So I'm working with this part the ADAU1761 it's a little dsp codec from Analog. I'm trying to get I2C communication up between it and my PIC32. I spent a good part of today trying to get this to work, thinking I would verify it by reading a register. I was getting ACKs but no data returned. Finally I tried manually programming the ADAU1761 and then reading registers worked fine. I'm suspicious that maybe I need to write some clock values to it first, but so far it's not too clear from the datasheet.

I am reading the datasheet and I did read their document on how to program the whole device. I was trying to take baby steps by verifying my i2c first before trying something more advanced though.

Anyone have an experience with these parts, who might know what I need to do?

  • \$\begingroup\$ Perhaps if you showed us what you've already tried we can tell you what you've done wrong. \$\endgroup\$ Dec 21, 2014 at 22:39
  • \$\begingroup\$ Well I wrote routines to read and write I2C using the PIC. Then I mucked around for hours trying to get read data back from the ADAU1761 control registers that matched a default setting. When I manually program the ADAU1761 first using sigmadsp, the dsp comes up and works. Now after that I get valid data back when I use the same routines to read the config registers. So I was just wondering if anyone knew if you have to program the DSP first, maybe to get clocks and enable processor, for it to work. I can see the transactions one my scope. \$\endgroup\$
    – confused
    Dec 21, 2014 at 22:49
  • \$\begingroup\$ Do you have pullup resistors on your I2C lines? \$\endgroup\$
    – Majenko
    Dec 21, 2014 at 23:08
  • \$\begingroup\$ Yes 2K on both lines, reads work fine after dsp is configured. They are acked before the dsp is configured, but data is all zeros. \$\endgroup\$
    – confused
    Dec 21, 2014 at 23:18

1 Answer 1


For future folks, it turns out that you do have to program the ADAU1761 completely first before you can read registers. I got it working after talking to some people at Analog and borrowing a Logic Analyzer.


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