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AR# 43248

14.x Timing - "Warning:Timing:3391 - Timing constraint does not specify a data valid duration..."


The following warning occurs during the Post-PAR static timing analysis:

"WARNING:Timing:3391 - Timing constraint< OFFSET IN constraint>does not specify a data valid duration and will not be hold checked. To enable hold checking on this offset constraint please specify a data valid duration using the VALID < duration > option."

What does this mean?


The Timing Analyzer can perform setup and hold checks for OFFSET IN constraint. However, the hold checkis performed only when a VALID value is specified in the OFFSET IN constraint.

For example:

OFFSET = IN 3 ns BEFORE "clk_in";

NET "wren"OFFSET = IN 3 ns BEFORE "clk_in";

TIMEGRP "wr_grp"OFFSET = IN 3 ns BEFORE "clk_in";

If the VALID value is not specified in the OFFSET IN constraint, the hold check will not be performed and a fast path setup calculation (at the slow corner)is performed instead; see (Xilinx Answer 42701)for more information.

To remove this warning, add VALID value in the OFFSET IN constraint.

AR# 43248
Date Created 04/30/2012
Last Updated 05/19/2012
Status Active
Type Error Message
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