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AR# 21367

12.1 Timing - How do I fix a Hold Time Violation?

Description

When I perform a timing report, I notice that I have a Hold Time Violation. How do I fix it?

Solution

If the Hold Time Violation is associated with an OFFSET IN constraint, the data path is faster than the clock path. Either increase the delay associated with the data path or decrease the delay associated with the clock path.

To decrease the clock path delay, verify that the design is using the global clocking resources. You can also run PAR with a -k option, which tries to perform limited rip up and rerouting to solve problems.

If the Hold Time Violation is associated with a PERIOD constraint, the data path is faster than the clock skew. The resolution is similar to a Hold Time Violation in an OFFSET IN constraint, but decrease the clock skew instead of just the clock path delay.

To decrease the clock path skew, verify that the design is using the global clocking resources. You can also run PAR with a -k option, which tries to perform limited rip up and rerouting to solve problems.

AR# 21367
Date Created 09/04/2007
Last Updated 01/23/2013
Status Active
Type General Article
Tools
  • ISE Design Suite - 11.1
  • ISE Design Suite - 11.2
  • ISE Design Suite - 11.3
  • More
  • ISE Design Suite - 11.4
  • ISE Design Suite - 11.5
  • ISE Design Suite - 12.1
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