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AR# 409

5.2 PPR - Defining point-to-point timespecs in cst file


It is possible to define point to point timespecs in a constraint
file for PPR 5.0. Here is an example:

in1 out1
|ipad>-------|ibuf>-----+-----{comb logic}-----|obuf>--------<opad|
| ____ q1 _____ q2 out2
+--|DFF |------{logic}----|DFF |------|obuf>----<opad|
---- -----

Constraint file:

timegrp="ned=pads(in1)"; # assign TNM of ned to ipad driving in1
timegrp="fred=pads(out1)"; # assign TNM of fred to opad loading out1
timegrp="ted=pads(out2)"; # assign TNM of ted to opad loading out2
timegrp="jon=ffs(q1)"; # assign TNM of jon to DFF driving q1
timegrp="don=ffs(q2)"; # assign TNM of don to DFF driving q2

timespec="TS01=FROM:ned:TO:fred=25"; # define p2p of 25ns
timespec="TS02=FROM:ned:TO:jon=15"; # define p2s of 15ns
timespec="TS03=FROM:jon:TO:don=30"; # define c2s of 30ns
timespec="TS04=FROM:don:TO:ted=10"; # define c2p of 10ns

AR# 409
Date Created 08/31/2007
Last Updated 03/22/2000
Status Archive