Different Channel Count with different sampling frequency

If you have a simple question and just want an answer.
dkybchoi
Member
Posts: 10
Joined: Thu Sep 29, 2016 3:03 am

Different Channel Count with different sampling frequency

Postby dkybchoi » Fri May 12, 2017 9:52 am

Hi ,

As I know in a bigger Audio Interface product, it is possible to change the channel count on the fly when we select different sampling frequency from PC ( Host)

For example :
At the sampling frequency 48KHz , the system can support 18 USB In and 18 USB Out . When we select higher sampling frequency .
e.g. At the sampling frequency 192KHz , the system will be changed to support 8 USB In and 8 USB Out only dynamically.

I guess that it is possible to use different alternatives settings in USB descriptor to inform HOST. Is my understanding correct ?

Could someone those who have experience to implement such feature to share more information with me ?

Many thinks
User avatar
johned
Experienced Member
Posts: 109
Joined: Tue Mar 26, 2013 12:10 pm
Contact:

Postby johned » Mon Jul 17, 2017 10:17 am

Hi,

I would implement this with AN00109: Multiple Firmware Booting : https://www.xmos.com/support/appnotes. You could boot different builds, for your different configurations.
Please note that this might cause problems under Windows because Windows caches the USB device configurations (e.g. number of channels) for a specific VID/PID combination.
You might like to try using a different PID for each configuration which should hopefully resolve this.

Best,
John
dkybchoi
Member
Posts: 10
Joined: Thu Sep 29, 2016 3:03 am

Postby dkybchoi » Mon Jul 17, 2017 11:37 am

Thanks for your reply. But I think it is different case. We need to change the channel count dynamically, it is not allowed to reboot the unit. Thanks anyway !

Return to “Q&A”

Who is online

Users browsing this forum: No registered users and 6 guests