editor's blog
Subscribe Now

Simpler CDC Exception Handling

For static timing analysis, it’s a concept that goes back years. You get a bunch of violations, and then you have to decide which ones represent false paths or multi-cycle paths and create “exceptions” for them. Tedious.

Well, apparently formal analysis can have the same issue. Only here they’re referred to as “waivers,” according to Real Intent. If you run analysis and get a long list of potential violations, you have to go through the list and, one by one, check them for “false positives” and mark them as such. Time-consuming and error-prone. And tedious. Especially when working on large-scale SoCs (so-called “giga-scale”).

In their latest release of Meridian CDC, which does clock-domain crossing verification, Real Intent has provided a different way of handling this: provide more granular control over the run parameters in the form of rules or constraints that can be successively refined.

Using the old method, if a particular over-reaching aspect of analysis caused 100 false positives, you’d have to find all 100 and “waive” them. With the new approach, when you find the first one, you make the refinement, and then, with a rerun of the analysis, the one you found and the other 99 all disappear. OK, not disappear per se, but they’re grouped together as not being an unexpected finding. You can also review that list to make sure nothing snuck through. (This is a simplification of a more sophisticated overall process, but it captures the essence.)

This may take some iterations, but in the end, you can have a clean run with no exceptions, and the way you got there is less likely to have involved a mistake here or there.

You can find out more about Real Intent’s latest Meridian CDC release in their announcement.

Leave a Reply

featured blogs
Mar 20, 2019
Over the past few years, 3D modeling capabilites on Samtec.com have progressed immensely. We’ve gone from a small library of static files to a massive library of dynamically generated models, that can be downloaded as virtually any file type, in just a few seconds. Thou...
Mar 20, 2019
One big highlight of the RSA conference is always The Cryptographers' Panel. This year the panel was: Ronald Rivest, the R of RSA. Whitfield Diffie, legendary cryptographer. Paul Kocher, who... [[ Click on the title to access the full blog on the Cadence Community site....
Mar 19, 2019
Deeper Dive into Non-Trivial Bug Escapes and Safety Critical Designs This blog is a continuation of a series of blogs related to the 2018 Wilson Research Group Functional Verification Study (click here).  In my previous blog (click here), I presented verification results fin...
Jan 25, 2019
Let'€™s face it: We'€™re addicted to SRAM. It'€™s big, it'€™s power-hungry, but it'€™s fast. And no matter how much we complain about it, we still use it. Because we don'€™t have anything better in the mainstream yet. We'€™ve looked at attempts to improve conven...