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eval-adf4350 register programming

Question asked by biff44 on Jun 2, 2013
Latest reply on Jun 3, 2013 by rbrennan

having all sorts of fun trying to get the five registers to program fro a microchip eval board.  then tried the pll boards with a usb connection on my desktop, and still had trouble using the included  ADF435x software and usb bus!!!

 

on first turn on, sw detects board.  Try to load a frequency, such as 2000 MHz, leaving all other values as in ADF435x software.  it does not take, green lock detect light stays dark.

 

If I manually load R1 register, then after that "load all registers", it will take.  Lock detect light turns green.

 

then I can change frequencies, hit "load all registers" only once and the new frequency takes.

 

but after manually doing maybe 5 or ten more frequencies, trouble again.  On spectrum analyzer, slight frequency error AND some weird modulation. 

 

Once again, I manually load R1 register, then "load all registers" and the weirdness goes away and I have clean spectrum at the desired frequency.

 

Well......what the heck is going on.  Is there a known defect in these boards.  2 different boards do the same weird stuff. !!!????

 

it is like the registers were corrupted, and loading just the R1 clears it and is ready to accept new data.

 

Of course, we are having trouble writing from our own software, so ...doubly screwed.

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