MS MIDI driver problem

[stever]

Still making progress on my project... I now have the MIDI>USB-MIDI state machine implemented and it appears to be working well. While trying to implement what I thought would be the simple part (USB-MIDI>MIDI), I ran into Sysex corruption, which had the symptoms of pointer mismanagement on my part. After checking my code over several times, however, I became convinced that the corruption was occurring elsewhere.

A quick Google and I discovered http://www.midiox.com/cgi/yabb/YaBB.pl?board=bugs;action=print;num=1130961608 (and TK had visited that page, too!). I searched for this on ucapps.de but didn't find anything so thought I'd post it in case it's of use to someone.

Turns out the MS MIDI class driver corrupts Sysex data if buffers are smaller than the total message size. Changing MIDI-OX's buffers fixed the problem! Fortunately, the application I'm using appears to use large enough buffers, as the corruption doesn't occur with MIDI-OX out of the chain.

Thorsten: my MIDI implementation on a PIC18F2550 is now almost complete and usable without the user interface and other features I plan to add. Let me know if you're still interested in testing it out and I'll send you the hex and the I/O info you'll need.

Steve.

[stryd_one]

Err yeh I heard about that on wdmaudiodev... Gotta love windoze ;)

Keep up the great work man!

[TK.]

Hi Steve,

yes, I'm interested in testing your firmware, especially under MacOS.

SysEx corruption: some weeks ago ASSI informed me about a proper software workaround: using MIDItrix V1.24 to defractment the MIDI stream before it will be sent to the USB interface.

He also contacted Microsoft, and got the answer, that they are aware of this issue, and fixed it in Vista. They are not planning to fix it for XP anymore, but they asked him for details, so that the issue can be properly documented in a KB note

Which reminds me, that I have to deliver some input... ok, I will do this while testing your firmware ;)

Best Regards, Thorsten.

[cimo]

He also contacted Microsoft, and got the answer, that they are aware of this issue, and fixed it in Vista. They are not planning to fix it for XP anymore, but they asked him for details, so that the issue can be properly documented in a KB note

that sounds to me like "well there are thousands of people (errr CUSTOMERS) out there using our buggy driver, who cares? they can buy vista!" nice service!

[bugfight]

..........

that sounds to me like "well t...

pblblblblblbblblblblblblblt

[cimo]

pblblblblblbblblblblblblblt

is that the sound of an iphone drive going nuts?  ???

EDIT: i am moron going offtopic for no reason

        (i hate windows anyway  :P)

[stever]

yes, I'm interested in testing your firmware, especially under MacOS.

Hi Thorsten, I've now finished the USB-MIDI>MIDI function and done some testing... Have successfully wrapped data through the PIC and back, including Sysex data. I now have a build you can take a look at if you want. Let me know how you'd like me to get it to you....

Let me know if you want Running Status implemented on the outbound stream... this will be a user option, but I haven't built the interface yet.

Thanks for the MIDItrix tip... don't need it at present, but a useful tool to have available.

Cheers, Steve.