# 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 |Key |Aliases |Description | |---------------|-----------|---------------------------------------------------------------------| |`RESET` | |Put the keyboard into DFU mode for flashing | |`DEBUG` | |Toggle debug mode | |`EEPROM_RESET` |`EEP_RST` |Resets EEPROM state by reinitializing it | |`KC_GESC` |`GRAVE_ESC`|Escape when tapped, ` when pressed with Shift or GUI| |`KC_LSPO` | |Left Shift when held, `(` when tapped | |`KC_RSPC` | |Right Shift when held, `)` when tapped | |`KC_LEAD` | |The [Leader key](feature_leader_key.md) | |`KC_LOCK` | |The [Lock key](feature_key_lock.md) | |`FUNC(n)` |`F(n)` |Call `fn_action(n)` (deprecated) | |`M(n)` | |Call macro `n` | |`MACROTAP(n)` | |Macro-tap `n` idk FIXME |