Volume controls on ADAU1701
Hi All
Just a quick heads up about a problem I found controlling the SigmaDSP volume controls from the I2C port.
If you capture what SigmaStudio does as it changes the volume settings, you can see it writing directly to the volume control memory. I used this captured procedure as the basis of my volume change routine in the micro-controller code. I sometimes got pops and bangs when I changed the volume levels with this code. I then changed the routine to use the safeload registers to do the volume change and so far all has been quite.
So it looks at though SigmaStudio is programmed to change the volume controls in an un-optimised way.
Regards
John
Audio Signal Processors
SigmaDSP Audio Processors
adau1701
HI John:
Thaks for the heads up. My guess (without confiriming the problem) is that you were direcly accessing memory and modifying it at the same time as the core trying to access it.
We certainly do recommend that you do safeload as much as possible. It doesn't hurt and will probably avoid these type of problems.
MIguel
Hello John and Miguel,
Although manually adjusting a Non-Slew volume control does a direct write (as John observed in the Capture Window), adjusting a Clickless SW Slew volume control does perform a safeload write:
Apparently, the SigmaStudio software designers originally figured that if you're not using slew, no need to bother with safeload. However, as John's experience and Miguel's comment shows, it's necessary to safeload even a one-parameter adjustment on a running DSP.
Best regards,
Bob
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