Synthesis estimates wires before placement exists, and physical design changes what those estimates missed. The handoff package of netlist, constraints, library views, scan definition, and reports plus a sanity checklist keeps the boundary clean.
Term | Meaning |
|---|---|
Wire-load model | A statistical fanout-to-length table used before any placement exists. |
Placement-aware estimate | A length taken from a trial placement, per net rather than per fanout. |
Congestion | Routing demand above routing supply in a region, guessed early from pin density. |
Handoff package | Everything physical design needs: netlist, constraints, views, scan, reports. |
Lesson | What it covers |
|---|---|
Fanout tables against trial-placement lengths, with a worked delay estimate. | |
A pin-density congestion proxy and why mapping choices matter physically. | |
Area, blockages, pin sides, and utilization arithmetic synthesis depends on. | |
Package contents, an illustrative constraint sketch, and the handoff checklist. | |
What physical design changes, correlation, and a netlist sanity checker. |
The wire estimate: synthesis timed ideal or modelled wires, and real routes added delay the estimate missed. Correlation, not the logic, is the suspect.