( ESNUG 201 Item 6 ) ---------------------------------------------- [11/10/94]
From: jmott@atmsys.com (James Mott)
Subject: Seeking User Wisdom On Floorplanning Tools
John,
I'm trying to decide the best approach to floorplanning, and I've never used
the Synopsys floorplanner, though I've used vendor floorplanning tools before.
Can anyone comment on the relative merits of Synopsys floorplanner vs.
vendor supplied floorplanners? I think it shapes up like this:
Vendor floorplanners:
You must have a vendor specific netlist to use a particular ASIC vendor's
floorplanner, which implies that the backannotation from the floorplanner
would not feed back to Synopsys at the RTL level (prior to the mapping to
vendor specific cells). Consequently some timing problems (those requiring
re-synthesis, as opposed to buffering) might not be solvable this way.
I think backannotation from a vendor's floorplanner would only work for
sizing buffers & outputs driving block to block in a design's top level.
Synopsys floorplanner:
Are there any ASIC vendors who support feeding the data forward to the
vendors placement tools from the Synopsys tool? Does Synopsys translate
to the ASIC vendor's coordinate system? Does it compute block utilization
levels for each vendor? What does it do when it doesn't know the target
vendor?
Has anyone used this tool, and did it reduce their design time? If so, is
it worth the admission price?
Which is the better route for timing analysis (Synopsys or vendor)? Is a
combined approach (both tools) best, or are they redundant or incompatible?
Please either write publically or anonymously to ESNUG on this!
- Jim Mott
ATM Systems
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