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| author | Alex Ong <the.onga@gmail.com> | 2019-01-04 19:43:45 +1100 |
|---|---|---|
| committer | Alex Ong <the.onga@gmail.com> | 2019-01-04 19:43:45 +1100 |
| commit | 2bb2977c133646c4e056960e72029270d77cc1eb (patch) | |
| tree | 235d491f992121ac1716c5bf2fafb80983748576 /docs/how_keyboards_work.md | |
| parent | a55c838961c89097ab849ed6cb1f261791e6b9b4 (diff) | |
| parent | 47c91fc7f75ae0a477e55b687aa0fc30da0a283c (diff) | |
| download | qmk_firmware-2bb2977c133646c4e056960e72029270d77cc1eb.tar.gz qmk_firmware-2bb2977c133646c4e056960e72029270d77cc1eb.zip | |
Merge branch 'master' into debounce_refactor
# Conflicts:
# tmk_core/common/keyboard.c
Diffstat (limited to 'docs/how_keyboards_work.md')
| -rw-r--r-- | docs/how_keyboards_work.md | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/docs/how_keyboards_work.md b/docs/how_keyboards_work.md index fac2b5a489..cc54e566a1 100644 --- a/docs/how_keyboards_work.md +++ b/docs/how_keyboards_work.md @@ -27,17 +27,17 @@ This usually happens with a periodic scan of key presses. This speed often is li ## 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 scancodes which are simple numbers from `0x00` to `0xE7`. The firmware assigns a scancode to each key of the keyboard. +The [HID specification](https://www.usb.org/sites/default/files/documents/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 scancodes which are simple numbers from `0x00` to `0xE7`. The firmware assigns a scancode to each key of the keyboard. -The firmware does not send actually letters or characters, but only scancodes. -Thus, by modifying the firmware, you only can modify what scancode is sent over +The firmware does not send actual letters or characters, but only scancodes. +Thus, by modifying the firmware, you can only modify what scancode 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: +layout is set to QWERTY, a sample of the matching table is as follows: | keycode | character | |---------|-----------| @@ -55,11 +55,11 @@ As the layout is generally fixed (unless you create your own), the firmware can ## 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**. +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 are only 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. +For example, this means that if you have a QWERTY US layout, and you want to assign one 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. +You may wonder why a keyboard layout containing all of Unicode is not devised then? The limited number of keycodes available through USB simply disallows such a thing. ## How to (Maybe) Enter Unicode Characters |