XTag2 query

Technical discussions related to any XMOS development kit or reference design. Eg XK-1A, sliceKIT, etc.
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Folknology
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Re: XTag2 query

Postby Folknology » Thu Feb 18, 2010 11:05 pm

audio master clocks?
Yes all of those extra crystals and gates to drive them.

Obviously the reference board is designed to be a "Pro" audio board.

I'm just thinking out loud here, being new to the audio processing, trying to find an economical way to add 'good enough' audio to Amino. (Pro can be added anyhow if that's required by a more specialist add on).

I was just thinking a single 12Mhz clock could derive the important good digital rates 32khz,48khz,96khz.

The others 8khz,44.1khz,88.2khz are less important to me and on the ADC side seem a little pointless.

Obviously with this newer version of USB using a 13Mhz crystal isn't as easy as for the 12Mhz USB.

So please be gentle with this digital audio newbie, I'm still getting my head around all of this stuff

regards
Al
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oar_some
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Postby oar_some » Thu Feb 18, 2010 11:36 pm

Folknology wrote:
audio master clocks?
Yes all of those extra crystals and gates to drive them.

Obviously the reference board is designed to be a "Pro" audio board.


I'm just thinking out loud here, being new to the audio processing, trying to find an economical way to add 'good enough' audio to Amino. (Pro can be added anyhow if that's required by a more specialist add on).

I was just thinking a single 12Mhz clock could derive the important good digital rates 32khz,48khz,96khz.

The others 8khz,44.1khz,88.2khz are less important to me and on the ADC side seem a little pointless.

Obviously with this newer version of USB using a 13Mhz crystal isn't as easy as for the 12Mhz USB.

So please be gentle with this digital audio newbie, I'm still getting my head around all of this stuff

regards
Al
Its all down to the master clock for quality.... do you mean deriving the master clock from the 12MHz clock in the XCore? if so, that won't be good enough.

To avoid all the clocking requirements just use a codec that supports master mode.

This has gone a bit off topic now...
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Folknology
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Postby Folknology » Thu Feb 18, 2010 11:43 pm

Well not completely off topic, the reason I noticed the 13Mhz clock in the first place was down to me exploring the existing schematics of all Xmos USB and Audio I could find to help me as I plan on using both for Amino. My intention is to use a CODEC with a single clock (12Mhz), not use the Xmos to derive the rates from this clock.

Which also poses the question of : Can the USB fall back to the older mode (12Mhz) when using the USB3318?

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