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+# Quantum Keycodes
+
+All keycodes within quantum are numbers between `0x0000` and `0xFFFF`. Within your `keymap.c` it may look like you have functions and other special cases, but ultimately the C preprocessor will translate those into a single 4 byte integer. QMK has reserved `0x0000` through `0x00FF` for standard keycodes. These are keycodes such as `KC_A`, `KC_1`, and `KC_LCTL`, which are basic keys defined in the USB HID specification. 
+
+On this page we have documented keycodes between `0x00FF` and `0xFFFF` which are used to implement advanced quantum features. If you define your own custom keycodes they will be put into this range as well. Keycodes above `0x00FF` may not be used with any of the mod/layer-tap keys listed 
+
+## QMK keycodes
+
+|Name|Description|
+|----|-----------|
+|`RESET`|Put the keyboard into DFU mode for flashing|
+|`DEBUG`|Toggles debug mode|
+|`KC_GESC`/`GRAVE_ESC`|Acts as escape when pressed normally but when pressed with Shift or GUI will send a `~`|
+|`KC_LSPO`|Left shift when held, open paranthesis when tapped|
+|`KC_RSPC`|Right shift when held, close paranthesis when tapped|
+|`KC_LEAD`|The [leader key](leader_key.md)|
+|`FUNC(n)`/`F(n)`|Call `fn_action(n)`|
+|`M(n)`|to call macro n|
+|`MACROTAP(n)`|to macro-tap n idk FIXME|
+
+## Bootmagic Keycodes
+
+Shortcuts for bootmagic options (these work even when bootmagic is off.)
+
+|Name|Description|
+|----|-----------|
+|`MAGIC_SWAP_CONTROL_CAPSLOCK`|Swap Capslock and Left Control|
+|`MAGIC_CAPSLOCK_TO_CONTROL`|Treat Capslock like a Control Key|
+|`MAGIC_SWAP_LALT_LGUI`|Swap the left Alt and GUI keys|
+|`MAGIC_SWAP_RALT_RGUI`|Swap the right Alt and GUI keys|
+|`MAGIC_NO_GUI`|Disable the GUI key|
+|`MAGIC_SWAP_GRAVE_ESC`|Swap the Grave and Esc key.|
+|`MAGIC_SWAP_BACKSLASH_BACKSPACE`|Swap backslack and backspace|
+|`MAGIC_HOST_NKRO`|Force NKRO on|
+|`MAGIC_SWAP_ALT_GUI`/`AG_SWAP`|Swap Alt and Gui on both sides|
+|`MAGIC_UNSWAP_CONTROL_CAPSLOCK`|Disable the Control/Capslock swap|
+|`MAGIC_UNCAPSLOCK_TO_CONTROL`|Disable treating Capslock like Control |
+|`MAGIC_UNSWAP_LALT_LGUI`|Disable Left Alt and GUI switching|
+|`MAGIC_UNSWAP_RALT_RGUI`|Disable Right Alt and GUI switching|
+|`MAGIC_UNNO_GUI`|Enable the GUI key |
+|`MAGIC_UNSWAP_GRAVE_ESC`|Disable the Grave/Esc swap |
+|`MAGIC_UNSWAP_BACKSLASH_BACKSPACE`|Disable the backslash/backspace swap|
+|`MAGIC_UNHOST_NKRO`|Force NKRO off|
+|`MAGIC_UNSWAP_ALT_GUI`/`AG_NORM`|Disable the Alt/GUI switching|
+|`MAGIC_TOGGLE_NKRO`|Turn NKRO on or off|
+
+## Audio
+
+```c
+#ifdef AUDIO_ENABLE
+    AU_ON,
+    AU_OFF,
+    AU_TOG,
+
+    #ifdef FAUXCLICKY_ENABLE
+        FC_ON,
+        FC_OFF,
+        FC_TOG,
+    #endif
+
+    // Music mode on/off/toggle
+    MU_ON,
+    MU_OFF,
+    MU_TOG,
+
+    // Music voice iterate
+    MUV_IN,
+    MUV_DE,
+#endif
+```
+
+### Midi
+
+#if !MIDI_ENABLE_STRICT || (defined(MIDI_ENABLE) && defined(MIDI_BASIC))
+    MI_ON,  // send midi notes when music mode is enabled
+    MI_OFF, // don't send midi notes when music mode is enabled
+#endif
+
+MIDI_TONE_MIN,
+MIDI_TONE_MAX
+
+MI_C = MIDI_TONE_MIN,
+MI_Cs,
+MI_Db = MI_Cs,
+MI_D,
+MI_Ds,
+MI_Eb = MI_Ds,
+MI_E,
+MI_F,
+MI_Fs,
+MI_Gb = MI_Fs,
+MI_G,
+MI_Gs,
+MI_Ab = MI_Gs,
+MI_A,
+MI_As,
+MI_Bb = MI_As,
+MI_B,
+
+MIDI_TONE_KEYCODE_OCTAVES > 1
+
+where x = 1-5:
+MI_C_x,
+MI_Cs_x,
+MI_Db_x = MI_Cs_x,
+MI_D_x,
+MI_Ds_x,
+MI_Eb_x = MI_Ds_x,
+MI_E_x,
+MI_F_x,
+MI_Fs_x,
+MI_Gb_x = MI_Fs_x,
+MI_G_x,
+MI_Gs_x,
+MI_Ab_x = MI_Gs_x,
+MI_A_x,
+MI_As_x,
+MI_Bb_x = MI_As_x,
+MI_B_x,
+
+MI_OCT_Nx 1-2
+MI_OCT_x 0-7
+MIDI_OCTAVE_MIN = MI_OCT_N2,
+MIDI_OCTAVE_MAX = MI_OCT_7,
+MI_OCTD, // octave down
+MI_OCTU, // octave up
+
+MI_TRNS_Nx 1-6
+MI_TRNS_x 0-6
+MIDI_TRANSPOSE_MIN = MI_TRNS_N6,
+MIDI_TRANSPOSE_MAX = MI_TRNS_6,
+MI_TRNSD, // transpose down
+MI_TRNSU, // transpose up
+
+MI_VEL_x 1-10
+MIDI_VELOCITY_MIN = MI_VEL_1,
+MIDI_VELOCITY_MAX = MI_VEL_9,
+MI_VELD, // velocity down
+MI_VELU, // velocity up
+
+MI_CHx 1-16
+MIDI_CHANNEL_MIN = MI_CH1
+MIDI_CHANNEL_MAX = MI_CH16,
+MI_CHD, // previous channel
+MI_CHU, // next channel
+
+MI_ALLOFF, // all notes off
+
+MI_SUS, // sustain
+MI_PORT, // portamento
+MI_SOST, // sostenuto
+MI_SOFT, // soft pedal
+MI_LEG,  // legato
+
+MI_MOD, // modulation
+MI_MODSD, // decrease modulation speed
+MI_MODSU, // increase modulation speed
+#endif // MIDI_ADVANCED
+
+## Backlight
+
+These keycodes control the backlight. Most keyboards use this for single color in-switch lighting.
+
+|Name|Description|
+|----|-----------|
+|`BL_x`|Set a specific backlight level between 0-9|
+|`BL_ON`|An alias for `BL_9`|
+|`BL_OFF`|An alias for `BL_0`|
+|`BL_DEC`|Turn the backlight level down by 1|
+|`BL_INC`|Turn the backlight level up by 1|
+|`BL_TOGG`|Toggle the backlight on or off|
+|`BL_STEP`|Step through backlight levels, wrapping around to 0 when you reach the top.|
+
+## RGBLIGHT WS2818 LEDs
+
+This controls the `RGBLIGHT` functionality. Most keyboards use WS2812 (and compatible) LEDs for underlight or case lighting.
+
+|Name|Description|
+|----|-----------|
+|`RGB_TOG`|toggle on/off|
+|`RGB_MOD`|cycle through modes|
+|`RGB_HUI`|hue increase|
+|`RGB_HUD`|hue decrease|
+|`RGB_SAI`|saturation increase|
+|`RGB_SAD`|saturation decrease|
+|`RGB_VAI`|value increase|
+|`RGB_VAD`|value decrease|
+
+## Thermal Printer (experimental)
+
+|Name|Description|
+|----|-----------|
+|`PRINT_ON`|Start printing everything the user types|
+|`PRINT_OFF`|Stop printing everything the user types|
+
+## Keyboard output selection
+
+This is used when multiple keyboard outputs can be selected. Currently this only allows for switching between USB and Bluetooth on keyboards that support both.
+
+|Name|Description|
+|----|-----------|
+|`OUT_AUTO`|auto mode|
+|`OUT_USB`|usb only|
+|`OUT_BT`|bluetooth (when `BLUETOOTH_ENABLE`)|
+
+## Modifiers
+
+These are special keycodes that simulate pressing several modifiers at once.
+
+|Name|Description|
+|----|-----------|
+|`KC_HYPR`|Hold down LCTL + LSFT + LALT + LGUI|
+|`KC_MEH`|Hold down LCTL + LSFT + LALT|
+
+/* FIXME: Should we have these in QMK too?
+ * |`KC_LCAG`|`LCTL` + `LALT` + `LGUI`|
+ * |`KC_ALTG`|`RCTL` + `RALT`|
+ * |`KC_SCMD`/`KC_SWIN`|`LGUI` + `LSFT`|
+ * |`KC_LCA`|`LCTL` + `LALT`|
+ */
+
+### Modifiers with keys
+
+|Name|Description|
+|----|-----------|
+|`LCTL(kc)`|`LCTL` + `kc`|
+|`LSFT(kc)`/`S(kc)`|`LSFT` + `kc`|
+|`LALT(kc)`|`LALT` + `kc`|
+|`LGUI(kc)`|`LGUI` + `kc`|
+|`RCTL(kc)`|`RCTL` + `kc`|
+|`RSFT(kc)`|`RSFT` + `kc`|
+|`RALT(kc)`|`RALT` + `kc`|
+|`RGUI(kc)`|`RGUI` + `kc`|
+|`HYPR(kc)`|`LCTL` + `LSFT` + `LALT` + `LGUI` + `kc`|
+|`MEH(kc)`|`LCTL` + `LSFT` + `LALT` + `kc`|
+|`LCAG(kc)`|`LCTL` + `LALT` + `LGUI` + `kc`|
+|`ALTG(kc)`|`RCTL` + `RALT` + `kc`|
+|`SCMD(kc)`/`SWIN(kc)`|`LGUI` + `LSFT` + `kc`|
+|`LCA(kc)`|`LCTL` + `LALT` + `kc`|
+
+### One Shot Keys
+
+Most modifiers work by being held down while you push another key. You can use `OSM()` to setup a "One Shot" modifier. When you tap a one shot mod it will remain is a pressed state until you press another key. 
+
+To specify a your modifier you need to pass the `MOD` form of the key. For example, if you want to setup a One Shot Control you would use `OSM(MOD_LCTL)`.
+
+|Name|Description|
+|----|-----------|
+|`OSM(mod)`|use mod for one keypress|
+|`OSL(layer)`|switch to layer for one keypress|
+
+### Mod-tap keys
+
+These keycodes will press the mod(s) when held, and the key when tapped. They only work with [basic keycodes](basic_keycodes.md). 
+
+|Name|Description|
+|----|-----------|
+|`CTL_T(kc)`/`LCTL_T(kc)`|`LCTL` when held, `kc` when tapped|
+|`RCTL_T(kc)`|`RCTL` when held, `kc` when tapped|
+|`SFT_T(kc)`/`LSFT_T(kc)`|`LSFT` when held, `kc` when tapped|
+|`RSFT_T(kc)`|`RSFT` when held, `kc` when tapped|
+|`ALT_T(kc)`/`LALT_T(kc)`|`LALT` when held, `kc` when tapped|
+|`RALT_T(kc)`/`ALGR_T(kc)`|`RALT` when held, `kc` when tapped|
+|`GUI_T(kc)`/`LGUI_T(kc)`|`LGUI` when held, `kc` when tapped|
+|`RGUI_T(kc)`|`RGUI` when held, `kc` when tapped|
+|`C_S_T(kc)`|`LCTL` + `LSFT` when held, `kc` when tapped|
+|`MEH_T(kc)`|`LCTL` + `LSFT` + `LALT` when held, `kc` when tapped|
+|`LCAG_T(kc)`|`LCTL` + `LALT` + `LGUI` when held, `kc` when tapped|
+|`RCAG_T(kc)`|`RCTL` + `RALT` + `RGUI` when held, `kc` when tapped|
+|`ALL_T(kc)`|`LCTL` + `LSFT` + `LALT` + `LGUI` when held, `kc` when tapped [more info](http://brettterpstra.com/2012/12/08/a-useful-caps-lock-key/)|
+|`SCMD_T(kc)`/`SWIN_T(kc)`|`LGUI` + `LSFT` when held, `kc` when tapped|
+|`LCA_T(kc)`|`LCTL` + `LALT` when held, `kc` when tapped|
+
+## US ANSI Shifted symbols
+
+These keycodes correspond to characters that are "shifted" on a standard US ANSI keyboards. They do not have dedicated keycodes but are instead typed by holding down shift and then sending a keycode. 
+
+It's important to remember that all of these keycodes send a left shift - this may cause unintended actions if unaccounted for. The short code is preferred in most situations.
+
+|Short Name|Long Name|Description|
+|----------|---------|-----------|
+|`KC_TILD`|`KC_TILDE`|tilde `~`|
+|`KC_EXLM`|`KC_EXCLAIM`|exclamation mark `!`|
+|`KC_AT`||at sign `@`|
+|`KC_HASH`||hash sign `#`|
+|`KC_DLR`|`KC_DOLLAR`|dollar sign `$`|
+|`KC_PERC`|`KC_PERCENT`|percent sign `%`|
+|`KC_CIRC`|`KC_CIRCUMFLEX`|circumflex `^`|
+|`KC_AMPR`|`KC_AMPERSAND`|ampersand `&`|
+|`KC_ASTR`|`KC_ASTERISK`|asterisk `*`|
+|`KC_LPRN`|`KC_LEFT_PAREN`|left parenthesis `(`|
+|`KC_RPRN`|`KC_RIGHT_PAREN`|right parenthesis `)`|
+|`KC_UNDS`|`KC_UNDERSCORE`|underscore `_`|
+|`KC_PLUS`||plus sign `+`|
+|`KC_LCBR`|`KC_LEFT_CURLY_BRACE`|left curly brace `{`|
+|`KC_RCBR`|`KC_RIGHT_CURLY_BRACE`|right curly brace `}`|
+|`KC_LT`/`KC_LABK`|`KC_LEFT_ANGLE_BRACKET`|left angle bracket `<`|
+|`KC_GT`/`KC_RABK`|`KC_RIGHT_ANGLE_BRACKET`|right angle bracket `>`|
+|`KC_COLN`|`KC_COLON`|colon `:`|
+|`KC_PIPE`||pipe `\|`|
+|`KC_QUES`|`KC_QUESTION`|question mark `?`|
+|`KC_DQT`/`KC_DQUO`|`KC_DOUBLE_QUOTE`|double quote `"`|
+
+## Layer Changes
+
+These are keycodes that can be used to change the current layer.
+
+|Name|Description|
+|----|-----------|
+|`LT(layer, kc)`|turn on layer (0-15) when held, kc ([basic keycodes](basic_keycodes.md)) when tapped|
+|`TO(layer)`|turn on layer when depressed|
+|`MO(layer)`|momentarily turn on layer when depressed (requires `KC_TRNS` on destination layer)|
+|`DF(layer)`|sets the base (default) layer|
+|`TG(layer)`|toggle layer on/off|
+|`TT(layer)`|tap toggle? idk FIXME|
+|`OSL(layer)`|switch to layer for one keycode|
+
+## Unicode
+
+These keycodes can be used in conjuction with the [Unicode](unicode_and_additional_language_support.md) support.
+
+|`UNICODE(n)`/`UC(n)`|if `UNICODE_ENABLE`, this will send characters up to `0x7FFF`|
+|`X(n)`|if `UNICODEMAP_ENABLE`, also sends unicode via a different method|
+
+# `SAFE_RANGE`, or safely defining custom keycodes
+
+Sometimes you want to define your own custom keycodes to make your keymap easier to read. QMK provides `SAFE_RANGE` to help you do that. `SAFE_RANGE` is the first available keycode in the `0x0000`-`0xFFFF` range and you can use it when creating your own custom keycode enum:
+
+```
+enum my_keycodes {
+  FOO = SAFE_RANGE,
+  BAR
+};
+```
+
+You can then use `process_record_user()` to do something with your keycode:
+
+```
+bool process_record_user(uint16_t keycode, keyrecord_t *record) {
+  switch (keycode) {
+    case FOO:
+      // Do something here
+      break;
+    case BAR:
+      // Do something here
+      break;
+  }
+}
+```