path: root/Home.md

# Getting started

Before you are able to compile, you'll need to install an environment for AVR development. You'll find the instructions for any OS below. If you find another/better way to set things up from scratch, please consider [making a pull request](https://github.com/qmk/qmk_firmware/pulls) with your changes!

## [Build Environment Setup](wiki/Build-Environment-Setup)

# Customizing your keymap

In every keymap folder, the following files are recommended:

* `config.h` - the options to configure your keymap
* `keymap.c` - all of your keymap code, required
* `Makefile` - the features of QMK that are enabled, required to run `make` in your keymap folder
* `readme.md` - a description of your keymap, how others might use it, and explanations of features

## The `make` command

The `make` command is how you compile the firmware into a .hex file, which can be loaded by a dfu programmer (like dfu-progammer via `make dfu`) or the [Teensy loader](https://www.pjrc.com/teensy/loader.html) (only used with Teensys).

**NOTE:** To abort a make command press `Ctrl-c`

The following instruction refers to these folders.

* The `root` (`/`) folder is the qmk_firmware folder, in which are `doc`, `keyboard`, `quantum`, etc.
* The `keyboard` folder is any keyboard project's folder, like `/keyboards/planck`.
* The `keymap` folder is any keymap's folder, like `/keyboards/planck/keymaps/default`.
* The `subproject` folder is the subproject folder of a keyboard, like `/keyboards/ergodox/ez`

### Simple instructions for building and uploading a keyboard

**Most keyboards have more specific instructions in the keyboard specific readme.md file, so please check that first**

If the `keymap` folder contains a file name `Makefile`

1. Change the directory to the `keymap` folder
2. Run `make <subproject>-<programmer>`

Otherwise, if there's no `Makefile` in the `keymap` folder

1. Enter the `keyboard` folder
2. Run `make <subproject>-<keymap>-<programmer>`

In the above commands, replace:

* `<keymap>` with the name of your keymap
* `<subproject>` with the name of the subproject (revision or sub-model of your keyboard). For example, for Ergodox it can be `ez` or `infinity`, and for Planck `rev3` or `rev4`.
  * If the keyboard doesn't have a subproject, or if you are happy with the default (defined in `rules.mk` file of the `keyboard` folder), you can leave it out. But remember to also remove the dash (`-`) from the command.
* `<programmer>` The programmer to use. Most keyboards use `dfu`, but some use `teensy`. Infinity keyboards use `dfu-util`. Check the readme file in the keyboard folder to find out which programmer to use.
  * If you  don't add `-<programmer` to the command line, the firmware will be still be compiled into a hex file, but the upload will be skipped.

**NOTE:** Some operating systems will refuse to program unless you run the make command as root for example `sudo make dfu`

### More detailed make instruction

The full syntax of the `make` command is the following, but parts of the command can be left out if you run it from other directories than the `root` (as you might already have noticed by reading the simple instructions).

`<keyboard>-<subproject>-<keymap>-<target>`, where:

* `<keyboard>` is the name of the keyboard, for example `planck`
  * Use `allkb` to compile all keyboards
* `<subproject>` is the name of the subproject (revision or sub-model of the keyboard). For example, for Ergodox it can be `ez` or `infinity`, and for Planck `rev3` or `rev4`.
  * If the keyboard doesn't have any subprojects, it can be left out
  * To compile the default subproject, you can leave it out, or specify `defaultsp`
  * Use `allsp` to compile all subprojects
* `<keymap>` is the name of the keymap, for example `algernon`
  * Use `allkm` to compile all keymaps
* `<target>` will be explained in more detail below.

**Note:** When you leave some parts of the command out, you should also remove the dash (`-`).

As mentioned above, there are some shortcuts, when you are in a:

* `keyboard` folder, the command will automatically fill the `<keyboard>` part. So you only need to type `<subproject>-<keymap>-<target>`
* `subproject` folder, it will fill in both `<keyboard>` and `<subproject>`
* `keymap` folder, then `<keyboard>` and `<keymap>` will be filled in. If you need to specify the `<subproject>` use the following syntax `<subproject>-<target>`
  * Note in order to support this shortcut, the keymap needs its own Makefile (see the example [here](/doc/keymap_makefile_example.mk))
* `keymap` folder of a `subproject`, then everything except the `<target>` will be filled in

The `<target>` means the following
* If no target is given, then it's the same as `all` below
* `all` compiles the keyboard and generates a `<keyboard>_<keymap>.hex` file in whichever folder you run `make` from. These files are ignored by git, so don't worry about deleting them when committing/creating pull requests.
* `dfu`, `teensy` or `dfu-util`, compile and upload the firmware to the keyboard. If the compilation fails, then nothing will be uploaded. The programmer to use depends on the keyboard. For most keyboards it's `dfu`, but for Infinity keyboards you should use `dfu-util`, and `teensy` for standard Teensys. To find out which command you should use for your keyboard, check the keyboard specific readme. **Note** that some operating systems needs root access for these commands to work, so in that case you need to run for example `sudo make dfu`.
* `clean`, cleans the build output folders to make sure that everything is built from scratch. Run this before normal compilation if you have some unexplainable problems.

Some other targets are supported but, but not important enough to be documented here. Check the source code of the make files for more information.

You can also add extra options at the end of the make command line, after the target

* `make COLOR=false` - turns off color output
* `make SILENT=true` - turns off output besides errors/warnings
* `make VERBOSE=true` - outputs all of the gcc stuff (not interesting, unless you need to debug)
* `make EXTRAFLAGS=-E` - Preprocess the code without doing any compiling (useful if you are trying to debug #define commands)

The make command itself also has some additional options, type `make --help` for more information. The most useful is probably `-jx`, which specifies that you want to compile using more than one CPU, the `x` represents the number of CPUs that you want to use. Setting that can greatly reduce the compile times, especially if you are compiling many keyboards/keymaps. I usually set it to one less than the number of CPUs that I have, so that I have some left for doing other things while it's compiling. Note that not all operating systems and make versions supports that option.

Here are some examples commands

* `make allkb-allsp-allkm` builds everything (all keyboards, all subprojects, all keymaps). Running just `make` from the `root` will also run this.
* `make` from within a `keyboard` directory, is the same as `make keyboard-allsp-allkm`, which compiles all subprojects and keymaps of the keyboard. **NOTE** that this behaviour has changed. Previously it compiled just the default keymap.
* `make ergodox-infinity-algernon-clean` will clean the build output of the Ergodox Infinity keyboard. This example uses the full syntax and can be run from any folder with a `Makefile`
* `make dfu COLOR=false` from within a keymap folder, builds and uploads the keymap, but without color output.

## The `Makefile`

There are 5 different `make` and `Makefile` locations:

* root (`/`)
* keyboard (`/keyboards/<keyboard>/`)
* keymap (`/keyboards/<keyboard>/keymaps/<keymap>/`)
* subproject (`/keyboards/<keyboard>/<subproject>`)
* subproject keymap (`/keyboards/<keyboard>/<subproject>/keymaps/<keymap>`)

The root contains the code used to automatically figure out which keymap or keymaps to compile based on your current directory and commandline arguments. It's considered stable, and shouldn't be modified. The keyboard one will contain the MCU set-up and default settings for your keyboard, and shouldn't be modified unless you are the producer of that keyboard. The keymap Makefile can be modified by users, and is optional. It is included automatically if it exists. You can see an example [here](/doc/keymap_makefile_example.mk) - the last few lines are the most important. The settings you set here will override any defaults set in the keyboard Makefile. **The file is required if you want to run `make` in the keymap folder.**

For keyboards and subprojects, the make files are split in two parts `Makefile` and `rules.mk`. All settings can be found in the `rules.mk` file, while the `Makefile` is just there for support and including the root `Makefile`. Keymaps contain just one `Makefile` for simplicity.

### Makefile options

Set these variables to `no` to disable them, and `yes` to enable them.

`BOOTMAGIC_ENABLE`

This allows you to hold a key and the salt key (space by default) and have access to a various EEPROM settings that persist over power loss. It's advised you keep this disabled, as the settings are often changed by accident, and produce confusing results that makes it difficult to debug. It's one of the more common problems encountered in help sessions.

Consumes about 1000 bytes.

`MOUSEKEY_ENABLE`

This gives you control over cursor movements and clicks via keycodes/custom functions.

`EXTRAKEY_ENABLE`

This allows you to use the system and audio control key codes.

`CONSOLE_ENABLE`

This allows you to print messages that can be read using [`hid_listen`](https://www.pjrc.com/teensy/hid_listen.html). 

By default, all debug (*dprint*) print (*print*, *xprintf*), and user print (*uprint*) messages will be enabled. This will eat up a significant portion of the flash and may make the keyboard .hex file too big to program. 

To disable debug messages (*dprint*) and reduce the .hex file size, include `#define NO_DEBUG` in your `config.h` file.

To disable print messages (*print*, *xprintf*) and user print messages (*uprint*) and reduce the .hex file size, include `#define NO_PRINT` in your `config.h` file.

To disable print messages (*print*, *xprintf*) and **KEEP** user print messages (*uprint*), include `#define USER_PRINT` in your `config.h` file.

To see the text, open `hid_listen` and enjoy looking at your printed messages.

**NOTE:** Do not include *uprint* messages in anything other than your keymap code. It must not be used within the QMK system framework. Otherwise, you will bloat other people's .hex files. 

Consumes about 400 bytes.

`COMMAND_ENABLE`

This enables magic commands, typically fired with the default magic key combo `LSHIFT+RSHIFT+KEY`. Magic commands include turning on debugging messages (`MAGIC+D`) or temporarily toggling NKRO (`MAGIC+N`).

`SLEEP_LED_ENABLE`

Enables your LED to breath while your computer is sleeping. Timer1 is being used here. This feature is largely unused and untested, and needs updating/abstracting.

`NKRO_ENABLE`

This allows the keyboard to tell the host OS that up to 248 keys are held down at once (default without NKRO is 6). NKRO is off by default, even if `NKRO_ENABLE` is set. NKRO can be forced by adding `#define FORCE_NKRO` to your config.h or by binding `MAGIC_TOGGLE_NKRO` to a key and then hitting the key.

`BACKLIGHT_ENABLE`

This enables your backlight on Timer1 and ports B5, B6, or B7 (for now). You can specify your port by putting this in your `config.h`:

    #define BACKLIGHT_PIN B7

`MIDI_ENABLE`

This enables MIDI sending and receiving with your keyboard. To enter MIDI send mode, you can use the keycode `MI_ON`, and `MI_OFF` to turn it off. This is a largely untested feature, but more information can be found in the `quantum/quantum.c` file.

`UNICODE_ENABLE`

This allows you to send unicode symbols via `UC(<unicode>)` in your keymap. Only codes up to 0x7FFF are currently supported.

`UNICODEMAP_ENABLE`

This allows sending unicode symbols using `X(<unicode>)` in your keymap. Codes
up to 0xFFFFFFFF are supported, including emojis. You will need to maintain
a separate mapping table in your keymap file.

Known limitations:
- Under Mac OS, only codes up to 0xFFFF are supported.
- Under Linux ibus, only codes up to 0xFFFFF are supported (but anything important is still under this limit for now).

Characters out of range supported by the OS will be ignored.

`BLUETOOTH_ENABLE`

This allows you to interface with a Bluefruit EZ-key to send keycodes wirelessly. It uses the D2 and D3 pins.

`AUDIO_ENABLE`

This allows you output audio on the C6 pin (needs abstracting). See the [audio section](#audio-output-from-a-speaker) for more information.

`FAUXCLICKY_ENABLE`

Uses buzzer to emulate clicky switches. A cheap imitation of the Cherry blue switches. By default, uses the C6 pin, same as AUDIO_ENABLE.

`VARIABLE_TRACE`

Use this to debug changes to variable values, see the [tracing variables](#tracing-variables) section for more information.

`API_SYSEX_ENABLE`

This enables using the Quantum SYSEX API to send strings (somewhere?)

This consumes about 5390 bytes.

### Customizing Makefile options on a per-keymap basis

If your keymap directory has a file called `Makefile` (note the filename), any Makefile options you set in that file will take precedence over other Makefile options for your particular keyboard.

So let's say your keyboard's makefile has `BACKLIGHT_ENABLE = yes` (or maybe doesn't even list the `BACKLIGHT_ENABLE` option, which would cause it to be off). You want your particular keymap to not have the debug console, so you make a file called `Makefile` and specify `BACKLIGHT_ENABLE = no`.

You can use the `doc/keymap_makefile_example.md` as a template/starting point.

## The `config.h` file

There are 2 `config.h` locations:

* keyboard (`/keyboards/<keyboard>/`)
* keymap (`/keyboards/<keyboard>/keymaps/<keymap>/`)

The keyboard `config.h` is included only if the keymap one doesn't exist. The format to use for your custom one [is here](/doc/keymap_config_h_example.h). If you want to override a setting from the parent `config.h` file, you need to do this:

```c
#undef MY_SETTING
#define MY_SETTING 4
```

For a value of `4` for this imaginary setting. So we `undef` it first, then `define` it.

You can then override any settings, rather than having to copy and paste the whole thing.

# Going beyond the keycodes

Aside from the [basic keycodes](https://github.com/qmk/qmk_firmware/wiki/Keycodes), your keymap can include shortcuts to common operations.

## Quick aliases to common actions

Your keymap can include shortcuts to common operations (called "function actions" in tmk). To learn more about them check out the [Key Functions](Key-Functions) page.

## Space Cadet Shift: The future, built in

Steve Losh [described](http://stevelosh.com/blog/2012/10/a-modern-space-cadet/) the Space Cadet Shift quite well. Essentially, you hit the left Shift on its own, and you get an opening parenthesis; hit the right Shift on its own, and you get the closing one. When hit with other keys, the Shift key keeps working as it always does. Yes, it's as cool as it sounds. Head on over to the [Space Cadet Shift](Space-Cadet-Shift) page to read about it.

## The Leader key: A new kind of modifier

Most modifiers have to be held or toggled. But what if you had a key that indicated the start of a sequence? You could press that key and then rapidly press 1-3 more keys to trigger a macro, or enter a special layer, or anything else you might want to do. To learn more about it check out the [Leader Key](Leader-Key) page.

## Tap Dance: A single key can do 3, 5, or 100 different things

Hit the semicolon key once, send a semicolon. Hit it twice, rapidly -- send a colon. Hit it three times, and your keyboard's LEDs do a wild dance. That's just one example of what Tap Dance can do. Read more about it on the [Tap Dance](Tap-Dance) page.

## 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.

## Prevent stuck modifiers

Consider the following scenario:

1. Layer 0 has a key defined as Shift.
2. The same key is defined on layer 1 as the letter A.
3. User presses Shift.
4. User switches to layer 1 for whatever reason.
5. User releases Shift, or rather the letter A.
6. User switches back to layer 0.

Shift was actually never released and is still considered pressed.

If such situation bothers you add this to your `config.h`:

    #define PREVENT_STUCK_MODIFIERS

This option uses 5 bytes of memory per every 8 keys on the keyboard
rounded up (5 bits per key). For example on Planck (48 keys) it uses
(48/8)\*5 = 30 bytes.

## 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 possible, but a bad idea.

### Advanced macro functions

To get more control over the keys/actions your keyboard takes, the following functions are available to you in the `action_get_macro` function block:

* `record->event.pressed`

This is a boolean value that can be tested to see if the switch is being pressed or released. An example of this is

```c
if (record->event.pressed) {
  // on keydown
} else {
  // on keyup
}
```

* `register_code(<kc>);`

This sends the `<kc>` keydown event to the computer. Some examples would be `KC_ESC`, `KC_C`, `KC_4`, and even modifiers such as `KC_LSFT` and `KC_LGUI`.

* `unregister_code(<kc>);`

Parallel to `register_code` function, this sends the `<kc>` keyup event to the computer. If you don't use this, the key will be held down until it's sent.

* `layer_on(<n>);`

This will turn on the layer `<n>` - the higher layer number will always take priority. Make sure you have `KC_TRNS` for the key you're pressing on the layer you're switching to, or you'll get stick there unless you have another plan.

* `layer_off(<n>);`

This will turn off the layer `<n>`.

* `clear_keyboard();`

This will clear all mods and keys currently pressed.

* `clear_mods();`

This will clear all mods currently pressed.

* `clear_keyboard_but_mods();`

This will clear all keys besides the mods currently pressed.

* `update_tri_layer(layer_1, layer_2, layer_3);`

If the user attempts to activate layer 1 AND layer 2 at the same time (for example, by hitting their respective layer keys), layer 3 will be activated. Layers 1 and 2 will _also_ be activated, for the purposes of fallbacks (so a given key will fall back from 3 to 2, to 1 -- and only then to 0).

#### Naming your macros

If you have a bunch of macros you want to refer to from your keymap, while keeping the keymap easily readable, you can just name them like so:

```
#define AUD_OFF M(6)
#define AUD_ON M(7)
#define MUS_OFF M(8)
#define MUS_ON M(9)
#define VC_IN M(10)
#define VC_DE M(11)
#define PLOVER M(12)
#define EXT_PLV M(13)
```

As was done on the [Planck default keymap](/keyboards/planck/keymaps/default/keymap.c#L33-L40)

#### Timer functionality

It's possible to start timers and read values for time-specific events - here's an example:

```c
static uint16_t key_timer;
key_timer = timer_read();
if (timer_elapsed(key_timer) < 100) {
  // do something if less than 100ms have passed
} else {
  // do something if 100ms or more have passed
}
```

It's best to declare the `static uint16_t key_timer;` outside of the macro block (top of file, etc).

#### Example: Single-key copy/paste (hold to copy, tap to paste)

With QMK, it's easy to make one key do two things, as long as one of those things is being a modifier. :) So if you want a key to act as Ctrl when held and send the letter R when tapped, that's easy: `CTL_T(KC_R)`. But what do you do when you want that key to send Ctrl-V (paste) when tapped, and Ctrl-C (copy) when held?

Here's what you do:


```
static uint16_t key_timer;

const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt)
{
      switch(id) {
        case 0: {
            if (record->event.pressed) {
                key_timer = timer_read(); // if the key is being pressed, we start the timer.
            }
            else { // this means the key was just released, so we can figure out how long it was pressed for (tap or "held down").
                if (timer_elapsed(key_timer) > 150) { // 150 being 150ms, the threshhold we pick for counting something as a tap.
                    return MACRO( D(LCTL), T(C), U(LCTL), END  );
                }
                else {
                    return MACRO( D(LCTL), T(V), U(LCTL), END  );
                }
            }
            break;