STA Numericals
Quick numeric intuition for timing reports.
Setup Slack Example
Required time = clock period - setup - uncertainty.
Arrival time = launch clock + data path delay.
Slack = required - arrival. Negative slack indicates violation.
Hold Slack Example
Required time = launch clock + hold + uncertainty.
Arrival time = capture clock + data path minimum delay.
Slack = arrival - required. Negative slack indicates violation.
Interpretation Tips
WNS is the single worst path; TNS sums all negative slacks.
Fix the root cause, not just the worst number, to avoid churn.
Always confirm constraints before changing implementation.