( ESNUG 382 Item 7 ) -------------------------------------------- [11/15/01]
Subject: ( ESNUG 381 #2 ) ECO's And Arcadia, LEF, DEF, GDSII, PrimeTime
> In our sign-off procedure we use Arcadia and PrimeTime. We use Arcadia
> for RC extraction, and Primetime reads the DSPF file generated by
> Arcadia for static timing analysis. In our regular flow, the input
> to Arcadia are the LEF and DEF files. When we're doing a manual ECO, the
> data of the ECO is in GDS2 format only. To extract the data, we need to
> run LVS on the GDS2 data and then invoke Arcadia. The output DSPF
> generated by Arcadia (in this case) is in transistor level, while PrimeTime
> annotates only gate level DSPF!!! This is a very severe limitation! The
> timing on the ECO nets cannot be verified.
>
> - Eyal Landesberg
> Zoran Israel
From: Ken Maples <maples@synopsys.com>
John,
The fundamental problem Eyal has is that once his database has been
converted to GDSII, all the LEF/DEF information has been lost. There is no
way for any extractor to know what the gate level primitives are such that
they could be reformed at the gate level and fed back to a gate level timing
engine like PrimeTime.
There really are only two solutions to such a problem.
The first would be to not smash the LEF/DEF data into GDSII. His ECO edits
would need to be made on the LEF/DEF data. The other solution would be to
run a transistor level static timing engine such as PathMill. I'm not
trying to get Eyal to buy more Synopsys tools - it's just that the flow he
is proposing is trying to merge a gate level tool to a polygon level
database. It just won't fit.
If Eyal would like to discuss this with us in more detail, we'd be happy to
discuss alternate ways to implement his ECO's. Tell him to feel free to
contact me directly.
- Ken Maples
Synopsys, Inc. Mountain View, CA
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