I'd like to capture the audio with my digital ADMP421 microphones on my EVAL-ADAU1761Z board. Is this possible? If not, does Analog make an eval board that works the ADMP421 microphones?
I don't have any experience with that Maxim chip, but I can certainly recommend this solution from XMOS (since this is actually what we will be using in our new evaluation board designs). http://www.xmos.com/products/development-kits/usbaudio2
Perhaps there is no real advantage or disadvantage to either solution, but if you design in the XMOS solution, it will match ours and therefore it will probably give you out-of-the-box compatibility when we integrate that into SigmaStudio.
J4 on the ADAU1761 breaks out the digital microphone connections. I have used this before and it has worked. Make sure you jumper correctly on J7 and J8.
Be aware that the ADAU1761 can output audio in I2S format or as an analog signal. If you want to then capture that audio, you'll have to use an appropriate recording interface that can accept one of those inputs.
I was hoping the USB bus could capture the digital microphone data via the UAC driver. Is that not possible on the EVAL-ADAU1761Z? Is there any Analog eval card that will let me capture audio so I can perform audio tests on the ADMP421 (e.g., measure SNR, do subjective tests for speech)? Do I need to get a non-Analog codec eval board to do this?
The existing USB interface board that comes standard with all SigmaDSP evaluation kits has support for I2C and SPI only. It does not (yet) have support for USB Audio. We are planning on creating a new board that will have support for audio streaming to and from the evaluation board, but this is not yet ready.
At the moment, the easiest solution would be a high-quality USB audio interface. As long as the converters are high performance, you should be able to out-perform the microphone's noise floor.
Can you recommend any USB board I can use to capture audio from the ADMP421? How about:
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