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AR# 30705

ISE MAP - "ERROR:Pack:2239 due to improper replication of LUTNM or HLUTNM constraint"


This error occurs with a module synthesized using Synplify-PRO Version 9.0.2.

LUTNM properties are used to constrain two LUTs to the same LUT complex by assigning the same LUTNM value to the two LUTs.

It is not legal to assign the same LUTNM value to three or more LUTs as the following error message indicates. 
Note: This Answer Record is only a good match for your case if the error message specifically contains the sentence "A LUTNM constraint instance may only be applied to two function generator symbols". 


ERROR:Pack:2239 - Unable to obey design constraints 
op_0_lutnm000181) which require the combination of the following function 
generator symbols into a single LUT site: 
LUT symbol 
"u_mem_if_top_0/u_phy_top_0/u_phy_io_0/u_phy_calib_0/count_dq_5_1[0]" (Output 
Signal = 
LUT symbol 
(Output Signal = 
LUT symbol 
"u_mem_if_top_0/u_phy_top_0/u_phy_io_0/u_phy_calib_0/count_dq_5[0]" (Output 
Signal = u_mem_if_top_0/u_phy_top_0/u_phy_io_0/u_phy_calib_0/count_dq_5[0]/O) 
A LUTNM constraint instance may only be applied to two function generator 
symbols. Please correct the design constraints accordingly.


You can correct this error condition by examining the LUT symbol names in the Pack error message and identifying the replicated LUT based on naming convention.

This LUT symbol can then be assigned a new unique LUTNM value that does not conflict with any other LUT.

There is no problem associated with using unique LUTNM values; those LUTNM constraints are ignored. 
For the example error message above, the following UCF constraint corrects the problem: 

INST "u_mem_if_top_0/u_phy_top_0/u_phy_io_0/u_phy_calib_0/count_dq_5_1[0]" LUTNM = XLNX_WA_1 ; 

A separate constraint with a unique value is needed for every occurrence of the error message. 
Note: Although the error message always reports an issue with "LUTNM" properties, the offending constraint might actually be a HLUTNM property.
AR# 30705
Date Created 04/11/2008
Last Updated 06/10/2015
Status Active
Type General Article
  • FPGA Device Families
  • ISE