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[Bug Report] ADAU145x multi rate problems

Question asked by InoJosh on Oct 13, 2016
Latest reply on Oct 25, 2016 by InoJosh

SigmaStudio version 3.13

Windows 7 Pro 64-bit Service Pack 1


I am seeing some really strange behavior with the new mulitrate blocks on an ADAU1451.

I created a small project to show the issue:


The Sigma is running at 192k (START PULSE is Base_FS * 4) with four 48k stereo inputs (4 ASRCS with output rate set to Internal FS) . That is, every wire before the upsampler shows 48000 and those after show 192000.

Notice the second pair of readbacks showing the same levels as the third pair of readbacks, which it should show the same as the first pair of readbacks.

With the "Input Source" selector in the first position, you hear the oscillator regardless of which position the "Osc Enable" switch is in.


Take the same setup and add a couple of blocks after the upsampler (what they are isn't super important, it's the result that matters):

Now, "Input Source" is set to the 4th position... but the audio passing to the output is that of the first pair of inputs. Haven't a clue what's happening there.


If you take the first example again, and remove two pairs of inputs from the "Input Source" mux:

This fixes the problem, and now the "Osc Enable" switch does switch between the inputs and the oscillator. The readbacks show the correct levels.


If you take the same setup again but remove the upsampling block:

This also fixes the problem.


I've attached the project, but the IO is set up for my hardware. I don't have the dev board, but I imagine this can easily be tweaked to show some similar results on it.