USBHost_t36 and High Speed USB MIDI messages

[AlanK]

Hi,
I have a simple program outputting MIDI messages over USB running on both a T3.6 and a T4.0 (Teensyduino 1.56, Arduino 1.8.19) - both tested. When I run the USBHost_t36 MIDI InputFunctions example on a T4.1 with USB host, or on a MicroMod Teensy on an ATP carrier board, it detects the messages from the T3.6 but not from the T4.0. Is this a known limitation, or am I doing something wrong?
All the best,
Alan

[kd5rxt-mark]

...or am I doing something wrong?

Post your source code (even if it is an unmodified example) & we can take a look to see if we can spot the possible cause. As a point of reference, I can attest to the fact that I have made use of the USB MIDI capability for both input & output MIDI messages successfully.

Mark J Culross
KD5RXT

[AlanK]

Thanks Mark,

The code for the transmitter is simply:

void setup() {
}


void loop() {
  while (usbMIDI.read()) { }
  usbMIDI.sendNoteOn(38, 100, 10);
  delay(200);
}

USB type is Serial+MIDI.

The code for the receiver is the unmodified InputFunctions example (again, Serial+MIDI). Works fine for T3.6 sending messages to T4.1 or TMM, but not for T4.0 sending messages. T4.0 is sending MIDI messages - no doubt about that.

All the best,

Alan

[AlanK]

Hi,

With USBHOST_PRINT_DEBUG defined, the output when the T4.0 Serial+MIDI device is connected to the TMM USB Host is given below. If the T4.0 is changed to a MIDI device, there's a similar result with Descriptor 36 = ??? and Descriptor 37 = ???. I presume this is connected to the issue raised here Teensy 4.1 serial host can't recognize another teensy (pjrc.com)

All the best,

Alan


new_Device: 480 Mbit/sec
new_Pipe
enumeration:
enumeration:
enumeration:
Device Descriptor:
12 01 00 02 EF 02 01 40 C0 16 89 04 79 02 01 02 03 01
VendorID = 16C0, ProductID = 0489, Version = 0279
Class/Subclass/Protocol = 239 / 2 / 1
Number of Configurations = 1
enumeration:
enumeration:
Manufacturer: Teensyduino
enumeration:
Product: Teensy MIDI
enumeration:
Serial Number: 7364090
enumeration:
Config data length = 149
enumeration:
Configuration Descriptor:
09 02 95 00 03 01 00 C0 32
NumInterfaces = 3
ConfigurationValue = 1
08 0B 00 02 02 02 01 00
Interface Association = 0 through 1
Class / Subclass / Protocol = 2 / 2 / 0
09 04 00 00 01 02 02 01 00
Interface = 0
Number of endpoints = 1
Class/Subclass/Protocol = 2 / 2 / 1
05 24 00 10 01
05 24 01 01 01
04 24 02 06
05 24 06 00 01
07 05 82 03 10 00 05
Endpoint = 2 IN
Type = Interrupt
Max Size = 16
Polling Interval = 5
09 04 01 00 02 0A 00 00 00
Interface = 1
Number of endpoints = 2
Class/Subclass/Protocol = 10 / 0 / 0
07 05 03 02 00 02 00
Endpoint = 3 OUT
Type = Bulk
Max Size = 512
Polling Interval = 0
07 05 83 02 00 02 00
Endpoint = 3 IN
Type = Bulk
Max Size = 512
Polling Interval = 0
09 04 02 00 02 01 03 00 00
Interface = 2
Number of endpoints = 2
Class/Subclass/Protocol = 1 / 3 / 0
07 24 01 00 01 25 00
06 24 02 01 01 00
06 24 02 02 02 00
09 24 03 01 03 01 02 01 00
09 24 03 02 04 01 01 01 00
09 05 04 02 00 02 00 00 00
Endpoint = 4 OUT
Type = Bulk
Max Size = 512
Polling Interval = 0
05 25 01 01 01
09 05 84 02 00 02 00 00 00
Endpoint = 4 IN
Type = Bulk
Max Size = 512
Polling Interval = 0
05 25 01 01 03
enumeration:
USBHub memory usage = 960
USBHub claim_device this=200031E0
USBHub memory usage = 960
USBHub claim_device this=200035A0
Descriptor 11 = IAD
Descriptor 4 = INTERFACE
MIDIDevice claim this=20003960
len = 132
Descriptor 36 = ???
Descriptor 36 = ???
Descriptor 36 = ???
Descriptor 36 = ???
Descriptor 5 = ENDPOINT
Descriptor 4 = INTERFACE
MIDIDevice claim this=20003960
len = 97
Descriptor 5 = ENDPOINT
Descriptor 5 = ENDPOINT
Descriptor 4 = INTERFACE
MIDIDevice claim this=20003960
len = 74
Interface is MIDI
type: 36, len: 7
MIDI Header (ignored)
type: 36, len: 6
MIDI IN Jack (ignored)
type: 36, len: 6
MIDI IN Jack (ignored)
type: 36, len: 9
MIDI OUT Jack (ignored)
type: 36, len: 9
MIDI OUT Jack (ignored)
type: 5, len: 9
MIDI Endpoint: 4
tx_size = 512
type: 37, len: 5
MIDI Endpoint Jack Association (ignored)
type: 5, len: 9
MIDI Endpoint: 84
rx_size = 512
type: 37, len: 5
MIDI Endpoint Jack Association (ignored)
Descriptor 36 = ???
Descriptor 36 = ???
Descriptor 36 = ???
Descriptor 36 = ???
Descriptor 36 = ???
Descriptor 5 = ENDPOINT
Descriptor 37 = ???
Descriptor 5 = ENDPOINT
Descriptor 37 = ???

[KurtE]

Note: I know very very little on MIDI, but as I mentioned on the USB Serial issue of plugging in a t4 into host and try a different class, it may be similar issue with midi...
Which is where I first saw classes with (BigBuffer)

So you might try changing MIDIDevice to MIDIDevice_BigBuffer

And see if that helps.

[AlanK]

Thanks Kurt,

That works perfectly. Would be good if it was included in comments in USBHost_t36 examples,

All the best,

Alan

[AlanK]

Hi,

This may be useful for someone. I can confirm that the PCB layout shown below for a USB Host connector for a T4.1 (2 layer PCB, 1.6 mm thick, USB connector on bottom of board) works at 480 Mbps. The D- and D+ traces are 1.6 mm wide with a 0.4 mm gap between them (should give, for that board, roughly 90 ohm impedance as required, but one trace is 3.5 mm longer than the other).



All the best,

Alan