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-# How keys are registered, and interpreted by computers
-
-In this file, you can will learn the concepts of how keyboards work over USB,
-and you'll be able to better understand what you can expect from changing your
-firmware directly.
-
-## Schematic view
-
-Whenever you type on 1 particular key, here is the chain of actions taking
-place:
-
-``` text
-+------+ +-----+ +----------+ +----------+ +----+
-| User |-------->| Key |------>| Firmware |----->| USB wire |---->| OS |
-+------+ +-----+ +----------+ +----------+ |----+
-```
-
-This scheme is a very simple view of what's going on, and more details follow
-in the next sections.
-
-## 1. You Press a Key
-
-Whenever you press a key, the firmware of your keyboard can register this event.
-It can register when the key is pressed, held and released.
-
-This usually happens with a [periodic scan of key presses with a frequency around 100 hz](https://github.com/benblazak/ergodox-firmware/blob/master/references.md#typical-keyboard-information).
-This speed often is limited by the mechanical key response time, the protocol
-to transfer those key presses (here USB HID), and by the software it is used in.
-
-## 2. What the Firmware Sends
-
-The [HID specification](http://www.usb.org/developers/hidpage/Hut1_12v2.pdf)
-tells what a keyboard can actually send through USB to have a chance to be
-properly recognised. This includes a pre-defined list of keycodes which are
-simple numbers from `0x00` to `0xE7`. The firmware assigns a keycode to each
-key of the keyboard.
-
-The firmware does not send actually letters or characters, but only keycodes.
-Thus, by modifying the firmware, you only can modify what keycode is sent over
-USB for a given key.
-
-## 3. What the Operating System Does
-
-Once the keycode reaches the operating system, a piece of software has to have
-it match an actual character thanks to a keyboard layout. For example, if your
-layout is set to QWERTY, a sample of the matching table is as follow:
-
-``` text
-| keycode | character |
-|---------+-----------|
-| 0x04 | a/A |
-| 0x05 | b/B |
-| 0x06 | c/C |
-| ... | ... |
-| 0x1C | y/Y |
-| 0x1D | z/Z |
-| ... | ... |
-|---------+-----------|
-```
-
-## Back to the firmware
-
-As the layout is generally fixed (unless you create your own), the firmware can
-actually call a keycode by its layout name directly to ease things for you.
-
-This is exactly what is done here with `KC_A` actually representing `0x04` in
-QWERTY. The full list can be found in `keycode.txt`.
-
-## List of Characters You Can Send
-
-Putting aside shortcuts, having a limited set of keycodes mapped to a limited
-layout means that **the list of characters you can assign to a given key only
-is the ones present in the layout**.
-
-For example, this means that if you have a QWERTY US layout, and you want to
-assign 1 key to produce `€` (euro currency symbol), you are unable to do so,
-because the QWERTY US layout does not have such mapping. You could fix that by
-using a QWERTY UK layout, or a QWERTY US International.
-
-You may wonder why a keyboard layout containing all of Unicode is not devised
-then? The limited number of keycode available through USB simply disallow such
-a thing.
-
-## How to (Maybe) Enter Unicode Characters
-
-You can have the firmware send *sequences of keys* to use the [software Unicode
-Input
-Method](https://en.wikipedia.org/wiki/Unicode_input#Hexadecimal_code_input) of
-the target operating system, thus effectively entering characters independently
-of the layout defined in the OS.
-
-Yet, it does come with multiple disadvantages:
-
- - Tied to a specific OS a a time (need recompilation when changing OS);
- - Within a given OS, does not work in all software;
- - Limited to a subset of Unicode on some systems.