1 # Frequently Asked Keymap Questions
3 This page covers questions people often have about keymaps. If you haven't you should read [Keymap Overview](keymap.html) first.
5 ## What Keycodes Can I Use?
6 See [Basic Keycodes](keycodes.html) and [Quantum Keycodes](quantum_keycodes.html) for most of the keys you can define.
8 Keycodes are actually defined in [common/keycode.h](https://github.com/qmk/qmk_firmware/blob/master/tmk_core/common/keycode.h).
10 ## `KC_SYSREQ` isn't working
11 Use keycode for Print Screen(`KC_PSCREEN` or `KC_PSCR`) instead of `KC_SYSREQ`. Key combination of 'Alt + Print Screen' is recognized as 'System request'.
13 See [issue #168](https://github.com/tmk/tmk_keyboard/issues/168) and
14 - http://en.wikipedia.org/wiki/Magic_SysRq_key
15 - http://en.wikipedia.org/wiki/System_request
17 ## Power key doesn't work
18 Use `KC_PWR` instead of `KC_POWER` or vice versa.
19 - `KC_PWR` works with Windows and Linux, not with OSX.
20 - `KC_POWER` works with OSX and Linux, not with Windows.
22 More info: http://geekhack.org/index.php?topic=14290.msg1327264#msg1327264
25 Solves my personal 'the' problem. I often got 'the' or 'THe' wrongly instead of 'The'. Oneshot Shift mitgates this for me.
26 https://github.com/tmk/tmk_keyboard/issues/67
28 ## Modifier/Layer stuck
29 Modifier keys or layers can be stuck unless layer switching is configured properly.
30 For Modifier keys and layer actions you have to place `KC_TRANS` on same position of destination layer to unregister the modifier key or return to previous layer on release event.
32 - https://github.com/tmk/tmk_core/blob/master/doc/keymap.md#31-momentary-switching
33 - http://geekhack.org/index.php?topic=57008.msg1492604#msg1492604
34 - https://github.com/tmk/tmk_keyboard/issues/248
37 ## Mechanical Lock Switch Support
39 This feature is for *mechanical lock switch* like [this Alps one](http://deskthority.net/wiki/Alps_SKCL_Lock). You can enable it by adding this to your `config.h`:
42 #define LOCKING_SUPPORT_ENABLE
43 #define LOCKING_RESYNC_ENABLE
46 After enabling this feature use keycodes `KC_LCAP`, `KC_LNUM` and `KC_LSCR` in your keymap instead.
48 Old vintage mechanical keyboards occasionally have lock switches but modern ones don't have. ***You don't need this feature in most case and just use keycodes `KC_CAPS`, `KC_NLCK` and `KC_SLCK`.***
50 ## Input special charactors other than ASCII like Cédille 'Ç'
51 NO UNIVERSAL METHOD TO INPUT THOSE WORKS OVER ALL SYSTEMS. You have to define **MACRO** in way specific to your OS or layout.
53 See this post for example **MACRO** code.
55 http://deskthority.net/workshop-f7/tmk-keyboard-firmware-collection-t4478-120.html#p195620
57 On **Windows** you can use `AltGr` key or **Alt code**.
58 - http://en.wikipedia.org/wiki/AltGr_key
59 - http://en.wikipedia.org/wiki/Alt_code
61 On **Mac** OS defines `Option` key combinations.
62 - http://en.wikipedia.org/wiki/Option_key#Alternative_keyboard_input
64 On **Xorg** you can use `compose` key, instead.
65 - http://en.wikipedia.org/wiki/Compose_key
67 And see this for **Unicode** input.
68 - http://en.wikipedia.org/wiki/Unicode_input
71 ## Apple/Mac keyboard Fn
74 Apple/Mac keyboard sends keycode for Fn unlike most of other keyboards.
75 I think you can send Apple Fn key using Apple venter specific Page 0xff01 and usage 0x0003. But you have to change HID Report Descriptor for this, of course.
77 https://opensource.apple.com/source/IOHIDFamily/IOHIDFamily-606.1.7/IOHIDFamily/AppleHIDUsageTables.h
80 ## Media control keys in Mac OSX
81 #### KC_MNXT and KC_MPRV does not work on Mac
82 Use `KC_MFFD`(`KC_MEDIA_FAST_FORWARD`) and `KC_MRWD`(`KC_MEDIA_REWIND`) instead of `KC_MNXT` and `KC_MPRV`.
83 See https://github.com/tmk/tmk_keyboard/issues/195
86 ## Keys supported in Mac OSX?
87 You can know which keycodes are supported in OSX from this source code.
89 `usb_2_adb_keymap` array maps Keyboard/Keypad Page usages to ADB scancodes(OSX internal keycodes).
91 https://opensource.apple.com/source/IOHIDFamily/IOHIDFamily-606.1.7/IOHIDFamily/Cosmo_USB2ADB.c
93 And `IOHIDConsumer::dispatchConsumerEvent` handles Consumer page usages.
95 https://opensource.apple.com/source/IOHIDFamily/IOHIDFamily-606.1.7/IOHIDFamily/IOHIDConsumer.cpp
98 ## JIS keys in Mac OSX
99 Japanese JIS keyboard specific keys like `無変換(Muhenkan)`, `変換(Henkan)`, `ひらがな(hiragana)` are not recognized on OSX. You can use **Seil** to enable those keys, try following options.
101 * Enable NFER Key on PC keyboard
102 * Enable XFER Key on PC keyboard
103 * Enable KATAKANA Key on PC keyboard
105 https://pqrs.org/osx/karabiner/seil.html
108 ## RN-42 Bluetooth doesn't work with Karabiner
109 Karabiner - Keymapping tool on Mac OSX - ignores inputs from RN-42 module by default. You have to enable this option to make Karabiner working with your keyboard.
110 https://github.com/tekezo/Karabiner/issues/403#issuecomment-102559237
112 See these for the deail of this problem.
113 https://github.com/tmk/tmk_keyboard/issues/213
114 https://github.com/tekezo/Karabiner/issues/403
117 ## Esc and `~ on a key
119 Use `GRAVE_ESC` or `KC_GESC` in your keymap.
121 ## Arrow on Right Modifier keys with Dual-Role
122 This turns right modifer keys into arrow keys when the keys are tapped while still modifiers when the keys are hold. In TMK the dual-role function is dubbed **TAP**.
125 #include "keymap_common.h"
128 /* Arrow keys on right modifier keys with TMK dual role feature
130 * https://github.com/tmk/tmk_core/blob/master/doc/keymap.md#213-modifier-with-tap-keydual-role
131 * https://en.wikipedia.org/wiki/Modifier_key#Dual-role_keys
133 const uint8_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
136 ESC, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, MINS,EQL, NUHS,BSPC, \
137 TAB, Q, W, E, R, T, Y, U, I, O, P, LBRC,RBRC,BSLS, \
138 LCTL,A, S, D, F, G, H, J, K, L, SCLN,QUOT,ENT, \
139 LSFT,NUBS,Z, X, C, V, B, N, M, COMM,DOT, SLSH,FN0, ESC, \
140 FN4, LGUI,LALT, SPC, APP, FN2, FN1, FN3),
142 GRV, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, TRNS,TRNS, \
143 TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,\
144 TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS, \
145 TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,TRNS,FN5, TRNS, \
146 TRNS,TRNS,TRNS, TRNS, TRNS,FN7, FN6, FN8),
149 const uint16_t PROGMEM fn_actions[] = {
150 [0] = ACTION_MODS_TAP_KEY(MOD_RSFT, KC_UP),
151 [1] = ACTION_MODS_TAP_KEY(MOD_RGUI, KC_DOWN),
152 [2] = ACTION_MODS_TAP_KEY(MOD_RALT, KC_LEFT),
153 [3] = ACTION_MODS_TAP_KEY(MOD_RCTL, KC_RIGHT),
154 [4] = ACTION_LAYER_MOMENTARY(1),
155 [5] = ACTION_MODS_TAP_KEY(MOD_RSFT, KC_PGUP),
156 [6] = ACTION_MODS_TAP_KEY(MOD_RGUI, KC_PGDN),
157 [7] = ACTION_MODS_TAP_KEY(MOD_RALT, KC_HOME),
158 [8] = ACTION_MODS_TAP_KEY(MOD_RCTL, KC_END),
163 Dual-role key: https://en.wikipedia.org/wiki/Modifier_key#Dual-role_keys
167 `KC_EJCT` keycode works on OSX. https://github.com/tmk/tmk_keyboard/issues/250
168 It seems Windows 10 ignores the code and Linux/Xorg recognizes but has no mapping by default.
170 Not sure what keycode Eject is on genuine Apple keyboard actually. HHKB uses `F20` for Eject key(`Fn+f`) on Mac mode but this is not same as Apple Eject keycode probably.
173 ## What's weak_mods and real_mods in action_util.c
176 real_mods is intended to retains state of real/physical modifier key state, while
177 weak_mods retains state of virtual or temprary modifiers which should not affect state real modifier key.
179 Let's say you hold down physical left shift key and type ACTION_MODS_KEY(LSHIFT, KC_A),
182 * (1) hold down left shift: real_mods |= MOD_BIT(LSHIFT)
183 * (2) press ACTION_MODS_KEY(LSHIFT, KC_A): weak_mods |= MOD_BIT(LSHIFT)
184 * (3) release ACTION_MODS_KEY(LSHIFT, KC_A): waek_mods &= ~MOD_BIT(LSHIFT)
185 real_mods still keeps modifier state.
188 * (1) hold down left shift: real_mods |= MOD_BIT(LSHIFT)
189 * (2) press ACTION_MODS_KEY(LSHIFT, KC_A): real_mods |= MOD_BIT(LSHIFT)
190 * (3) release ACTION_MODS_KEY(LSHIFT, KC_A): real_mods &= ~MOD_BIT(LSHIFT)
191 here real_mods lost state for 'physical left shift'.
193 weak_mods is ORed with real_mods when keyboard report is sent.
194 https://github.com/tmk/tmk_core/blob/master/common/action_util.c#L57
196 ## Timer functionality
198 It's possible to start timers and read values for time-specific events - here's an example:
201 static uint16_t key_timer;
202 key_timer = timer_read();
204 if (timer_elapsed(key_timer) < 100) {
205 // do something if less than 100ms have passed
207 // do something if 100ms or more have passed
211 It's best to declare the `static uint16_t key_timer;` at the top of the file, outside of any code blocks you're using it in.