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AR# 34632

NGDBuild - ERROR:NGDBuild:995

Description

The following message is a general purpose error designed to catch scenarios of constraint file parsing failure which are not otherwise covered by a more specific error or warning message:

ERROR:NGDBuild:995 - Line < line_number > in < ucf_file > : < reason for failure >

Solution


The most common scenario for this message is a syntax error in the constraints file syntax. 

Ensure that your constraints file is free from syntax errors.

Below are some examples:

Example 1

ERROR:NgdBuild:995 - Line 2 in top.ucf: Constraint 'PERIOD' has a value
   'TS_test/clk' which is invalid. Use the following:
   Text that matches the regular expression: *i:ts[a-z_0-9\\]+"

The constraint that is causing the error is:

TIMESPEC TS_test/clk = PERIOD test/clk 70 MHz HIGH 50%;

This error indicates that there are invalid characters in the TS identifier name. 

The supported expressions are listed in the error message.

This error is resolved by removing the slash "/" from the TS identifier.

Example 2

ERROR:ConstraintSystem - In file: top.ucf(3): Constraint 'PERIOD' has a value
   'Phase+180' which is invalid. Use the following:
   Text that matches the regular expression: *i:^(PHASE)([+-])?$
   Please see the Constraints Guide for more information on this constraint."

The constraint that is causing the error is:

TIMESPEC "TS_ddrclk_90" = PERIOD "ddrclk_90"  "TS_ddrclk_0"  * 1.000000 PHASE+1.600ns HIGH 50.00%;

When you apply a PERIOD constraint with the PHASE relationship you must use a space between the PHASE and + sign, and the + sign and number as follows:

TIMESPEC "TS_ddrclk_90" = PERIOD "ddrclk_90"  "TS_ddrclk_0"  * 1.000000 PHASE + 1.600ns HIGH 50.00%;


This error message can also be triggered by conditions specified in the constraints file that NGDBuild cannot resolve. 

Such scenarios can include specifying invalid values for constraints, or specifying a value that prevents satisfying some other condition for the logic in your design.

AR# 34632
Date Created 04/05/2010
Last Updated 03/24/2015
Status Active
Type Error Message
Tools
  • ISE
  • ISE Design Suite