1 Keymap framework - how to define your keymap
2 ============================================
3 ***NOTE: This is not final version, may be inconsistent with source code and changed occasionally for a while.***
5 ## 0. Keymap and layers
6 **Keymap** is comprised of multiple layers of key layout, you can define **32 layers** at most.
7 **Layer** is an array of **keycodes** to define **actions** for each physical keys.
8 respective layers can be validated simultaneously. Layers are indexed with 0 to 31 and higher layer has precedence.
10 Keymap: 32 Layers Layer: Keycode matrix
11 ----------------- ---------------------
12 stack of layers array_of_keycode[row][column]
13 ____________ precedence _______________________
14 / / | high / ESC / F1 / F2 / F3 ....
15 31 /___________// | /-----/-----/-----/-----
16 30 /___________// | / TAB / Q / W / E ....
17 29 /___________/ | /-----/-----/-----/-----
18 : _:_:_:_:_:__ | : /LCtrl/ A / S / D ....
19 : / : : : : : / | : / : : : :
20 2 /___________// | 2 `--------------------------
21 1 /___________// | 1 `--------------------------
22 0 /___________/ V low 0 `--------------------------
27 Keymap has its state in two parameters:
28 **`default_layer`** indicates a base keymap layer(0-31) 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.
30 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`.
31 To change `default_layer` will be useful when you switch key layout completely, say you want Colmak instead of Qwerty.
33 Initial state of Keymap Change base layout
34 ----------------------- ------------------
42 1 / / ,->1 /___________/
43 ,->0 /___________/ | 0
45 `--- default_layer = 0 `--- default_layer = 1
46 layer_state = 0x00000001 layer_state = 0x00000002
48 On the other hand, you shall change `layer_state` to overlay base layer with some layers for feature such as navigation keys, function key(F1-F12), media keys or special actions.
51 --------------------- bit|status
52 ____________ ---+------
54 30 /___________// -----> 30 | 1
55 29 /___________/ -----> 29 | 1
59 ,->1 /___________/ -----> 1 | 1
62 `--- default_layer = 1 |
63 layer_state = 0x60000002 <-'
67 ### 0.2 Layer Precedence and Transparency
68 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.
70 You can place `KC_TRNS` on overlay layer changes just part of layout to fall back on lower or base layer.
71 Key with `KC_TRANS` doesn't has its own keycode and refers to lower valid layers for keycode, instead.
75 ### 0.3 Keymap Example
76 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.
78 This is a keymap example for [HHKB](http://en.wikipedia.org/wiki/Happy_Hacking_Keyboard) keyboard.
79 This example has three layers, 'Qwerty' as base layer, 'Cursor' and 'Mousekey'.
82 `Fn0` is a **momentary layer switching** key, you can use keys on Cursor layer while holding the key.
84 `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.
86 `Fn2` is a **toggle layer switch** key, you can stay switched layer after releasing the key unlike momentary switching.
88 You can find other keymap definitions in file `keymap.c` located on project directories.
90 static const uint8_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
92 * ,-----------------------------------------------------------.
93 * |Esc| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| -| =| \| `|
94 * |-----------------------------------------------------------|
95 * |Tab | Q| W| E| R| T| Y| U| I| O| P| [| ]|Backs|
96 * |-----------------------------------------------------------|
97 * |Contro| A| S| D| F| G| H| J| K| L|Fn1| '|Enter |
98 * |-----------------------------------------------------------|
99 * |Shift | Z| X| C| V| B| N| M| ,| .| /|Shift |Fn0|
100 * `-----------------------------------------------------------'
101 * |Gui|Alt |Space |Alt |Fn2|
102 * `-------------------------------------------'
104 KEYMAP(ESC, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, MINS,EQL, BSLS,GRV, \
105 TAB, Q, W, E, R, T, Y, U, I, O, P, LBRC,RBRC,BSPC, \
106 LCTL,A, S, D, F, G, H, J, K, L, FN1, QUOT,ENT, \
107 LSFT,Z, X, C, V, B, N, M, COMM,DOT, SLSH,RSFT,FN0, \
108 LGUI,LALT, SPC, RALT,FN2),
109 /* 1: Cursor(HHKB mode)
110 * ,-----------------------------------------------------------.
111 * |Pwr| F1| F2| F3| F4| F5| F6| F7| F8| F9|F10|F11|F12|Ins|Del|
112 * |-----------------------------------------------------------|
113 * |Caps | | | | | | | |Psc|Slk|Pus|Up | |Backs|
114 * |-----------------------------------------------------------|
115 * |Contro|VoD|VoU|Mut| | | *| /|Hom|PgU|Lef|Rig|Enter |
116 * |-----------------------------------------------------------|
117 * |Shift | | | | | | +| -|End|PgD|Dow|Shift | |
118 * `-----------------------------------------------------------'
119 * |Gui |Alt |Space |Alt |Gui|
120 * `--------------------------------------------'
122 KEYMAP(PWR, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, INS, DEL, \
123 CAPS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,PSCR,SLCK,PAUS,UP, TRNS,BSPC, \
124 LCTL,VOLD,VOLU,MUTE,TRNS,TRNS,PAST,PSLS,HOME,PGUP,LEFT,RGHT,ENT, \
125 LSFT,TRNS,TRNS,TRNS,TRNS,TRNS,PPLS,PMNS,END, PGDN,DOWN,RSFT,TRNS, \
126 LGUI,LALT, SPC, RALT,RGUI),
128 * ,-----------------------------------------------------------.
129 * |Esc| F1| F2| F3| F4| F5| F6| F7| F8| F9|F10|F11|F12|Ins|Del|
130 * |-----------------------------------------------------------|
131 * |Tab | | | | | |MwL|MwD|MwU|MwR| | | |Backs|
132 * |-----------------------------------------------------------|
133 * |Contro| | | | | |McL|McD|McU|McR| | |Return |
134 * |-----------------------------------------------------------|
135 * |Shift | | | | |Mb3|Mb2|Mb1|Mb4|Mb5| |Shift | |
136 * `-----------------------------------------------------------'
137 * |Gui |Alt |Mb1 |Alt | |
138 * `--------------------------------------------'
139 * Mc: Mouse Cursor / Mb: Mouse Button / Mw: Mouse Wheel
141 KEYMAP(ESC, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, INS, DEL, \
142 TAB, TRNS,TRNS,TRNS,TRNS,TRNS,WH_L,WH_D,WH_U,WH_R,TRNS,TRNS,TRNS,BSPC, \
143 LCTL,TRNS,ACL0,ACL1,ACL2,TRNS,MS_L,MS_D,MS_U,MS_R,TRNS,QUOT,ENT, \
144 LSFT,TRNS,TRNS,TRNS,TRNS,BTN3,BTN2,BTN1,BTN4,BTN5,SLSH,RSFT,TRNS, \
145 LGUI,LALT, BTN1, RALT,TRNS),
148 static const uint16_t PROGMEM fn_actions[] = {
149 ACTION_LAYER_MOMENTARY(1), // FN0
150 ACTION_LAYER_TAP_KEY(2, KC_SCLN), // FN1
151 ACTION_LAYER_TOGGLE(2), // FN2
158 See [`common/keycode.h`](../common/keycode.h) or keycode table below for the detail. Keycode is internal **8bit code** to indicate 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 control keys, System control keys and Mousekeys.
160 ***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()`.
163 - `KC_NO` for no action
164 - `KC_TRNS` for layer transparency (See above)
167 - `KC_A` to `KC_Z`, `KC_1` to `KC_0` for alpha numeric key
168 - `KC_MINS`, `KC_EQL`, `KC_GRV`, `KC_RBRC`, `KC_LBRC`, `KC_COMM`, `KC_DOT`, `KC_BSLS`, `KC_SLSH`, `KC_SCLN`, `KC_QUOT`
169 - `KC_ESC`, `KC_TAB`, `KC_SPC`, `KC_BSPC`, `KC_ENT`, `KC_DEL`, `KC_INS`
170 - `KC_UP`, `KC_DOWN`, `KC_RGHT`, `KC_LEFT`, `KC_PGUP`, `KC_PGDN`, `KC_HOME`, `KC_END`
171 - `KC_CAPS`, `KC_NLCK`, `KC_SLCK`, `KC_PSCR`, `KC_PAUS`, `KC_APP`, `KC_F1` to `KC_F24`
172 - `KC_P1` to `KC_P0`, `KC_PDOT`, `KC_PCMM`, `KC_PSLS`, `KC_PAST`, `KC_PMNS`, `KC_PPLS`, `KC_PEQL`, `KC_PENT` for keypad.
175 There are 8 modifiers which has discrimination between left and right.
177 - `KC_LCTL` and `KC_RCTL` for Control
178 - `KC_LSFT` and `KC_RSFT` for Shift
179 - `KC_LALT` and `KC_RALT` for Alt
180 - `KC_LGUI` and `KC_RGUI` for Windows key or Command key in Mac
183 - `KC_MS_U`, `KC_MS_D`, `KC_MS_L`, `KC_MS_R` for mouse cursor
184 - `KC_WH_U`, `KC_WH_D`, `KC_WH_L`, `KC_WH_R` for mouse wheel
185 - `KC_BTN1`, `KC_BTN2`, `KC_BTN3`, `KC_BTN4`, `KC_BTN5` for mouse buttons
187 ### 1.4 System & Media key
188 - `KC_PWR`, `KC_SLEP`, `KC_WAKE` for Power, Sleep, Wake
189 - `KC_MUTE`, `KC_VOLU`, `KC_VOLD` for audio volume control
190 - `KC_MNXT`, `KC_MPRV`, `KC_MSTP`, `KC_MPLY`, `KC_MSEL` for media control
191 - `KC_MAIL`, `KC_CALC`, `KC_MYCM` for application launch
192 - `KC_WSCH`, `KC_WHOM`, `KC_WBAK`, `KC_WFWD`, `KC_WSTP`, `KC_WREF`, `KC_WFAV` for web browser operation
195 `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` keycode indicates the action defined in first element of the array. ***32 `Fn` keys can be defined at most.***
197 ### 1.6 Keycode Table
198 See keycode table in [`doc/keycode.txt`](./keycode.txt) for description of keycodes.
200 In regard to implementation side most of keycodes are identical with [HID usage][HID_usage](pdf) sent to host for real and some virtual keycodes are defined to support special actions.
201 [HID_usage]: http://www.usb.org/developers/devclass_docs/Hut1_11.pdf
206 See [`common/action_code.h`](../common/action_code.h). Action is a **16bit code** and defines function to perform on events of a key like press, release, holding and tapping.
208 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 compared to using just keycodes. To avoid this waste 8bit keycodes are used in `KEYMAP()` instead of action codes.
210 ***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[]`.***
214 This is a simple action that registers scancodes(HID usage in fact) to host on press event of key and unregister on release.
217 + **mods**: { ` MOD_LCTL`, ` MOD_LSFT`, ` MOD_LALT`, ` MOD_LGUI`,
218 ` MOD_RCTL`, ` MOD_RSFT`, ` MOD_RALT`, ` MOD_RGUI` }
222 #### 2.1.1 Normal key and Modifier
223 ***This action usually won't be used expressly in keymap*** because you can just use keycodes in `KEYMAP()` instead.
225 You can define these actions on *'A'* key and *'left shift'* modifier with:
230 #### 2.1.2 Modified key
231 This action is comprised of strokes of modifiers and a key. `Macro` action is needed if you want more complex key strokes.
233 Say you want to assign a key to `Shift + 1` to get character *'!'* or `Alt + Tab` to switch application windows.
235 ACTION_MODS_KEY(MOD_LSFT, KC_1)
236 ACTION_MODS_KEY(MOD_LALT, KC_TAB)
238 Or `Alt,Shift + Tab` can be defined. `ACTION_MODS_KEY(mods, key)` requires **4-bit modifier state** and a **keycode** as arguments. See `keycode.h` for `MOD_BIT()` macro.
240 ACTION_MODS_KEY(MOD_LALT | MOD_LSFT, KC_TAB)
242 #### 2.1.3 Multiple Modifiers
243 Registers multiple modifiers with pressing a key. To specify multiple modifiers use `|`.
245 ACTION_MODS(MOD_ALT | MOD_LSFT)
247 #### 2.1.3 Modifier with Tap key([Dual role][dual_role])
248 Works as a modifier key while holding, but registers a key on tap(press and release quickly).
251 ACTION_MODS_TAP_KEY(MOD_RCTL, KC_ENT)
256 These actions operate layers of keymap.
259 You can specify a **target layer** of action and **when the action is executed**. Some actions take a **bit value** for bitwise operation.
262 + **layer**: `0`-`31`
263 + **on**: { `ON_PRESS` | `ON_RELEASE` | `ON_BOTH` }
264 + **bits**: 4-bit value and 1-bit mask bit
267 #### 2.2.1 Default Layer
268 Default Layer is a layer which always is valid and referred to when actions is not defined on other overlay layers.
270 This sets Default Layer to given parameter `layer` and activate it.
272 ACTION_DEFAULT_LAYER_SET(layer)
276 Turns on `layer` momentarily while holding, in other words it activates when key is pressed and deactivate when released.
278 ACTION_LAYER_MOMENTARY(layer)
281 #### 2.2.3 Toggle Switch
282 Turns on `layer` with first type(press and release) and turns off with next.
284 ACTION_LAYER_TOGGLE(layer)
287 #### 2.2.4 Momentary Switch with tap key
288 Turns on `layer` momentary while holding, but registers key on tap(press and release quickly).
290 ACTION_LAYER_TAP_KEY(layer, key)
293 #### 2.2.5 Momentary Switch with tap toggle
294 Turns on `layer` momentary while holding and toggles it with serial taps.
296 ACTION_LAYER_TAP_TOGGLE(layer)
299 #### 2.2.6 Invert state of layer
300 Inverts current state of `layer`. If the layer is on it becomes off with this action.
302 ACTION_LAYER_INVERT(layer, on)
305 #### 2.2.7 Turn On layer
306 Turns on layer state.
308 ACTION_LAYER_ON(layer, on)
310 Turns on layer state on press and turns off on release.
312 ACTION_LAYER_ON_OFF(layer)
315 #### 2.2.8 Turn Off layer
316 Turns off layer state.
318 ACTION_LAYER_OFF(layer, on)
320 Turns off layer state on press and activates on release.
322 ACTION_LAYER_OFF_ON(layer)
327 `layer_state = (1<<layer) [layer: 0-31]`
329 ACTION_LAYER_SET(layer, on)
331 Turns on layer only and clear all layer on release..
333 ACTION_LAYER_SET_CLEAR(layer)
336 #### 2.2.10 Bitwise operation
338 **part** indicates which part of 32bit layer state(0-7). **bits** is 5-bit value. **on** indicates when the action is executed.
340 ACTION_LAYER_BIT_AND(part, bits, on)
341 ACTION_LAYER_BIT_OR(part, bits, on)
342 ACTION_LAYER_BIT_XOR(part, bits, on)
343 ACTION_LAYER_BIT_SET(part, bits, on)
345 These actions works with parameters as following code.
347 uint8_t shift = part*4;
348 uint32_t mask = (bits&0x10) ? ~(0xf<<shift) : 0;
349 uint32_t layer_state = layer_state <bitop> ((bits<<shift)|mask);
352 Default Layer also has bitwise operations, they are executed when key is released.
354 ACTION_DEFAULT_LAYER_BIT_AND(part, bits)
355 ACTION_DEFAULT_LAYER_BIT_OR(part, bits)
356 ACTION_DEFAULT_LAYER_BIT_XOR(part, bits)
357 ACTION_DEFAULT_LAYER_BIT_SET(part, bits)
364 `Macro` action indicates complex key strokes.
366 MACRO( D(LSHIFT), D(D), END )
367 MACRO( U(D), U(LSHIFT), END )
368 MACRO( I(255), T(H), T(E), T(L), T(L), W(255), T(O), END )
370 #### 2.3.1 Macro Commands
371 - **I()** change interval of stroke.
373 - **U()** release key
374 - **T()** type key(press and release)
380 ***TODO: sample implementation***
381 See `keyboard/hhkb/keymap.c` for sample.
385 ### 2.4 Function action
388 There are two type of action, normal `Function` and tappable `Function`.
389 These actions call user defined function with `id`, `opt`, and key event information as arguments.
392 To define normal `Function` action in keymap use this.
394 ACTION_FUNCTION(id, opt)
396 #### 2.4.2 Function with tap
397 To define tappable `Function` action in keymap use this.
399 ACTION_FUNCTION_TAP(id, opt)
401 #### 2.4.3 Implement user function
402 `Function` actions can be defined freely with C by user in callback function:
404 void keymap_call_function(keyrecord_t *event, uint8_t id, uint8_t opt)
406 This C function is called every time key is operated, argument `id` selects action to be performed and `opt` can be used for option. Function `id` can be 0-255 and `opt` can be 0-15.
408 `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.
426 ***TODO: sample implementation***
427 See `keyboard/hhkb/keymap.c` for sample.
431 ### 2.5 Backlight Action
432 These actions control the backlight.
434 #### 2.5.1 Change backlight level
435 Increase backlight level.
437 ACTION_BACKLIGHT_INCREASE()
439 Decrease backlight level.
441 ACTION_BACKLIGHT_DECREASE()
443 Step through backlight levels.
445 ACTION_BACKLIGHT_STEP()
447 Turn a specific backlight level on or off.
449 ACTION_BACKLIGHT_LEVEL(1)
451 #### 2.5.2 Turn on / off backlight
452 Turn the backlight on and off without changing level.
454 ACTION_BACKLIGHT_TOGGLE()
458 ## 3. Layer switching Example
459 There are some ways to switch layer with 'Layer' actions.
461 ### 3.1 Momentary switching
462 Momentary switching changes layer only while holding Fn key.
464 This action makes 'Layer 1' active(valid) on key press event and inactive on release event. Namely you can overlay a layer on lower layers or default layer temporarily with this action.
466 ACTION_LAYER_MOMENTARY(1)
469 Note that after switching on press the actions on destination layer(Layer 1) are performed.
470 ***Thus you shall need to place an action to go back on destination layer***, or you will be stuck in destination layer without way to get back. Usually you need to place same action or 'KC_TRNS` on destination layer to get back.
473 ### 3.2 Toggle switching
474 Toggle switching performed after releasing a key. With this action you can keep staying on the destination layer until you type the key again to return.
476 This performs toggle switching action of 'Layer 2'.
478 ACTION_LAYER_TOGGLE(2)
482 ### 3.3 Momentary switching with Tap key
483 These actions switch a layer only while holding a key but register the key on tap. **Tap** means to press and release a key quickly.
485 ACTION_LAYER_TAP_KEY(2, KC_SCLN)
487 With this you can place a layer switching action on normal key like ';' without losing its original key register function. This action allows you to have layer switching action without necessity of a dedicated key. It means you can have it even on home row of keyboard.
491 ### 3.4 Momentary switching with Tap Toggle
492 This switches layer only while holding a key but toggle layer with several taps. **Tap** means to press and release key quickly.
494 ACTION_LAYER_TAP_TOGGLE(1)
496 Number of taps can be configured with `TAPPING_TOGGLE` in `config.h`, `5` by default.
500 ### 3.5 Momentary switching with Modifiers
501 This registers modifier key(s) simultaneously with layer switching.
503 ACTION_LAYER_MODS(2, MOD_LSFT | MOD_LALT)
508 Tapping is to press and release a key quickly. Tapping speed is determined with setting of `TAPPING_TERM`, which can be defined in `config.h`, 200ms by default.
511 This is a feature to assign normal key action and modifier including layer switching to just same one physical key. This is a kind of [Dual role key][dual_role]. It works as modifier when holding the key but registers normal key when tapping.
513 Modifier with tap key:
515 ACTION_MODS_TAP_KEY(MOD_RSFT, KC_GRV)
517 Layer switching with tap key:
519 ACTION_LAYER_TAP_KEY(2, KC_SCLN)
521 [dual_role]: http://en.wikipedia.org/wiki/Modifier_key#Dual-role_keys
525 This is a feature to assign both toggle layer and momentary switch layer action to just same one physical key. It works as momentary layer switch when holding a key but toggle switch with several taps.
527 ACTION_LAYER_TAP_TOGGLE(1)
530 ### 4.3 Oneshot Modifier
531 This runs onetime effects which modify only on just one following key. It works as normal modifier key when holding down while oneshot modifier when tapping.
533 ACTION_MODS_ONESHOT(MOD_LSFT)
535 Say you want to type 'The', you have to push and hold Shift key before type 't' then release it before type 'h' and 'e', otherwise you'll get 'THe' or 'the' unintentionally. With Oneshot Modifier you can tap Shift then type 't', 'h' and 'e' normally, you don't need to holding Shift key properly here. This mean you can release Shift before 't' is pressed down.
537 Oneshot effect is cancel unless following key is pressed down within `ONESHOT_TIMEOUT` of `config.h`. No timeout when it is `0` or not defined.
540 ### 4.4 Tap Toggle Mods
541 Similar to layer tap toggle, this works as a momentary modifier when holding, but toggles on with several taps. A single tap will 'unstick' the modifier again.
543 ACTION_MODS_TAP_TOGGLE(MOD_LSFT)
549 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. ***It is not recommended to use Legacy Keymap for new project.***
551 To enable Legacy Keymap support define this macro in `config.h`.
553 #define USE_LEGACY_KEYMAP
555 Legacy Keymap uses two arrays `fn_layer[]` and `fn_keycode[]` to define Fn key. 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.
557 In following setting example, `Fn0`, `Fn1` and `Fn2` switch layer to 1, 2 and 2 respectively. `Fn2` registers `Space` key when tapping while `Fn0` and `Fn1` doesn't send any key.
559 static const uint8_t PROGMEM fn_layer[] = {
565 static const uint8_t PROGMEM fn_keycode[] = {
575 is comprised of multiple layers.
577 is matrix of keycodes.
579 is physical button on keyboard or logical switch on software.
581 is codes used on firmware.
583 is a function assigned on a key.
584 ### layer transparency
585 Using transparent keycode one layer can refer key definition on other lower layer.
587 Top layer has higher precedence than lower layers.
589 is to press and release a key quickly.
591 is key which executes a special action like layer switching, mouse key, macro or etc.
593 <http://en.wikipedia.org/wiki/Modifier_key#Dual-role_keys>