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USB Hub

Posted: Mon May 11, 2015 10:49 pm
by Olovskos
Hello,
I`m working on a Midi Interface but I have Problems connecting the Atmega to a USB Hub. It is working perfectly without a Hub. But when I put a Hub between the Device and the PC it is not showing up.... I`ve tried 4 Hubs.

Is there something I have to take care of?

Thanks in advance

Re: USB Hub

Posted: Tue May 12, 2015 3:42 am
by blargg
Hubs can be more picky about timing. Are you using a clock crystal for the Atmega?

Re: USB Hub

Posted: Tue May 12, 2015 4:26 pm
by Olovskos
Yes, I`m using a 16 Mhz Quarzoszillator (German notation, I don`t know the english ^^) like this http://upload.wikimedia.org/wikipedia/d ... llator.jpg

First I thought it is a Win 8.1 problem but the device doesn`t appear under Linux, too.

Re: USB Hub

Posted: Thu May 14, 2015 6:50 am
by blargg
Oh, I wonder whether it's the level-shifting zener diodes etc. Hub might be more picky about that too. Have you tried a minimal USB program on the Atmega in case there's some bug in the Midi adapter code? I think there's one that acts like a phantom key press that wouldn't need any external hardware.

Re: USB Hub

Posted: Thu May 14, 2015 12:53 pm
by Olovskos
Yes I think it is something about my wiring...

I use a bi- directional level shifter and thats the problem maybe.

I tried some examples from the V-USB download and they all act like this. Today is holiday so I think I go and buy some diodes tomorrow and try again.

I will post the results here

Re: USB Hub

Posted: Sat May 16, 2015 12:21 am
by Olovskos
UPDATE

Zener Diodes are working like a charm with hubs :D

Re: USB Hub

Posted: Mon May 18, 2015 8:47 am
by blargg
Thanks for updating us. Interesting how you got away with it on the PC but not the hubs. Another piece of evidence of hubs being more picky, and one more reason for my personal avoidance of hubs.

V USB Question

Posted: Wed May 20, 2015 9:26 pm
by BobbyJackson
Hello, Just new to this interface.

Please can someone tell me how can I buy the V USB PowerSwitch provides 8 bits of parallel output?

I am working on a project I in great need of this item

Re: USB Hub

Posted: Thu May 21, 2015 10:59 am
by blargg
Go back to the topic list and click New Topic and ask the question there. This will keep is from being mixed with this one.