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AR# 31708

141.x Timing Analyzer - When I run an OFFSET analysis in timing analyzer on its own, I receive different results than if I run a full timing analysis

Description

When running a timing analysis for only an OFFSET IN or OFFSET OUT constraint, I might see different results than if a full timing analysis is run. Why?

Solution

An OFFSET analysis on its own is not valid; you must run the corresponding PERIOD analysis for the results to be valid. The OFFSET analysis needs to know the phase shifting and clock period information from the PERIOD analysis in order to be correct. You can tell if an OFFSET analysis has been done without the corresponding PERIOD analysis if there is no clock arrival time listed in the entry for the OFFSET constraint in the timing report.

Do not do an OFFSET analysis on its own because without the information from the corresponding PERIOD analysis; it might be incorrect.
AR# 31708
Date Created 11/07/2008
Last Updated 12/15/2012
Status Active
Type General Article
Tools
  • ISE - 10.1
  • ISE Design Suite - 11.1
  • ISE Design Suite - 11.2
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  • ISE Design Suite - 11.3
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  • ISE Design Suite - 13
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