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**.
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**.
-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 Colemak instead of Qwerty.
+Keymap layer '0' is usually the `default_layer`, with other layers initially off after booting up the firmware, although this can configured differently in `config.h`. It is useful to change `default_layer` when you completely switch a key layout, for example, if you want to switch to Colemak instead of Qwerty.
-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.
+On the other hand, you can change `layer_state` to overlay the base layer with other layers for features such as navigation keys, function keys (F1-F12), media keys, and/or special actions.
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.
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.
// Each layer gets a name for readability.
// The underscores don't mean anything - you can
// have a layer called STUFF or any other name.
// Each layer gets a name for readability.
// The underscores don't mean anything - you can
// have a layer called STUFF or any other name.
-These are some handy definitions we can use when building our keymap and our custom function. The `GRAVE_MODS` definition will be used later in our custom function. The `_______` define makes it easier to see what keys a layer is overriding, while the `_BL`, `_FL`, and `_CL` defines make it easier to refer to each of our layers.
+These are some handy definitions we can use when building our keymap and our custom function. The `GRAVE_MODS` definition will be used later in our custom function, and the following `_BL`, `_FL`, and `_CL` defines make it easier to refer to each of our layers.
+
+Note: You may also find some older keymap files may also have a define(s) for `_______` and/or `XXXXXXX`. These can be used in place for `KC_TRNS` and `KC_NO` respectively, making it easier to see what keys a layer is overriding. These definitions are now unecessary, as they are included by default.
-After this you'll find a list of KEYMAP() macros. A KEYMAP() is simply a list of keys to define a single layer. Typically you'll have one or more "base layers" (such as QWERTY, Dvorak, or Colemak) and then you'll layer on top of that one or more "function" layers. Due to the way layers are processed you can't overlay a "lower" layer on top of a "higher" layer.
+After this you'll find a list of LAYOUT() macros. A LAYOUT() is simply a list of keys to define a single layer. Typically you'll have one or more "base layers" (such as QWERTY, Dvorak, or Colemak) and then you'll layer on top of that one or more "function" layers. Due to the way layers are processed you can't overlay a "lower" layer on top of a "higher" layer.
F(0), 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_GRV, KC_BSPC, KC_PGUP, \
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_BSLS, KC_PGDN, \
KC_CAPS, KC_A, KC_S, KC_D, KC_F, KC_G, KC_H, KC_J, KC_K, KC_L, KC_SCLN, KC_QUOT, KC_NUHS, KC_ENT, \
F(0), 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_GRV, KC_BSPC, KC_PGUP, \
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_BSLS, KC_PGDN, \
KC_CAPS, KC_A, KC_S, KC_D, KC_F, KC_G, KC_H, KC_J, KC_K, KC_L, KC_SCLN, KC_QUOT, KC_NUHS, KC_ENT, \
Our function layer is, from a code point of view, no different from the base layer. Conceptually, however, you will build that layer as an overlay, not a replacement. For many people this distinction does not matter, but as you build more complicated layering setups it matters more and more.
Our function layer is, from a code point of view, no different from the base layer. Conceptually, however, you will build that layer as an overlay, not a replacement. For many people this distinction does not matter, but as you build more complicated layering setups it matters more and more.
KC_GRV, 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_DEL, BL_STEP, \
_______, _______, _______,_______,_______,_______,_______,_______,KC_PSCR,KC_SLCK, KC_PAUS, _______, _______, _______, _______, \
_______, _______, MO(_CL),_______,_______,_______,_______,_______,_______,_______, _______, _______, _______, _______, \
KC_GRV, 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_DEL, BL_STEP, \
_______, _______, _______,_______,_______,_______,_______,_______,KC_PSCR,KC_SLCK, KC_PAUS, _______, _______, _______, _______, \
_______, _______, MO(_CL),_______,_______,_______,_______,_______,_______,_______, _______, _______, _______, _______, \