OpenROAD and nangate45

The OpenROAD-flow is an open-source, technology-independent VLSI toolchain. As of this writing, it has the ability to run synthesis, place-and-route, and drc through various open-source tools.

The OpenROAD-flow repository contains the nangate45 example pdk, which you might find useful for high-level architectural exploration.

Hammer has the ability to target the OpenROAD toolchain and it’s nangate45 pdk. So you can now simply push a button in Chipyard to go from your Chisel design to a somewhat reasonable gds at an example 45-nm node.

Instructions

In addition to following the chipyard and hammer setup instructions, you must also setup OpenROAD-flow before using it. The steps to run the default RocketConfig through OpenROAD’s drc are:

  1. install OpenROAD-flow (follow the repo’s instructions) on your machine
  2. cd /work/OpenROAD-flow && source setup_env.sh
  3. cd /work/chipyard/vlsi && make tech_name=nangate45 drc

This assumes you already have chipyard’s env.sh and hammer’s sourceme.sh already sourced into your shell.