Answers Database

NGDBUILD: "logical block" of type 'DFFRSE' is unexpanded with a SYNPLICITY design


Record #3611

Product Family:  Software

Product Line:  Synplicity

Problem Title:
NGDBUILD: "logical block" of type 'DFFRSE' is unexpanded with a
SYNPLICITY design



Problem Description:
Keywords: unexpanded, dffrse, synplify, ngdbuild

Urgency: Standard

Problem description: Ngdbuild issues a warning on a behaviorally
described asynchronous set/reset regesiter with clock enable

warning basnu:93-logical block 'rebk1' of type 'DFFRSE' is unexpanded.


Solution 1:

Synplify will infer a DFFRSE to describe an asynchronous set/reset
register with clock enable.  However, the DFFRSE is not a valid
Xilinx primitive.  Earier versions of synplify have this problem.
Version 3.0c1 and above correct the problem by inferring a DFFRS.

The generic DFFRSE is no longer generated for 9500 series devices.

The DFFRS is also not a Xilinx primitive.  See Xilinx Solution 3486
However, Synplicity provides the XNF netlist of the DFFRS.  Make sure
you either source the directory with '-sd' option in ngdbuild, or copy
the appropriate XNF file to your project directory so M1 could see the
files.	These XNF netlists are located in the C:\synplcty\lib\xilinx
directory on the PC, and $SYNPLICITY/lib/xilinx on the WS.

You will need to upgrade to a more recent version of synplify from
Synplicity:

http://www.synplicity.com/support.html



End of Record #3611