A hardware design consists of a number of modules interconnected by wires known as 'nets' (short for networks).
The interconnections between modules are typically structured as mating interfaces. An interface nominally consists of a number of terminals but these have no physical manifestation.
In a modern design flow, the protocol at an interface is specified once in a master file that is imported for the synthesis of each module that sports it.
A clock domain is a set of modules and a clock generator. Within a synchronous clock domain all flip-flops have their clocks commoned.
|1: (C) 2008-13, DJ Greaves, University of Cambridge, Computer Laboratory.|