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AR# 61391

Vivado - PROHIBIT contraints affect report_utilization

Description

When opening a Vivado project and running report_utilization on the synthesized design, the available logic is less than expected.
 
For example, on a xc70tfbg484, the following is expected:
 
SLICE LUT: 41000
SLICE REG: 82000
 
The following is what is actually shown from report_utilization:
 
SLICE LUT: 40940
SLICE REG: 81880;
 
Why is this the case?

Solution

The PROHIBIT constraints reduce the available logic shown in the utilization report.

Please check your XDC constraints for constraints of this type.
 
For example: 
set_property PROHIBIT [true/false] [get_sites SLICE_X3Y122]
AR# 61391
Date Created 07/06/2014
Last Updated 09/29/2014
Status Active
Type General Article
Tools
  • Vivado Design Suite