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AR# 33520

12.4/13.4/14.7 Spartan-6 Place - ERROR:Place:543 for design that should fit


My design fails with the following error which indicates that the design does not fit.

The design is not area constrained and should have no problem fitting into the target device.

What could be the problem?

ERROR:Place:543 - This design does not fit into the number of slices available
in this device due to the complexity of the design and/or constraints.

Unplaced instances by type:

FF 2 (0.0%)
LUT 2 (0.0%)
LUTL 4 (0.1%)

Please evaluate the following:

- If there are user-defined constraints or area groups:
Please look at the "User-defined constraints" section below to determine
what constraints might be impacting the fitting of this design.
Evaluate if they can be moved, removed or resized to allow for fitting.
Verify that they do not overlap or conflict with clock region restrictions.
See the clock region reports in the MAP log file (*map) for more details
on clock region usage.

- If there is difficulty in placing LUTs:
Try using the MAP LUT Combining Option (map lc area|auto|off).

- If there is difficulty in placing FFs:
Evaluate the number and configuration of the control sets in your design.

The following instances are the last set of instances that failed to place:

0. Placer RPM "BelCluster" (size: 8)


There is a known problem that can trigger this error on designs that should fit.

Scan the message text and look for the string "BelCluster".

If this string is found, it may be possible to work around the failure by setting the environment variable below.

Note: This Answer Record is only relevant to your case if the string "BelCluster" is in the error message body.

Place:545 errors are fitting errors that can occur for a variety of reasons that are unrelated to this Answer Record.



For general information about setting ISE environment variables, see (Xilinx Answer 11630)
AR# 33520
Date 10/22/2015
Status Active
Type General Article
  • Spartan-6 LX
  • Spartan-6 LXT
  • ISE Design Suite - 11.3
  • ISE Design Suite - 14
  • ISE Design Suite - 13
  • ISE Design Suite - 12