Incremental Implementation Flow Designs - 2022.1 English

Vivado Design Suite User Guide: Implementation (UG904)

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2022.1 English

The incremental run requires a reference checkpoint to be read in to start the incremental place and route. The read_checkpoint -incremental <reference>.dcp command initiates the incremental flow and must be issued before place_design.

Reference Design

The reference design is typically a fully routed checkpoint from a previous iteration or a different variation of the incremental design. If using a different variation or a design, it is important that the hierarchy names from the reference design match the incremental design.

The reference design must match the device and it is recommended to match the tool version but not a strict requirement.

Incremental Design

The incremental design is the updated design that is to be run through the implementation tools. It can include RTL changes, netlist changes, or both but these changes should be typically < 5%. Prior to issuing the read_checkpoint -incremental command, there is no knowledge that the incremental implementation flow is being used. Therefore it is important to not introduce significant netlist changes by changing synth_design or opt_design tool options when compared with the reference design.

Constraint changes are allowed but general tightening of constraints will significantly impact placement and routing and is generally best added outside of the incremental flow.