Setting Preservation Level - 2022.1 English

Vivado Design Suite User Guide : Hierarchical Design (UG905)

Document ID
UG905
Release Date
2022-04-20
Version
2022.1 English

After reading in the OOC checkpoint, the preservation level for this module must be defined.

To lock the placement and/or routing of an imported OOC checkpoint, use a lock_design command.

lock_design [-level <value>] [-unlock] [<cell>]

Within this command, the following preservation levels are available as values for the -level switch:

Logical
Preserves the logical design. Any placement or routing information is still used, but can be changed if the tools can achieve better results.
Placement
(default) Preserves the logical and placed design. Any routing information is still used, but can be changed if the tools can achieve better results.
Routing
Preserves the logical, placed and routed design. Internal routes are preserved, but interface nets are not. To preserve routing, the CONTAIN_ROUTING property must have been used on the Pblock during the OOC implementation. This ensures that there are no routing conflicts when the OOC implementation is reused.

Note that regardless of the desired preservation level, the entire physical database will still be read in (including routing) but will not be modified unless the tools determine that better results can be obtained.

Table 1. lock_design Arguments
Argument Name Description
-level Specifies the preservation level. Values are logical, placement, or routing. The default value is placement.
-unlock Unlock cells. If cells are not specified, the whole design is unlocked. The -level parameter must be specified for unlocking, and works the opposite of locking behavior. Specifying routing only unlocks routing, while specifying placement unlocks placement and routing.
<cell> This is the hierarchical cell name to be locked. If cells are not specified, the whole design is locked.