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AR# 7063

Synplify 6.0/NGDBuild 3.1i - "ERROR:NgdHelpers:312 - logical block "up_address[0].L1" of type "SLDPE_1" is unexpanded"


Keywords: Synplify, unexpanded, latch, infer

Urgency: Standard

General Description:
The Synplify netlist produces the following error in NGDBuild:

"ERROR:NgdHelpers:312 - logical block "up_address[0].L1" of type "SLDPE_1" is unexpanded."

Latches were inferred in the design, but no latches were instantiated.



The warning message from Synplify is unclear.

The SLDPE_1 is a correct component. The warning message regarding inferring latches should instruct you to copy the corresponding netlist for the latch from the Synplify directory. The SLDPE_1 is a latch that corresponds to the Xilinx LDPE_1 primitive.

The netlist, SLDPE_1.XNF, is located in the /synplify/lib/xilinx directory and should be copied to the design directory for implementation.

Latches are only primitive components in certain Xilinx Families, specifically Spartan-XL, 4000XL,XLA, and Virtex devices. Therefore, Synplicity has created its own latch components for families that do not have this LDPE_1 primitive.

Alternatively, you may change the code so that latches are not inferred.


Synplify 6.0 currently writes out SLDPE_1 for designs in Spartan-XL when a latch is inferred. SLDPE_1 should not be inferred because Spartan-XL has primitive latches.

This is a known Synplify bug (#12286). The current work-around is to edit the EDIF netlist, replacing SLDPE_1 with LDPE_1.
AR# 7063
Date Created 07/20/1999
Last Updated 09/10/2002
Status Archive
Type General Article