AR# 452: XNFPREP 5.0 issues error 7859 on a Timespec attribute.
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.
解决方案
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.