System design based on interface specifications

This paper examines a proposed design methodology that develops systems on the basis of their interface behaviour Systems are specified using HAAD (Hierarchical Annotated Action Diagrams); a specification methodology based on a set of structured timing diagrams. Timing diagrams are annotated with predicates and VHDL constructs to express functional aspects of the design. This allows the concurrent development of both the functional and interface behaviours. The fully refined systems are represented as Synchronous Signal Event Graphs (S-SEG) that are then converted into Hierarchal Concurrent Finite State Machines (HCFSM) and translated into synthesizable VHDL code that is used to generate the corresponding hardware of the system. The procedure is illustrated with a simple example.