Connecting EVAL-AD5933EBZ to an Arduino UNO

There is no particularly convenient spot to connect to the SCL and SDA traces on the evaluation board, on the schematic those are interpage connectors, no holes. Perhaps the least inconvenient would be to use the pads of R16 and R15 pullup resistors, it is pretty obvious which of their pads are connected to VDD, so you may consider soldering thin wires to the opposite ones. You have probably seen the schematic on page 24 of this document. Jumper LK6 needs to be placed so that the VDD-EXT could power the board, see page 25 of the same document. As long as the on-board microcontroller is not connected to USB and not initialized, its SCL and SDA pins should not interfere with the operation of the external Arduino.
Good luck with the rest of your project!

Hi Snorlax,

Thanks for your response!

Yes, that was just a clear image from DDG that I used as my board is wired at the moment. LK6 is jumped to "B" for the external power supply and is fed into the VDD-EXT --> 3.3V UNO and DGND --> GND UNO. I soldered wires to the R15 and R16 with resistors still intact because my understanding is that it is a necessity for the SDA and SCL, is this correct? or should I remove those 2k2 nano resistors?

Once doing so, when I ran a I2C test scanner on the arduino it still did not recognize the I2C and was stuck on "I2C scan starting"

Sciencerely, 

Ryan

RS89 said:

or should I remove those 2k2 nano resistors?

It depends, if you have these SCL and SDA pullup resistors on the Arduino side, then the ones on the EVAL board become excessive and potentially make the Arduino outputs sink unnecessarily high current.

RS89 said:

Once doing so, when I ran a I2C test scanner on the arduino it still did not recognize the I2C and was stuck on "I2C scan starting"

If the wires are connected correctly, the EVAL board is not connected by USB cable to the computer and the EVAL board shares ground and power with Arduino - it should all work. Beyond this, there is a risk of sending you an a wild goose chase...
Are SCL and SDA connected to the right pads of the resistors and not crossed between the EVAL board and Arduino?
Is there any way of checking your Arduino by hooking it up to a known functional I2C chip or device?
Do you have an oscilloscope to poke at the SCL and SDA lines to see the waveforms?
Was the EVAL board operational in its original state?

Yes, the wires are connected to the pull-up resistors (brown and purple wires draw as they are connected in the EVAL board image bellow) and reading 3.3V on the oscilloscope. The USB cable for the EVAL board is disconnected, and the board was/is able to measure impedance of known resistor values.

Snorlax said:

Are SCL and SDA connected to the right pads of the resistors and not crossed between the EVAL board and Arduino?

The wires are soldered to the SDA and SCL of the 24LC64 (Using the chip manufacturers datasheet) and I place the pins in A4 (SDA) and A5 (SCL) of the Arduino.

Snorlax said:

Is there any way of checking your Arduino by hooking it up to a known functional I2C chip or device?

Yes, I tested this with another Arduino running a "Controller" to "Target" script and it responded. I also am using the Arduino to control several relays, and this is not a problem. Thank you for your help!

Sorry to hear that the issue is more difficult than expected.
When Arduino is not connected to the powered-up EVAl board, are the voltage levels on both SCL and SDA lines high? When the Arduino is connected, with the oscilloscope, can you see the characteristic SCL and SDA waveforms while running the I2C scanner on Arduino?  

Yes, both waveforms were high and then the signal transition as expected. Arduino was outputing the proper signal as well. However when I connect my board now it is not allowing it to calculate gain factor and I think this may be due to the soldering to R15 & R16. Ive tested the continuity of these traces based on the circuit schematic and they appear continuous.  

RS89 said:

Yes, both waveforms were high and then the signal transition as expected. Arduino was outputing the proper signal as well.

This means that the un-initialized controller on the Eval board (I2C master in normal operation) did not interfere with the signals from Arduino, which was acting as the I2C master. It is hard to imagine that I2C test scanner does not see the AQD5933 and the 24LC64 chips on the board, while it sees other unrelated chips elsewhere.Assuming the oscilloscope screenshot is made with the Arduino, the I2C signals seem to comport to 100kHz speed and look normal. 

RS89 said:

However when I connect my board now it is not allowing it to calculate gain factor and I think this may be due to the soldering to R15 & R16.

Presumably with the Arduino disconnected from the board? The wires connected to the resistors and not connected to anything else should not affect the I2C operation. The Evaluation Software does not allow to calculate gain factor? How does this manifest itself, empty field in the UI or some error message? You may try sweeping frequency without calculating gain and storing the sweep data in a file by pushing  "Download Impedance Data" button. If there is no data in the file - something is quite wrong with the board.  

Without seeing your setup, not sure I can be of any further help with this. May be somebody from ADI can give some suggestions?