Add action 'Momentary switching with Modifiers'
[tmk_keyboard.git] / doc / keymap.md
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.***
4
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.
9
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 `--------------------------
23
24
25
26 ### 0.1 Keymap status
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.
29
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.
32
33 Initial state of Keymap Change base layout
34 ----------------------- ------------------
35
36 31 31
37 30 30
38 29 29
39 : :
40 : : ____________
41 2 ____________ 2 / /
42 1 / / ,->1 /___________/
43 ,->0 /___________/ | 0
44 | |
45 `--- default_layer = 0 `--- default_layer = 1
46 layer_state = 0x00000001 layer_state = 0x00000002
47
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.
49
50 Overlay feature layer
51 --------------------- bit|status
52 ____________ ---+------
53 31 / / 31 | 0
54 30 /___________// -----> 30 | 1
55 29 /___________/ -----> 29 | 1
56 : : | :
57 : ____________ : | :
58 2 / / 2 | 0
59 ,->1 /___________/ -----> 1 | 1
60 | 0 0 | 0
61 | +
62 `--- default_layer = 1 |
63 layer_state = 0x60000002 <-'
64
65
66
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.
69
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.
72 See example below.
73
74
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.
77
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'.
80 In this example,
81
82 `Fn0` is a **momentary layer switching** key, you can use keys on Cursor layer while holding the key.
83
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.
85
86 `Fn2` is a **toggle layer switch** key, you can stay switched layer after releasing the key unlike momentary switching.
87
88 You can find other keymap definitions in file `keymap.c` located on project directories.
89
90 static const uint8_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
91 /* 0: Qwerty
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 * `-------------------------------------------'
103 */
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 * `--------------------------------------------'
121 */
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),
127 /* 2: Mousekey
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
140 */
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),
146 };
147
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
152 };
153
154
155
156
157 ## 1. Keycode
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.
159
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()`.
161
162 ### 1.0 Other key
163 - `KC_NO` for no action
164 - `KC_TRNS` for layer transparency (See above)
165
166 ### 1.1 Normal key
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.
173
174 ### 1.2 Modifier
175 There are 8 modifiers which has discrimination between left and right.
176
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
181
182 ### 1.3 Mousekey
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
186
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
193
194 ### 1.5 Fn key
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.***
196
197 ### 1.6 Keycode Table
198 See keycode table in [`doc/keycode.txt`](./keycode.txt) for description of keycodes.
199
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
202
203
204
205 ## 2. Action
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.
207
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.
209
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[]`.***
211
212
213 ### 2.1 Key Action
214 This is a simple action that registers scancodes(HID usage in fact) to host on press event of key and unregister on release.
215
216 #### Parameters
217 + **mods**: { ` MOD_LCTL`, ` MOD_LSFT`, ` MOD_LALT`, ` MOD_LGUI`,
218 ` MOD_RCTL`, ` MOD_RSFT`, ` MOD_RALT`, ` MOD_RGUI` }
219 + **key**: keycode
220
221
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.
224
225 You can define these actions on *'A'* key and *'left shift'* modifier with:
226
227 ACTION_KEY(KC_A)
228 ACTION_KEY(KC_LSFT)
229
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.
232
233 Say you want to assign a key to `Shift + 1` to get character *'!'* or `Alt + Tab` to switch application windows.
234
235 ACTION_MODS_KEY(MOD_LSFT, KC_1)
236 ACTION_MODS_KEY(MOD_LALT, KC_TAB)
237
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.
239
240 ACTION_MODS_KEY(MOD_LALT | MOD_LSFT, KC_TAB)
241
242 #### 2.1.3 Multiple Modifiers
243 Registers multiple modifiers with pressing a key. To specify multiple modifiers use `|`.
244
245 ACTION_MODS(MOD_ALT | MOD_LSFT)
246
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).
249
250
251 ACTION_MODS_TAP_KEY(MOD_RCTL, KC_ENT)
252
253
254
255 ### 2.2 Layer Action
256 These actions operate layers of keymap.
257
258 #### Parameters
259 You can specify a **target layer** of action and **when the action is executed**. Some actions take a **bit value** for bitwise operation.
260
261
262 + **layer**: `0`-`31`
263 + **on**: { `ON_PRESS` | `ON_RELEASE` | `ON_BOTH` }
264 + **bits**: 4-bit value and 1-bit mask bit
265
266
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.
269
270 This sets Default Layer to given parameter `layer` and activate it.
271
272 ACTION_DEFAULT_LAYER_SET(layer)
273
274
275 #### 2.2.2 Momentary
276 Turns on `layer` momentarily while holding, in other words it activates when key is pressed and deactivate when released.
277
278 ACTION_LAYER_MOMENTARY(layer)
279
280
281 #### 2.2.3 Toggle Switch
282 Turns on `layer` with first type(press and release) and turns off with next.
283
284 ACTION_LAYER_TOGGLE(layer)
285
286
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).
289
290 ACTION_LAYER_TAP_KEY(layer, key)
291
292
293 #### 2.2.5 Momentary Switch with tap toggle
294 Turns on `layer` momentary while holding and toggles it with serial taps.
295
296 ACTION_LAYER_TAP_TOGGLE(layer)
297
298
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.
301
302 ACTION_LAYER_INVERT(layer, on)
303
304
305 #### 2.2.7 Turn On layer
306 Turns on layer state.
307
308 ACTION_LAYER_ON(layer, on)
309
310 Turns on layer state on press and turns off on release.
311
312 ACTION_LAYER_ON_OFF(layer)
313
314
315 #### 2.2.8 Turn Off layer
316 Turns off layer state.
317
318 ACTION_LAYER_OFF(layer, on)
319
320 Turns off layer state on press and activates on release.
321
322 ACTION_LAYER_OFF_ON(layer)
323
324
325 #### 2.2.9 Set layer
326 Turn on layer only.
327 `layer_state = (1<<layer) [layer: 0-31]`
328
329 ACTION_LAYER_SET(layer, on)
330
331 Turns on layer only and clear all layer on release..
332
333 ACTION_LAYER_SET_CLEAR(layer)
334
335
336 #### 2.2.10 Bitwise operation
337
338 **part** indicates which part of 32bit layer state(0-7). **bits** is 5-bit value. **on** indicates when the action is executed.
339
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)
344
345 These actions works with parameters as following code.
346
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);
350
351
352 Default Layer also has bitwise operations, they are executed when key is released.
353
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)
358
359
360
361 ### 2.3 Macro action
362 ***TBD***
363
364 `Macro` action indicates complex key strokes.
365
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 )
369
370 #### 2.3.1 Macro Commands
371 - **I()** change interval of stroke.
372 - **D()** press key
373 - **U()** release key
374 - **T()** type key(press and release)
375 - **W()** wait
376 - **END** end mark
377
378 #### 2.3.2 Examples
379
380 ***TODO: sample implementation***
381 See `keyboard/hhkb/keymap.c` for sample.
382
383
384
385 ### 2.4 Function action
386 ***TBD***
387
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.
390
391 #### 2.4.1 Function
392 To define normal `Function` action in keymap use this.
393
394 ACTION_FUNCTION(id, opt)
395
396 #### 2.4.2 Function with tap
397 To define tappable `Function` action in keymap use this.
398
399 ACTION_FUNCTION_TAP(id, opt)
400
401 #### 2.4.3 Implement user function
402 `Function` actions can be defined freely with C by user in callback function:
403
404 void keymap_call_function(keyrecord_t *event, uint8_t id, uint8_t opt)
405
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.
407
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.
409
410 typedef struct {
411 keyevent_t event;
412 uint8_t tap_count;
413 } keyrecord_t;
414
415 typedef struct {
416 key_t key;
417 bool pressed;
418 uint16_t time;
419 } keyevent_t;
420
421 typedef struct {
422 uint8_t col;
423 uint8_t row;
424 } key_t;
425
426 ***TODO: sample implementation***
427 See `keyboard/hhkb/keymap.c` for sample.
428
429
430
431 ### 2.5 Backlight Action
432 These actions control the backlight.
433
434 #### 2.5.1 Change backlight level
435 Increase backlight level.
436
437 ACTION_BACKLIGHT_INCREASE()
438
439 Decrease backlight level.
440
441 ACTION_BACKLIGHT_DECREASE()
442
443 Step through backlight levels.
444
445 ACTION_BACKLIGHT_STEP()
446
447 Turn a specific backlight level on or off.
448
449 ACTION_BACKLIGHT_LEVEL(1)
450
451 #### 2.5.2 Turn on / off backlight
452 Turn the backlight on and off without changing level.
453
454 ACTION_BACKLIGHT_TOGGLE()
455
456
457
458 ## 3. Layer switching Example
459 There are some ways to switch layer with 'Layer' actions.
460
461 ### 3.1 Momentary switching
462 Momentary switching changes layer only while holding Fn key.
463
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.
465
466 ACTION_LAYER_MOMENTARY(1)
467
468
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.
471
472
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.
475
476 This performs toggle switching action of 'Layer 2'.
477
478 ACTION_LAYER_TOGGLE(2)
479
480
481
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.
484
485 ACTION_LAYER_TAP_KEY(2, KC_SCLN)
486
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.
488
489
490
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.
493
494 ACTION_LAYER_TAP_TOGGLE(1)
495
496 Number of taps can be configured with `TAPPING_TOGGLE` in `config.h`, `5` by default.
497
498
499
500 ### 3.5 Momentary switching with Modifiers
501 This registers modifier key(s) simultaneously with layer switching.
502
503 ACTION_LAYER_MODS(2, MOD_LSFT | MOD_LALT)
504
505
506
507 ## 4. Tapping
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.
509
510 ### 4.1 Tap Key
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.
512
513 Modifier with tap key:
514
515 ACTION_MODS_TAP_KEY(MOD_RSFT, KC_GRV)
516
517 Layer switching with tap key:
518
519 ACTION_LAYER_TAP_KEY(2, KC_SCLN)
520
521 [dual_role]: http://en.wikipedia.org/wiki/Modifier_key#Dual-role_keys
522
523
524 ### 4.2 Tap Toggle
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.
526
527 ACTION_LAYER_TAP_TOGGLE(1)
528
529
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.
532
533 ACTION_MODS_ONESHOT(MOD_LSFT)
534
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.
536
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.
538
539
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.
542
543 ACTION_MODS_TAP_TOGGLE(MOD_LSFT)
544
545
546
547
548 ## 5. Legacy Keymap
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.***
550
551 To enable Legacy Keymap support define this macro in `config.h`.
552
553 #define USE_LEGACY_KEYMAP
554
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.
556
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.
558
559 static const uint8_t PROGMEM fn_layer[] = {
560 1, // Fn0
561 2, // Fn1
562 2, // Fn2
563 };
564
565 static const uint8_t PROGMEM fn_keycode[] = {
566 KC_NO, // Fn0
567 KC_NO, // Fn1
568 KC_SPC, // Fn2
569 };
570
571
572 ## 6. Terminology
573 ***TBD***
574 ### keymap
575 is comprised of multiple layers.
576 ### layer
577 is matrix of keycodes.
578 ### key
579 is physical button on keyboard or logical switch on software.
580 ### keycode
581 is codes used on firmware.
582 ### action
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.
586 ### layer precedence
587 Top layer has higher precedence than lower layers.
588 ### tapping
589 is to press and release a key quickly.
590 ### Fn key
591 is key which executes a special action like layer switching, mouse key, macro or etc.
592 ### dual role key
593 <http://en.wikipedia.org/wiki/Modifier_key#Dual-role_keys>
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