Timing Constraint Priority (1)
It is legal to constrain the same paths more than once
- Known as a constraint conflict
- Multiple sources constraining the same path
- UCF and schematic could constrain same path
- Multiple constraints on one net within one source
Resolution of conflicting constraints from multiple sources:
- Lowest Priority - input netlist or .ncf file
- .ucf file
- Highest Priority - .pcf file (usually from MAP)
Note: this priority only applies to timespecs with identical TSidentfiers (e.g. TS_03 =…)