keychron_qmk_firmware/README.md

# Quantum MK Firmware

This is a keyboard firmware based on the [tmk_keyboard firmware](http://github.com/tmk/tmk_keyboard) with some useful features for Atmel AVR controllers, and more specifically, the [OLKB product line](http://olkb.co) and the [ErgoDox EZ](http://www.ergodox-ez.com) keyboard.

QMK is developed and maintained by Jack Humbert of OLKB with contributions from the community, and of course, TMK.

This documentation is edited and maintained by Erez Zukerman of ErgoDox EZ. If you spot any typos or inaccuracies, please [open an issue](https://github.com/jackhumbert/qmk_firmware/issues/new).

## Important background info: TMK documentation

The documentation below explains QMK customizations and elaborates on some of the more useful features of TMK. To understand the base firmware, and especially what *layers* are and how they work, please see [TMK_README.md](/TMK_README.md).

## Getting started

* **If you're looking to customize a keyboard that currently runs QMK or TMK** , find your keyboard's directory under `/keyboard/` and read the README file. This will get you all set up.
* If you're looking to apply this firmware to an entirely new hardware project (a new kind of keyboard), you can create your own Quantum-based project by using `./new_project.sh <project_name>`, which will create `/keyboard/<project_name>` with all the necessary components for a Quantum project.

You have access to a bunch of goodies! Check out the Makefile to enable/disable some of the features. Uncomment the `#` to enable them. Setting them to `no` does nothing and will only confuse future you.

    BACKLIGHT_ENABLE = yes # Enable keyboard backlight functionality
    MIDI_ENABLE = yes      # MIDI controls
    # UNICODE_ENABLE = yes # Unicode support - this is commented out, just as an example. You have to use #, not //
    BLUETOOTH_ENABLE = yes # Enable Bluetooth with the Adafruit EZ-Key HID

## Quick aliases to common actions

Your keymap can include shortcuts to common operations (called "function actions" in tmk).

### Switching and toggling layers

`MO(layer)` - momentary switch to *layer*. As soon as you let go of the key, the layer is deactivated and you pop back out to the previous layer. When you apply this to a key, that same key must be set as `KC_TRNS` on the destination layer. Otherwise, you won't make it back to the original layer when you release the key (and you'll get a keycode sent). You can only switch to layers *above* your current layer. If you're on layer 0 and you use `MO(1)`, that will switch to layer 1 just fine. But if you include `MO(3)` on layer 5, that won't do anything for you -- because layer 3 is lower than layer 5 on the stack.

`LT(layer, kc)` - momentary switch to *layer* when held, and *kc* when tapped. Like `MO()`, this only works upwards in the layer stack (`layer` must be higher than the current layer).

`TG(layer)` - toggles a layer on or off. As with `MO()`, you should set this key as `KC_TRNS` in the destination layer so that tapping it again actually toggles back to the original layer. Only works upwards in the layer stack.

### Fun with modifier keys

* `LSFT(kc)` - applies left Shift to *kc* (keycode) - `S(kc)` is an alias
* `RSFT(kc)` - applies right Shift to *kc*
* `LCTL(kc)` - applies left Control to *kc*
* `RCTL(kc)` - applies right Control to *kc*
* `LALT(kc)` - applies left Alt to *kc*
* `RALT(kc)` - applies right Alt to *kc*
* `LGUI(kc)` - applies left GUI (command/win) to *kc*
* `RGUI(kc)` - applies right GUI (command/win) to *kc*
* `HYPR(kc)` - applies Hyper (all modifiers) to *kc*
* `MEH(kc)`  - applies Meh (all modifiers except Win/Cmd) to *kc*

You can also chain these, like this:

    LALT(LCTL(KC_DEL)) -- this makes a key that sends Alt, Control, and Delete in a single keypress.

The following shortcuts automatically add `LSFT()` to keycodes to get commonly used symbols. Their long names are also available and documented in `/quantum/keymap_common.h`.

    KC_TILD  ~
    KC_EXLM  !
    KC_AT    @
    KC_HASH  #
    KC_DLR   $
    KC_PERC  %
    KC_CIRC  ^
    KC_AMPR  &
    KC_ASTR  *
    KC_LPRN  (
    KC_RPRN  )
    KC_UNDS  _
    KC_PLUS  +
    KC_LCBR  {
    KC_RCBR  }
    KC_PIPE  |
    KC_COLN  :

`MT(mod, kc)` - is *mod* (modifier key - MOD_LCTL, MOD_LSFT) when held, and *kc* when tapped. In other words, you can have a key that sends Esc (or the letter O or whatever) when you tap it, but works as a Control key or a Shift key when you hold it down. 

These are the values you can use for the `mod` in `MT()` (right-hand modifiers are not available):

  * MOD_LCTL
  * MOD_LSFT
  * MOD_LALT
  * MOD_LGUI

These can also be combined like `MOD_LCTL | MOD_LSFT` e.g. `MT(MOD_LCTL | MOD_LSFT, KC_ESC)` which would activate Control and Shift when held, and send Escape when tapped.

We've added shortcuts to make common modifier/tap (mod-tap) mappings more compact:

  * `CTL_T(kc)` - is LCTL when held and *kc* when tapped 
  * `SFT_T(kc)` - is LSFT when held and *kc* when tapped 
  * `ALT_T(kc)` - is LALT when held and *kc* when tapped 
  * `GUI_T(kc)` - is LGUI when held and *kc* when tapped 
  * `ALL_T(kc)` - is Hyper (all mods) when held and *kc* when tapped. To read more about what you can do with a Hyper key, see [this blog post by Brett Terpstra](http://brettterpstra.com/2012/12/08/a-useful-caps-lock-key/)
  * `MEH_T(kc)` - is like Hyper, but not as cool -- does not include the Cmd/Win key, so just sends Alt+Ctrl+Shift.

### Temporarily setting the default layer 

`DF(layer)` - sets default layer to *layer*. The default layer is the one at the "bottom" of the layer stack - the ultimate fallback layer. This currently does not persist over power loss. When you plug the keyboard back in, layer 0 will always be the default. It is theoretically possible to work around that, but that's not what `DF` does.

### Remember: These are just aliases

These functions work the same way that their `ACTION_*` functions do - they're just quick aliases. To dig into all of the tmk ACTION_* functions, please see the [TMK documentation](https://github.com/jackhumbert/qmk_firmware/blob/master/tmk_core/doc/keymap.md#2-action).

Instead of using `FNx` when defining `ACTION_*` functions, you can use `F(x)` - the benefit here is being able to use more than 32 function actions (up to 4096), if you happen to need them.

## Macro shortcuts: Send a whole string when pressing just one key

Instead of using the `ACTION_MACRO` function, you can simply use `M(n)` to access macro *n* - *n* will get passed into the `action_get_macro` as the `id`, and you can use a switch statement to trigger it. This gets called on the keydown and keyup, so you'll need to use an if statement testing `record->event.pressed` (see keymap_default.c).

```c
const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt) // this is the function signature -- just copy/paste it into your keymap file as it is.
{
  switch(id) {
    case 0: // this would trigger when you hit a key mapped as M(0)
      if (record->event.pressed) {
        return MACRO( I(255), T(H), T(E), T(L), T(L), W(255), T(O), END  ); // this sends the string 'hello' when the macro executes
      } 
      break;
  }
  return MACRO_NONE;
};
```
A macro can include the following commands:

* I() change interval of stroke in milliseconds.
* D() press key.
* U() release key.
* T() type key(press and release).
* W() wait (milliseconds).
* END end mark.

So above you can see the stroke interval changed to 255ms between each keystroke, then a bunch of keys being typed, waits a while, then the macro ends.

Note: Using macros to have your keyboard send passwords for you is a bad idea.

### Additional keycode aliases for software-implemented layouts (Colemak, Dvorak, etc)

Everything is assuming you're in Qwerty (in software) by default, but there is built-in support for using a Colemak or Dvorak layout by including this at the top of your keymap:

   #include "keymap_<layout>.h"

Where <layout> is "colemak" or "dvorak". After including this line, you will get access to:
 
 * `CM_*` for all of the Colemak-equivalent characters
 * `DV_*` for all of the Dvorak-equivalent characters
 
These implementations assume you're using Colemak or Dvorak on your OS, not on your keyboard - this is referred to as a software-implemented layout. If your computer is in Qwerty and your keymap is in Colemak or Dvorak, this is referred to as a firmware-implemented layout, and you won't need these features. 

To give an example, if you're using software-implemented Colemak, and want to get an `F`, you would use `CM_F` - `KC_F` under these same circumstances would result in `T`.

## Additional language support

In `quantum/keymap_extras/`, you'll see various language files - these work the same way as the alternative layout ones do. Most are defined by their two letter country/language code followed by an underscore and a 4-letter abbreviation of its name. `FR_UGRV` which will result in a `ù` when using a software-implemented AZERTY layout. It's currently difficult to send such characters in just the firmware (but it's being worked on - see Unicode support).

## Unicode support

You can currently send 4 hex digits with your OS-specific modifier key (RALT for OSX with the "Unicode Hex Input" layout) - this is currently limited to supporting one OS at a time, and requires a recompile for switching. 8 digit hex codes are being worked on. The keycode function is `UC(n)`, where *n* is a 4 digit hexidecimal. Enable from the Makefile.

## Other firmware shortcut keycodes

* `RESET` - puts the MCU in DFU mode for flashing new firmware (with `make dfu`)
* `DEBUG` - the firmware into debug mode - you'll need hid_listen to see things
* `BL_ON` - turns the backlight on
* `BL_OFF` - turns the backlight off
* `BL_<n>` - sets the backlight to level *n*
* `BL_INC` - increments the backlight level by one
* `BL_DEC` - decrements the backlight level by one
* `BL_TOGG` - toggles the backlight
* `BL_STEP` - steps through the backlight levels

Enable the backlight from the Makefile.

## MIDI functionalty

This is still a WIP, but check out `quantum/keymap_midi.c` to see what's happening. Enable from the Makefile.

## Bluetooth functionality

This requires [some hardware changes](https://www.reddit.com/r/MechanicalKeyboards/comments/3psx0q/the_planck_keyboard_with_bluetooth_guide_and/?ref=search_posts), but can be enabled via the Makefile. The firmware will still output characters via USB, so be aware of this when charging via a computer. It would make sense to have a switch on the Bluefruit to turn it off at will.