Once upon a time I saw a number that told me what percentage of my project was unconstrained. I can't seem to get TRCE (Xilinx ISE) to show me that number again. Can someone point me in the right direction?
For the command line version of trce, it is the -u option
Philip Philip Freidin Fliptronics
trce used to report % of paths covered at the bottom of the .twr report, but that seems to have disappeared between trce v5.x to v6.x. It was a misleading number anyway becasue it included paths that could not be constrained, so 100% was not possible. Maybe that's why they quit reporting it. But, as Philip said, the trce -u option will report your unconstrained paths.
Your guess is correct. We stopped reporting the percentage of paths covered because it was inaccurate and making the number 100% accurate turns out to be a very run time inefficient operation. We're still looking for an acceptable run time solution...
Russ Panneton
Is there a way to list the unconstrained paths?
The timing report with trace -u only lists the number of unconstrained paths and the maximum delay. I would like to see them to assert that I have not missed a vital path in my constraints.
The timing analyzer has no way of knowing which paths are vital to you.
Use -u followed by a number, e.g., -u 100, and you'll get a report of that many unconstrained paths, sorted from longest to shortest.
Bob Perlman Cambrian Design Works
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