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Explorer
Explorer
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Registered: ‎11-28-2011

Ultrascale GTH Dynamic Change

Does the following AR apply to the Ultrascale GTH's as well? 

https://www.xilinx.com/support/answers/53779.html

Reason why I ask is that I'm attempting to change the line rate by changing rxrate only in simulation I don't see any resets occurring automatically as UG576 alludes to. 

"GTRXRESET or reset sequence is performed automatically due to RXRATE. See RX Rate Change, page 79 for more information."

"In most cases, in addition to changing the output divider, an RX rate change requires
changing the RX CDR loop filter settings via DRP. After writing in the proper RX CDR loop
filter setting and updating the RX_OUTDIV attribute via DRP, the RX must be reset by
toggling the GTRXRESET port. In cases where the CDR loop filter does not need to be
updated via DRP, rate change can be performed using the RXRATE port with RXRATEMODE
set to 1'b0. As a result, the required reset sequence is performed automatically.
RXRATEDONE being asserted in response to RXRATE indicates that both rate change and
the necessary reset sequence have been applied and completed.

Is it required to use DRP as well?

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Explorer
Explorer
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Registered: ‎11-28-2011

BTW the respective options in the Buffer Control section of the GTH wizard are Enabled as well. image.png

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Explorer
Explorer
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Registered: ‎11-28-2011

Ok, so more details. My state machine now issues a gtwiz reset_all after I change the rxrate and txrate ports to the gthwizard. I can see the tx path reset, then the rx path, but I don't see any rate changes out of the txoutclk and rxoutclk. Does simulating GTH's support rx and tx rate changes?

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