QMK is nearly infinitely configurable. Wherever possible we err on the side of allowing users to customize their keyboard, even at the expense of code size. That level of flexibility makes for a daunting configuration experience, however.
There are two main types of configuration files in QMK- config.h and rules.mk. These files exist at various levels in QMK and all files of the same type are combined to build the final configuration. The levels, from lowest priority to highest priority, are:
- QMK Default
- Keyboard
- Folders (Up to 5 levels deep)
- Keymap
Every available setting in QMK has a default. If that setting is not set at the Keyboard, Folder, or Keymap level this is the setting that will be used.
This level contains config options that should apply to the whole keyboard. Some settings won't change in revisions, or most keymaps. Other settings are merely defaults for this keyboard and can be overridden by folders and/or keymaps.
Some keyboards have folders and sub-folders to allow for different hardware configurations. Most keyboards only go 1 folder deep, but QMK supports structures up to 5 folders deep. Each folder can have its own config.h and rules.mk files that are incorporated into the final configuration.
This level contains all of the options for that particular keymap. If you wish to override a previous declaration, you can use #undef <variable> to undefine it, where you can then redefine it without an error.
This is a C header file that is one of the first things included, and will persist over the whole project (if included). Lots of variables can be set here and accessed elsewhere. The config.h file shouldn't be including other config.h files, or anything besides this:
#include "config_common.h"
#define VENDOR_ID 0x1234- defines your VID, and for most DIY projects, can be whatever you want
#define PRODUCT_ID 0x5678- defines your PID, and for most DIY projects, can be whatever you want
#define DEVICE_VER 0- defines the device version (often used for revisions)
#define MANUFACTURER Me- generally who/whatever brand produced the board
#define PRODUCT Board- the name of the keyboard
#define DESCRIPTION a keyboard- a short description of what the keyboard is
#define MATRIX_ROWS 5- the number of rows in your keyboard's matrix
#define MATRIX_COLS 15- the number of columns in your keyboard's matrix
#define MATRIX_ROW_PINS { D0, D5, B5, B6 }- pins of the rows, from top to bottom
#define MATRIX_COL_PINS { F1, F0, B0, C7, F4, F5, F6, F7, D4, D6, B4, D7 }- pins of the columns, from left to right
#define MATRIX_IO_DELAY 30- the delay in microseconds when between changing matrix pin state and reading values
#define UNUSED_PINS { D1, D2, D3, B1, B2, B3 }- pins unused by the keyboard for reference
#define MATRIX_HAS_GHOST- define is matrix has ghost (unlikely)
#define DIODE_DIRECTION COL2ROW- COL2ROW or ROW2COL - how your matrix is configured. COL2ROW means the black mark on your diode is facing to the rows, and between the switch and the rows.
#define DIRECT_PINS { { F1, F0, B0, C7 }, { F4, F5, F6, F7 } }- pins mapped to rows and columns, from left to right. Defines a matrix where each switch is connected to a separate pin and ground.
#define AUDIO_VOICES- turns on the alternate audio voices (to cycle through)
#define C4_AUDIO- enables audio on pin C4
#define C5_AUDIO- enables audio on pin C5
#define C6_AUDIO- enables audio on pin C6
#define B5_AUDIO- enables audio on pin B5 (duophony is enables if one of B[5-7]_AUDIO is enabled along with one of C[4-6]_AUDIO)
#define B6_AUDIO- enables audio on pin B6 (duophony is enables if one of B[5-7]_AUDIO is enabled along with one of C[4-6]_AUDIO)
#define B7_AUDIO- enables audio on pin B7 (duophony is enables if one of B[5-7]_AUDIO is enabled along with one of C[4-6]_AUDIO)
#define BACKLIGHT_PIN B7- pin of the backlight
#define BACKLIGHT_LEVELS 3- number of levels your backlight will have (maximum 31 excluding off)
#define BACKLIGHT_BREATHING- enables backlight breathing
#define BREATHING_PERIOD 6- the length of one backlight "breath" in seconds
#define DEBOUNCE 5- the delay when reading the value of the pin (5 is default)
#define LOCKING_SUPPORT_ENABLE- mechanical locking support. Use KC_LCAP, KC_LNUM or KC_LSCR instead in keymap
#define LOCKING_RESYNC_ENABLE- tries to keep switch state consistent with keyboard LED state
#define IS_COMMAND() (get_mods() == MOD_MASK_SHIFT)- key combination that allows the use of magic commands (useful for debugging)
#define USB_MAX_POWER_CONSUMPTION 500- sets the maximum power (in mA) over USB for the device (default: 500)
#define USB_POLLING_INTERVAL_MS 10- sets the USB polling rate in milliseconds for the keyboard, mouse, and shared (NKRO/media keys) interfaces
#define F_SCL 100000L- sets the I2C clock rate speed for keyboards using I2C. The default is
400000L, except for keyboards usingsplit_common, where the default is100000L.
- sets the I2C clock rate speed for keyboards using I2C. The default is
If you define these options you will disable the associated feature, which can save on code size.
#define NO_DEBUG- disable debugging
#define NO_PRINT- disable printing/debugging using hid_listen
#define NO_ACTION_LAYER- disable layers
#define NO_ACTION_TAPPING- disable tap dance and other tapping features
#define NO_ACTION_ONESHOT- disable one-shot modifiers
#define NO_ACTION_MACRO- disable old-style macro handling using
MACRO(),action_get_macro()(deprecated)
- disable old-style macro handling using
#define NO_ACTION_FUNCTION- disable old-style function handling using
fn_actions,action_function()(deprecated)
- disable old-style function handling using
If you define these options you will enable the associated feature, which may increase your code size.
#define FORCE_NKRO- NKRO by default requires to be turned on, this forces it on during keyboard startup regardless of EEPROM setting. NKRO can still be turned off but will be turned on again if the keyboard reboots.
#define STRICT_LAYER_RELEASE- force a key release to be evaluated using the current layer stack instead of remembering which layer it came from (used for advanced cases)
#define TAPPING_TERM 200- how long before a tap becomes a hold, if set above 500, a key tapped during the tapping term will turn it into a hold too
#define TAPPING_TERM_PER_KEY- enables handling for per key
TAPPING_TERMsettings
- enables handling for per key
#define RETRO_TAPPING- tap anyway, even after TAPPING_TERM, if there was no other key interruption between press and release
- See Retro Tapping for details
#define TAPPING_TOGGLE 2- how many taps before triggering the toggle
#define PERMISSIVE_HOLD- makes tap and hold keys trigger the hold if another key is pressed before releasing, even if it hasn't hit the
TAPPING_TERM - See Permissive Hold for details
- makes tap and hold keys trigger the hold if another key is pressed before releasing, even if it hasn't hit the
#define PERMISSIVE_HOLD_PER_KEY- enabled handling for per key
PERMISSIVE_HOLDsettings
- enabled handling for per key
#define IGNORE_MOD_TAP_INTERRUPT- makes it possible to do rolling combos (zx) with keys that convert to other keys on hold, by enforcing the
TAPPING_TERMfor both keys. - See Ignore Mod Tap Interrupt for details
- makes it possible to do rolling combos (zx) with keys that convert to other keys on hold, by enforcing the
#define IGNORE_MOD_TAP_INTERRUPT_PER_KEY- enables handling for per key
IGNORE_MOD_TAP_INTERRUPTsettings
- enables handling for per key
#define TAPPING_FORCE_HOLD- makes it possible to use a dual role key as modifier shortly after having been tapped
- See Tapping Force Hold
- Breaks any Tap Toggle functionality (
TTor the One Shot Tap Toggle)
#define TAPPING_FORCE_HOLD_PER_KEY- enables handling for per key
TAPPING_FORCE_HOLDsettings
- enables handling for per key
#define LEADER_TIMEOUT 300- how long before the leader key times out
- If you're having issues finishing the sequence before it times out, you may need to increase the timeout setting. Or you may want to enable the
LEADER_PER_KEY_TIMINGoption, which resets the timeout after each key is tapped.
- If you're having issues finishing the sequence before it times out, you may need to increase the timeout setting. Or you may want to enable the
- how long before the leader key times out
#define LEADER_PER_KEY_TIMING- sets the timer for leader key chords to run on each key press rather than overall
#define LEADER_KEY_STRICT_KEY_PROCESSING- Disables keycode filtering for Mod-Tap and Layer-Tap keycodes. Eg, if you enable this, you would need to specify
MT(MOD_CTL, KC_A)if you want to useKC_A.
- Disables keycode filtering for Mod-Tap and Layer-Tap keycodes. Eg, if you enable this, you would need to specify
#define ONESHOT_TIMEOUT 300- how long before oneshot times out
#define ONESHOT_TAP_TOGGLE 2- how many taps before oneshot toggle is triggered
#define QMK_KEYS_PER_SCAN 4- Allows sending more than one key per scan. By default, only one key event gets
sent via
process_record()per scan. This has little impact on most typing, but if you're doing a lot of chords, or your scan rate is slow to begin with, you can have some delay in processing key events. Each press and release is a separate event. For a keyboard with 1ms or so scan times, even a very fast typist isn't going to produce the 500 keystrokes a second needed to actually get more than a few ms of delay from this. But if you're doing chording on something with 3-4ms scan times? You probably want this.
- Allows sending more than one key per scan. By default, only one key event gets
sent via
#define COMBO_COUNT 2- Set this to the number of combos that you're using in the Combo feature.
#define COMBO_TERM 200- how long for the Combo keys to be detected. Defaults to
TAPPING_TERMif not defined.
- how long for the Combo keys to be detected. Defaults to
#define TAP_CODE_DELAY 100- Sets the delay between
register_codeandunregister_code, if you're having issues with it registering properly (common on VUSB boards). The value is in milliseconds.
- Sets the delay between
#define TAP_HOLD_CAPS_DELAY 80- Sets the delay for Tap Hold keys (
LT,MT) when usingKC_CAPSLOCKkeycode, as this has some special handling on MacOS. The value is in milliseconds, and defaults to 80 ms if not defined. For macOS, you may want to set this to 200 or higher.
- Sets the delay for Tap Hold keys (
#define RGB_DI_PIN D7- pin the DI on the WS2812 is hooked-up to
#define RGBLIGHT_ANIMATIONS- run RGB animations
#define RGBLIGHT_LAYERS- Lets you define lighting layers that can be toggled on or off. Great for showing the current keyboard layer or caps lock state.
#define RGBLED_NUM 12- number of LEDs
#define RGBLIGHT_SPLIT- Needed if both halves of the board have RGB LEDs wired directly to the RGB output pin on the controllers instead of passing the output of the left half to the input of the right half
#define RGBLED_SPLIT { 6, 6 }- number of LEDs connected that are directly wired to
RGB_DI_PINon each half of a split keyboard - First value indicates number of LEDs for left half, second value is for the right half
- When RGBLED_SPLIT is defined, RGBLIGHT_SPLIT is implicitly defined.
- number of LEDs connected that are directly wired to
#define RGBLIGHT_HUE_STEP 12- units to step when in/decreasing hue
#define RGBLIGHT_SAT_STEP 25- units to step when in/decreasing saturation
#define RGBLIGHT_VAL_STEP 12- units to step when in/decreasing value (brightness)
#define RGBW- Enables RGBW LED support
#define MOUSEKEY_INTERVAL 20#define MOUSEKEY_DELAY 0#define MOUSEKEY_TIME_TO_MAX 60#define MOUSEKEY_MAX_SPEED 7#define MOUSEKEY_WHEEL_DELAY 0
Split Keyboard specific options, make sure you have 'SPLIT_KEYBOARD = yes' in your rules.mk
SPLIT_TRANSPORT = custom- Allows replacing the standard split communication routines with a custom one. ARM based split keyboards must use this at present.
One thing to remember, the side that the USB port is plugged into is always the master half. The side not plugged into USB is the slave.
There are a few different ways to set handedness for split keyboards (listed in order of precedence):
- Set
SPLIT_HAND_PIN: Reads a pin to determine handedness. If pin is high, it's the left side, if low, the half is determined to be the right side - Set
EE_HANDSand flasheeprom-lefthand.eep/eeprom-righthand.eepto each half- For boards with DFU bootloader you can use
:dfu-split-left/:dfu-split-rightto flash these EEPROM files - For boards with Caterina bootloader (like stock Pro Micros), use
:avrdude-split-left/:avrdude-split-right - For boards with ARM DFU bootloader (like Proton C), use
:dfu-util-split-left/:dfu-util-split-right
- For boards with DFU bootloader you can use
- Set
MASTER_RIGHT: Half that is plugged into the USB port is determined to be the master and right half (inverse of the default) - Default: The side that is plugged into the USB port is the master half and is assumed to be the left half. The slave side is the right half
-
#define SPLIT_HAND_PIN B7- For using high/low pin to determine handedness, low = right hand, high = left hand. Replace
B7with the pin you are using. This is optional, and if you leaveSPLIT_HAND_PINundefined, then you can still use the EE_HANDS method or MASTER_LEFT / MASTER_RIGHT defines like the stock Let's Split uses.
- For using high/low pin to determine handedness, low = right hand, high = left hand. Replace
-
#define EE_HANDS(only works ifSPLIT_HAND_PINis not defined)- Reads the handedness value stored in the EEPROM after
eeprom-lefthand.eep/eeprom-righthand.eephas been flashed to their respective halves.
- Reads the handedness value stored in the EEPROM after
-
#define MASTER_RIGHT- Master half is defined to be the right half.
-
#define USE_I2C- For using I2C instead of Serial (defaults to serial)
-
#define SOFT_SERIAL_PIN D0- When using serial, define this.
D0orD1,D2,D3,E6.
- When using serial, define this.
-
#define MATRIX_ROW_PINS_RIGHT { <row pins> } -
#define MATRIX_COL_PINS_RIGHT { <col pins> }- If you want to specify a different pinout for the right half than the left half, you can define
MATRIX_ROW_PINS_RIGHT/MATRIX_COL_PINS_RIGHT. Currently, the size ofMATRIX_ROW_PINSmust be the same asMATRIX_ROW_PINS_RIGHTand likewise for the definition of columns.
- If you want to specify a different pinout for the right half than the left half, you can define
-
#define DIRECT_PINS_RIGHT { { F1, F0, B0, C7 }, { F4, F5, F6, F7 } }- If you want to specify a different direct pinout for the right half than the left half, you can define
DIRECT_PINS_RIGHT. Currently, the size ofDIRECT_PINSmust be the same asDIRECT_PINS_RIGHT.
- If you want to specify a different direct pinout for the right half than the left half, you can define
-
#define RGBLED_SPLIT { 6, 6 } -
#define SELECT_SOFT_SERIAL_SPEED <speed>(default speed is 1)- Sets the protocol speed when using serial communication
- Speeds:
- 0: about 189kbps (Experimental only)
- 1: about 137kbps (default)
- 2: about 75kbps
- 3: about 39kbps
- 4: about 26kbps
- 5: about 20kbps
-
#define SPLIT_USB_DETECT- Detect (with timeout) USB connection when delegating master/slave
- Default behavior for ARM
- Required for AVR Teensy
-
#define SPLIT_USB_TIMEOUT 2000- Maximum timeout when detecting master/slave when using
SPLIT_USB_DETECT
- Maximum timeout when detecting master/slave when using
-
#define SPLIT_USB_TIMEOUT_POLL 10- Poll frequency when detecting master/slave when using
SPLIT_USB_DETECT
- Poll frequency when detecting master/slave when using
This is a make file that is included by the top-level Makefile. It is used to set some information about the MCU that we will be compiling for as well as enabling and disabling certain features.
DEFAULT_FOLDER- Used to specify a default folder when a keyboard has more than one sub-folder.
FIRMWARE_FORMAT- Defines which format (bin, hex) is copied to the root
qmk_firmwarefolder after building.
- Defines which format (bin, hex) is copied to the root
SRC- Used to add files to the compilation/linking list.
LIB_SRC- Used to add files as a library to the compilation/linking list.
The files specified byLIB_SRCis linked after the files specified bySRC.
For example, if you specify:The link order is as follows.SRC += a.c LIB_SRC += lib_b.c SRC += c.c LIB_SRC += lib_d.c... a.o c.o ... lib_b.a lib_d.a ...
- Used to add files as a library to the compilation/linking list.
LAYOUTS- A list of layouts this keyboard supports.
LINK_TIME_OPTIMIZATION_ENABLE- Enables Link Time Optimization (LTO) when compiling the keyboard. This makes the process take longer, but it can significantly reduce the compiled size (and since the firmware is small, the added time is not noticeable).
However, this will automatically disable the legacy TMK Macros and Functions features, as these break when LTO is enabled. It does this by automatically defining
NO_ACTION_MACROandNO_ACTION_FUNCTION. (Note: This does not affect QMK Macros and Layers.)
- Enables Link Time Optimization (LTO) when compiling the keyboard. This makes the process take longer, but it can significantly reduce the compiled size (and since the firmware is small, the added time is not noticeable).
However, this will automatically disable the legacy TMK Macros and Functions features, as these break when LTO is enabled. It does this by automatically defining
LTO_ENABLE- Has the same meaning as
LINK_TIME_OPTIMIZATION_ENABLE. You can useLTO_ENABLEinstead ofLINK_TIME_OPTIMIZATION_ENABLE.
- Has the same meaning as
MCU = atmega32u4F_CPU = 16000000ARCH = AVR8F_USB = $(F_CPU)OPT_DEFS += -DINTERRUPT_CONTROL_ENDPOINTBOOTLOADER = atmel-dfuwith the following options:atmel-dfulufa-dfuqmk-dfuhalfkaycaterinabootloadHIDUSBasp
Use these to enable or disable building certain features. The more you have enabled the bigger your firmware will be, and you run the risk of building a firmware too large for your MCU.
BOOTMAGIC_ENABLE- Virtual DIP switch configuration
MOUSEKEY_ENABLE- Mouse keys
EXTRAKEY_ENABLE- Audio control and System control
CONSOLE_ENABLE- Console for debug
COMMAND_ENABLE- Commands for debug and configuration
COMBO_ENABLE- Key combo feature
NKRO_ENABLE- USB N-Key Rollover - if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
AUDIO_ENABLE- Enable the audio subsystem.
RGBLIGHT_ENABLE- Enable keyboard underlight functionality
LEADER_ENABLE- Enable leader key chording
MIDI_ENABLE- MIDI controls
UNICODE_ENABLE- Unicode
BLUETOOTH_ENABLE- Legacy option to Enable Bluetooth with the Adafruit EZ-Key HID. See BLUETOOTH
BLUETOOTH- Current options are AdafruitEzKey, AdafruitBLE, RN42
SPLIT_KEYBOARD- Enables split keyboard support (dual MCU like the let's split and bakingpy's boards) and includes all necessary files located at quantum/split_common
CUSTOM_MATRIX- Allows replacing the standard matrix scanning routine with a custom one.
DEBOUNCE_TYPE- Allows replacing the standard key debouncing routine with an alternative or custom one.
WAIT_FOR_USB- Forces the keyboard to wait for a USB connection to be established before it starts up
NO_USB_STARTUP_CHECK- Disables usb suspend check after keyboard startup. Usually the keyboard waits for the host to wake it up before any tasks are performed. This is useful for split keyboards as one half will not get a wakeup call but must send commands to the master.
In order to provide services over USB, QMK has to use USB endpoints. These are a finite resource: each microcontroller has only a certain number. This limits what features can be enabled together. If the available endpoints are exceeded, a build error is thrown.
The following features can require separate endpoints:
MOUSEKEY_ENABLEEXTRAKEY_ENABLECONSOLE_ENABLENKRO_ENABLEMIDI_ENABLERAW_ENABLEVIRTSER_ENABLE
In order to improve utilisation of the endpoints, the HID features can be combined to use a single endpoint.
By default, MOUSEKEY, EXTRAKEY, and NKRO are combined into a single endpoint.
The base keyboard functionality can also be combined into the endpoint,
by setting KEYBOARD_SHARED_EP = yes.
This frees up one more endpoint,
but it can prevent the keyboard working in some BIOSes,
as they do not implement Boot Keyboard protocol switching.
Combining the mouse also breaks Boot Mouse compatibility.
The mouse can be uncombined by setting MOUSE_SHARED_EP = no if this functionality is required.