What are the Rules of Timescale directive
Rules
- 'Timescale directive, like all compiler directives, affects all modules compiled after directive, whether in same file, or in files that are compiled separately, until next 'timescale or a 'resetall directive.
- Precision unit must be less than or equal to the time unit.
- Precision for a simulation run is the smallest of all precision units in 'timescale directives. All delays are rounded to the nearest precision unit.
$time task reports simulation time in terms of the reference time unit for module in which it's invoked.