We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 9468

14.x Constraints - How do I use the EXCEPT command within a FROM TO constraint?


How do I use the EXCEPT command within a FROM TO constraint if a few of the paths within the FROM TO TIMEGRPs must be excluded?


For the FROM TO constraint, two TIMEGRPs must be created: one for the destination elements and one for the source elements. To exclude a signal(s) from either theTIMEGRP for the FROM TO constraint, you can use an EXCEPT command.

For example, the syntax would look like the following:

  • TIMEGRP new_srcgrp = srcgrp EXCEPT sig1;
  • TIMEGRP new_destgrp = dest_grp EXCEPT sig2;

If you must apply a FROM TO TIG constraint, make sure that the TIMESPEC line contains the TIG notifier as follows:

TIMESPEC "TS_constraintA" = FROM "new_srcgrp" TO "new_destgrp" TIG;

Additional Information

AR# 9468
Date 12/15/2012
Status Active
Type General Article
Tools More Less
Page Bookmarked