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Need a simple circuit for ADC to SPiDF

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Nominal Animal:
Technically, it is S/PDIF: "Sony/Philips Digital Interface", also known as "IEC 60958 type II".

If you want more flexibility, look for "I2S to SPDIF" solutions - you'll find "a lot" of ready-made boards for this. Then you can use whatever ADC board that has an I2S output and connect them. That'll give you more choice.

ok, my spelling is wrong, sorry.  I have other boards that use I2S but nothing with USB on the other side.  I have some DSP boards that incorporate the ADAU1401 that I connect to a Crystal Semi board using I2S.  Here's a question then, I assume the USB audio gets stripped out and sent to the DAC using I2S in my USB audio adapter.  I wonder if I can intercept it easily? Standard DACs and if it is just I2S drive to SPDIF, I can yank that output circuit out of an old broken CD player maybe.  Now I am starting to sound cheap...

Thanks for the extensive post on the device tree. That was very helpful.  I looked around after you mentioned it and would have thought someone would have tried it by now, but SPDIF is old and if I didn't have the cables pulled, I would have come up with another idea.  It was cool 30yrs ago when we built the house. I will ultimately try to get it working out of the BBB.

I have some old CD players, etc, in various junk boxes and I can pull out the the SPDIF (got the spelling right except for the slash) boards.  I've done that before.  The issue with all this stuff is that it takes so much reading that I often forget what I was working on in the first place.  I remember how long it took to come up to speed on the STM32 boards. The beaglebone boards are right up there with them.  A number of people use the R-PI with an application called VolumIO and they use I2S output to the DAC and to SPDIF->DAC.  I'll search on that app as it was popular on the BBB too.  If I get the I2S out of the BBB, with the device tree configured, then the SPDIF output should be easy.

I have the wireless working and the BBB boots right into the userid and starts the application, pretty much automatic but my lovely spouse will still not be able to work it.  If I can get it down to a headless unit, that drives a DAC, I can skip the wireless adapter and use ethernet, skip the HDMI display and basically just have the BBB and some interface to the DAC.  That would be cheap enough to replicate.  Right now, I have the BBB, wireless adapter, USB audio, 7" touchscreen with HDMI audio (duplicated audio I don't need) and a remote control sized keyboard.

Thanks for all the input.  I like when all the hobbies come together - electronics, audio, do some 3D printing for cases, etc!


ps: so I found a crystal cs4228a-KS and tested it with SPDIF output and it works, not from the beaglebone but that's a software issue now.  I ran it into a Crystal DAC and I have nice clean audio at the ends of three SPDIF coax lines.  In the process of digging for a chip, I found my as-new, original box, etc minidisc player.  that is a nice little unit.  I forgot how hi-tech that package looked what, 30yrs ago?  I was hesitant to put a disc in it but it works perfectly.  I wish my DAT worked instead.  I guess the minidisc will go back on the shelf for another 30yrs.

To make thing easier, I just need the I2S out of the beaglebone.  I have an old Audio Alchemy DAC and the companion DTI that takes I2S input.  So I just need to figure out the beaglebone and supposedly it is already setup.  I've had this DAC for 30yrs, forgot about it, found it cleaning out the closet where the BBB setup will reside.  Still haven't found my missing HP 15c and 11c calculators. 



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