AnsweredAssumed Answered

AD9361 VCO calibration lock

Question asked by Super on Jul 13, 2014
Latest reply on Oct 8, 2014 by jd20878

HI guys.

 

I work with on AD9361(FMCOMMS2) with my XILINX-V6 board.

I make it work on FDD mode and the REF_CLK is 40MHz, and the working frequency is 2.45GHz. I follow the instructions of the AD9361_Design_File_Package to configure the chip, the problem is as follows:

 

During my initialzation, I first enter the chip into ALERT state with FDD mode. BBPLL VCO calibration and RF synthesizer charge pump calibration is done. Then I configure the RF related registers(based on LUT form ADI) and follow the order to triger the RF synthesizer VCO calibraion, BUT the PLL lock bit in register 0x287[1] donot go high to indicate the calibration is done.

 

I re-check my settings twice to confirm my HDL code agrees with the PDF saying.

And I also notice that the lock detector 0x28A has a lock detect count setting. I let this time to be maximum as 2048 reference clock time. After calculating, this time is still less than my calculated VCO calibtation time.

 

Is that the reason why I couldnot detect the PLL lock state ?

What other methods can I know the PLL is lock ?  Or

whar other methods can I check sth is wrong with my design ?

 

THX all.

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