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
Nov 20, 2018
Samtec’s full line of high speed interconnect products was on display and in demonstrations at Electronica 2018.  Focus products included high speed mezzanine high speed cable assemblies high speed backplane connectors active optical cable assemblies 28 G Product Demon...
Nov 20, 2018
In yesterday's post I gave the details of the TPU hardware from Cliff Young's keynote on the second day of the recent Linley Processor Conference. Today, I'll look at what Cliff said about software and co-design, creating both the hardware and the software as a...
Nov 14, 2018
  People of a certain age, who mindfully lived through the early microcomputer revolution during the first half of the 1970s, know about Bill Godbout. He was that guy who sent out crudely photocopied parts catalogs for all kinds of electronic components, sold from a Quon...
Nov 13, 2018
Podcast Interview with the authors of The Hitchhikers Guide to PCB Design eBook by Mike Beutow with PCB Chat....