#### 0.1.2 The default layer
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.
- Initial state of Keymap Change base layout
- ----------------------- ------------------
+ Initial state of Keymap Change base layout
+ ----------------------- ------------------
31 31
30 30
### 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.
+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.
+
+**Note:** a layer must be activated before it may be included in the stack search.
+
+`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.
-You can place `KC_TRNS` on overlay layer changes just part of layout to fall back on lower or base layer.
-Key with `KC_TRANS` doesn't has its own keycode and refers to lower valid layers for keycode, instead.
-See example below.
### 0.3 Keymap Example
-Keymap is **`keymaps[]`** C array in fact and you can define layers in it with **`KEYMAP()`** C macro and keycodes. To use complex actions you need to define `Fn` keycode in **`fn_actions[]`** array.
+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.
-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, 'Cursor' and 'Mousekey'.
+This is a keymap example for the [HHKB](http://en.wikipedia.org/wiki/Happy_Hacking_Keyboard) keyboard.
+This example has three layers: the QWERTY base layer, and two overlay layers for cursor and mousekey control, respectively.
In this example,
- `Fn0` is a **momentary layer switching** key, you can use keys on Cursor layer while holding the key.
+ `Fn0` is a **momentary layer switching** key--you can use keys on the Cursor layer while holding the key.
- `Fn1` is a momentary layer switching key with tapping feature, you can get semicolon **';'** with taping the key and switch layers while holding the key. The word **'tap'** or **'tapping'** mean to press and release a key quickly.
+ `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.
- `Fn2` is a **toggle layer switch** key, you can stay switched layer after releasing the key unlike momentary switching.
+ `Fn2` is a **toggle layer switch** key--pressing the key toggles the layer on until you press it again.
You can find other keymap definitions in file `keymap.c` located on project directories.
- static const uint8_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+ const uint8_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
/* 0: Qwerty
* ,-----------------------------------------------------------.
* |Esc| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| -| =| \| `|
LGUI,LALT, BTN1, RALT,TRNS),
};
- static const uint16_t PROGMEM fn_actions[] = {
+ const action_t PROGMEM fn_actions[] = {
ACTION_LAYER_MOMENTARY(1), // FN0
ACTION_LAYER_TAP_KEY(2, KC_SCLN), // FN1
ACTION_LAYER_TOGGLE(2), // FN2
- `KC_WSCH`, `KC_WHOM`, `KC_WBAK`, `KC_WFWD`, `KC_WSTP`, `KC_WREF`, `KC_WFAV` for web browser operation
### 1.5 Fn key
-`KC_FNnn` are keycodes for `Fn` key which not given any actions at the beginning unlike most of keycodes has its own inborn action. To use these keycodes in `KEYMAP()` you need to assign action you want at first. Action of `Fn` key is defined in `fn_actions[]` and its index of the array is identical with number part of `KC_FNnn`. Thus `KC_FN0` keycode indicates the action defined in first element of the array. ***32 `Fn` keys can be defined at most.***
+`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.***
### 1.6 Keycode Table
See keycode table in [`doc/keycode.txt`](./keycode.txt) for description of keycodes.
#### 2.4.3 Implement user function
`Function` actions can be defined freely with C by user in callback function:
- void keymap_call_function(keyrecord_t *event, uint8_t id, uint8_t opt)
+ void action_function(keyrecord_t *record, uint8_t id, uint8_t opt);
This C function is called every time key is operated, argument `id` selects action to be performed and `opt` can be used for option. Function `id` can be 0-255 and `opt` can be 0-15.
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.
- static const uint8_t PROGMEM fn_layer[] = {
+ const uint8_t PROGMEM fn_layer[] = {
1, // Fn0
2, // Fn1
2, // Fn2
};
- static const uint8_t PROGMEM fn_keycode[] = {
+ const uint8_t PROGMEM fn_keycode[] = {
KC_NO, // Fn0
KC_NO, // Fn1
KC_SPC, // Fn2
projects / max / tmk_keyboard.git / blobdiff