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AR# 39263

14.x Timing - Using "HIGH/LOW" keywords in OFFSET IN constraint ignores DCM phase in analysis

Description

If I use "HIGH/LOW" keywords in the OFFSET IN constraint, the timing analyzer ignores the DCM phase shift.

Constraint in UCF:
NET "I_tcam_rbus[0]" OFFSET = IN 1.9 ns VALID 1.4 ns BEFORE "I_tcam0_clko" HIGH;

The DCM phase appears in the PERIOD constraint, but the OFFSET IN reports "rising at 0". What is the problem?

Solution

The "HIGH/LOW" keywords are no longer supported in OFFSET constraints.This issue can be resolved by using "Rising/Falling" keywords instead.

NET "I_tcam_rbus[0]" OFFSET = IN 1.9 ns VALID 1.4 ns BEFORE "I_tcam0_clko" RISING;
AR# 39263
Date 12/15/2012
Status Active
Type General Article
Tools
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