USB Overflow using Novation Launchkey Mini MK2

#1

I'm having an issue connecting a Novation Launchkey Mini MK2 to the Axoloti core on a Windows 10 Surface Book using Axoloti build version 1.0.12-0.

When using the knobs faster than a slow speed, I "crash" the patch. No more midi messages will be interpreted until the controller is power cycled by removing the USB cable between the Axoloti and the MK2. I've tried two different Axoloti core boards, I've cycled through 5 different USB cables that I've used on development projects and am relatively sure they're okay. I've applied external 12V power for extra current.

When using the keyboard, or buttons, I can bang on them as fast as I can, and have not been able to crash a patch.

It doesn't matter what code is in the "MIDI Code" section. I've commented everything out except "ntrig = 1;" and the patch will crash.

Here is an example patch that will crash:

I've looked through the forum and found @mongrol confirms that the MK2 works with the Axoloti core.

I also found this topic that sounds like progress has been made on version https://github.com/axoloti/axoloti/releases/tag/1.0.11

Can anyone verify on their own MK2 that the knobs can be turned rapidly with no drop-out or patch crashes? Can anyone think of anything else for me to try?

Usb host midi output ringbuffer overflow?
USB Midi Controllers
#2

I've confirmed that a Korg nanoKONTROL2 handles very fast knob turning CC messages in my setup.

I'm totally willing to dig into the underlying code and hook up diagnostic equipment, but I would need confirmation that someone else's setup is experiencing the same thing. Let me know if you can replicate / refute this.

#3

I guess the LaunchKey sends out MIDI CCs at a faster rate than the NanoCONTROL.

I doubt you'll be able to fix the problem in object code. It sounds like the MIDI data buffer is overflowing.

a|x

#4

I don't use my Mini that much. I've found it pretty flakey, resets randomly or won't stay powered properly. This is mainly with my Midibox but I think I found the same with Axo after awhile. I think it's just sensitive to voltage.

#5

Wonderful news! Now I don't have to debug it anymore. Thank you!

I got an Akai MPK Mini instead and haven't had any problems since. Plus it has a joystick.

#6

@DazzlingDuke

I am wondering what you mean by the patch will crash?

I am trying to use my Launchkey mini with Axoloti at the moment and I experience problems when I turn a dial too fast. It doesnt crash the patch, but it freezes the input from the LKM, so Axoloti doesn't recognise the cc values send to it anymore.

#7

Hi @jaffasplaffa, sorry it isn't working for you. When I said I "crash the patch", I meant what you said. It won't read the CC values anymore until you power cycle. It's been a couple of years since I've read this thread though. I've moved onto other controllers. You aren't going to get far with the Launchkey Mini MK2 and the axo together. It's good for another project thought. Best of luck!

#8

Thanks for the answer @DazzlingDuke :slight_smile:

It can actually be reconnected without having to do a power cycle, you just need to turn off the incontrol and then turn it on again, then it works. It can be done from within the patcher. But yeah, it is a hassle and not something that is really useful, cause it happens pretty much everytime you play with one of the dials.

I use the Launch Key Mini with Pure data and sending it 1000s of messages a second and it works fine over there. And so does the Launch Pad mini. But non of them work well with Axoloti.

I do also have a Launch Control XL and that one works very well with Axoloti. No ringbuffer issues or anything. So for these "mini" devices, it seems like they don't work to well with Axo.

#9

not a launchkey owner, but i have similar issues where a midibox connected over USB would overflow the axolotis and/or the whole system when sending too much aftertouch data via fast USB midi. it will choke the DIN midi connections further down the line, and if the source sends too fast i could also see it choking just a single connected axoloti.
not sure if this is an axoloti-specific issue but fwiw i never experienced this with any other midi HW before.

#10

I think for the Launch MINI series, Novation have probably cut some corners. The Launch Pad MINI gives a ring buffer overflows if send data too fast. The Launch Key MINI kind of freezes when turning just a single knob.

I have used both the Launch Pad mini and the Launch Key Mini with Pure Data and both works fine, never had any issues, abit the same experience as you had with Axo and some controllers. So there might be some weird voodoo mismatch between between Axo and the mini series. But it's really hard to say what's going on, I don't know too much about it.

#11

reading ricards explanations on k-rate/s-rate cycles yesterday i could imagine it having to do with how often the middi-routine is called. imagine the midi buffer only gets emptied at k-rate too, would explain some of this behaviour.

(man i always imagine the real rech-savy people reading my comments, throwing their hands up in despair and despise, just like how i react when "amateurs" talk about music production...)

#12

I think weasel might be on to something there.

Fwiw, I've never had a problem with the launchpad mini, works fine. Incoming messages are received no problem. Sure, if I send a ton of data to it at once it might overflow the buffer, but that would be the same for any midi device as it's the axo buffer that's overflowing. I just coded objects so they sent one message per k cycle and that works fine. Plenty fast enough.