The timing methodology checks identify potential issues in design constraints, clock definitions, clock relationships, and timing exceptions that can lead to inaccurate timing analysis or failures in hardware. These checks run automatically as part of the design rule check (DRC) process in the AMD Vivado™ Design Suite.
Each timing methodology check is assigned a unique identifier (for example, TIMING-1) and includes the following information:
- Description of the condition that triggers the check.
- Resolution steps to address or prevent the issue.
- Example (if applicable) showing diagrams, constraint code, or other illustrations.
The checks cover a wide range of scenarios, including:
- Invalid clock definitions and waveform mismatches.
- Improperly related clocks without a common source, node, or period.
- Unsafe or incomplete clock domain crossing (CDC) synchronizations.
- Missing or incorrect input/output delay constraints.
- Large setup or hold violations caused by skew or design topology.
- Improper use of timing exceptions such as
set_max_delaywith-datapath_only.
Not every timing methodology check includes an example, but all provide a clear description of the problem and recommended steps to resolve it. Following these recommendations improves the accuracy of timing analysis, reduces the risk of hardware failures, and increases the likelihood of successful timing closure.