[chbot] MIDI over USB for nanoKONTROL2 control surface

[Paul Davey]

SYSEX is likely badly documented as the SYSEX messages exist for the
purpose of having a way for system exclusive functionality to fit into the
standard, but since the actual messages will differ somewhat by
manufacturer and device it seems natural that they would be less well
documented as the docs would come only from one source.

It also worries me that the MIDI specification never had any mechanism
added to it to interrogate the current state of a control, then again MIDI
seems to not be entirely the correct protocol to use for such a device as
it is lacking this somewhat important feature...


On Tue, Apr 2, 2013 at 8:47 PM, Mark Atherton <markaren1 at xtra.co.nz> wrote:

> Hi Dave,
>
> Finally managed to work through all of your comments in detail and I think
> you may be correct.
>
> Fetching current scene, saving as file1, moving slider, fetching current
> scene, saving as file2 then comparing file1 vs file2 did not result in any
> differences.
>
> Is it me, or is SYSEX really badly documented ? - this has all been quite
> painful.
>
> Quite disappointed that something so simple as control surface slider/knob
> read is missing.
>
> Anyway, the video you reference does offer a reasonable solution. You
> certainly don't want to move a fader that was at -60dB suddenly up to-10
> just because that is the new position due to a context switch of the
> control surface. That was the dilemma I was faced with.
>
> Thanks for your help.
>
>
> Mark
>
>
> At 09:11 p.m. 1/04/2013, you wrote:
>
>> Hi Mark,
>>
>> You can get some information back by sending it MIDI sysex messages, but
>> it looks like it will only dump the current scene configuration, which
>> isn't (as I understand it) the current position of the sliders. The MIDI
>> implementation doc is here: http://www.korg.co.uk/support/**
>> downloads/nano_dl.php<http://www.korg.co.uk/support/downloads/nano_dl.php>in nano_MIDI_implementation.zip, and there is some Python code for sending
>> and reading scenes using sysex on https://github.com/royvegard/**
>> Nano-Basket/blob/master/nano_**basket_backend.py<https://github.com/royvegard/Nano-Basket/blob/master/nano_basket_backend.py>
>>
>> If the Korg editor software can read the current position of the sliders
>> then there's a chance that there's an undocumented message that will do it,
>> otherwise I don't think it's possible. In software you can either just jump
>> the controlled parameter to the fader position as soon as someone moves it,
>> or wait until they move the fader to the current parameter position before
>> changing the parameter, as in this video:
>> http://youtu.be/PgRTyMnosSI?t=**1m54s<http://youtu.be/PgRTyMnosSI?t=1m54s>
>>
>> Dave
>>
>> On 01/04/2013 14:39, Mark Atherton wrote:
>>
>>> Hi All,
>>>
>>> Hopefully someone here can save me some work digging around for a
>>> solution to this question:
>>>
>>> I am building a small wireless interface for a KORG nanoKONTROL2
>>> MIDI-over-USB control surface. The system is based on a Microchip dsPIC
>>> device with USB host port, so far so good; everything works as expected in
>>> terms of controlling LEDs on the control surface, and reading back sliders,
>>> knobs etc. as Control Change messages.
>>>
>>> As an example, after moving a slider, a message is received like 0x0B,
>>> 0xB0, 0x02, 0x78 -- Cable 0, Control Change, Address 2, Data 0x78, etc.
>>>
>>> I need to be able to read the whole control surface at power up, so for
>>> example I need to know how to interrogate slider 2, to find it's current
>>> position without moving it.
>>>
>>> Any ideas how I go about doing this will be appreciated, or a more
>>> appropriate forum.
>>>
>>> Thanks,
>>>
>>> Mark
>>>
>>
>>
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