC_MYCM
for application launchKC_WSCH
,KC_WHOM
,KC_WBAK
,KC_WFWD
,KC_WSTP
,KC_WREF
,KC_WFAV
for web browser operation
1.5 Fn key
KC_FNnn
are keycodes for Fn
key which not given any actions at the beginning unlike most of keycodes has its own inborn action. To use these keycodes in KEYMAP
you need to assign action you want at first. Action of Fn
key is defined in fn_actions[]
and its index of the array is identical with number part of KC_FNnn
. Thus KC_FN0
keyocde indicates the action defined in first element of the array. 32 Fn
keys can be defined at most.
1.6 Keycode Table
See keycode table in doc/keycode.txt
for description of keycodes.
In regard to implementation side most of keycodes are identical with [HID usage]HID_usage sent to host for real and some virtual keycodes are defined to support special actions. [HID_usage]: http://www.usb.org/developers/devclass_docs/Hut1_11.pdf
2. Action
See common/action.h
. Action is a 16bit code and defines function to perform on events of a key like press, release, holding and tapping.
Most of keys just register 8bit scancode to host, but to support other complex features needs 16bit extended action codes internally. However, using 16bit action codes in keymap results in double size in memory against using jsut keycodes. To avoid this waste 8bit keycodes are used in KEYMAP
instead of action codes.
You can just use keycodes of Normal key
, Modifier
, Mousekey
and System & Media key
in keymap to indicate corresponding actions instead of using action codes. While to use other special actions you should use keycode of Fn
key defined in fn_actions[]
.
Usually action codes are needed only when you want to use layer switching, or
2.1 Key action
This is a simple action that registers scancodes(HID usage in fact) to host on press event of key and unregister on release.
2.1.1 Normal key and Modifier
This action usually won't be used expressly because you can use keycodes in KEYMAP()
instead.
You can define Key
action on 'A' key and 'left shift' modifier with:
ACTION_KEY(KC_A)
ACTION_KEY(KC_LSHIFT)
2.1.2 Key with modifiers
This action is comprised of strokes of modifiers and a key. Macro
action is needed if you want more complex key strokes.
Say you want to assign a key to Shift + 1
to get charactor '!' or Alt + Tab
to switch application windows.
ACTION_LMOD_KEY(KC_LSHIFT, KC_1)
ACTION_LMOD_KEY(KC_LALT, KC_TAB)
Or Alt,Shift + Tab
can be defined. ACTION_LMODS_KEY()
requires 4-bit modifier state and a keycode as arguments. See keycode.h
for MOD_BIT()
macro.
ACTION_LMODS_KEY((MOD_BIT(KC_LALT) | MOD_BIT(KC_LSHIFT)), KC_TAB)
2.2 Layer Action
These actions operate layers of keymap.
Parameters:
- layer: 0-15
- on: { press | release | both }
2.2.0 Default Layer
default_layer
is layer which always is valid and referred to when actions is not defined on other layers.
Return to Default Layer
Turns on only default layer
with clearing other all layers.
ACTION_DEFAULT_LAYER
Set Default Layer
Sets 'default layer' to layer and turn it on.
ACTION_DEFAULT_LAYER_SET_TO(layer)
ACTION_DEFAULT_LAYER_SET(layer, on)
2.2.1 Keymap
These actions operate layer status of keymap.
Momentary Switch
Turns on layer momentary while holding, in other words turn on when key is pressed and off when released.
ACTION_KEYMAP_MOMENTARY(layer)
Toggle Switch
Turns on layer on first type and turns off on next.
ACTION_KEYMAP_TOGGLE(layer)
Momentary Switch with tap key
Turns on layer momentary while holding but registers key on tap.
ACTION_KEYMAP_TAP_KEY(layer, key)
Momentary Switch with tap toggle
Turns on layer momentary while holding but toggles it with serial taps.
ACTION_KEYMAP_TAP_TOGGLE(layer)
Invert layer
Inverts current layer state. If the layer is on it becomes off with this action.
ACTION_KEYMAP_INV(layer, on)
Turn On layer
Turns on layer state.
ACTION_KEYMAP_ON(layer, on)
Turns on layer state on press and turn off on release. This is identical to 'Switch to layer' action.
ACTION_KEYMAP_ON_OFF(layer)
Turn Off layer
Turns off layer state.
ACTION_KEYMAP_OFF(layer, on)
Set layer
Turn on layer only.
keymap_stat = (1<<layer) [layer: 0-15]
ACTION_KEYMAP_SET(layer, on)
Turns on layer only and clear all layer on release..
ACTION_KEYMAP_SET_CLEAR(layer)
2.2.2 Overlay
TBD
In addition to actions of Keymap
above these actions are also available.
Invert 4bit layer states
Invert 4bits out of 16bits of overlay status on both press and release.
overlay_stat = (overlay_stat ^ bits<<(shift*4)) [bits: 0-15, shift: 0-3]
ACTION_OVERLAY_INV4(bits, shift)
2.3 Macro action
TBD
Macro
action indicates complex key strokes.
MACRO( MD(LSHIFT), D(D), END )
MACRO( U(D), MU(LSHIFT), END )
MACRO( I(255), T(H), T(E), T(L), T(L), W(255), T(O), END )
2.3.1 Normal mode
- I() change interavl of stroke.
- D() press key
- U() release key
- T() type key(press and release)
- W() wait
- MD() modifier down
- MU() modifier up
- END end mark
2.3.2 Extended mode
TODO: sample impl
See keyboard/hhkb/keymap.c
for sample.
2.4 Function action
TBD
There are two type of action, normal Function
and tappable Function
.
These actions call user defined function with id
, opt
, and key event information as arguments.
2.4.1 Function
To define normal Function
action in keymap use this.
ACTION_FUNCTION(id, opt)
2.4.2 Function with tap
To define tappable Function
action in keymap use this.
ACTION_FUNCTION_TAP(id, opt)
2.4.3 Implement user function
Function
actions can be defined freely with C by user in callback function:
void keymap_call_function(keyrecord_t *event, uint8_t id, uint8_t opt)
This C function is called every time key is operated, argument id
selects action to be performed and opt
can be used for option. Functon id
can be 0-255 and opt
can be 0-15.
keyrecord_t
is comprised of key event and tap count. keyevent_t
indicates which and when key is pressed or released. From tap_count
you can know tap state, 0 means no tap. These information will be used in user function to decide how action of key is performed.
typedef struct {
keyevent_t event;
uint8_t tap_count;
} keyrecord_t;
typedef struct {
key_t key;
bool pressed;
uint16_t time;
} keyevent_t;
typedef struct {
uint8_t col;
uint8_t row;
} key_t;
TODO: sample impl
See keyboard/hhkb/keymap.c
for sample.
4. Layer switching Example
There are some ways to switch layer with 'Layer' actions.
4.1 Momentary switching
Momentary switching changes layer only while holding Fn key.
This action makes 'Layer 1' active(valid) on key press event and inactive on release event. Namely you can overlay a layer on base layer temporarily with this.
ACTION_KEYMAP_MOMENTARY(1)
After switch actions of destination layer are perfomed. Thus you shall need to place action to come back on destination layer, or you will be stuck in destination layer without way to get back. Usually you need to palce same action or 'KC_TRNS` on destination layer to get back.
4.2 Toggle switching
Toggle switching changes layer after press then release. With this you can keep staying on the layer until you press the key again to return.
This is toggle action of 'Layer 2'.
ACTION_KEYMAP_TOGGLE(2)
4.3 Momentary switching with Tap key
These actions switch layer only while holding Fn
key and register key on tap. Tap means to press and release key quickly.
ACTION_KEYMAP_TAP_KEY(2, KC_SCLN)
With this you can place layer switching function on normal key like ';' without losing its original key register function.
4.4 Momentary switching with Tap Toggle
This switches layer only while holding Fn
key and toggle layer after several taps. Tap means to press and release key quickly.
ACTION_KEYMAP_TAP_TOGGLE(1)
Number of taps can be defined with TAPPING_TOGGLE
in config.h
, 5
by default.
Tapping
Tapping is to press and release key quickly. Tapping speed is determined with setting of TAPPING_TERM
, which can be defined in config.h
, 200ms by default.
Tap Key
This is feature to assign normal key action and modifier including Fn
to just one physical key. This is a kind of Dual role modifier. It works as modifier or Fn
when holding a key but registers normal key when tapping.
Action for modifier with tap key.
ACTION_LMODS_TAP_KEY(mods, key)
Action for Fn
with tap key.
ACTION_KEYMAP_TAP_KEY(layer, key)
Tap Toggle
This is feature to assign both toggle layer and momentary switch layer action to just one physical key. It works as mementary switch when holding a key but toggle switch when tapping.
ACTION_KEYMAP_TAP_TOGGLE(layer)
One Shot Modifier
This adds oneshot feature to modifier key. 'One Shot Modifier' is one time modifier which has effect only on following one alpha key. It works as normal modifier key when holding but oneshot modifier when tapping.
ACTION_LMODS_ONESHOT(mods)
Say you want to type 'The', you have to push and hold Shift before type 't' then release Shift before type 'h' and 'e' or you'll get 'THe'. With One Shot Modifier you can tap Shift then type 't', 'h' and 'e' normally, you don't need to holding Shift key properly here.
Legacy Keymap
This was used in prior version and still works due to legacy support code in common/keymap.c
. Legacy keymap doesn't support many of features that new keymap offers.
In comparison with new keymap how to define Fn key is different. It uses two arrays fn_layer[]
and fn_keycode[]
. The index of arrays corresponds with postfix number of Fn
key. Array fn_layer[]
indicates destination layer to switch and fn_keycode[]
has keycodes to send when tapping Fn
key.
In following setting example, Fn0
, Fn1
and Fn2
switch layer to 1, 2 and 2 respectively. Fn2
registers Space
key when tap while Fn0
and Fn1
doesn't send any key.
static const uint8_t PROGMEM fn_layer[] = {
1, // Fn0
2, // Fn1
2, // Fn2
};
static const uint8_t PROGMEM fn_keycode[] = {
KC_NO, // Fn0
KC_NO, // Fn1
KC_SPC, // Fn2
};
Terminology
- keymap
- layer
- layout
- key
- keycode
- scancode
- action
- layer transparency
- layer precedence
- register
- tap
- Fn key