Is it possible to have 2 USB MIDI ports in different cables numbers?

[sanotronics]

Hi!

I am trying to make my device show 2 different USB-MIDI ports to the computer.

Is this possible?

I am trying like this:

USBMIDI_CREATE_DEFAULT_INSTANCE()
USBMIDI_CREATE_INSTANCE(4, MIDIOUT)

and then

MIDI.begin(MIDI_CHANNEL_OMNI); 
MIDI.turnThruOff(); 

MIDIOUT.begin(MIDI_CHANNEL_OMNI); 
MIDIOUT.turnThruOff(); 

But I only see the first MIDI port.

In the examples I see that there is one for a Hardware MIDI and USB midi ports, but I don't see an example with 2 USB ports.

Thanks!

[sanotronics]

I just found this one in the repo (i had an outdated version downloaded)
https://github.com/lathoub/Arduino-USBMIDI/blob/master/examples/SysEx_Teensy4.1/SysEx_Teensy4.1.ino

but I don't see the USB ports when I load it to my board (Arduino M0 based)

[lathoub]

Hi @sanotronics Cable's are indeed the way to go. This lib using the underlying MIDIUSB lib for all USB heavylifting. Have you tried to get the M0 to work in that?

[sanotronics]

Hi!

I am using the code I paste below compiling for my board to try and make it work. It is derived from the example I linked before

The USB stuff is there cause I made changes to the main.cpp, so I can set the name of the device and set PID from an EEPROM configuration.

The MIDI instance on cable 0 works alright, I can see it and I can see the incoming MIDI messages.
The second MIDI instance I cannot see it as a separate port.

Maybe I am missing something of the theory but I'd expect the second port/cable to appear as a "KilomuxV2-2" or something similar to the original name of the USB-MIDI device.
If this weren't the case, then how would I address each cable separately from a DAW, for example?

Thanks for the help!

#include <USB-MIDI.h>

byte sysex11[] = { 0xF0, 0x43, 0x20, 0x7E, 0x4C, 0x4D, 0x20, 0x20, 0x38, 0x39, 0xF7 };
byte sysex15[] = { 0xF0, 0x43, 0x20, 0x7E, 0x4C, 0x4D, 0x20, 0x20, 0x38, 0x39, 0x37, 0x33, 0x50, 0x4D, 0xF7 };

// Make sure the USB-TYPE is set to MIDIx4 in Tools
USBMIDI_CREATE_INSTANCE(0, MIDI1) // Cable 0
USBMIDI_CREATE_INSTANCE(1, MIDI2) // Cable 1

// DEFINITIONS FOR USB INITIALIZATION
#define MICROCHIP_VID         0x04D8  // Microchip's USB sub-licensing program (https://www.microchip.com/usblicensing)
#define DEFAULT_PID           0xEBCA  // Assigned to Yaeltex

// Arduino core definitions for product name, manufacturer name, and PIDs
extern uint8_t STRING_PRODUCT[];
extern uint8_t STRING_MANUFACTURER[];
extern DeviceDescriptor USB_DeviceDescriptorB;
extern DeviceDescriptor USB_DeviceDescriptor;

unsigned long t0 = millis();

// -----------------------------------------------------------------------------
//
// -----------------------------------------------------------------------------
void setup()
{
  // MODIFY DESCRIPTORS TO RENAME CONTROLLER
  strcpy((char*)STRING_PRODUCT, "KilomuxV2");
  strcpy((char*)STRING_MANUFACTURER, "Yaeltex");
  USB_DeviceDescriptor.idVendor = MICROCHIP_VID;
  USB_DeviceDescriptorB.idVendor = MICROCHIP_VID;
  USB_DeviceDescriptor.idProduct = DEFAULT_PID;
  USB_DeviceDescriptorB.idProduct = DEFAULT_PID;

  
  // INIT USB DEVICE (this was taken from Arduino zero's core main.cpp - It was done before setup())
  #if defined(USBCON)
    USBDevice.init();
    USBDevice.attach();
  #endif
    
  MIDI1.begin(1);
  MIDI2.begin(1);
}

// -----------------------------------------------------------------------------
//
// -----------------------------------------------------------------------------
void loop()
{
  // Listen to incoming notes
  //MIDI1.read();
 //MIDI2.read();

  // send 10 SysEx per second
  if ((millis() - t0) > 400)
  {
    t0 = millis();

    MIDI1.sendSysEx(sizeof(sysex11), sysex11, true);
    MIDI2.sendSysEx(sizeof(sysex15), sysex15, true);
  }

}

[sanotronics]

I also tried to change the cable number to something different than 0 on the first port and then I still see the port on the midi monitor but not the Sysex messages.

And if I set the second instance to cable 0 (MIDI2) I see the sysex15 message in the monitor, instead of the sysex11.

If I set both instances to cable 0, both messages, sysex11 and sysex15 arrive.

Could only cable 0 be working properly?

[sanotronics]

It'd be really useful to get to the bottom of this, please @lathoub can you tell me if for you this just works and you see 2 USB-MIDI ports on your computer just by defining two instances of the MIDI objects?

thanks

[BobKerns]

I've been trying to do the same thing—OSX Catalina, Seeeduiono XIAO.
Oddly, the cable # doesn't seem to actually matter—usually. I saw some inconsistent results that seemed to suggest that the order of definition mattered, but wasn't able to reproduce it.

But when I feel back again to a single cable, and tried a cable # of 7 to confirm the cable # doesn't matter for this report, the result was it killed my box (as in, now I have to perform surgery on a sealed box to get it back to the bootloader—yeah, I lost the bet that I'd not ever have to do that again!)

This suggests to me an inconsistency in how it's registering and accessing by cable #.

And possibly an easily-reproduced test case: Allocate a single cable with idx 7 (or perhaps other indexes depending on memory layout) but no cable 0.

I hope that helps—and wish me luck on opening this sealed Altoid box, if you can stop laughing! LOL

[BobKerns]

Alas, it appears to not be so easily reproduced. It only took me about 10 minutes to get into my Altoid box; the debonder solution was impressive! But a bare cable 7 seems to work, so I may not have added much information here.

I do know the Mac supports multiple virtual cables via USB, as my Prosonus ATOM SQ manages the feat.

[BobKerns]

One more bit of info: the cable # does matter for receive.