04. PDK Setup

— The Most Expensive Asset. Build Once. Never Rebuild —

1. Purpose of This Chapter (Critical)

The Process Design Kit (PDK) is:

• Large in size
• Time-consuming to build
• Extremely sensitive to version mismatches
• Difficult to reproduce exactly
• The single most valuable asset in the OpenLane environment

This chapter exists to ensure that:

• sky130 / gf180 PDKs are installed correctly
• OpenLane1 and OpenLane2 can safely reference them
• The PDK is built exactly once
• You will never rebuild it again

Rebuilding a PDK is a failure, not a maintenance task.

2. Absolute Placement Rules (Non-Negotiable)

Mandatory Rules

• PDKs must live inside WSL, never on /mnt/c
• PDKs must be stored in one canonical location
• All tools must reference the same PDK tree

Required Location

~/pdk

If your PDK exists anywhere else, you are creating future failure.

3. open_pdks Repository

3.1 Clone Repository

From WSL home:

cd ~
git clone https://github.com/RTimothyEdwards/open_pdks.git
cd open_pdks

3.2 Version Policy

• Use the cloned commit as-is
• Do not chase newer commits
• Treat this commit as frozen

The first working commit is the correct one.

4. System Dependencies

Before building, ensure required packages exist.

sudo apt update
sudo apt install -y \
  git make \
  autoconf automake libtool \
  python3 python3-pip \
  tcl-dev tk-dev \
  libcairo2-dev

Do not skip this step.

5. Build sky130 PDK

5.1 Configure

cd ~/open_pdks
./configure --enable-sky130-pdk

5.2 Build and Install

make
sudo make install

⚠️ This step takes a long time.
⚠️ Interrupting it may corrupt the build.

5.3 Verify Installation

ls /usr/local/share/pdk/sky130A

You should see directories such as:

• libs.ref
• libs.tech

If not, do not proceed.

6. Build gf180 PDK (Optional)

If you do not need gf180, skip this section.

6.1 Clean Previous Build

cd ~/open_pdks
make clean

6.2 Configure and Build

./configure --enable-gf180mcu-pdk
make
sudo make install

6.3 Verify

ls /usr/local/share/pdk/gf180mcuC

7. Verify Tool Access

7.1 OpenLane1

cd ~/OpenLane
ls pdks

Expected to see symlinks or directories pointing to:

• sky130A
• gf180mcu* (if built)

7.2 OpenLane2

cd ~/openlane2
ls ~/.volare

PDK references should be visible and consistent.

8. Absolute Prohibitions (Read Carefully)

Never do the following:

• ❌ Re-clone open_pdks
• ❌ Rebuild PDK “just to be safe”
• ❌ Keep multiple PDK versions
• ❌ Copy PDKs between directories
• ❌ Place PDKs under /mnt/c

One PDK. One location. One truth.

9. Pass Criteria

You pass this chapter if:

• sky130 PDK is usable
• gf180 (if built) is usable
• OpenLane1 and OpenLane2 both see the same PDK
• You have no intention of rebuilding it

At this point, the environment’s asset value peaks.

10. Next Step

Now we must prove that everything works.

➡️ 05_Verification_Test.md

Only after successful verification are you allowed to export the environment.

Final Warning

If you rebuild your PDK later:

You ignored this chapter.
Rollback and start from export.