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Booting and loading via I2C to ADAU1761

Question asked by GUSADI12 on Sep 5, 2012
Latest reply on Sep 19, 2012 by BrettG

Hello:  I am trying to use a PIC 16LF1937 on a F1 evaluation platform to I2C load / boot a ADAU1761 on a  EVAL-ADAU1761Z board.  I have connected the ADAU1761Z board J1 pin one to SCL pin on the PIC and J1 pin 3 to SDA pin on the PIC.  Power and ground are appropriate on both boards i.e. common, the 10k pullups are on the ADAU1761Z board and there are none on the PIC side.

I am trying to establish communications to the 1761 from the PIC being the master of course.

I am simply sending the address to the 1761 on the ADAU1761Z board as 0x70 and looking for a ACK.   I never see a ACK.  I have attached a .JPG of a scope shot of the write, SDA top trace SCL bottom trace, and can not see anything wrong in the data, i.e. writing a address of 0x70, except of course no ACK on the ninth bit.  If you see anything wrong with this timing please advise.

I believe the start bit is appropriate at the beginning of the trace as defined as

The I2C master initiates a data transfer by establishing a start condition, defined by a high-to-low transition on SDA while SCL remains high

The start is 20us in duration as outlined by the vertical cursors in the shot.

I do not have the USBi connected and am powering the ADAU1761Z board external.

Is there anything I need to be doing before trying to write to the 1761 ?

Does my I2C data look correct? or ?

 

I have seen the tutorial and code at http://ez.analog.com/docs/DOC-1806

as well as http://ez.analog.com/docs/DOC-1946 and http://ez.analog.com/message/36630

I am trying to do something “much simpler “then that, as mealy getting the 1761 to tell me its there by a ACK to its address.

 

Any suggestions would be of help... Thanks

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