General Description: M1.4: The DROP_SPEC is a TIMESPEC-related constraint that allows you to designate that timing analysis should not be performed on a specific TIMESPEC property. DROP_SPEC can only be specified within constraint files.
Map does not follow standard constraint priority ordering when implementing the DROP_SPEC constraint. The standard way of determining which set of constraints takes priority depends on what point in the flow the set of constraints is specified, as follows:
This means that constraints specified in a .NCF file (including DROP_SPEC), may be overridden by other constraints specified in constraint files read in by M1 at later stages of the implementation flow.
Currently the DROP_SPEC constraint takes priority no matter where it is specified within the flow.