Back annotating to RTL

Apr 12, 2007 2 Replies

Tracing timing violations in the post-p&r generated netlist can be cumbersome with all signal merging/renaming and inserted buffer. I was wondering if there is a way that I can back annotate the post place and route delays back to the RTL code? even approximate delays can reveal some design errors I would think.



Thank you.



You don't seem to understand the processing from RTL to gates. When you do the answer will become self-evident.

It would be great wouldn't it?

The main problem seems to be that there are at least two, and sometimes three or more tools in the chain between RTL and placed & routed gates. Tracing the heritage of gates back to RTL requires that all of those tools cooperate in providing the necessary information in a uniform manner. Often there is no direct heritage, given re-timing and pipelining optimizations. Also, the RTL may have "hidden" some of the gates in expressions or variables that cannot be directly annotated with delays without major re-writing of the code.

I have found that if I do a good job simulating the RTL, and verifying the constraints used for STA, the set of problems encountered during full timing simulation is very limited.

Andy

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required