[Erez & Jack] Documents audio output

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Erez Zukerman 2016-05-10 20:48:14 -04:00
parent e4e0b4e105
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@ -377,6 +377,55 @@ You can currently send 4 hex digits with your OS-specific modifier key (RALT for
Enable the backlight from the Makefile.
## Driving a speaker - audio support
Your keyboard can make sounds! If you've got a Planck, Preonic, or basically any keyboard that allows access to the C6 port, you can hook up a simple speaker and have it beep. You can use those beeps to indicate layer transitions, modifiers, special keys, or just to play some funky 8bit tunes.
The audio code lives in [quantum/audio/audio.h](/quantum/audio/audio.h) and in the other files in the audio directory. It's enabled by default on the Planck [stock keymap](/keyboard/planck/keymaps/default/keymap.c). Here are the important bits:
```
#include "audio.h"
```
Then, lower down the file:
```
float tone_startup[][2] = {
ED_NOTE(_E7 ),
E__NOTE(_CS7),
E__NOTE(_E6 ),
E__NOTE(_A6 ),
M__NOTE(_CS7, 20)
};
```
This is how you write a song. Each of these lines is a note, so we have a little ditty composed of five notes here.
Then, we have this chunk:
```
float tone_qwerty[][2] = SONG(QWERTY_SOUND);
float tone_dvorak[][2] = SONG(DVORAK_SOUND);
float tone_colemak[][2] = SONG(COLEMAK_SOUND);
float tone_plover[][2] = SONG(PLOVER_SOUND);
float tone_plover_gb[][2] = SONG(PLOVER_GOODBYE_SOUND);
float music_scale[][2] = SONG(MUSIC_SCALE_SOUND);
float goodbye[][2] = SONG(GOODBYE_SOUND);
```
Wherein we bind predefined songs (from [audio/song_list.h](/audio/song_list.h)) into named variables. This is one optimization that helps save on memory: These songs only take up memory when you reference them in your keymap, because they're essentially all preprocessor directives.
So now you have something called `tone_plover` for example. How do you make it play the Plover tune, then? If you look further down the keymap, you'll see this:
```
PLAY_NOTE_ARRAY(tone_plover, false, 0); // Signature is: Song name, repeat, rest style
```
This is inside one of the macros. So when that macro executes, your keyboard plays that particular chime.
"Rest style" in the method signature above (the last parameter) specifies if there's a rest (a moment of silence) between the notes.
## MIDI functionalty
This is still a WIP, but check out `quantum/keymap_midi.c` to see what's happening. Enable from the Makefile.