More details about the midi implementation

[eh2k]

The MIDI section of the docs could be expanded - not completely clear to me how you assign MIDI to an engine, if you can trigger the drum voices from MIDI (if so what notes are triggers?), explanation of how to set up program change messages etc.

Originally posted by @rheslip in #1 (comment)

@rheslip

thanks for your feedback.
If you have any questions, just post them here - I'll try to summarize it like a FAQ...

In summary:

In the midi page you can assign a midi channel to each engine (1-4). If midi notes are received, they are translated into an trigger, gate and CV value, that is passed to the corresponding engine within the ControlFrame struct.

With the following control changes (hardcoded) you can control the engine parameters.

Suppose the parameter 0 is the pitch (the most engines). Consequently you can control the pitch with the CC 0x20. The pitch generally has a special role, because it is still controlled by the default CV, and therefore can also be changed by the midi note.
And then there is also the pitchbend control.

HEX	DEC	parameter-index	CH
20	32	0	*
21	33	1	*
22	34	2	*
23	35	3	*
24	36	4	*
25	37	5	*
26	38	6	*
27	39	7	*

The following Midi messages are also still implemented (currently not documented):

• ProgramChange: allows to change the engines (Drum Engines causing freeze #28)
• PitchBend
• Note Velocity (CC 7) (Modulate the volume/output gain with cv or midi velocity. #9)