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Timing Constraints (SDC)
LiveLint, merge, and formally prove your timing constraints - and draft them from natural language.
Why it exists
Bad SDC is invisible until timing signoff disagrees with reality. Constraints drift across blocks, merges silently conflict, and nobody can prove an exception is actually safe - the tools that can are six-figure enterprise seats.
VisSDC treats constraints as a first-class design artifact: a rule-based linter for SDC hygiene, structured merging across blocks, formal proofs of constraint properties using Yosys and the Z3 solver, and natural-language drafting for the boilerplate.
What it does
A comprehensive rule set catches malformed, conflicting, and suspicious constraints before they poison a timing run.
Formally check constraint properties against the design with Yosys + Z3 - turning "we think this false path is safe" into a proof.
Merge constraints across hierarchy with conflicts surfaced explicitly, not discovered at top-level timing.
Describe the constraint you mean; get syntactically correct SDC to review - the deterministic checks still gate everything.
How it compares
Where this tool stands against the open-source path and the commercial incumbents - capability by capability.
| Capability | VisSDC | Ad-hoc scripts | Commercial constraint-verification tools |
|---|---|---|---|
| SDC lint rules | Comprehensive rule set | Homegrown, partial | Comprehensive |
| Formal proof of constraints | Yosys + Z3, included | None | Yes, licence-gated |
| NL → SDC drafting | Built in, verified after | None | Emerging add-ons |
| Cross-block merge | Structured, conflict-aware | Manual concatenation | Yes |
| Deployment | Local-first via Escanor | Local | Licence server, per-seat |
Qualitative capability comparison based on publicly documented behavior of the referenced tools. No performance figures are implied.
Built on proven engines: Yosys · Z3
Where it sits: stage S2 - RTL Quality / Static Signoff in the 02 Verify bucket - one node in the platform flow.
Keep exploring
Catch RTL issues before they reach signoff - deep SystemVerilog linting in your editor and your CI.
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Explore SAC →A modern RTL synthesis suite - clean C++ core, built to be scripted, inspected, and trusted.
Explore Stella →Book a demo, or get early access to the platform.