USB Audio 2.0 Reference Design 32bit/192kHz support?

Sub forums for various specialist XMOS applications. e.g. USB audio, motor control and robotics.
patw
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USB Audio 2.0 Reference Design 32bit/192kHz support?

Post by patw »

Hi,

Currently the USB Audio 2.0 Reference Design supports bit perfect audio data up to 24-bit @ 192kHz. Is it anyway to make to to support 32bit data @ 192kHz too?

Many thanks,

Pat


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Bianco
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Post by Bianco »

The audio codec used only supports 24 bits.

http://www.cirrus.com/en/pubs/proDatash ... 270_F1.pdf
Corin
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Post by Corin »

Hi Pat,

At this moment in time the XMOS USB Audio 2.0 Reference Design is designed to support up to 24bit/192kHz.

It can be (and has been) modified by the user to support 32bit and up to 384kHz, but this is not included or supported in the reference design.

I hope this helps.

Kind Regards,
Corin
patw
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Post by patw »

>The audio codec used only supports 24 bits.

Yes, correct. I will jumper out the I2S signal to another 32 bit DAC chip.
patw
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Post by patw »

"It can be (and has been) modified by the user to support 32bit and up to 384kHz. "

There is MAX_FREQ in the firmware which I can now see to change the max supported freq.

What I am still unsure is the 32bit thing, as SPDIF standard only support a max audio date length of 24bit (20 + 4 AUX bits), how can one transmit a 32bit audio data via SPDIF?

Many thanks,

Pat
patw
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Post by patw »

ah... let me answer my own question ... SPDIF can't do 32bit audio data. Yes USB can, but then USB must directly convert to I2S, can't convert to SPDIF first.

I still have the question, how do I modify the XMOS to make it stream 32bit USB audio data?

Many thanks,

Pat
Heater
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Post by Heater »

patw,

I'm intrigued as to why you would want to do so.
The is not an ADC or DAC in the world that can resolve to one part in 4 billion.
patw
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Post by patw »

there are DAC chip out there which support that resolution, whether it makes a difference in final listening is another matter.
patw
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Post by patw »

Hi Corin,

"It can be (and has been) modified by the user to support 32bit and up to 384kHz, but this is not included or supported in the reference design."

Can you kindly give me some pointer in this matter, especially the 32bit support in the USB.

Many thanks for your help. :P

Pat
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lilltroll
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Post by lilltroll »

Does your question include a Windows driver for that or only the SW on the XMOS side ?
Probably not the most confused programmer anymore on the XCORE forum.
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