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AR# 17765

11.1 MAP - A change in the functionality of the MAP "-u" switch disables logic trimming

Description


Beginning with ISE version 6.1i, the functionality of the MAP "-u" option (Trim Unconnected Signals in Project Navigator) has changed. In ISE version 5.2i, MAP processed all signals as if there are "S" properties attached to them. In ISE 6.1i, MAP only processes signals without drivers or without load as if there are "S" properties attached to them.

This change results in some functional differences from previous releases; for example, an optimization can now occur that was previously disabled. Specifically, circular logic that feeds back on itself without ever driving anything "off-chip" is more likely to be optimized away even when trimming is disabled.

Solution


;The old 5.2i trimming functionality can be restored by setting the following environment variable:

PCs
set XIL_MAP_NOCLIP_ON_ALL_SIGS_U=1

Workstations
setenv XIL_MAP_NOCLIP_ON_ALL_SIGS_U 1

For general information about setting ISE environment variables, see (Xilinx Answer 11630).
AR# 17765
Date Created 09/03/2007
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
  • Less