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Question on Programming AD9837 on EVAL board

Question asked by Mikeg on Oct 23, 2014
Latest reply on Nov 9, 2014 by LouijieC

I am trying to program an AD9837 EVAL board from SPI port on my ZYNQ dev system.  I do not seem to consistently program the part and can sometimes affect a change but never see what I expect.  I have not even been able to get the part into reset as shown in the attached scope shot.  I also found that the EVAL board comes with jumper LK1 placed and that connects VDD to the CAP/2.5V pin of the AD9837.  I am running VDD at 3.3V and am worried that I may have damaged the internal core leading to the SPI issues.  I never saw a high current situation and when I remove the jumper I do see 2.5V on the CAP/2.5V pin.  I think the SPI timing looks OK and have been slowing it down as well as increasing speed/drive of ZYNQ SPI outputs, but to no avail.

Looking for ideas on how to approach this.