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AR# 39602

14.x Constraints - How do you separate one LUT6 into two LUTs?

Description

How do you separate one LUT6 into two LUTs?

Solution

There are several ways to do this as follows:
  • Add BLKNM constraints to the LUTs with different names. They will be separated into two different SLICEs.
  • If you want to put these two LUTs into one SLICE, but not one LUT6, you can add LOCto these LUTs with different BEL types.
  • XST has one option -lc to control LUT combining, but it applies to the entire design.
  • Synplify has one option "Enable Advanced LUT Combining", but it applies to the entire design.
  • Add XBLKNM constraints to the LUTs with different names. They will be separated into two different SLICEs.
AR# 39602
Date Created 10/25/2011
Last Updated 12/15/2012
Status Active
Type General Article
Tools
  • ISE - 10.1
  • ISE Design Suite - 11.1
  • ISE Design Suite - 11.2
  • More
  • ISE Design Suite - 11.3
  • ISE Design Suite - 11.4
  • ISE Design Suite - 11.5
  • ISE Design Suite - 12.1
  • ISE Design Suite - 12.2
  • ISE Design Suite - 12.3
  • ISE Design Suite - 12.4
  • ISE Design Suite - 13
  • ISE Design Suite - 13.1
  • ISE Design Suite - 13.2
  • ISE Design Suite - 13.3
  • ISE Design Suite - 13.4
  • ISE Design Suite - 14.1
  • Less