# Quantum Keycodes Quantum keycodes allow for easier customisation of your keymap than the basic ones provide, without having to define custom actions. 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. ## 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](feature_leader_key.md)| |`KC_LOCK`|The [lock key](key_lock.md)| |`FUNC(n)`/`F(n)`|Call `fn_action(n)` (deprecated)| |`M(n)`|to call macro n| |`MACROTAP(n)`|to macro-tap n idk FIXME|