Does the MIDIusb support play notes on multiple channels?

[weshi]

Hello,

When I tried to use the MIDIusb class to send notes (by calling the noteON) with different values of channels, it seems that it only worked for channel 0. Is this a known issue?

Thanks,
Wenbo

[chegewara]

Hi,
to be honest i had no chance to play with midi too much, as i am not an expert.
Only tests i remember were with android smartphone, but i dont remember what or how it worked.

[weshi]

Thank you for the quick reply @chegewara.

I did futher investigation and testing, and figured out that it was caused by the way function tud_midi_stream_write was called. Let's take noteON for example:

In your current version, it's defined as:

void MIDIusb::noteON(uint8_t note, uint8_t velocity, uint8_t channel)
{
log_v("ON: %d\n", note);
uint8_t buf[] = {0x90, note, velocity};
tud_midi_stream_write(channel, buf, 3);
}

I looked at the definition of tud_midi_stream_write, the first parameter is: uint8_t cable_num;

I'm not sure what's the definition of this cable num, but if I always pass 0 to it, and OR the channel value to the status byte (i.e., buf[0]), then it worked correctly:

void MIDIusb::noteON(uint8_t note, uint8_t velocity, uint8_t channel)
{
log_v("ON: %d\n", note);
uint8_t buf[] = {(uint8_t)(0x90 | channel), note, velocity};
tud_midi_stream_write(0, buf, 3);
}

Thanks,
Wenbo

[DavidMR91]

Hello, I would like to ask if this correction has already been implemented, as I am facing the same issue where when I try to use channels other than the default one, the MIDI information transmission fails. Thank you.

[jsonslim]

In my case the Windows PC recognises the midi device, but no notes are sent, when i call midi.noteOn(), does anyone have this prob?