00. Project Plan

🧱 OpenLane2 + SRAM Hard Macro Integration

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🎯 Objective

The objective of this project is to demonstrate how OpenLane2 can be used to:

• 🔗 Integrate an SRAM hard macro into a top-level SoC-style design
• 🧭 Perform macro-aware place-and-route
• 📦 Generate a final GDS that includes the SRAM macro

The SRAM itself is not a design target.
It is treated strictly as an external hard macro (physical constraint) to showcase a realistic, macro-inclusive physical design flow.

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📌 Scope

✅ In Scope

• Install OpenLane2 in an isolated, non-destructive environment
• Establish a baseline OpenLane2 flow (standard-cell-only)
• Integrate an SRAM hard macro (LEF / GDS / blackbox)
• Perform macro-aware floorplanning
  • FIXED macro placement
  • Halo / keepout configuration
• Complete placement, routing, and final GDS generation
• Document the entire flow in a reproducible and educational manner

🚫 Out of Scope

• SRAM circuit design or memory compiler usage
• Redistribution of proprietary SRAM macro files
• Full commercial sign-off (complete DRC/LVS closure)
• Replacement or modification of OpenLane (v1)

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📦 Deliverables

📚 Documentation

• docs/00_plan.md — Project plan and milestones (this document)
• docs/10_env.md — Environment setup and non-destructive installation
• docs/20_openlane2.md — Baseline OpenLane2 flow
• docs/30_macro_sram.md — SRAM macro integration details
• docs/40_results.md — Results, warnings, and lessons learned

🛠 Design Artifacts

• Baseline GDS (standard-cell-only design)
• Final GDS including the SRAM macro
• OpenLane2 reports
  • Area
  • Timing
  • Routing
  • DRC summary

⚠️ PDKs and SRAM macro files are not included in this repository.

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🗺 Milestones and Status

🟢 M0: OpenLane2 Installation (Non-Destructive) ✅

Goal

• Install OpenLane2 while preserving existing OpenLane (v1) setups

Result

• OpenLane2 runs inside a Python virtual environment
• Existing OpenLane (v1) flows remain fully unaffected

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🟢 M1: Baseline Flow (No SRAM) ✅

Goal

• Validate a minimal end-to-end OpenLane2 flow

Result

• A small design completes placement and routing
• GDS is generated successfully
• All steps are documented and reproducible

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🟢 M2: SRAM Macro Integration (Floorplan / Placement) ✅

Goal

• Integrate the SRAM hard macro into the design

Result

• SRAM is declared as a blackbox at the RTL level
• Macro is placed as FIXED
• Halo / keepout regions are applied
• Floorplan is stabilized prior to routing

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🟢 M3: Final GDS with SRAM ✅

Goal

• Generate a final GDS including the SRAM macro

Result

• Placement and routing complete successfully
• Final GDS including the SRAM macro is generated
• Warnings, limitations, and tool behavior are analyzed and documented

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⚙️ Technical Policy

• SRAM is treated as a FIXED hard macro
• Only abstract views (LEF / maglef) are used for macro checking
• Internal SRAM DRC/LVS is intentionally excluded
• PDKs and macros are referenced externally via environment variables
• Reproducibility is prioritized over manual intervention or tuning

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⚠️ Risks and Mitigations

Risk	Mitigation
SRAM macro redistribution restrictions	Do not include macros; document integration steps only
PDN issues around macro	Address via floorplan constraints and early checks
Excessive DRC violations	Use abstract views and exclude macro internals
Environment dependency	Use venv and explicit configuration files

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🧭 Positioning

This repository serves as a:

Minimal, practical, and reproducible example of macro-aware physical design using OpenLane2

It is intended for:

• Engineers transitioning from standard-cell-only flows
• OpenLane / OpenROAD users integrating hard macros
• Educational, tutorial, and reference use cases

The focus is on clarity, realism, and reproducibility,
not on maximum performance optimization or commercial sign-off.

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Last updated: Final GDS generation completed ✅