Example Flow

An end-to-end digital implementation reference that combines Synopsys Design Compiler for RTL-to-gate synthesis and Cadence Innovus for physical implementation, wrapped in a set of lightweight Python/FastAPI micro-services plus automation scripts.

Overview

The goal is to let you:

  • Spin up every step (setup → compile → floor-plan → place → CTS → power-plan → route → save) with a single command
  • Or drive / debug individual steps via simple REST calls
  • Keep all tool settings under version control (CSV + TCL) for fully repeatable runs

Repository Layout 

.
├── config/                  # CSV knobs for each stage
│   ├── synthesis.csv
│   ├── imp_global.csv
│   ├── placement.csv
│   └── cts.csv
├── designs/
│   └── des/                 # example AES-DES design
│       ├── rtl/             # Verilog sources
│       └── implementation/  # auto-generated results
├── libraries/               # FreePDK45 timing/lib/LEF
├── scripts/
│   └── FreePDK45/
│       ├── tech.tcl         # common tech setup
│       ├── frontend/        # Design-Compiler TCL
│       └── backend/         # Innovus TCL (1–8)
├── server/                  # FastAPI micro-services
│   ├── synth_setup_server.py
│   ├── synth_compile_server.py
│   ├── floorplan_server.py
│   ├── placement_server.py
│   ├── cts_server.py
│   ├── powerplan_server.py
│   ├── route_server.py
│   └── save_server.py
└── run_pipeline.sh          # one-shot driver

Prerequisites

Tool Version (known good) Notes
Synopsys Design Compiler V-2023.12-SP2 dc_shell in $PATH
Cadence Innovus 21.1 s075 innovus in $PATH
Python 3.9+ tested with venv
FreePDK45 Nangate OpenCell v1.3 timing/LEF already included

Licenses: You need valid DC & Innovus licenses on the host.

Quick Start

Run all 8 stages with a single command:

./run_pipeline.sh       # runs ALL 8 stages, logs to ./logs/

Behind the scenes the script:

  1. Spins up (or re-uses) the 8 REST services on localhost :3333…3340
  2. Calls them in sequence, passing the parameter sets from config/*.csv
  3. Streams JSON back to the console for each stage; artefacts go under designs/des/FreePDK45/{synthesis,implementation}/…

If you see ✅ at the end you have a routed & saved GDS/V files ready.

Running Individual Stages

Every stage is a tiny FastAPI app exposing POST /<stage>/run.

Example: Placement Stage 

curl -X POST http://localhost:3337/place/run \
     -H 'Content-Type: application/json' \
     -d '{
           "design": "des",
           "tech":   "FreePDK45",
           "impl_ver":"cpV1_clkP1_drcV1__g0_p0",
           "g_idx":0, "p_idx":0,
           "force": true
         }' | jq .

All servers honour two rules:

  • Idempotent – rerun with force=true to wipe previous logs/reports
  • Stateless – all context (version tags, CSV indices) comes from the JSON

Service Endpoints

Port Service Endpoint Depends on
3333 synth_setup_server /setup/run source RTL
3334 synth_compile_server /compile/run setup artefacts
3335 floorplan_server /floorplan/run .mapped.v/.sdc
3337 placement_server /place/run floorplan.enc.dat
3338 cts_server /cts/run placement
3336 powerplan_server /power/run floorplan (striped)
3339 route_server /route/run CTS
3340 save_server /save/run route

See docs/api_examples.http for ready-to-paste requests in VS Code.

Configuration System

CSV → Environment → TCL

Instead of duplicating parameters in TCL, every tunable knob lives in CSV:

  • imp_global.csv – global flow effort, target util, etc.
  • placement.csv – setPlaceMode switches, density caps…
  • cts.csv – CCOpt properties
  • synthesis.csv – compile options, clock period…

At runtime the Python server:

  1. Picks a row by index (g_idx, p_idx, c_idx…)
  2. Exports the key/values as environment variables
  3. The stage-specific *.tcl scripts reference them:
setDesignMode -flowEffort $env(design_flow_effort)
floorPlan -r $env(ASPECT_RATIO) $env(target_util)

Change a cell in CSV → commit → rerun only the affected stage.

Logs, Reports & Artifacts

Path Contents
logs/<stage>/ Full tool std-out per run (timestamped)
designs/.../synthesis/<syn_ver>/results .mapped.v, .sdc, QOR
designs/.../implementation/<impl_ver>/pnr_reports/ floorplan_summary.rpt, place_timing.rpt.gz, …
pnr_save/ floorplan.enc.dat, final.enc.dat – for restore
pnr_out/ DEF, SPEF, net-delays, etc.

Reports that matter (WNS/TNS, DRC counts, routing congestion) are collected and returned in JSON by each service – so your CI can grep them directly.

Adapting for Your Design

  1. Place your RTL under designs/<name>/rtl/*.v

  2. Add a minimal config.tcl under designs/<name>/ containing at least: 
    set TOP_NAME "<top_module>"
set RTL_LIST  [glob $::env(BASE_DIR)/designs/<name>/rtl/*.v]

  3. Keep using the default CSV rows or add new ones

  4. Update the REST calls / run_pipeline.sh with design="<name>"

No other path hard-coding required.

Troubleshooting

Symptom Likely Cause Fix
*.mapped.sdc not found during floorplan RTL top name ≠ file prefix Either rename file or use the new auto-detect logic in backend/1_setup.tcl
Placement fails with row not legalised Target util too high Tweak placement.csv → place_global_max_density
Route DRC over 1M Missing power stripes on M4/M5 Revisit 3_powerplan.tcl stripe pitch
REST call returns error: … enc.dat not found Previous stage crashed Look at logs/<stage>/…log and fix first

Roadmap

  • 🚧 Add OpenROAD support for fully open-source flow
  • Parameter sweep driver (sweep.py) to explore CSV grids
  • Prometheus metrics endpoint on each server

License

See LICENSE. Free to use for academic & evaluation purposes; no guarantees.

Made with ❤️ by the MCP team – feel free to open issues / PRs!