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hyperiono
Visitor
Visitor
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Registered: ‎02-16-2020

Use PCIe refclk to generate second clock

I am working on a design using AXI Mapped Memory to PCI Express IP. So far the design used two clock inputs from different sources:
1.) pcie_clk (100 Mhz) from MGTREFCLK0 pins as REFCLK for the AXI Mapped Memory IP
2.) sys_clk (100 Mhz) from two MRCC pins to generate a system clock of 200 Mhz.

From my understanding it is better to avoid asynchronous clocks.

Is there a proper way to generate the system clock avoiding the second clock input? So far i have tried connecting a Clock Wizard to the IBUFDS_GTE2 .O output and selected "No buffer" as Source for the Clock Wizard Input Clock. This works, however i am curious whether there is a better solution.

hyperiono_0-1614872194645.png

This shows the current solution with Clock Wizard being connected to IBUFDS_GTE2 .O output.
Target is an xc7k70t

Thanks

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pvenugo
Moderator
Moderator
145 Views
Registered: ‎07-31-2012

@hyperiono ,

I guess if are looking to generate the system clock avoiding the second clock input on board then using MMCM to IBUFDS_GTE is good solution.

 

Regards

Praveen


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