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AR# 41015

13.1 PAR - "ERROR:ConstraintSystem:300 - In file: ddc.pcf(287): Syntax error at or before 'clk75': 'clk75' is not a valid constraint type"


When PAR is invoked I see the following error:

"ERROR:ConstraintSystem:300 - In file: ddc.pcf(287): Syntax error at or before 'clk75': 'clk75' is not a valid constraint type.
ERROR:Par:51 - The .pcf file contains errors. PAR cannot proceed."

How can I work around the issue?


This problem occurs when the -global_opt option is turned on during MAP. It appears that invalid characters are written to the physical constraints file (.pcf) at the end of MAP.

This issue will not be fixed as the -global_opt option is being deprecated and will not be available to use for the newer devices or next generation tools.

The following options can be used as possible workarounds:

  1. Turn off the global_opt option before running MAP.
  2. Edit the .pcf file after MAP and before PAR and correct the constraint syntax at the line specified in error message.
  3. This issue has not been seen on Linux and is supposed to have occurred only on windows OS. Use Linux OS as an alternate option.

In the above mentioned error message, the line number with the syntax error is line 287.

For example, if the syntax error happens to occur due to the following line in the PCF file,



Correct the TIMEGRP name to work around the issue.

Some occurrences of this issue have been fixed in ISE 14.1 Design Suite. It was found that this did not fix all cases and so another bug fix has been made for ISE 14.4 Design Suite.

AR# 41015
Date 03/08/2013
Status Active
Type General Article
  • ISE Design Suite - 13.1
  • ISE Design Suite - 12.4
  • ISE Design Suite - 13.2
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  • ISE Design Suite - 13.3
  • ISE Design Suite - 13.4
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