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dballesteros
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Registered: ‎12-17-2008

Signal to determine CDR is locked in GTP?

 

Cannot find in UG196 what signal should I use to determine CDR is locked in GTP.  I only find PLLLKDET but that one is for the shared PLL. Anyone knows what signal to use?

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dballesteros
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Registered: ‎12-17-2008

 ok, found the answer from UG196, but not happy with it. I was expecting a signal directly from GTP to determine CDR is locked.

 

Page 167,   Normally, CDR lock is detected by measuring the quality of incoming data. Methods for detecting CDR lock include: Finding known data in the incoming data stream (for example, commas or A1/A2,  etc...

 

I think that is an incorrect way to determine CDR is locked. Easily, TX far-end point can be sending A1/A2 wrongly, but that doesn't mean CDR is not locked. 

 

About the documentation, I didn't find this information before because is on the RX phase alignment part. I think that information should be under RX clock data recovery part.

 

Any thoughts about this?

 

Diego

 

 

 

 

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ezequielsasky
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Registered: ‎02-22-2010

Diego,

 

This was a long time ago

 

Did you get any comment/answer?

 

Thanks,

Ezequiel

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