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AR# 31109

10.1 Incremental Design and Timing - Timing constraint change causes partitions to be reimplemented

Description

I have a design with two partitions on lower-level instances (rnd1, rnd2) which are unrelated to any other logic. I add some logic with a new clock and other signals which are also irrelevant to the two modules, and put a period constraint on this clock. When I save the constraint, these modules are marked out of date, and changed to orange status.  

 

The NGDBuild report indicates the following: 

 

Partition Implementation Status 

------------------------------- 

Preserved Partitions: 

Implemented Partitions: 

 

Partition "/Top": 

Logic within this Partition was modified by a Period change. 

 

Partition "/Top/rnd1": 

Logic within this Partition was modified by inheriting a Period change. 

 

Partition "/Top/rnd2": 

Logic within this Partition was modified by inheriting a Period change.

Solution

This is correct behavior. A timing constraint change affecting the top partition will make all partitions as out of date. To override this behavior, set the following environment variable as 1: 

 

XIL_NTRC_NO_TIMING_CHILDREN 

 

setenv XIL_NTRC_NO_TIMING_CHILDREN 1

AR# 31109
Date Created 06/12/2008
Last Updated 05/22/2014
Status Archive
Type General Article