( ESNUG 469 Item 8 ) -------------------------------------------- [09/27/07]
Subject: ( ESNUG 468 #8 ) Atrenta's response to 0-in vs. Spyglass CDC eval
> Overall of the two CDC tools [0-in vs. Spyglass], 0-in is in my opinion
> easier to use, and the more robust and bug free of the two.
>
> - Mike Birenbach
> Qualcomm Cary, NC
From: Kiran Vittal <kvittal=user domain=atrenta hot mom>
Hi John,
Wow, when I first read your headline regarding SpyGlass vs. 0-in, I was
shocked. ("Mentor 0-in kicks ass vs. Atrenta Spyglass CDC")
At first, I thought you had the two companies mixed up (because we've
been doing a lot of winning these days against 0-in). After reading the
details, I see what happened. Mike Birenbach was unaware/did not evaluate
many of the features in SpyGlass CDC. Some details:
> 0. Simulation Model CDC checks
>
> 0-in not only performs static CDC checks, it can also support dynamic
> CDC checks in simulation... Spyglass does not support any of this.
SpyGlass has a formal verification engine for CDC checks to functionally
verify data-hold for fast-to-slow crossings, data-correlation (convergence),
handshake verification, FIFO underflow/overflow verification and many other
critical CDC checks. We also support metastability verification in a
dynamic verification flow.
> 3. Looking at Warnings using their GUIs
>
> There were initially ~350 total warning messages from 0-in, far less
> than the ~900 clock_sync01 (one of several message types) Spyglass
> reported.
>
> Due to the grouping by message type by function (or block) by the 0-in
> GUI, it is very easy to see patterns in messages and quickly determine
> what to do. Spyglass only groups by message type (at least in the
> part of the GUI that lets you use a context sensitive menu to view
> schematics and create waivers).
>
> Further refinement of the 0-in setup file brought the total warnings
> down to around 200. Same was true for Spyglass clock_sync01 warning;
> however Spyglass required runs with multiple settings to get similar
> conclusions.
First of all, if some of the advanced capabilities mentioned in the prior
response had been used, the number of warnings would have been less.
In addition, SpyGlass has a spreadsheet view of all violations which can
be sorted by source/destination clock or source/destination flop or reason
for failure, and provides interactive capabilities to automatically waive
violations shown in this spreadsheet view. This feature was not used in
Mike's evaluation.
> 4. Defining Custom Synchronizers
>
> Defining custom synchronizers is MUCH simpler in 0-in... The Spyglass
> method of "recognizing" a structure by building a Verilog model of the
> synthesized result is not only more complex it is subject to possible
> error due to potential changes in the synthesis and/or RTL source for
> the edge detect. 0-in recognizes custom synchronizers by name; fewer
> mistakes are made...
SpyGlass does support synchronizer cells without using patterns. Patterns
provide additional flexibility not available in other tools.
> Overall of the two CDC tools, 0-in is in my opinion easier to use, and the
> more robust and bug free of the two.
Mike used an earlier ver 3.8.3 of SpyGlass CDC. Things get more robust with
each release, and we're currently shipping 3.9.0.
- Kiran Vittal
Atrenta, Inc. San Jose, CA
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