ADAU1701 propagate non-standard SR failing
We're using an available clock on our board that happens to be running at 2.77MHz to drive our 1701. With 64 x fs mode, this implies a 43.2kHz actual sample rate.
Inside Sigma Studio, the drop-down sample rate menu is limited to standards - 44.1kHz, 48kHz, etc.
We can right click on the input block to set sample rate manually, but the result will not propagate. Instead it returns an error "Uncompatible Sample Rates. Please Verify." If everything is set to 44.1kHz it seems to work.
Are there specific blocks that are allowed only "standard" sample rates?
Audio Signal Processors
sigmastudio
SigmaDSP Audio Processors
SigmaDSP
adau1701
Please check the Set System Sample Rate FAQ:
https://ez.analog.com/docs/DOC-1431
If you scroll half-way down the page, you'll find a section labeled "Setting "Non-Standard" Software Sample Rates".
This information is also available (in a slightly altered form) on our wiki, at this link:
I hope this helps.
Thanks for the quick response - I had actually followed these instructions exactly to set a non-standard rate, and experienced the problem I described. What is the cause of the propagation error? Are there any blocks that cannot accept nonstandard rates?
Hmmm. One possible source of the problem would be if you use several "source" cells in your project. All of those need to be set by right-clicking and selecting "Set Sample Rate."
Examples include:
Input cell
ASRC input cell
GPIO input cell
DC source cell
Sine tone generator cell
Beep source cell
Sine tone sweep cell
Basically, any cell that only has output pins (no input pins) will have a right-click menu option allowing you to set the rate, and if you missed any of these cells in the project, you may get the error you described.
Thanks, that's what it was. Manually setting them fixed it.
But isn't this what the "Propagate Sample Rate" button is supposed to do? I was under the impression the SigmaDSP couldn't support multiple sample rates within one schematic, so I would have assumed all blocks should always be the same.
SigmaDSPs can't support multiple rates within the same chip, but SigmaStudio can support multiple ICs in the same project, so you could (for example) have an ADAU1701 in a project running at 48 kHz and an ADAU1442 in the same project running at 44.1 kHz.
In that case, you'd have to manually set the signal path for the ADAU1701 to 44.1 kHz and the signal path for the ADAU1442 to 48 kHz.
I'm not really sure why anybody would ever want to do this in a real system, but the option is there in case you need it.
Please log in to reply.