I'm developing a USB MIDI device for my own hobby use and I've run into
a bit of an issue. I plan to release it as OSHW, but for now it is not
in a presentable state.
My device presents a USB Midistreaming interface with the following
characteristics:
- A single embedded MIDI IN jack with ID 1
- A single embedded MIDI OUT jack with ID 2
- A single element with ID 3
- The embedded MIDI IN jack is attached to the single input pin.
- The embeeded MIDI OUT jack is attached to the single output pin.
Right now I have my device programmed to send (what I think is) a
control change event on control 7 to some value every so often. It sends
it through the endpoint associated with the MIDI OUT jack.
Here's the result of some commands when I have the device plugged in to
my PC (running Arch):
$ aseqdump -l
Port Client name Port name
0:0 System Timer
0:1 System Announce
14:0 Midi Through Midi Through Port-0
28:0 Midi-Fader Midi-Fader MIDI 1
$ aconnect -i
client 0: 'System' [type=kernel]
0 'Timer '
1 'Announce '
client 14: 'Midi Through' [type=kernel]
0 'Midi Through Port-0'
client 28: 'Midi-Fader' [type=kernel,card=3]
0 'Midi-Fader MIDI 1'
$ aconnect -o
client 14: 'Midi Through' [type=kernel]
0 'Midi Through Port-0'
client 28: 'Midi-Fader' [type=kernel,card=3]
0 'Midi-Fader MIDI 1'
My device is the "Midi-Fader". When I run "aseqdump -p 28:0" I see
nothing appear. However, Wireshark shows that my device is sending
USB-MIDI Event Packets (just Bulk IN packets with a length of 4) with
the following binary content:
2b 07 31 00
What I intended this event to say is:
- Cable 2
- Event 0xb: Control change
- Control # 0x07
- Value 0x31
However, I don't see these events show up in aseqdump. Here are my
questions:
- Does aseqdump not show this kind of packet? I've tried others like
Note On with the same result.
- Are my packets malformed? Perhaps my cable number is wrong? I've tried
0, 1, 2, and 3.
- Do I need to send some sort of additional packet to cause the events
to appear? Like a flush?
- Is there a way to debug the insides of alsa to see where my events are
getting lost?
I have a Yamaha MOXF8, but it appears to enumerate as a custom device
and does not use the standard USB-MIDI interface. I can't use it as an
example (it does work with aseqdump however).
If this isn't the right mailing list, please let me know.
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