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. Defines the level of reuse for this Partition,
that is, 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 are open for re-implementation.
Placement and routing are only re-implemented if another Partition
requires these resources.
- If set to placement, the synthesized
netlist and placement are preserved. Routing is open for re-implementation.
Routing is only re-implemented if another Partition requires these
resources.
- If set to routing, the synthesized netlist,
placement and routing are preserved. All implementation data preserved
with this setting. 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 set back to routing for full preservation.