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Visitor
Visitor
624 Views
Registered: ‎06-24-2018

Delay Calculation

what is the difference between path delay obtained from vivado simulation tool and delay calculated by cadence .

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Teacher
Teacher
591 Views
Registered: ‎07-09-2009

Which cadence program you asking about ,
Vivado is a FPGA design tool for Xilinx Parts,
BTW: simulation of what are you refering to.
pre synthesis / post synthesis , post place and route ?

pre synthesis does not have any timing information
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Observer
Observer
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Registered: ‎06-19-2019

cadence will give (smart) assumptions about the delay, so that you will be able to analyze critical path in the synthesis stage and handle them early.
Vivado (which is not simulation tool) will give the same capability (timing after synthesis) and will give you also the actual timing (after implementation) -> sign off.
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Visitor
Visitor
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Registered: ‎06-24-2018

for a module implemented using VIVADO KINTEX-7 FPGA. simulation tool ,i obtain a path delay of 3.12 ps,the same module  synthesized using   Cadence Genius with 180nm  got  a  delay of 2452ps.

Is this different  beacuse of logic family?

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Teacher
Teacher
489 Views
Registered: ‎07-09-2009

whats this 180nm ?
there is no difference in numbers,
Xilinx knows its chips and its tools reflect that
Cadence works knowing what you have told it.

I would strongly suggest that as Cadence tout Genius as giving a better P&R than Xilinx tools, then this is a question for Cadence as to why they are so different to the correct Xilinx Answer.
Im certain they would be very interested in why they are almost 1000 times worse than Xilinx tools,
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Teacher
Teacher
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Registered: ‎06-16-2013

Hi latha@2017 

 

Since you don't consider the difference between different process node (180nm and 28nm).

So, you must use same process node between Xilinx's tool and Cadence's tool.

 

Best regards,

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