Keymap framework - how to define your keymap ============================================ ***NOTE: This is updated for QMK but this is still work in progress. This may still be inconsistent with the source code.*** QMK is based on TMK. Understanding the essential changes made should help you understand variable names etc. ## TMK vs. QMK | Firmware |TMK |QMK | |---------------------------|-----------------------|-------------------------| | Maintainer |hasu |Jack Humbert et al. | | Build path customization | `TMK_DIR = ...` | `include .../Makefile` | | `keymaps` data | 3D array of `uint8_t` holding **keycode** | 3D array of `uint16_t` holding **action code** | | `fn_actions` data | 1D array of `uint16_t` holding **action code** | 1D array of `uint16_t` holding **action code** | Since QMK is based on TMK and uses major portion of TMK code as is, understanding the essential changes made should help you understand the code. ## 0. Keymap and layers In QMK, **`const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS]`** holds multiple **layers** of keymap information in **16 bit** data holding the **action code**. You can define **32 layers** at most. For trivial key definitions, the higher 8 bits of the **action code** are all 0 and the lower 8 bits holds the USB HID usage code generated by the key as **keycode**. Respective layers can be validated simultaneously. Layers are indexed with 0 to 31 and higher layer has precedence. Keymap: 32 Layers Layer: action code matrix ----------------- --------------------- stack of layers array_of_action_code[row][column] ____________ precedence _______________________ / / | high / ESC / F1 / F2 / F3 .... 31 /___________// | /-----/-----/-----/----- 30 /___________// | / TAB / Q / W / E .... 29 /___________/ | /-----/-----/-----/----- : _:_:_:_:_:__ | : /LCtrl/ A / S / D .... : / : : : : : / | : / : : : : 2 /___________// | 2 `-------------------------- 1 /___________// | 1 `-------------------------- 0 /___________/ V low 0 `-------------------------- Sometimes, the action code stored in keymap may be referred as keycode in some documents due to the TMK history. ### 0.1 Keymap layer status Keymap layer has its state in two 32 bit parameters: * **`default_layer_state`** indicates a base keymap layer(0-31) which is always valid and to be referred. * **`layer_state`** () has current on/off status of the layer on its each bit. Keymap has its state in two parameter **`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. 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 switch key layout completely, say you want Colmak instead of Qwerty. Initial state of Keymap Change base layout ----------------------- ------------------ 31 31 30 30 29 29 : : : : ____________ 2 ____________ 2 / / 1 / / ,->1 /___________/ ,->0 /___________/ | 0 | | `--- default_layer = 0 `--- default_layer = 1 layer_state = 0x00000001 layer_state = 0x00000002 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. Overlay feature layer --------------------- bit|status ____________ ---+------ 31 / / 31 | 0 30 /___________// -----> 30 | 1 29 /___________/ -----> 29 | 1 : : | : : ____________ : | : 2 / / 2 | 0 ,->1 /___________/ -----> 1 | 1 | 0 0 | 0 | + `--- default_layer = 1 | layer_state = 0x60000002 <-' ### 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_TRANS` on overlay layer changes just part of layout to fall back on lower or base layer. Key with `KC_TRANS` (`KC_TRNS` and `_______` are the alias) doesn't has its own keycode and refers to lower valid layers for keycode, instead. See example below. ### 0.3 Keymap Example Keymap in this QMK is **`static const uint16_t PROGMEM 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. It holds the 16 bit quantum keycode (action code). > Please note that keymap in the TMK, which QMK was forked from, is **`static const uint8_t PROGMEM keymaps[]`** C array which holds the 8 bit keycode (~USB HID usage code). This is a keymap example for [HHKB](http://en.wikipedia.org/wiki/Happy_Hacking_Keyboard) keyboard. This example has three layers, 'QWERTY' as base layer, 'FN' and 'MOUSE'. In this example, `MO(layer)` is a **momentary layer switching** key. You can find other keymap definitions in file `keymap.c` located on project directories. ``` /* * dbroqua HHKB Layout */ #include "hhkb.h" #define BASE 0 #define FN 1 #define MOUSE 2 const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = { /* BASE Level: Default Layer * ,-----------------------------------------------------------------------------------------. * | Esc | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 0 | - | = | \ | ` | * |-----------------------------------------------------------------------------------------+ * | Tab | Q | W | E | R | T | Y | U | I | O | P | [ | ] | Bksp | * |-----------------------------------------------------------------------------------------+ * | Ctrl | A | S | D | F | G | H | J | K | L | ; | ' | Enter | * |-----------------------------------------------------------------------------------------+ * | Shift | Z | X | C | V | B | N | M | , | . | / | Shift | fn | * +-----------------------------------------------------------------------------------------+ * | Gui | Alt | Space | AltGr |Mouse| * `----------------------------------------------------------------´ */ [BASE] = KEYMAP( KC_ESC, KC_1, KC_2, KC_3, KC_4, KC_5, KC_6, KC_7, KC_8, KC_9, KC_0, KC_MINS, KC_EQL, KC_BSLS, KC_GRV, \ KC_TAB, KC_Q, KC_W, KC_E, KC_R, KC_T, KC_Y, KC_U, KC_I, KC_O, KC_P, KC_LBRC, KC_RBRC, KC_BSPC, \ KC_LCTL, KC_A, KC_S, KC_D, KC_F, KC_G, KC_H, KC_J, KC_K, KC_L, KC_SCLN, KC_QUOT, KC_ENT, \ KC_LSFT, KC_Z, KC_X, KC_C, KC_V, KC_B, KC_N, KC_M, KC_COMM, KC_DOT, KC_SLSH, KC_RSFT, MO(FN), \ KC_LGUI, KC_LALT, /* */ KC_SPC, KC_RALT, MO(MOUSE) ), /* FN Layer * ,-----------------------------------------------------------------------------------------. * | Pwr | F1 | F2 | F3 | F4 | F5 | F6 | F7 | F8 | F9 | F0 | F11 | F12 | Ins | Del| * |-----------------------------------------------------------------------------------------+ * | Caps | | | | | | | |PrtSc| Slck| Paus| Up | | | * |-----------------------------------------------------------------------------------------+ * | | Vol-| Vol+| Mute| | | * | / | Home| PgUp| Left |Right| | * |-----------------------------------------------------------------------------------------+ * | | Prev| Play| Next| | | + | - | End |PgDwn| Down| | | * +-----------------------------------------------------------------------------------------+ * | | | | Stop | | * `----------------------------------------------------------------´ */ [FN] = KEYMAP( KC_PWR, KC_F1, KC_F2, KC_F3, KC_F4, KC_F5, KC_F6, KC_F7, KC_F8, KC_F9, KC_F10, KC_F11, KC_F12, KC_INS, KC_DEL, \ KC_CAPS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_PSCR, KC_SLCK, KC_PAUS, KC_UP, KC_TRNS, KC_TRNS, \ KC_TRNS, KC_VOLD, KC_VOLU, KC_MUTE, KC_TRNS, KC_TRNS, KC_PAST, KC_PSLS, KC_HOME, KC_PGUP, KC_LEFT, KC_RGHT, KC_TRNS, \ KC_TRNS, KC_MPRV, KC_MPLY, KC_MNXT, KC_TRNS, KC_TRNS, KC_PPLS, KC_PMNS, KC_END, KC_PGDN, KC_DOWN, KC_TRNS, KC_TRNS, \ KC_TRNS, KC_TRNS, KC_TRNS, KC_MSTP, KC_TRNS ), /* MOUSE Layer * ,-----------------------------------------------------------------------------------------. * | | | | | | | | | | | | | | | | * |-----------------------------------------------------------------------------------------+ * | | | WUp | | | | | | | | Btn1| Up | Btn2| | * |-----------------------------------------------------------------------------------------+ * | | WLt | WDn | WRt | | | | | | | Left |Right| | * |-----------------------------------------------------------------------------------------+ * | | | | | | | | | | Btn3| Down| | | * +-----------------------------------------------------------------------------------------+ * | | | | | | * `----------------------------------------------------------------´ */ [MOUSE] = KEYMAP( KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, \ KC_TRNS, KC_TRNS, KC_WH_U, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_BTN1, KC_MS_U, KC_BTN2, KC_TRNS, \ KC_TRNS, KC_WH_L, KC_WH_D, KC_WH_R, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_MS_L, KC_MS_R, KC_TRNS, \ KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_BTN3, KC_MS_D, KC_TRNS, KC_TRNS, \ KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS ) }; const uint16_t PROGMEM fn_actions[] = { }; const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt) { // MACRODOWN only works in this function switch(id) { case 0: if (record->event.pressed) { register_code(KC_RSFT); } else { unregister_code(KC_RSFT); } break; } return MACRO_NONE; }; ``` ## 1. Keycode See [`tmk_core/common/keycode.h`](../tmk_core/common/keycode.h) or keycode table below for the detail. Keycode is internal **8bit code** to indicate action performed on key in keymap. Keycodes are based on [HID Usage Keyboard/Keypad Page(0x07)](http://www.usb.org/developers/hidpage/Hut1_12v2.pdf) plus special codes in the `0xA5-DF` range. 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. keymaps[] In `KEYMAP()` macro, TMK recommends you to keep prefix part `KC_` of keycode to keep keymap compact. For example, just use `A` instead you place `KC_A` in `KEYMAP()`. But this doesn't apply for QMK. The `KEYMAP()` macro defines correspondence between the physical key location to the electrical key connection. Some keycodes has 7-letter **short name** such as `KC_COMM` in addition to descriptive name `KC_COMMA`, you'll prefer short one in `KEYMAP()`. ### 1.0 Other key - `KC_NO` for no action - `KC_TRNS` for layer transparency (See above) ### 1.1 Normal key - `KC_A` to `KC_Z`, `KC_1` to `KC_0` for alpha numeric key - `KC_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` to `KC_F24` - `KC_P1` to `KC_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` and `KC_RCTL` for Control - `KC_LSFT` and `KC_RSFT` for Shift - `KC_LALT` and `KC_RALT` for Alt - `KC_LGUI` and `KC_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 cursor - `KC_WH_U`, `KC_WH_D`, `KC_WH_L`, `KC_WH_R` for mouse wheel - `KC_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, Wake - `KC_MUTE`, `KC_VOLU`, `KC_VOLD` for audio volume control - `KC_MNXT`, `KC_MPRV`, `KC_MSTP`, `KC_MPLY`, `KC_MSEL` for media control - `KC_MAIL`, `KC_CALC`, `KC_MYCM` for application launch - `KC_WSCH`, `KC_WHOM`, `KC_WBAK`, `KC_WFWD`, `KC_WSTP`, `KC_WREF`, `KC_WFAV` for web browser operation ### 1.5 Fn key You don't need to use this functionality under QMK since this is a backward compatibility functionality. Unlike TMK, you can write action code itself directly in **`static const uint16_t PROGMEM keymaps[]`** C array using `MO(layer)`, etc. `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. ***Only 32 `Fn` keys can be defined at most.*** ### 1.6 Keycode Table See keycode table in [`doc/keycode.txt`](./keycode.txt) for description of keycodes. 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. [HID_usage]: http://www.usb.org/developers/hidpage/Hut1_12v2.pdf ## 2. Action 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. 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. ***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[]`.*** ### 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. #### Parameters + **mods**: { ` MOD_LCTL`, ` MOD_LSFT`, ` MOD_LALT`, ` MOD_LGUI`, ` MOD_RCTL`, ` MOD_RSFT`, ` MOD_RALT`, ` MOD_RGUI` } + **key**: keycode #### 2.1.1 Normal key and Modifier ***This action usually won't be used expressly in keymap*** because you can just use keycodes in `KEYMAP()` instead. You can define these actions on *'A'* key and *'left shift'* modifier with: ACTION_KEY(KC_A) ACTION_KEY(KC_LSFT) #### 2.1.2 Modified key 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 character *'!'* or `Alt + Tab` to switch application windows. ACTION_MODS_KEY(MOD_LSFT, KC_1) ACTION_MODS_KEY(MOD_LALT, KC_TAB) 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. ACTION_MODS_KEY(MOD_LALT | MOD_LSFT, KC_TAB) #### 2.1.3 Multiple Modifiers Registers multiple modifiers with pressing a key. To specify multiple modifiers use `|`. ACTION_MODS(MOD_ALT | MOD_LSFT) #### 2.1.3 Modifier with Tap key([Dual role][dual_role]) Works as a modifier key while holding, but registers a key on tap(press and release quickly). ACTION_MODS_TAP_KEY(MOD_RCTL, KC_ENT) ### 2.2 Layer Action These actions operate layers of keymap. #### Parameters You can specify a **target layer** of action and **when the action is executed**. Some actions take a **bit value** for bitwise operation. + **layer**: `0`-`31` + **on**: { `ON_PRESS` | `ON_RELEASE` | `ON_BOTH` } + **bits**: 4-bit value and 1-bit mask bit #### 2.2.1 Default Layer Default Layer is a layer which always is valid and referred to when actions is not defined on other overlay layers. This sets Default Layer to given parameter `layer` and activate it. ACTION_DEFAULT_LAYER_SET(layer) #### 2.2.2 Momentary Turns on `layer` momentarily while holding, in other words it activates when key is pressed and deactivate when released. ACTION_LAYER_MOMENTARY(layer) #### 2.2.3 Toggle Switch Turns on `layer` with first type(press and release) and turns off with next. ACTION_LAYER_TOGGLE(layer) #### 2.2.4 Momentary Switch with tap key Turns on `layer` momentary while holding, but registers key on tap(press and release quickly). ACTION_LAYER_TAP_KEY(layer, key) #### 2.2.5 Momentary Switch with tap toggle Turns on `layer` momentary while holding and toggles it with serial taps. ACTION_LAYER_TAP_TOGGLE(layer) #### 2.2.6 Invert state of layer Inverts current state of `layer`. If the layer is on it becomes off with this action. ACTION_LAYER_INVERT(layer, on) #### 2.2.7 Turn On layer Turns on layer state. ACTION_LAYER_ON(layer, on) Turns on layer state on press and turns off on release. ACTION_LAYER_ON_OFF(layer) #### 2.2.8 Turn Off layer Turns off layer state. ACTION_LAYER_OFF(layer, on) Turns off layer state on press and activates on release. ACTION_LAYER_OFF_ON(layer) #### 2.2.9 Set layer Turn on layer only. `layer_state = (1< ((bits<