General Description: In A1.5 a new form of OFFSET constraint is permitted with the
following syntax:
TIMEGRP "group" OFFSET={IN | OUT} offset_time [units] {BEFORE | AFTER} NET
["clk_net"] [TIMEGRP "reggroup"];
For example:
TIMEGRP INPUT_PADS OFFSET = IN 20 BEFORE CLK;
Using the Timing Analyzer GUI, the Disable Constraints Dialog box (Path Filters ->
Timing Constraint Filters -> Disable Timing Constraints) cannot be used to select
and disable timing constraints of the above type.
This is fixed in M1.5i and Service Packs.
A current workaround for this problem requires hand editing the PCF file.
Open the DESIGN.PCF file in a text editor and comment out the constraint that you
wish to disable.
For example:
TIMEGRP INPUT_PADS OFFSET = IN 20 BEFORE CLK;
Would become:
#TIMEGRP INPUT_PADS OFFSET = IN 20 BEFORE CLK;
Save the PCF file and then re-run the Timing Analyzer. The commented out
constraints will no longer be analyzed.
AR# 4479 | |
---|---|
日期 | 01/18/2010 |
状态 | Archive |
Type | 综合文章 |