Add note for L/R side bit being ignored
[tmk_keyboard.git] / tmk_core / 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 The **keymap** is an array composed of one or more layers.
7 Each **layer** is an array of **keycodes**, defining **actions** for each physical key.
8 Layers can be activated and deactivated independently. Multiple layers may be active at once, resulting in the currently-active **layer state**. Each layer has an index between 0-31. As active layers are stacked together, higher layers take precedence over lower layers.
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 **Note:** The keymap array is limited to **32 layers**.
25
26
27
28 ### 0.1 Layer state
29 The current keymap layer state is determined by two parameters: the *default layer*, and the individual *layer states*. Changing the default layer is useful for switching key layouts completely; for example, switching to Dvorak, Colemak or Workman instead of QWERTY. Individual layer states, on the other hand, can be used to overlay the base layer with other functions such as navigation keys, function keys (F1-F12), media keys or other actions.
30
31 Because the default layer is really just a special case affecting the overall layer state, it is important to first understand how the layer state is determined.
32
33 #### 0.1.1 The layer state
34 The **layer state** indicates the current on/off status of all layers. It is defined in the firmware by a 32-bit integer, `layer_state`, which stores each layer's on/off status in a single bit: 0 for off, 1 for on. As layers are activated and deactivated, their respective bits are flipped, changing the value of `layer_state`.
35
36 Overlay feature layer
37 --------------------- bit|status
38 ____________ ---+------
39 31 / / 31 | 0
40 30 /___________// -----> 30 | 1
41 29 /___________/ -----> 29 | 1
42 : : | :
43 : ____________ : | :
44 2 / / 2 | 0
45 ,->1 /___________/ -----> 1 | 1
46 | 0 0 | 0
47 | +
48 `--- default_layer = 1 |
49 layer_state = 0x60000002 <-'
50
51 #### 0.1.2 The default layer
52 The **default layer** is the base keymap layer (0-31) which is always active and considered the "bottom" of the stack. When the firmware boots, the default layer is the only active layer. It is set to layer 0 by default, though this can be changed ~~in *config.h*~~ via Boot Magic settings.
53
54 Initial state of Keymap Change base layout
55 ----------------------- ------------------
56
57 31 31
58 30 30
59 29 29
60 : :
61 : : ____________
62 2 ____________ 2 / /
63 1 / / ,->1 /___________/
64 ,->0 /___________/ | 0
65 | |
66 `--- default_layer = 0 `--- default_layer = 1
67 layer_state = 0x00000001 layer_state = 0x00000002
68
69 Note that the `default_layer_state` variable only determines the lowest value to which `layer_state` may be set, and that `default_layer_state` is used by the core firmware when determining the starting value of `layer_state` before applying changes. In other words, the default layer will *always* be set to *on* in `layer_state`.
70
71 The default layer is defined in the firmware by the `default_layer_state` variable, which is identical in format to the `layer_state` variable exlpained above. The value may be changed using the following functions:
72
73 - `default_layer_state_set(state)` sets the state to the specified 32-bit integer value.
74 - AND/OR/XOR functions set the state based on a boolean logic comparison between the current state and the specified 32-bit integer value:
75 - `default_layer_state_and(state)`
76 - `default_layer_state_or(state)`
77 - `default_layer_state_xor(state)`
78
79 For example, to set layer 3 as the default layer:
80
81 ```C
82 // convert 3 to a 32-bit unsigned long value, and set the default layer
83 default_layer_state_set(1UL<<3);
84 ```
85
86
87
88 ### 0.2 Layer Precedence and Transparency
89 Note that ***higher layers have priority in the layer stack***. The firmware starts at the topmost active layer, and works down to the bottom to find the an active keycode. Once the search encounters any keycode other than **`KC_TRNS`** (transparent) on an active layer, the search is halted and the remaining lower layers aren't examined, even if they are active.
90
91 **Note:** a layer must be activated before it may be included in the stack search.
92
93 `KC_TRNS` is a special placeholder which can be used on overlay layers. This allows for the creation of "partial" layers which fall back on the lower layers, eliminating a good deal of repetition in keymap files.
94
95
96
97 ### 0.3 Keymap Example
98 The keymap is defined in the **`uint8_t keymaps[]`** array, a 2-dimensional array of rows and columns corresponding to positions in the keyboard matrix. But most often the layers are defined using C macros to allow for easier reading and editing of the keymap files. To use complex actions you need to define `Fn` action in the **`action_t fn_actions[]`** array.
99
100 This is a keymap example for the [HHKB](http://en.wikipedia.org/wiki/Happy_Hacking_Keyboard) keyboard.
101 This example has three layers: the QWERTY base layer, and two overlay layers for cursor and mousekey control, respectively.
102 In this example,
103
104 `Fn0` is a **momentary layer switching** key--you can use keys on the Cursor layer while holding the key.
105
106 `Fn1` is a momentary layer switching key with tapping function--tapping the key as one would normally use it, sends the semicolon **';'** keycode, while holding the key down switches layers.
107
108 `Fn2` is a **toggle layer switch** key--pressing the key toggles the layer on until you press it again.
109
110 You can find other keymap definitions in file `keymap.c` located on project directories.
111
112 const uint8_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
113 /* 0: Qwerty
114 * ,-----------------------------------------------------------.
115 * |Esc| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| -| =| \| `|
116 * |-----------------------------------------------------------|
117 * |Tab | Q| W| E| R| T| Y| U| I| O| P| [| ]|Backs|
118 * |-----------------------------------------------------------|
119 * |Contro| A| S| D| F| G| H| J| K| L|Fn1| '|Enter |
120 * |-----------------------------------------------------------|
121 * |Shift | Z| X| C| V| B| N| M| ,| .| /|Shift |Fn0|
122 * `-----------------------------------------------------------'
123 * |Gui|Alt |Space |Alt |Fn2|
124 * `-------------------------------------------'
125 */
126 KEYMAP(ESC, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, MINS,EQL, BSLS,GRV, \
127 TAB, Q, W, E, R, T, Y, U, I, O, P, LBRC,RBRC,BSPC, \
128 LCTL,A, S, D, F, G, H, J, K, L, FN1, QUOT,ENT, \
129 LSFT,Z, X, C, V, B, N, M, COMM,DOT, SLSH,RSFT,FN0, \
130 LGUI,LALT, SPC, RALT,FN2),
131 /* 1: Cursor(HHKB mode)
132 * ,-----------------------------------------------------------.
133 * |Pwr| F1| F2| F3| F4| F5| F6| F7| F8| F9|F10|F11|F12|Ins|Del|
134 * |-----------------------------------------------------------|
135 * |Caps | | | | | | | |Psc|Slk|Pus|Up | |Backs|
136 * |-----------------------------------------------------------|
137 * |Contro|VoD|VoU|Mut| | | *| /|Hom|PgU|Lef|Rig|Enter |
138 * |-----------------------------------------------------------|
139 * |Shift | | | | | | +| -|End|PgD|Dow|Shift | |
140 * `-----------------------------------------------------------'
141 * |Gui |Alt |Space |Alt |Gui|
142 * `--------------------------------------------'
143 */
144 KEYMAP(PWR, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, INS, DEL, \
145 CAPS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,PSCR,SLCK,PAUS,UP, TRNS,BSPC, \
146 LCTL,VOLD,VOLU,MUTE,TRNS,TRNS,PAST,PSLS,HOME,PGUP,LEFT,RGHT,ENT, \
147 LSFT,TRNS,TRNS,TRNS,TRNS,TRNS,PPLS,PMNS,END, PGDN,DOWN,RSFT,TRNS, \
148 LGUI,LALT, SPC, RALT,RGUI),
149 /* 2: Mousekey
150 * ,-----------------------------------------------------------.
151 * |Esc| F1| F2| F3| F4| F5| F6| F7| F8| F9|F10|F11|F12|Ins|Del|
152 * |-----------------------------------------------------------|
153 * |Tab | | | | | |MwL|MwD|MwU|MwR| | | |Backs|
154 * |-----------------------------------------------------------|
155 * |Contro| | | | | |McL|McD|McU|McR| | |Return |
156 * |-----------------------------------------------------------|
157 * |Shift | | | | |Mb3|Mb2|Mb1|Mb4|Mb5| |Shift | |
158 * `-----------------------------------------------------------'
159 * |Gui |Alt |Mb1 |Alt | |
160 * `--------------------------------------------'
161 * Mc: Mouse Cursor / Mb: Mouse Button / Mw: Mouse Wheel
162 */
163 KEYMAP(ESC, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, INS, DEL, \
164 TAB, TRNS,TRNS,TRNS,TRNS,TRNS,WH_L,WH_D,WH_U,WH_R,TRNS,TRNS,TRNS,BSPC, \
165 LCTL,TRNS,ACL0,ACL1,ACL2,TRNS,MS_L,MS_D,MS_U,MS_R,TRNS,QUOT,ENT, \
166 LSFT,TRNS,TRNS,TRNS,TRNS,BTN3,BTN2,BTN1,BTN4,BTN5,SLSH,RSFT,TRNS, \
167 LGUI,LALT, BTN1, RALT,TRNS),
168 };
169
170 const action_t PROGMEM fn_actions[] = {
171 ACTION_LAYER_MOMENTARY(1), // FN0
172 ACTION_LAYER_TAP_KEY(2, KC_SCLN), // FN1
173 ACTION_LAYER_TOGGLE(2), // FN2
174 };
175
176
177
178
179 ## 1. Keycode
180 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.
181
182 ***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()`.
183
184 ### 1.0 Other key
185 - `KC_NO` for no action
186 - `KC_TRNS` for layer transparency (See above)
187
188 ### 1.1 Normal key
189 - `KC_A` to `KC_Z`, `KC_1` to `KC_0` for alpha numeric key
190 - `KC_MINS`, `KC_EQL`, `KC_GRV`, `KC_RBRC`, `KC_LBRC`, `KC_COMM`, `KC_DOT`, `KC_BSLS`, `KC_SLSH`, `KC_SCLN`, `KC_QUOT`
191 - `KC_ESC`, `KC_TAB`, `KC_SPC`, `KC_BSPC`, `KC_ENT`, `KC_DEL`, `KC_INS`
192 - `KC_UP`, `KC_DOWN`, `KC_RGHT`, `KC_LEFT`, `KC_PGUP`, `KC_PGDN`, `KC_HOME`, `KC_END`
193 - `KC_CAPS`, `KC_NLCK`, `KC_SLCK`, `KC_PSCR`, `KC_PAUS`, `KC_APP`, `KC_F1` to `KC_F24`
194 - `KC_P1` to `KC_P0`, `KC_PDOT`, `KC_PCMM`, `KC_PSLS`, `KC_PAST`, `KC_PMNS`, `KC_PPLS`, `KC_PEQL`, `KC_PENT` for keypad.
195
196 ### 1.2 Modifier
197 There are 8 modifiers which has discrimination between left and right.
198
199 - `KC_LCTL` and `KC_RCTL` for Control
200 - `KC_LSFT` and `KC_RSFT` for Shift
201 - `KC_LALT` and `KC_RALT` for Alt
202 - `KC_LGUI` and `KC_RGUI` for Windows key or Command key in Mac
203
204 ### 1.3 Mousekey
205 - `KC_MS_U`, `KC_MS_D`, `KC_MS_L`, `KC_MS_R` for mouse cursor
206 - `KC_WH_U`, `KC_WH_D`, `KC_WH_L`, `KC_WH_R` for mouse wheel
207 - `KC_BTN1`, `KC_BTN2`, `KC_BTN3`, `KC_BTN4`, `KC_BTN5` for mouse buttons
208
209 ### 1.4 System & Media key
210 - `KC_PWR`, `KC_SLEP`, `KC_WAKE` for Power, Sleep, Wake
211 - `KC_MUTE`, `KC_VOLU`, `KC_VOLD` for audio volume control
212 - `KC_MNXT`, `KC_MPRV`, `KC_MSTP`, `KC_MPLY`, `KC_MSEL` for media control
213 - `KC_MAIL`, `KC_CALC`, `KC_MYCM` for application launch
214 - `KC_WSCH`, `KC_WHOM`, `KC_WBAK`, `KC_WFWD`, `KC_WSTP`, `KC_WREF`, `KC_WFAV` for web browser operation
215
216 ### 1.5 Fn key
217 `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 `action_t 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.***
218
219 ### 1.6 Keycode Table
220 See keycode table in [`doc/keycode.txt`](./keycode.txt) for description of keycodes.
221
222 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.
223 [HID_usage]: http://www.usb.org/developers/hidpage/Hut1_12v2.pdf
224
225
226
227 ## 2. Action
228 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.
229
230 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.
231
232 ***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[]`.***
233
234
235 ### 2.1 Key Action
236 This is a simple action that registers scancodes(HID usage in fact) to host on press event of key and unregister on release.
237
238 #### Parameters
239 + **mods**: { ` MOD_LCTL`, ` MOD_LSFT`, ` MOD_LALT`, ` MOD_LGUI`,
240 ` MOD_RCTL`, ` MOD_RSFT`, ` MOD_RALT`, ` MOD_RGUI` }
241 + **key**: keycode
242
243
244 #### 2.1.1 Normal key and Modifier
245 ***This action usually won't be used expressly in keymap*** because you can just use keycodes in `KEYMAP()` instead.
246
247 You can define these actions on *'A'* key and *'left shift'* modifier with:
248
249 ACTION_KEY(KC_A)
250 ACTION_KEY(KC_LSFT)
251
252 #### 2.1.2 Modified key
253 This action is comprised of strokes of modifiers and a key. `Macro` action is needed if you want more complex key strokes.
254
255 Say you want to assign a key to `Shift + 1` to get character *'!'* or `Alt + Tab` to switch application windows.
256
257 ACTION_MODS_KEY(MOD_LSFT, KC_1)
258 ACTION_MODS_KEY(MOD_LALT, KC_TAB)
259
260 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.
261
262 ACTION_MODS_KEY(MOD_LALT | MOD_LSFT, KC_TAB)
263
264 #### 2.1.3 Multiple Modifiers
265 Registers multiple modifiers with pressing a key. To specify multiple modifiers use `|`.
266
267 ACTION_MODS(MOD_ALT | MOD_LSFT)
268
269 #### 2.1.3 Modifier with Tap key([Dual role][dual_role])
270 Works as a modifier key while holding, but registers a key on tap(press and release quickly).
271
272
273 ACTION_MODS_TAP_KEY(MOD_RCTL, KC_ENT)
274
275
276
277 ### 2.2 Layer Action
278 These actions operate layers of keymap.
279
280 #### Parameters
281 You can specify a **target layer** of action and **when the action is executed**. Some actions take a **bit value** for bitwise operation.
282
283
284 + **layer**: `0`-`31`
285 + **on**: { `ON_PRESS` | `ON_RELEASE` | `ON_BOTH` }
286 + **bits**: 4-bit value and 1-bit mask bit
287
288
289 #### 2.2.1 Default Layer
290 Default Layer is a layer which always is valid and referred to when actions is not defined on other overlay layers.
291
292 This sets Default Layer to given parameter `layer` and activate it.
293
294 ACTION_DEFAULT_LAYER_SET(layer)
295
296
297 #### 2.2.2 Momentary
298 Turns on `layer` momentarily while holding, in other words it activates when key is pressed and deactivate when released.
299
300 ACTION_LAYER_MOMENTARY(layer)
301
302
303 #### 2.2.3 Toggle Switch
304 Turns on `layer` with first type(press and release) and turns off with next.
305
306 ACTION_LAYER_TOGGLE(layer)
307
308
309 #### 2.2.4 Momentary Switch with tap key
310 Turns on `layer` momentary while holding, but registers key on tap(press and release quickly).
311
312 ACTION_LAYER_TAP_KEY(layer, key)
313
314
315 #### 2.2.5 Momentary Switch with tap toggle
316 Turns on `layer` momentary while holding and toggles it with serial taps.
317
318 ACTION_LAYER_TAP_TOGGLE(layer)
319
320
321 #### 2.2.6 Invert state of layer
322 Inverts current state of `layer`. If the layer is on it becomes off with this action.
323
324 ACTION_LAYER_INVERT(layer, on)
325
326
327 #### 2.2.7 Turn On layer
328 Turns on layer state.
329
330 ACTION_LAYER_ON(layer, on)
331
332 Turns on layer state on press and turns off on release.
333
334 ACTION_LAYER_ON_OFF(layer)
335
336
337 #### 2.2.8 Turn Off layer
338 Turns off layer state.
339
340 ACTION_LAYER_OFF(layer, on)
341
342 Turns off layer state on press and activates on release.
343
344 ACTION_LAYER_OFF_ON(layer)
345
346
347 #### 2.2.9 Set layer
348 Turn on layer only.
349 `layer_state = (1<<layer) [layer: 0-31]`
350
351 ACTION_LAYER_SET(layer, on)
352
353 Turns on layer only and clear all layer on release..
354
355 ACTION_LAYER_SET_CLEAR(layer)
356
357
358 #### 2.2.10 Bitwise operation
359
360 **part** indicates which part of 32bit layer state(0-7). **bits** is 5-bit value. **on** indicates when the action is executed.
361
362 ACTION_LAYER_BIT_AND(part, bits, on)
363 ACTION_LAYER_BIT_OR(part, bits, on)
364 ACTION_LAYER_BIT_XOR(part, bits, on)
365 ACTION_LAYER_BIT_SET(part, bits, on)
366
367 These actions works with parameters as following code.
368
369 uint8_t shift = part*4;
370 uint32_t mask = (bits&0x10) ? ~(0xf<<shift) : 0;
371 uint32_t layer_state = layer_state <bitop> ((bits<<shift)|mask);
372
373
374 Default Layer also has bitwise operations, they are executed when key is released.
375
376 ACTION_DEFAULT_LAYER_BIT_AND(part, bits)
377 ACTION_DEFAULT_LAYER_BIT_OR(part, bits)
378 ACTION_DEFAULT_LAYER_BIT_XOR(part, bits)
379 ACTION_DEFAULT_LAYER_BIT_SET(part, bits)
380
381
382 ### 2.3 Macro action
383 `Macro` actions allow you to register a complex sequence of keystrokes when a key is pressed, where macros are simple sequences of keypresses.
384
385 ACTION_MACRO(id)
386 ACTION_MACRO_TAP(id)
387
388 `id` is an 8-bit user-defined value the macro getter function can use to pick the specific macro.
389
390
391 #### 2.3.1 Implementing Macro getter function
392 To implement `macro` functions, the macro lookup list must be implemented:
393
394 const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt);
395
396 The function must always return a valid macro, and default implementation of `action_get_macro` always returns `MACRO_NONE` which has no effect.
397
398 #### 2.3.1.1 Limitations
399 Similar to the Function Action system, the selector functions is passed a `keyrecord_t` object, so it can inspect the key state (e.g. different macros on key press or release), and key itself.
400
401 Unlike the Function Action system,`macros` are pre-recorded key sequences, so you can only select from a list. If you want to use dynamic macros then you should look at the more complex function action system.
402
403 #### 2.3.2 Implementing/Defining Macro sequences
404 Macros are of the form (must be wrapped by the `MACRO` function, and end with an `END` mark)
405
406 MACRO( ..., END )
407
408 Within each macro, the following commands can be used:
409
410 - **I()** change interval of stroke.
411 - **D()** press key
412 - **U()** release key
413 - **T()** type key(press and release)
414 - **W()** wait
415 - **SM()** store modifier state
416 - **RM()** restore modifier state
417 - **CM()** clear modifier state
418
419 e.g.:
420
421 MACRO( D(LSHIFT), D(D), END ) // hold down LSHIFT and D - will print 'D'
422 MACRO( U(D), U(LSHIFT), END ) // release U and LSHIFT keys (an event.pressed == False counterpart for the one above)
423 MACRO( I(255), T(H), T(E), T(L), T(L), W(255), T(O), END ) // slowly print out h-e-l-l---o
424
425 #### 2.3.2 Examples
426
427 in keymap.c, define `action_get_macro`
428
429 const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt)
430 {
431 switch (id) {
432 case 0:
433 return (record->event.pressed ?
434 MACRO( I(0), T(H), T(E), T(L), T(L), W(255), T(O), END ) :
435 MACRO_NONE );
436 case 1:
437 return (record->event.pressed ?
438 MACRO( D(LALT), D(TAB), END ) :
439 MACRO( U(TAB), END ));
440 }
441 return MACRO_NONE;
442 }
443
444 in keymap.c, bind items in `fn_actions` to the macro function
445
446 const action_t PROGMEM fn_actions[] = {
447 [0] = ACTION_MACRO(0), // will print 'hello' for example
448 [1] = ACTION_MACRO(1),
449 };
450
451
452 ### 2.4 Function action
453 ***TBD***
454
455 There are two type of action, normal `Function` and tappable `Function`.
456 These actions call user defined function with `id`, `opt`, and key event information as arguments.
457
458 #### 2.4.1 Function
459 To define normal `Function` action in keymap use this.
460
461 ACTION_FUNCTION(id, opt)
462
463 #### 2.4.2 Function with tap
464 To define tappable `Function` action in keymap use this.
465
466 ACTION_FUNCTION_TAP(id, opt)
467
468 #### 2.4.3 Implement user function
469 `Function` actions can be defined freely with C by user in callback function:
470
471 void action_function(keyrecord_t *record, uint8_t id, uint8_t opt);
472
473 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.
474
475 `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.
476
477 typedef struct {
478 keyevent_t event;
479 uint8_t tap_count;
480 } keyrecord_t;
481
482 typedef struct {
483 key_t key;
484 bool pressed;
485 uint16_t time;
486 } keyevent_t;
487
488 typedef struct {
489 uint8_t col;
490 uint8_t row;
491 } key_t;
492
493 ***TODO: sample implementation***
494 See `keyboard/hhkb/keymap.c` for sample.
495
496
497
498 ### 2.5 Backlight Action
499 These actions control the backlight.
500
501 #### 2.5.1 Change backlight level
502 Increase backlight level.
503
504 ACTION_BACKLIGHT_INCREASE()
505
506 Decrease backlight level.
507
508 ACTION_BACKLIGHT_DECREASE()
509
510 Step through backlight levels.
511
512 ACTION_BACKLIGHT_STEP()
513
514 Turn a specific backlight level on or off.
515
516 ACTION_BACKLIGHT_LEVEL(1)
517
518 #### 2.5.2 Turn on / off backlight
519 Turn the backlight on and off without changing level.
520
521 ACTION_BACKLIGHT_TOGGLE()
522
523
524
525 ## 3. Layer switching Example
526 There are some ways to switch layer with 'Layer' actions.
527
528 ### 3.1 Momentary switching
529 Momentary switching changes layer only while holding Fn key.
530
531 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.
532
533 ACTION_LAYER_MOMENTARY(1)
534
535
536 Note that after switching on press the actions on destination layer(Layer 1) are performed.
537 ***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.
538
539
540 ### 3.2 Toggle switching
541 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.
542
543 This performs toggle switching action of 'Layer 2'.
544
545 ACTION_LAYER_TOGGLE(2)
546
547
548
549 ### 3.3 Momentary switching with Tap key
550 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.
551
552 ACTION_LAYER_TAP_KEY(2, KC_SCLN)
553
554 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.
555
556
557
558 ### 3.4 Momentary switching with Tap Toggle
559 This switches layer only while holding a key but toggle layer with several taps. **Tap** means to press and release key quickly.
560
561 ACTION_LAYER_TAP_TOGGLE(1)
562
563 Number of taps can be configured with `TAPPING_TOGGLE` in `config.h`, `5` by default.
564
565
566
567 ### 3.5 Momentary switching with Modifiers
568 This registers modifier key(s) simultaneously with layer switching.
569
570 ACTION_LAYER_MODS(2, MOD_LSFT | MOD_LALT)
571
572 This function can only register left-sided modifiers. The handedness of the modifier (left/right) is an extra bit that is not able to be passed through into the layer system. See: [`common/action_code.h`](../common/action_code.h), the spec for ACT_LAYER_TAP only allows four bits for the mods, whereas the mods themselves require five bits, with the high bit being the left/right handedness.
573
574
575 ## 4. Tapping
576 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.
577
578 ### 4.1 Tap Key
579 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.
580
581 Modifier with tap key:
582
583 ACTION_MODS_TAP_KEY(MOD_RSFT, KC_GRV)
584
585 Layer switching with tap key:
586
587 ACTION_LAYER_TAP_KEY(2, KC_SCLN)
588
589 [dual_role]: http://en.wikipedia.org/wiki/Modifier_key#Dual-role_keys
590
591
592 ### 4.2 Tap Toggle
593 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.
594
595 ACTION_LAYER_TAP_TOGGLE(1)
596
597
598 ### 4.3 Oneshot Modifier
599 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.
600
601 ACTION_MODS_ONESHOT(MOD_LSFT)
602
603 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.
604
605 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.
606
607
608 ### 4.4 Tap Toggle Mods
609 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.
610
611 ACTION_MODS_TAP_TOGGLE(MOD_LSFT)
612
613
614
615
616 ## 5. Legacy Keymap
617 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.***
618
619 To enable Legacy Keymap support define this macro in `config.h`.
620
621 #define USE_LEGACY_KEYMAP
622
623 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.
624
625 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.
626
627 const uint8_t PROGMEM fn_layer[] = {
628 1, // Fn0
629 2, // Fn1
630 2, // Fn2
631 };
632
633 const uint8_t PROGMEM fn_keycode[] = {
634 KC_NO, // Fn0
635 KC_NO, // Fn1
636 KC_SPC, // Fn2
637 };
638
639
640 ## 6. Terminology
641 ***TBD***
642 ### keymap
643 is comprised of multiple layers.
644 ### layer
645 is matrix of keycodes.
646 ### key
647 is physical button on keyboard or logical switch on software.
648 ### keycode
649 is codes used on firmware.
650 ### action
651 is a function assigned on a key.
652 ### layer transparency
653 Using transparent keycode one layer can refer key definition on other lower layer.
654 ### layer precedence
655 Top layer has higher precedence than lower layers.
656 ### tapping
657 is to press and release a key quickly.
658 ### Fn key
659 is key which executes a special action like layer switching, mouse key, macro or etc.
660 ### dual role key
661 <http://en.wikipedia.org/wiki/Modifier_key#Dual-role_keys>
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