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Building an open embedded audio applicance.

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Looked,

It is a limitation of the hardware not the distro miero's is running, IF the board is powered down externally with any gpio or processor pins high with the processor unpowered it WILL damage the BBB. Stated quite clearly in the manual iirc.
When it comes, it comes.

Chuz,

Drew.

Yes, Drew, this is clearly a designing choice. But for example i have not heard the Pie suffering such shortcoming for a computer frequently used as an embedded device.

BR
Jean-Louis
 
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Chris,

Looking through the BBB documentation, they seem to have only implemented I2S & HDMI audio outputs.

As I understand it, SPDIF is typically generated with hardware, not a software process. So you could get an I2S-SPDIF adapter board (I've not looked for these, but suspect they are out there in our DIY world) and use it to provide a SPDIF output. Or use a USB-SPDIF adapter (I know these exist). Or look at moving over to an I2S-input DAC.

The Botic, from the latest images, does have a SPDIF input to feed to the connected DAC, but that doesn't help you.

2 cents.

Greg in Mississippi
 
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And no better pedigree than Wolfson and TP!

Greg in Mississippi

P.S. I should add that I'm inclined to connect my I2S-input DIY DAC directly to the I2S out from the BBB via short connections. Adding two jitter-prone conversions in the digital music stream never seemed like a good idea to me!
 
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Can someone with knowledge of
Japanese check following article if guy's BBB was damaged
while disconnecting power by removing the power plug?

Beaglebone Black???

Using google translator it seems so, but there might not be true.

Acording to the blog author above, his BBB appears to have been damaged while he was fiddling with cables for wiring (probably due to faulty connection between P9_ pins, I guess); not due to abrupt removal of the power plug.

twluke
 
BBB for ADC

twluke: OK, thanks for checking that :)

The BBB works well as ADC too. Here is FFT plot 1kHz signal from Buffalo3+IVY captured at 48kHz/24bit by analog part of ESI Juli@ PCI soundcard and I2S signal recorded by BBB.
 

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If the analogue signal is actually captured by another external device (ESI Juli@ PCI soundcard) then it mean that the AD conversion was/is made on that device, which also output a digital stream as I2S, further to BBB.
If BBB it record the digital stream (I2S), that do no mean that BBB it works as ADC, but as a digital signal recorder... This function it does not have something special in it...

The plot published it may represent the parameters of the AD conversion of the sound card, and it may not have anything to do with the BBB as a recorder of a digital stream, and may not reflect its parameters...

If the analogue signal should get directly into the BBB, through its (supposedly) analogue stage or an own (on board) ADC chip, then the BBB it could be called as an ADC... But anyway, an analogue to digital conversion may not have something to do with BBB as a embedded digital device...

In my opinion the above assertion it may not be quite right...
 
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Thanks for clarification Coris. Digital recorder is the right term for this usage :)

The plot demonstrates that BBB is capable to record I2S digital signal with 24 bit precision.

(( Just a while ago I've assembled ESI Juli@ back into its original state and now it's PCI audio interface again ))
 
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Yes, it is right your observation.
As many other such chips, the main processor on BBB it have analogue inputs. There are of course, some internal AD converters on that inputs, but I do not think their performances it may meed the demands for an enough high end ADC device. I mean the sampling frequencies for these analogue inputs may be limited for quite slow rate measurements/AD conversions... But I do not know actually how it works in details these inputs, or about their really performances.
For sure the BBB it may be a usefully add on in a DAC/ADC system (with the right capes), but using it as it is for such tasks/functions it may be highly improbable...
 
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