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AR# 37292

TRCE - Unconstrained timing failures contribute to timing score


When I run a timing analysis and report unconstrained paths with the -u switch I see a timing score due to hold violations. Is this correct?


Yes, this is correct and expected. The unconstrained timing report may include hold errors that are not explicitly covered by user timing constraints and this is designed to alert the end user that these unconstrained paths have hold violations. Please see the following:


PAR implements the design to the end-user's timing constraints, and does not perform analysis on unconstrained paths, hence the zero timing score in PAR. Under these circumstances trce without the unconstrained option will also get a zero timing score, reflecting only the timing constraints explicitly specified for implementation. But, when the unconstrained analysis is run then any failures will contribute to the timing score.

Linked Answer Records

Associated Answer Records

Answer Number Answer Title Version Found Version Resolved
31881 12.1 Timing Analyzer - Why is my unconstrained path report highlighting a hold violation? N/A N/A
AR# 37292
Date 01/30/2013
Status Active
Type General Article
  • ISE Design Suite - 12.1
  • ISE Design Suite - 12.2
  • ISE Design Suite - 12.3
  • ISE Design Suite - 13.1
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