[Bug Report] Audio Quality degraded above ~390 SDSP instructions (ADAU1787)

ADI'ers,

I've got what I think is an interesting bug on the ADAU1787 and I suspect it is something to do with the compiler/linker.

I'm feeding audio in through serial port 0 and using ASRCI0 to upsample the 44.1k to the 48k that my application is running at. Everything is working great and the audio sounds good if I keep the instruction count for the SDSP below ~387 (out of a possible 512 at 48kHz). I'm not using the FDSP at all currently.

If I add a DC source and SDSP Output that are in no way connected to the main audio signal path, this bumps me up to 391 instructions and audio quality is reduced but not absolutely atrocious.

If I add a second DC source and SDSP Output, this bumps me up to 395 instructions and audio quality is absolute garbage.

What's even more interesting is that IT DOESN'T MATTER WHAT SAMPLE RATE IT'S RUNNING AT!!!

I've dropped the sample rate down as low as 22k and the behavior is exactly the same. Everything is fine up to 387 instructions and above that audio quality is degraded.

Data RAM usage is at 1390 out of 2048 and Parameter RAM usage is at 609 out of 2048.

Have you ever seen anything like this? Is it possible I'm doing something silly in my application? I'm happy to share the project directly with an ADI employee if you DM me. I need to get this resolved ASAP so I can finish building my application.

Thanks for your time,

Trey

bug_report

ADAU1787

Integrated/Special Purpose A/D Converters

sigmastudio

Audio CODECs