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Problem with 10MHz External Reference

Question asked by pwz on Apr 27, 2018
Latest reply on May 3, 2018 by srimoyi

hi, 

When using 10M as external reference clock input and set scale to 1x 2x 1/2x but fonnd out all initial script fail. The reference clock is from VSG generator, AC couple, 1.3Vpp。

When changing to  20M / 40M,  AD9361 works!   So there is no need to doubt my hardware & software  driver is not OK.

 

1/4 scale setting is possible as  vco frenquency range  of bbpll  limits. 

 

I found  two tips 

one   is 

 mhennerich    in

 

https://ez.analog.com/thread/48632#202363 

 

said: "I just checked again - and 10MHz work without problem.
A few things need to be considered."

a) using external clock the XO must be disabled.

See here: AD9361 Device Driver Customization [Analog Devices Wiki]

adi,xo-disable-use-ext-refclk-enable must be set.

 

b) The clock must be specified for 10MHz

 

ad9361_clkin: clock@0 {
#clock-cells = <0>;
compatible = "fixed-clock";
clock-frequency = <10000000>;
clock-output-names = "ad9361_ext_refclk";
};

 

c) And then most important the level at the XTALN pin must not exceed 1.3Vpp.

I used a board with the Crystal removed.

 

Then everything works expected.

 

 

But I stil working on this ways. It c code writing in driver style , i need some time to go through and figure out how to mapping to my initiial scripts.

 

Other tips as follow but..., you know ,still helpless to me .

 

Problem with 10MHz External Reference 

 

And all initial script code are post there, can someone show me how me some tips to figure out this issue.

  Sincerely thanks !

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