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AR# 452

XNFPREP 5.0 issues error 7859 on a Timespec attribute.

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


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.


AR# 452
Date Created 08/31/2007
Last Updated 10/01/2008
Status Archive
Type General Article