Partition
properties give directives to the implementation tools about how to
operate on the Partition.
The preserve property determines what implementation data will be preserved if
the Partition has not been modified. The possible settings are synthesis, placement and routing which determine the level of reuse for the Partition.
The implementation results of the Partition are preserved up to and
including the Preserve setting when you implement your design.
- If set to synthesis, the synthesized
netlist is preserved. Placement and routing may be modified during
re-implementation. Placement and routing are only modified if another
Partition requires these resources.
- If set to placement, the synthesized
netlist and placement are preserved. Routing may be modified during
re-implementation. Routing is only modified if another Partition requires
preserved resources.
- If set to routing, the synthesized netlist,
placement and routing are preserved. All implementation data is preserved
with this setting which is the maximum level of preservation. This
is the default setting when starting a new project.
If a Partition is having difficulty meeting timing or fitting
into a dense design, it may help to relax the preserve property on
neighboring Partitions. After a successful implementation the preserve
property can be reset to routing for full preservation.