vir pnr

Place-and-route your design.

Usage

$ vir pnr

vir pnr places and routes an already-synthesized design, reusing the netlist that vir synth left at build/<project>.json. It re-runs only the place-and-route (and pack) steps, so it’s the counterpart of vir synth for when you want to re-run those steps without re-synthesizing.

The source-level checks and constraint emission still run, so the constraints stay in sync with the sources — but the netlist is not re-synthesized, so source edits since the last vir synth are not reflected in it.

Options

--tries <N>

Run place-and-route across several seeds (default: 1), and keep the best result.

--seed <N>

Use a specific seed for the place-and-route algorithm.

--allow-timing-failure

Do not fail when the design does not meet its timing constraints.

Next steps

• vir bitstream: Generate a bitstream from the placed-and-routed design.