Answers Database

PPR 5.0 and Timespec: How to use the timespec 'ignore' property


Record #478

Problem Title:
PPR 5.0 and Timespec: How to use the timespec 'ignore' property


Problem Description:



Solution 1:




PROGRAM: PPR

VERSION: 5.0

PLATFORM(s): All

SHORT DESCRIPTION:

How to use timespec ignore

LONG DESCRIPTION:

There has been some confusion as to how to properly use timespec ignore in
XACT-Performance 5.0 and above.  Page 1-82 of the XACT Reference Guide I
(April 1994) states:

   You can use IGNORE to disable any paths that you do not need to
   control by using the following syntax within the TIMESPEC primitive:

      TSid=IGNORE

   Attaching this TS flag to a net or load pin causes PPR to ignore any
   paths that include the net or load pin.

Note that the TSid=IGNORE is attached to the TIMESPEC primitive and NOT to
the net or pin whose path you wish to ignore.  The net or pin instead
receives the TSid attribute WITHOUT an IGNORE value.  (On schematic editors
that require an attribute value, you typically attach TSid=TSid.)  The
phrase "TS flag" in the second paragraph above refers ONLY to TSid and NOT
to TSid=IGNORE.





End of Record #478