Answers Database

XNFPREP 5.0 issues error 7859 on a Timespec attribute.


Record #452

Product Family:  Software

Product Line:  FPGA Core

Problem Title:
XNFPREP 5.0 issues error 7859 on a Timespec attribute.


Problem Description:
XNFPREP issues an error on a Timespec attribute, such as the following.
XNFPREP: ERROR 7859:
      'C2P' type TS attribute 'TS32' needs an associated TS flag attached
      to a net or pin.


Solution 1:


Xnfprep complains that a Timespec attribute 'TS##' needs an associated net
or pin attached. It issues an error message such as the following.

    XNFPREP: ERROR 7859:
      'C2P' type TS attribute 'TS32' needs an associated TS flag attached
      to a net or pin.

When running a Synopsys design through SYN2XNF pre-3.5.0k and XACT 5.0,
XNFPREP issues ERROR 7859. This indicates that there is a Timespec
property defined, but it is not associated with any nets or pins.

Syn2xnf is unable to merge the TS flags from lower-level XNF files created
after compiling a hierarchical design, where the hierarchy has been maintained.
Synopsys FPGA Compiler (Not Design Compiler) writes Timespec attributes into
the XNF files.

First make sure that Syn2xnf is calling XNFMERGE 5.0.0,
and not an earlier version.

There are 3 options:

1) Before the user writes out his design in XNF format (*.sxnf file), execute
   the Synopsys command 'ungroup -all -flatten' which would cause only 1
   design.sxnf to be written out.  This doesn't affect the hierarchical compile
   algorithm in Synopsys and still preserves the hierarchical
   structure of the design since the 'ungroup -all -flatten' command is
   flattening the design after Synopsys 'compile' & 'replace_fpga'. Its sole
   function is to get rid of the hierarchical boundaries and eliminate
   merging in Syn2xnf.

2) Newer versions of XSI  do not exhibit this problem.


3) Manually move the TS flags to the nets.





End of Record #452