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ADAU1761 I2C only works after programming device

Question asked by eric_engineer on Dec 21, 2014
Latest reply on Jan 8, 2015 by eric_engineer

I've done a bunch of work with my ADAU1761 board and now I'm ready to have my microcontroller program it.  I've read the presentation/guide on how to do it from analog.   My codec programs fine when I use SigmaDSP.


I built up some I2C functions to test the interface between the codec and my mcu.  When I try to read a control register to verify my connection I get ACKS, but the data always comes back 0x00.  But then I thought to load the codec using SigmaDSP first, and then my reads worked fine (default values shown in the datasheet were returned).


So I feel like maybe you have to do a bunch of writes to configure clock and start the processor before you can read control registers?  Is that true?  Is there a simple register I can read for verification?  It would be nice to have a register to read that said yes this is an ADAU1761.


Thank you.