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AD9850 W32 !=0 problem

Question asked by rectifier on May 13, 2012
Latest reply on May 20, 2012 by rectifier

Hello, and my apologies if this has already been covered elsewhere. I have tried to search for an answer but I'm new here and I always get zero search results for this.

 

I seem to have destroyed three AD9850 chips (working in serial mode) by using some borrowed code that was intended for AD9851 chips. The AD9851 code sets W32 high (i.e. use 6x clock multiplier). Unfortunately having W32 high (in serial mode) is not allowed on the AD9850 because it is one of the code combinations that are disallowed as in this warning (page 9 of the AD9850 data sheet) :

 

     Note: There are specific control codes, used for factory test

     purposes, that render the AD9850 temporarily inoperable. The

     user must take deliberate precaution to avoid inputting the

     codes listed in Table II.

 

So three of my four chips are no longer communicating with me . The above paragraph suggests it is temporary, but all three are still incommunicado

despite resets, and rewrites of the 40 bit tuning word.

 

Any ideas?

 

Andy.

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