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Registered: ‎10-08-2019

Vivado simulation not working for IBUFDS

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I'm trying the Vivado simulator for the first time. I've written a testbench, and can see that those signals including the clock, are passed through and recognized by the UUT. However, the signals aren't "passing through" the IBUFDS component. See the images. The UUT's "sys_clk_n" and "sys_clk_p" are recognized and oscillating. Those are inputs to a IBUFDS, as seen in the second picture. But the output, "sys_clk_i" is undefined for the whole simulation.

Is there something wrong with how I implemented the differential clock? I've tried this with the behavioral, post-synthesis, and post-implementation simulations and get the same thing.

simu1.png
simu2.png
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Voyager
Voyager
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Registered: ‎06-20-2012

Re: Vivado simulation not working for IBUFDS

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I think you added the signal sys_clk_i after simulating the first 1000 ns ( default value).

Vivado only displays the signals after they are added.

Simulate again1000 ns ( run 1000 ns).

== If this was helpful, please feel free to give Kudos, and close if it answers your question ==

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Voyager
Voyager
124 Views
Registered: ‎06-20-2012

Re: Vivado simulation not working for IBUFDS

Jump to solution

I think you added the signal sys_clk_i after simulating the first 1000 ns ( default value).

Vivado only displays the signals after they are added.

Simulate again1000 ns ( run 1000 ns).

== If this was helpful, please feel free to give Kudos, and close if it answers your question ==

View solution in original post