Use SPDIF input without ASRC
Thread Summary
The user inquires about bypassing the ASRC block to directly use the S/PDIF input on the ADAU1452 and ADAU1467. The final answer confirms that the S/PDIF input can be directly accessed by the DSP core using the S/PDIF input cell, but warns that the core's start pulse must be set to the SPDIF input rate to avoid sample issues. The ASRC is typically used to match the S/PDIF rate to the DSP core rate, so if using both S/PDIF and Dante inputs, a system controller can switch between the two rates.AI Generated Content
Here's one for someone who knows the SigmaDSP internals (Dave, is this one for you ?)
Our products make use of the S/PDIF input on the ADAU1452 and ADAU1467, usually through one of the ASRC blocks - but we have had a customer who has asked if we can do it without the ASRC !!
We have explained that the Sending Device would have to be locked to the same Sample Rate clock (in our case this would be a Dante Network Audio system) and they are OK with that.
My question is - While specifying that the ASRC is driven by the SPDIF and taken a signal from the ASRC block, is there a way to take a signal directly from the SPDIF input into the Schematic and then use a switch to select one or the other ?
EDIT: I should add that I found in the ADAU1467 data-sheet (page 50) that it says "The S/PDIF receiver can be accessed directly in the DSP core by using the S/PDIF input cell" - but I can't find the S/PDIF Input Cell in the Toolbox Tree in Sigma Studio.
Thanks
PhilipJ
Edit Notes
added an Edit note at the end
[edited by: philipj451 at 1:23 PM (GMT -4) on 16 Jul 2026]
spdif
hardware
adau1467
processors and dsp
adau1467z
Processors and Microcontrollers
asrc
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Hello PhillipJ,
Yes, you can take the SPDIF input directly into the core. However, you will face some problems.
I attached a project that does this.
However, also note that the Start Pulse for the core is set to the SPDIF input rate.
This way the DSP core will not miss any samples or use any samples twice.
The ASRC is there to convert the SPDIF rate to whatever the DSP core rate is.
So if you are also taking signals from the Dante network and mixing them or somehow using them at the same time you will have a sampling rate problem.
I guess unless you know the SPDIF sending device is also using the same Dante sampling rate then you can just run the core at the Dante rate coming into the serial port.
If you are only listening to one or the other then some system controller can switch the inputs and then switch the core rate to the correct setting.
Dave T
ADAU1462 SPDIFStereoWithOutASRC.dspproj
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