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

AR#	17765	Search For Another Answer
Topic	Map
Last Updated	09/09/2010
Status	Active

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).