( DAC 03 Item 17 ) ----------------------------------------------- [ 01/20/04 ]
Subject: Novas DeBussy & nSchema & Verdi, Veritools Undertow
MORE FREEDOM ISSUES: The waveform viewing market suffers from that same
damn-they're-giving-it-away-for-free problem that linters & code coverage
tools have. VCS, NC, and Modelsim all have free, built-in waveform
viewers -- hence Novas and Veritools have to stay 5 steps ahead to stay
in business. So far, they've done it with Novas DeBussy having the high
ground and Veritools claiming the cheaper (but not free) seats.
Debug Environments
Novas sells Debussy, their not so cheap but highly capable debug
environment, plus Verdi, which allows for RTL debug. Paul Stein said
you don't need a sales pitch at all for tools like this - just show it
to anyone who has ever debugged a chip and they immediately see how
much time they would save. Not ones to put all their eggs in one basket,
Navas support openVera now, plan to support SystemC and System Verilog
by the end of the year, and "e" and Sugar/PSL early next year.
Veritools sells Undertow, which now had capabilities similar to Verdi,
included at no extra cost. They use a binary format (fastfile) that is
more compact than VCD (many vendors have formats like this - there needs
to be a new binary waveform standard).
Synplicity sells Identify, an RTL debugger (Bridges2Silicon).
Sandwork Design sells a SPICE level debug environment that hooks into
Cadence, and has things like a SPICE linter (boy would that be handy
sometimes).
- John Weiland of Intrinsix
I chose Nova Debussy as a company waveform viewer tool a long time ago
(8 years ago, in 2 companies), while UnderTow was the most popular. The
main reason I chose Debussy is that Nova had a schematic feature which
was quite unique. Since then, I find that Nova gained a lot of market
share in the waveform viewer area, and I believe this is due to its
easy-to-use feature and minimum learning curve. There is another
important factor for customers to stay with them is: Novas R&D team is
listening what the customer wants.
Novas seems to have a good idea with Verdi. Unfortunately, the ordinary
user can hardly catch it up well. It may take some time to become
popular.
The weakest part of Nova's product is pricing. We don't have enough
licenses all the time. Fortunately, we can take advantage of 1 nWave
license to open multiple waveform windows and not bother with Synopsys
free VCS waveform viewer at all.
- Fred Huang of PLX Technology
I have seen the Modelsim viewer, about 3 years ago, but it was awful
compared to Novas' Debussy. I haven't tried Cadence's or Synopsys'
built-in versions as I'm quite happy with Debussy.
I have tried Novas' Verdi and was fairly impressed with the behavioral
view of equations and such. While we haven't yet purchased Verdi, we
have had engineers here say, "I wish we had it as that behavioral view
would have been very useful for debugging the <XYZ> problem."
I saw the demo for Debussy 5 years ago and bought the tool without
trying it.
Debussy's Strengths:
1. Active annotation - directly see signal values in your code.
2. Double click to driver - traverse unknown design files to find
problem.
The combination of these two features enables other designers to debug
unknown code. They don't have to be intimately familiar with where
everything is in the file to traverse through the logic, trying to
figure out what signals may be wrong. They can track backward from an
incorrect signal. By seeing the transitions (up or down) and signal
values, they can evaluate expressions in their head and pick a wrong
signal value to track. They will eventually find the spot (or close to
it) where a problem exists.
- [ An Anon Engineer ]
We have been using Debussy for a number of years, and have been recently
evaluating Verdi. We have not taken the time to look at any simulator's
built-in viewer, and don't have any plans to do this type of evaluation
any time soon. Past experience suggests that there is not much return
on investment doing this.
Also, we have tended recently to switch simulators chasing the best
price/performance mix. Debussy gives us a common look-n-feel thus
enabling an easy migration.
- Tim Short of Via-ARL
But I use Debussy, and I must say that out of all the tools I use on a
regular basis, Debussy is by far the best-designed, and most satisfying
tool to use.
I don't use their waveform viewer nWave as frequently as their logic
schematic viewer nSchema, so I can't give you a really deep, meaningful
analysis of that portion of the tool.
Positives:
1) The fsdb dump file is orders of magnitude smaller than VCD dumps
2) nWave is very fast (although SimVision ain't too shabby either)
3) The interface is intuitive and easier to use than other waveform
viewers I've used (SimVision, Modelsim)
Negatives:
1) It sucks to have to load in the entire design into the tool before
using the waveform viewer (maybe there's a way to just load the fsdb
file, but I haven't been able to do that)
2) The complex event search feature is, well, complex and cumbersome;
but then I don't know if other tools can do what it does.
In case you're interested in what I think about nSchema:
Positives:
1) It works as advertised. No bugs, no glitches, nothing.
2) Has several different ways of tracing the logic (such as displaying
cross-hierarchical connections or just within one hierarchical block)
3) It's fast.
Negatives: (I'm just nitpicking)
1) Proportions of the display objects are ridiculous at times. If the
display is showing an AND gate connected to a huge hierarchical
block, then it's impossible to find the AND gate. I mean, logically
that might make sense, but from a usability standpoint, this
arrangement is not optimal.
2) Their drawing engine needs to be optimized. Sometimes a net going
between two adjacent object is drawn to go all over the place, making
you waste time tracing through the net. This happens more often than
it should, and is very annoying.
Debussy has some other features like nStateMachineThingy and such, which
I don't use. But based on the features I do use, I really do think this
is a great tool, one of the best I've encountered. Do you know of any
other tool that really is a legitimate competitor to Debussy? This
company seems to have come out of nowhere but is now like the only
player in the arena. Anyway, that's are my two cents."
- Steve Park of Agere Systems
I have used SignalScan in the past, but switched to Debussy for good
about 3 years ago. SignalScan is a freebie so maybe it's an unfair
comparison. In addition, I'm using ModelSim, but rarely use its
waveform viewing feature.
What Debussy offers is beyond waveform viewing capability. It offers
debugging capability which ModelSim doesn't. Whether one likes to debug
with waveform, RTL, shematic, or state-machine flow graph Debussy allow
an integrated environment for all of the aboves.
The most powerful feature I like about Debussy is its capability to
trace 'X' or unknown value. Most of my debugging effort spent during
backannotating process. This is where tracing 'X' come into very
helpful. Verdi, in short, improves this feature one more level.
- Phuong Nguyen of Mindspeed Technologies
Novas Debussy & Verdi is a very powerful debug tool. Its signal tracing
is the best. And I like its partial schematic very much, only the part
interested is showed up and expended as you want. But some little things
need to be improved, such as FFT, it is only available for analog signals
now.
- LaiQing Ping of ESS Tech.
Liked what I saw at the Debussy booth. They are full on supporting
assertion based verification in their environment. Excellent, since ABV
is new to some folks, any help in debugging such is greatly appreciated!
- [ An Anon Engineer ]
I like what I've seen of DeBussy/Verdi -- it's on my Christmas list!
- [ An Anon Engineer ]
Of the waveform viewing tools, Novas Debussy was still the stand out.
They demonstrated Verdi, the next generation Debussy. Shows promise, but
lacks VHDL coverage.
- [ An Anon Engineer ]
I wanted to stop at the Novas booth/suite, but ran out of time.
- [ An Anon Engineer ]
The Novas tools are all singing and dancing, but I wonder how many users
actually use more than a very small percentage of what they offer.
- Kevin Jones of Rambus
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