Xilinx Answer #497 : LCA files tied by Makebits tie do not always pass DRC, possible Fatal Error 301's

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LCA files tied by Makebits tie do not always pass DRC, possible Fatal Error 301's

Record #497
Problem Title:
LCA files tied by Makebits tie do not always pass DRC, possible Fatal Error 301's

Problem Description:

Solution 1:

PROGRAM: Makebits

VERSION: 5.1 and earlier

PLATFORM(s): all

BITA #: N/A

SHORT DESCRIPTION: LCA files tied by Makebits tie do not always pass DRC

ERROR MESSAGE: **FATAL 301: Input P31.T unused in IOB `LED/LED2_P' (P31), but 1 input pip is on

LONG DESCRIPTION:

      PROBLEM: LCA files created by using makebits tie and saved via
           the interactive makebits "norestore" option (or the command
           line makebits -n option) will not necessarily pass cleanly
           through DRC.

      CAUSE: Tie currently does not guarantee that the resulting .lca file
           (output from tie-save) is drc-error free, as it
           does not go into programmable blocks and "use" the pins
           it ties. None of the errors will affect the proper
           operation of the part.

           Note that the same fatal error coming from an untied design
           *would* need to be addressed.

      SOLUTION: Errors of this type in a tied design referring to unused
           inputs with input pips that are "on" (which are not
           also in the untied version of the design) can be
           safely ignored.

End of Record #497 - Last Modified: 04/01/97 07:46

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