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  3. AR# 38620: ISE 12.2 Pack Virtex-6 - Pack:2784 - Directed packing was unable to obey the user design constraint

AR# 38620

ISE 12.2 Pack Virtex-6 - Pack:2784 - Directed packing was unable to obey the user design constraint

Description

The following error is being received during Map:

ERROR:Pack:2784 - Directed packing was unable to obey the user design constraint
   (LUTNM=Transceiver/INST_PROCESSING_CHAIN.TRX_Data_Chain/INST_FFT_IFFT.FFT_IFF
   T_1/V6_FFT_Core_Gen.FFT_Core/blk00000003/U0/non_floating_point.arch_d.xfft_in
   st/pe_gen[3].natural_order_input.PE/delay_addr_bf2/SRL16_2) which requires
   combining the symbols listed below into a single SLICEM component.
...
The directed pack was not possible because:
   The top reasons for failure were:
           -> A legal placement was never found for shift register symbol
...
How can I resolve this error?

Solution

This is a known issue which has been resolved in ISE 12.3.

The issue can be worked around by disabling power optimization (Removing the -power switch) of Map.


AR# 38620
Date 07/30/2014
Status Active
Type General Article
Devices
  • Virtex-6 CXT
  • Virtex-6 HXT
  • Virtex-6 LX
  • More
  • Virtex-6 LXT
  • Virtex-6 SXT
  • Less
Tools
  • ISE Design Suite - 12.1
  • ISE Design Suite - 12.2