Different sample rates over USB Audio

Sub forums for various specialist XMOS applications. e.g. USB audio, motor control and robotics.
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Different sample rates over USB Audio

Post by tbjr6 »

I am looking if anyone has done this successfully, or knows it can not be done, before I spend too much time trying to get it to work.

I would like to run 2 simultaneous i2s input and output.
IO1 would be running at either 44.1, 48, or 192k
IO2 would be running at a consistent 216k

Then I would like them to both be available through USB. The Multichannel example seems to be a unified clock for all channels. Is there a way to set some channels to different clocks. Or would you have to run 2 instances of i2s. If so would both be able to be used over USB without SRC?

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Post by akp »

I have not done this. However, it seems to me if you did a composite USB device you could probably do it, where you had one endpoint for the variable sampling rate and another endpoint for the fixed sampling rate. I think it should show up as two sound cards rather than one. So far as I know no OS supports using two sampling rates on the same USB endpoint at the same time. You'll need two i2s instances.

So, long story short: I haven't done it successfully, but neither do I know if it cannot be done. So that won't help you much.