We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 10550

3.1i NGDBuild, SYNPLIFY 6.1 - "ERROR:NgdBuild:432 - logical block '<instance>' with type 'DFFRS(or LDCP_1)' is unexpanded."


Keywords: Spartan, Spartan-XL, 4000, translate, NGDBuild

Urgency: Standard

General Description:
When I run NGDBuild on an EDIF netlist produced from Synplify, the following error appears:

"ERROR:NgdBuild:432 - logical block '<instance>' with type 'DFFRS' is unexpanded."


"ERROR:NgdBuild:432 - logical block '<instance>' with type 'LDCP_1' is unexpanded."

This occurs on XC4000/X/XL/XLA and Spartan/XL devices.

This problem is fixed in Synplify version 7.0.


The DFFRS and LDCP_1 primitives are not supported in XC4000/X/XL/XLA or Spartan/XL devices. However, Synplify incorrectly instantiates these primitives when it recognizes the construct in the HDL code.

To work around this, copy "dffrs.xnf" and "ldcp_1.xnf" from the following directory:


to the directory where the top-level EDIF project file resides.

(NOTE: $SYNPLICITY is the directory of Synplify software install.)

Please see (Xilinx Answer 3486) for more information.
AR# 10550
Date Created 11/27/2000
Last Updated 03/05/2006
Status Archive
Type General Article