Re: Strange sysex problems
Re: Strange sysex problems
- Subject: Re: Strange sysex problems
- From: Pete Gontier <email@hidden>
- Date: Mon, 10 Jan 2005 11:57:03 -0800
>> I have made some experiments and can now tell what the problem is. It's a
>> MIDISport 4x4 USB data toggle problem again...
>>
> Sigh ..... though, if you have just one MIDI device connected that sends
> active sensing all the time, that might be enough to make the problem
> invisible (assuming the MIDISport sends the active sensing to the computer and
> doesn't filter it out).
The USB data toggle problem I've seen on 8x8/s is that the first inbound
message gets lost. Actually, the first 1 to 4 bytes get lost, and since the
first byte starts the message, the driver drops the whole message. To
determine whether this is what's happening, while the driver is open, have
the synth first send at least one message other than the one you care about.
For example, while your app is waiting for the user to press the button on
the synth which will send the series of sysex messages, instead tap one of
the keys to generate NOTE ON and NOTE OFF messages. I assume the software,
of course, will be designed to ignore such messages, but for diagnostic
purposes you can log them to see them arrive. If the USB data toggle issue
is relevant, your code should not see the NOTE ON but see the NOTE OFF
message. (Of course, depending on how your log works, you may see a NOTE ON
with velocity 0 instead of a NOTE OFF.) And, after having received the NOTE
OFF message, you should be able to hit the button which generates the sysex
message series and see all messages received.
--
Pete Gontier
http://www.m-audio.com/
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