Answers Database
M1.5i/2.1i: When a group gets made and a TIG is placed THRU this group the TIG gets ignored
Record #5939
Product Family: Software
Product Line: Merged Core
Product Part: Timing
Problem Title:
M1.5i/2.1i: When a group gets made and a TIG is placed THRU this group the TIG gets ignored
Problem Description:
Urgency: Standard
General Description:
When a group gets made and a TIG is placed THRU this group the TIG gets
ignored.
Solution 1:
The TIG constraint is a superset of a smaller FFS timegrp. The two constraints
intersect, but the TIG is not a subset of the FFS Timegrp constraint
Unfortunately the online documentation of the TIG constraint does not explain
the limitations of path TIGs and exceptions in general, but in order for an
exception to be applied by the timing software, the exception/TIG must be a
subset of another constraint. The TIG is actually a superset of FFS Timegrp
constraint, and therefor no TIG/exception can be applied.
A simple work around is to just a global ignore on the pins defined in the
timegroup, or a timespec-specific ignore of these pins.
End of Record #5939 - Last Modified: 07/13/99 15:19 |
