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Explorer
Explorer
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Registered: ‎03-27-2017

Theory: Use of TX Phase Interpolator

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Hello transceiver experts,

 

Reference: Ultrascale+ GTY (p. 165-167)

 

There is example code given on p. 165 on the usage of the TX phase interpolator to match TARGET_CLOCK to TXUSRCLK2.

 

From my understanding: TXUSRCLK2 is output from the transceiver to clock the TX interface logic and TARGET_CLOCK is some clock signal. The disparity between the two will control the signals TXPIPPMEN and TXPIPPMSTEPSIZE to perform phase matching, but which clock signal will be modified? I'm thinking it's TXUSRCLK2 which is internal to the transceiver channel (refer to p. 157)? From the code comments:

 

// This is an example of using TXPIPPM to match TARGET_CLK to TXUSRCLK2
// TARGET_CLK is running at the same frequency as TXUSRCLK2

  This suggests TARGET_CLK will be the clock which will be modified???

 

Please help clarify my understanding of this!

 

 

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Moderator
Moderator
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Registered: ‎07-30-2007

Refer to the diagram on page 157.  The code is actually matching the TXUSRCLK to the Target clock.  Not the other way around.




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Moderator
Moderator
1,724 Views
Registered: ‎07-30-2007

Refer to the diagram on page 157.  The code is actually matching the TXUSRCLK to the Target clock.  Not the other way around.




----------------------------------------------------------------------------
Don't forget to reply, kudo, and accept as solution
----------------------------------------------------------------------------


View solution in original post

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Registered: ‎03-01-2019

Thanks for pointing out there is a sample code. I just used it on artix 7 gtp. It matched tx clock with target clock. 

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