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AR# 29363

10.1 Timing Analyzer - "WARNING:Timing:3328 - Timing Constraint "%s" fails the minimum period check for the output clock %s from %s %s"

Description

The following warnings are reported in the timing report: 

WARNING:Timing:3327 - Timing Constraint "TS_SysClk_P = PERIOD TIMEGRP "SysClk_P" 125 MHz HIGH 50% INPUT_JITTER 0.2 ns;" fails the minimum period check for the input clock SysClk_CLKIN to DCM_ADV DCM_instance because the period constraint value (8000 ps) is less than the minimum internal period limit of 8332 ps. Please increase the period of the constraint to remove this timing failure. 

WARNING:Timing:3328 - Timing Constraint "TS_SysClk_P = PERIOD TIMEGRP "SysClk_P" 125 MHz HIGH 50% INPUT_JITTER 0.2 ns;" fails the minimum period check for the input clock SysClk_CLK0 from DCM_ADV DCM_instance because the period constraint value (8000 ps) is less than the minimum internal period limit of 8332 ps. Please increase the period of the constraint to remove this timing failure.

Solution

This problem is caused by an incorrect input clock period constraint which is greater than the maximum frequency of the DCM working mode. 

It can also be caused by incorrect settings for the DCM working mode.  

To resolve this problem, either correct the working mode or change the constraint value.

AR# 29363
Date Created 03/24/2008
Last Updated 12/02/2014
Status Active
Type General Article
Tools
  • ISE - 10.1