Setup and Hold time calculation for Multi Frequency clocks:

How PT find clock edges for same clock freq:



For multi-freq clocks:
Which edges need to be considered for Setup and Hold times calculation:
1. Evaluate waveforms over smallest common base period.
2. For each capture edge, find the closest setup launch edge. Call these the primary pairs.

For Setup:
3. Out of the primary pairs, pick the most restrictive setup launch and capture edges.

For Hold:
4. For each primary pair, draw 2 hold relationships: Launch to (Capture-1); (L+1) to Capture. Form all of these hold relationships, pick the most restrictive.