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AR# 14835

6.1i Virtex II PAR - "ERROR:Place:79 - There were not enough sites to place all selected components."

Description

Keywords: PAR, 4.2i, SP2, warning, place, Virtex-II, error, component

Urgency: Standard

General Description:
When I implement a design that contains FMAP functions, the design fails to place in Placement Pass 1, which is then repeated before PAR quits and writes out an initial ".ncd" file. There is adequate room for the offending components to be placed in the device, and no apparent conflicts exist. PAR reports error messages similar to the following:

"WARNING:Place:78 - The SLICE component "component_path/nx1825" could not be placed."

"ERROR:Place:79 - There were not enough sites to place all selected components."

Solution

1. This problem generally occurs because of a lack of resources, preference conflicts, or macro configuration placement requirements that cannot be met.

If PAR has been run, please check the ".par" file for resource allocation and utilization, and verify that there are sufficient resources for placing the component(s). Additionally, ensure that all placement conflicts have been resolved.

If neither of these appears to be a problem, examine the size and shape of the macros in the design to ensure that they may all be placed on the device at the same time.

2. The problem can also be caused by unrelated packs that are performed because the compression factors are being applied to area groups.

For example, the compression factor on an area group may result in a slice that contains both distributed RAM and a carry chain in such a way that there is no placement that can satisfy both the carry chain and the RAM.

To work around this, comment out the line corresponding to that area group in your UCF file:

AREA_GROUP area_group_name COMPRESSION=1;

It is also possible to apply mapping constraints to the instances involved to prevent the unwanted pack while maintaining the compression.
AR# 14835
Date Created 08/29/2007
Last Updated 10/22/2008
Status Archive
Type General Article