Group together two ADAU1701s for 8 outputs, SP/DIF, DTS/AC3 decoding

Hello Leon,

LeonFunnell said:

I would like to know if it is possible to build something like a 2-input, 8-output DSP using a pair of ADAU1701s connected together digitally

I would like selectable stereo analog inputs. Could I somehow use the audio inputs on both DSPs and reverse the direction of the digital interconnect? Alternatively, could I nominate one channel per-DSP and just share a control-plane somehow?

You can connect the serial ports between the two units and how you use them is up to you and the program you create. The serial port in this part can support up to TDM8 for each channels in and out.

LeonFunnell said:
Is there a way of setting up an SP/DIF input on one of the DSPs then chain the signal digitally to the other one?

This part does not have an SPDIF input. You would have to jump up to the ADAU1452 which will complicate the design quite a bit.

You can use an external SPDIF receiver but then you would have to use the serial port to get the data and that would mess up your first question about communication between DSPs.

LeonFunnell said:
Is it possible to add time alignment for each analog output/speaker? Can this be calibrated with a tone and microphone somehow?

Yes, you can insert delay cells in your program to adjust the timing of different outputs.

LeonFunnell said:
Finally, is it possible to decode AC3/DTS from the SP/DIF input into 7 discrete channels (front/rear/surround/bass)?

No, you have to jump up to a SHARC processor which will really complicate the design. We do have the SHARC Audio Module if you want to investigate this option. https://www.analog.com/en/design-center/evaluation-hardware-and-software/evaluation-boards-kits/sharc-audio-module.html

This all said, if you are new then the SAM board is a huge leap. I suggest you start slowly and build a small project. All of your questions you asked are answered here on the forum already so use this forum to help you learn about programming SigmaDSPs and how to use SigmaStudio. The ADAU1701 is a great place to start so you are doing well to start there.

Dave T

Hi Dave, thanks for your detailed reply and sorry for the delay in mine! I ended up ordering a Chinese ADAU1452 board with a separate codec board for around GBP£50. It's very similar to the development board you produce. It's a great little board and has enough inputs and outputs for my needs, including SPDIF in and out, 4 audio inputs and 8 audio outputs.. I think rather than complicating my design it has simplified it immensely. I did manage to connect the two ADAU1701 boards via serial but it was annoying to programme and I couldn't use things like stereo widening effects, etc. The new board also has a micro controller on it but I'm yet to work out how to programme it, not sure if I can use the Arduino SDK or if there's something in Sigma Studio I can use.

I've managed to hook up my board with a Wondom USBi interface which also includes a Bluetooth-LE interface. It would be great if Sigmastudio could access the board over Bluetooth from my PC. Any ideas?

Thanks again for your advice!

Hello Leon,

Glad you are making progress. We cannot communicate over Bluetooth although it is an interesting idea but in reality I think there would be too many issues.

Dave T