[wdmaudiodev] Re: Reg: USB Audio class 2.0
- From: swarna jakka <swarna.jakka@xxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Wed, 9 Dec 2009 09:32:46 +0530
Thanks for your support
I will enumerate the device with your suggestions.
Is there any full Compliance Test for USB Audio Class device.
Thanks
Swarna.
On Thu, Dec 3, 2009 at 11:08 PM, Tim Roberts <timr@xxxxxxxxx> wrote:
> swarna jakka wrote:
> >
> > Actually my question is that i am developing an USB Audio class 1.0,
> > and using USB 2.0 device.
> > This device is operating in Full speed mode only and i am able to
> > operate Audio class1.0 in full speed only and not in High speed mode.
> > Enumeration is going to be completed in High speed mode but i
> > can't play audio file in High Speed.
> > But the device using will operate in High speed as well as Full speed.
>
> Your message is confused. If you are enumerating as high speed, then
> you are operating in high speed mode. If you can only support full
> speed, then your device should enumerate in full speed.
>
> The key limitation of usbaudio.sys is that it cannot drive an
> isochronous pipe that does more than 1 request per frame. There are
> several ways to meet that requirement. One is to go full speed, and set
> the isochronous interval to 1. The other is to go high speed, and set
> the isochronous interval to 4 (meaning 1 packet every 8 microframes).
> Your device would not see any difference in the two -- the throughput
> will be the same.
>
> --
> Tim Roberts, timr@xxxxxxxxx
> Providenza & Boekelheide, Inc.
>
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