( ESNUG 254 Item 6 ) -------------------------------------------- [11/6/96]
From: charles@efficient.com (Charles Shelor)
Subject: The DC 3.5 "-scan" Option Is Great! But I Hate Its Licencing!
John,
Some of your ESNUG readers might be as happy as I was to learn about
the "-scan" option to the "compile" command in rev. 3.5 of Design Compiler.
This is a relatively 'painless' way to map scan test devices into a
design. Prior to version 3.5, a "compile" command was required; followed
by the "insert_scan" command which replaced non-scan devices with their
scan equivalents; then another "compile -only_design_rule" had to be
performed as the scan devices would have changed the timing and loading
of the design. My experience has been that a 1 hour compile would be
followed by a 5 minute "insert_scan" followed by a 10 minute compile. Using
the "-scan" option resulted in a single 1 hour compile! Thus, 3.5 required
20% less time to synthesize my design.
Now the 'gotcha'. The "-scan" option checks out a Test Compiler license.
In the version 3.4 compile scenario the Test Compiler license was only
needed during the 5 minute "insert_scan" operation. Thus, I could easily
run 4 or 5 compile jobs that 'shared' a single Test Compiler license by
waiting until the license was available, performing the "insert_scan"
and then releasing the license for the other jobs to use. In 3.5, the
Test-Compiler license is 'held' for the entire duration of the "compile"
operation rather than the 5 minutes of "insert_scan".
Thus, I must shell out additional $$$ to buy enough Test-Compiler licenses
to equal my Design Compiler licenses or I cannot use the "-scan" option.
My opinion is that the "-scan" option should not need a Test Compiler
license. The "-scan" option only affects library element selection, it does
not produce a scanned design, that still requires the "insert_scan"
operation. That should still require the separate Test Compiler license.
- Charles F. Shelor
Efficient Networks, Inc
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