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Adventurer
Adventurer
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Registered: ‎05-08-2019

Intra clock hold slack violation in vivado: how to fix it?

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Hello everyone,

I have hold timing violation in my design. How can i solve it. I have tried "Performance Explore directive" and also "Vivado implementation default and enable phys_opt_design in implementation setting and add -hold_fix" in more options. But same issue. Please assist me in this. thank you.

 

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Xilinx Employee
Xilinx Employee
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Registered: ‎05-08-2012

Re: Intra clock hold slack violation in vivado: how to fix it?

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Hi @chandu_sathi 

Reviewing the routed DCP, there are no timing constraints applied. After applying a 100 MHz clock constraint, I do see a hold failure, but you would need to apply the constraint before running place and route. Below is from the implementation log (runme.log)

Phase 2 Router Initialization
INFO: [Route 35-64] No timing constraints were detected. The router will operate in resource-optimization mode.

 

The constraints can be added to the project via the constraints set. 

 

I ran an interactive test to see if timing would be met, and it was after the following commands.

create_clock -name CLK -period 100.000 [get_ports clk]
report_timing_summary  
route_design -unroute ; place_design -unplace; place_design ; route_design
report_timing_summary  

  

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Xilinx Employee
Xilinx Employee
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Registered: ‎05-22-2018

Re: Intra clock hold slack violation in vivado: how to fix it?

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Hi @chandu_sathi ,

Can you share the post opt dcp file with us?

Thanks,

Raj

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Adventurer
Adventurer
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Registered: ‎05-08-2019

Re: Intra clock hold slack violation in vivado: how to fix it?

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@rshekhaw 

Thanks for your reply. please find attached dcp files in following link.

  

Best Regards,

Chandu Sathi

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Xilinx Employee
Xilinx Employee
47 Views
Registered: ‎05-08-2012

Re: Intra clock hold slack violation in vivado: how to fix it?

Jump to solution

Hi @chandu_sathi 

Reviewing the routed DCP, there are no timing constraints applied. After applying a 100 MHz clock constraint, I do see a hold failure, but you would need to apply the constraint before running place and route. Below is from the implementation log (runme.log)

Phase 2 Router Initialization
INFO: [Route 35-64] No timing constraints were detected. The router will operate in resource-optimization mode.

 

The constraints can be added to the project via the constraints set. 

 

I ran an interactive test to see if timing would be met, and it was after the following commands.

create_clock -name CLK -period 100.000 [get_ports clk]
report_timing_summary  
route_design -unroute ; place_design -unplace; place_design ; route_design
report_timing_summary  

  

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

View solution in original post

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