OpenROAD RTL-to-GDS Flow for SCL180 (FS120)

This repository provides a fully functional OpenROAD RTL-to-GDS flow for the SCL180 FS120 technology node.

The flow has been validated end-to-end on:

• ✅ GitHub Codespaces
• ✅ Local Ubuntu 22.04 (x86-64)

The repository includes:

• A prebuilt OpenROAD binary (Ubuntu 22.04, x86)
• A complete OpenROAD-Flow-Scripts (ORFS) setup
• Platform integration for SCL180FS120

⚠️ Important Note on Licensing Foundry PDK files (LEF, GDS, LIB, CDL) are NOT included in this repository. Users must supply the SCL180 PDK from their licensed source.

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Repository Layout

vsd-scl180-orfs/
├── images/                  # Screenshots used in this README
├── orfs/
│   ├── flow/                # Run the OpenROAD flow from here
│   └── tools/openroad/      # Prebuilt OpenROAD binary
├── .devcontainer/           # GitHub Codespaces configuration
├── README.md                # This file (shown on repo main page)

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1️⃣ Running the Flow on GitHub Codespaces (Recommended)

This is the fastest and zero-install way to run the flow.

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Step 1: Launch GitHub Codespaces

1. Open the repository 👉 https://github.com/vsdip/vsd-scl180-orfs
2. Click Code → Codespaces → Create codespace
3. Wait for the container to build (OpenROAD, GUI, and noVNC are preinstalled)

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Step 2: Obtain the SCL180 PDK

You may download the PDK using any method:

• wget from your private cloud
• Firefox inside Codespaces
• OneDrive / Google Drive / S3 / DigitalOcean

Example:

wget <your-private-link>/SCLPDK_V3.0_KIT.tar

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Step 3: Extract the PDK

tar -xf SCLPDK_V3.0_KIT.tar
cd SCLPDK_V3.0_KIT
tar -xzf scl180.tar.gz

This creates:

scl180/
├── stdcell/
├── pdk/
├── digital_pnr_kit/
└── ...

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Step 4: Copy Technology LEF

cp scl180/stdcell/fs120/6M1L/lef/scl18fs120_tech.lef \
   orfs/flow/platforms/scl180fs120/lef/

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Step 5: Copy Standard-Cell LEF

cp scl180/stdcell/fs120/6M1L/lef/scl18fs120_std.lef \
   orfs/flow/platforms/scl180fs120/lef/scl18fs120_merged.lef

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Step 6: Verify LEFs in ORFS Platform

ls orfs/flow/platforms/scl180fs120/lef/

Expected:

scl18fs120_tech.lef
scl18fs120_merged.lef

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Step 7: Copy Standard-Cell GDS

cp scl180/stdcell/fs120/6M1L/gds/scl18fs120.gds \
   orfs/flow/platforms/scl180fs120/gds/

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Step 8: Copy Liberty (.lib)

cp scl180/stdcell/fs120/6M1L/liberty/lib_flow_ss/tsl18fs120_scl_ss.lib \
   orfs/flow/platforms/scl180fs120/lib/

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Step 9: Filter srlab Cells (VERY IMPORTANT)

export SCL_LIB=orfs/flow/platforms/scl180fs120/lib/tsl18fs120_scl_ss.lib

awk '
BEGIN{skip=0}
/^[ \t]*cell\(/ {
  skip=0
  if ($0 ~ /cell\(srlab(1|2|4)\)/) skip=1
}
{ if (!skip) print }
' "$SCL_LIB" \
> orfs/flow/platforms/scl180fs120/lib/tsl18fs120_scl_ss.nosrlab.lib

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Step 10: Run the Flow

cd orfs/flow
make clean_all
make

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Step 11: Verify Completion & View Layout

make klayout_6_final.gds

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Step 12: Access GUI via noVNC

• Open Ports tab in Codespaces
• Click Port 6080
• XFCE desktop opens in browser
• KLayout launches graphically

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Opening the noVNC Desktop (GUI Access)

Once Port 6080 is opened in GitHub Codespaces, the noVNC web interface becomes accessible.
This page confirms that the browser-based VNC server is running.

Recommended action:

• Click vnc_lite.html for a faster and lightweight desktop session.

This opens an XFCE desktop directly inside your browser, with access to graphical EDA tools such as KLayout, GTKWave, and Magic.

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Viewing the Final Layout in KLayout

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2️⃣ Running the Flow on a Local Ubuntu Machine

Supported Environment

• Ubuntu 22.04
• x86-64
• No OpenROAD installation required

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Step 1: Clone the Repository

git clone https://github.com/vsdip/vsd-scl180-orfs.git
cd vsd-scl180-orfs

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Step 2: Use the Bundled OpenROAD Binary

Prebuilt OpenROAD location:

orfs/tools/openroad/bin/openroad

Add it to your PATH:

export PATH=$PWD/orfs/tools/openroad/bin:$PATH
openroad -version

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Step 3: Provide the SCL180 PDK

Repeat Steps 2–9 from the Codespaces section to populate:

orfs/flow/platforms/scl180fs120/
├── lef/
├── gds/
├── lib/

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Step 4: Run the Flow

cd orfs/flow
make clean_all
make

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Step 5: View Final Layout (Optional)

make klayout_6_final.gds

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Summary

• ✅ Fully open-source RTL-to-GDS flow
• ✅ Works on GitHub Codespaces and local Ubuntu
• ✅ No OpenROAD installation required
• ✅ Clean separation of licensed PDK content
• ✅ Suitable for education, research, and prototyping