( ESNUG 317 Item 1 ) --------------------------------------------- [5/13/99]
Subject: The Difference Between Cadence Cell Ensemble & Silicon Ensemble?
> Please pardon the potentially obvious question, but I can't figure out
> what the difference is between Cell Ensemble and Silicon Ensemble.
> We're running Cadence 97A and it seems like both CE and SE do back-end
> place and route. SE seems to have a few more features, but to be less
> well integrated with the rest of the Cadence tools. Other than that,
> the on-oline documentation is unclear about how these two tools relate
> to each other and with the rest of Cadence.
>
> Can somone give me a quick insight into the difference between these
> two tools? If one is trying to generate placed and routed layout from
> Verilog or mixed Verilog/schematic designs, which tool should I be
> looking at? Thanks!
>
> - Erik Brunvand
> University of Manchester UK
From: Grant Erwin <grant_erwin@halcyon.com>
It has been a long time since I worked at Cadence, so this should be taken
with a grain of salt, but ...
Cell Ensemble was a two-layer metal tool. If you are using two layers
of metal (only) in your design, then CE will work just fine for you.
Silicon Ensemble, which used to be called Cell3 Ensemble, or just Cell3,
can handle much more sophisticated metallizations, up to six layers of
metal.
On a different note, I suspect you will see startlingly differing levels
of R&D support for these two tools. I don't know if CE is still even
officially supported, if it is, I bet bugs get fixed s-l-o-w-l-y ... on
the other hand, SE is their mainline APAR tool, with heavy competition
in the marketplace, so they are doing lots of maintenance on it.
The "bells and whistles" you refer to in Silicon Ensemble are critical
for doing deep submicron designs. If you're doing 2 micron stuff still
then it isn't mandatory to do clock tree synthesis, have accurate
timing models, et cetera.
- Grant Erwin
Halcyon
---- ---- ---- ---- ---- ---- ----
From: Jeroen Vermeeren <Jeroen.Vermeeren@nym.sc.philips.com>
The difference between Silicon Ensemble (SEDSM) and Cell Ensemble (CE) is
that CE is a channel router, and SE is an area based router. It is true, CE
is usually used for 2 routing layers and SEDSM for more then 2, but you can
use 3 layers in CE and "just" 2 in SEDSM.
My experience is that SEDSM gives better results. Even for 2 routing layers
you should be able to create a 10% smaller circuit with SEDSM then with CE.
Taken that you even get a result with CE, because it's so buggy. I thought
I read an End-Of-Life statement for CE in about a year or so, but I'm not
exactly sure.
- Jeroen Vermeeren
Philips Semiconductors CS Nijmegen
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