STA tool and multi-cycle paths

[vikas_lakhanpal27]

Hi friends,
Assume in a design we have 2 flops. There is very big combo-cloud in between these two flops. Now assume the combo delay is so big that the data is getting registered after 1 extra clk edge at second flop (it is becoming multicycle path but actuaaly it is not) and also assume we are not getting any violataion as the data is not changing in between setup or hold window.

Is it possible for STA tool to catch this issue?

Thanks and Best Regards,
Vikas

Happy Valentines day too!

 

[santuvlsi]

Re: STA doubt

Dear vikas_lakhanpal27,

Multi cycle path must be configured during synthesis, to ensure

synthesis tool doesnot try to optimise the path into a single clk

cycle.

Multi cycle path needs timimg analyse its a need and must. it must be optimised

santu

 

[vikas_lakhanpal27]

STA doubt

Thanks!

 

[lty]

Re: STA doubt

Hi,
If you do not set this path as multi-cycle, and your combo-cloud delay is bigger than one clock cycle, your sta tool will warn this violation in report!

 

[sam536]

Re: STA doubt

STA tools work on one clock cycle .It assumes design will be a single cycle from register to register. If your combo is optimized to one single clock cycle and if it doesnt have vioaltions in timing. STA tools doenst report it as MCP.

Fish tail came up with product called FOCUS and they claims they can find Multi cycle paths .Check with them. https://www.fishtail-da.com/ look for the detais.

Regards,
Sam