( ESNUG 362 Item 2 ) --------------------------------------------- [11/30/00]
From: Dennis Milton <Dennis_Minton@stratus.com>
Subject: Customer Musings On Tcl, DC, Presto, PrimeTime, ACS, & PhysOpt
John,
I didn't get to add my voice to your Boston SNUG review so I thought I'd
share them now concerning Synopsys synthesis. I loved Gregg Lahti's talk
on Tcl. At least somebody addressed the Synopsys Tcl short falls. Maybe
Synopsys will include Tk toolkit in the future. Until then, I don't see
a complete tcl solution.
Presto makes me nervous. Changing the way MUXes and arrays are translated
to gtech sounds like two different circuits to me. Infer enumerated types
should be defaulted to off to be compatible with earlier releases.
I have started using the -path full_clock switch for report timing. I was
pleased to see it common to Primetime tcl and dc-shell.
ACS is just another way to become tool dependant. Fundamentally I agree
with it, but I don't see any reason to move from Primetime budgeting to
Design Compiler budgeting. Primetime is much faster, and more accurate.
The budgeting step has generated some unrealistic constraints for feedbacks
to flip-flops, feedthroughs, and progated constants. I still need to
"tweak" budgeted constraints to minimize negative slack.
No, I probably will not change from dc-shell during this project phase (till
June 2001). What is working is generally left alone... unless of course
if Synopsys phases out dc-shell.
Concerning PhysOpt, the biggest problem I have with this flow, is the list
of qualified vendor libraries. Most vendors I deal with do not have
qualified libraries for their scan and DFT macros. As far as I know, most
designs require ATPG or BIST.
- Dennis Milton
Stratus Computer Marlboro, MA
|
|
