ADAU1401 Connection with PCM5102A Troubble shooting

Lawmann10 Question

Feb 10, 2025 00:00

Hello there,

I have recently created my first project in sigma studio for an amplifier I am putting together. The Project had been running fine using the DAC's Build into the ADAU1401 however I have been trying to upgrade it and connect some PCM5102A DAC's over I2S to increase output amplitude before my apm stage. I have been following This post however i am unable to get it to work at all.

The project I have built is I think on the more complex side, however I can see that I have metering on the outputs inside sigma studio while the DSP is running, however no output to the I2S DAC's.

Any help is much appreciated, Thanks.

i2s outputs

Audio Signal Processors

hardware

ADAU1401 I2S

adau1401

SigmaDSP Audio Processors

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DaveThib Reply

Feb 10, 2025 00:00

Hello Lawmann10

First little thing I noticed is that the fourth output channel is still set to use the DAC and not the Digital output. Not a huge deal, you would have noticed the missing channel had you gotten further.

I also want to mention that you should be using a DC block at the very input of your schematic to block the DC offset of the ADC converters. Again, this is not exactly what you are asking about. the reading on the meters is very likely the DC offset unless you have a roll-off of the low end in your filters.

I attached an example project where I did a digital loopback to show how to do digital in and out.

I did not notice a reason for why it is not working. It seems from my first quick initial look at your info you posted that you have the registers setup correctly.

I suggest you look at what is coming out on a scope. This will help you narrow into what the problem is.

I wrote this post a long time ago on how to take screenshots of I2S data. This may help you setup the scope properly.

Post what you find and see if something is missing so we have an anomaly to chase down, or post your project.

(+) How to Take Meaningful Screenshots of I2S Audio Signals - Q&A - Audio - EngineerZone

7065.ADAU1701 Digital Out with Digital In Loopback test.dspproj

Thanks,

Dave T

7065.ADAU1701-Digital-Out-with-Digital-In-Loopback-test.dspproj31.2 KB

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Lawmann10 Reply

Feb 14, 2025 00:00

Hi DaveThib,

Thank you for the response! Unfortunately I wasn't able to get your example project running either.

I have also added the DC Block and I'm still getting level metering just before the outputs so I dont believe it's the input chain. I dont have access to an osciliscope at the moment as university is still shut for summer break down here in AUS, but when I can, I will measure the outpouts and make a follow up post if I still can't get them working.

Thanks, Lawson

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