ABSTRACT
VFSM is the central object in the RTDB, storing the behavior specification and allowing the Vfsm Executor to carry out the specification. To realize that task the VFSM object has links to other objects. The diagram in Figure 15.1 shows all participating interface elements. There are a few interfaces between:
State machines: realized by CMD objects and a direct access to VFSM states (the “state” links between VFSM are shown using thick lines)
State machines and I/O handlers: realized by UNIT objects
State machines and output functions (via OFUN objects): realized by UNIT objects
The diagram does not show objects owned by VFSMs (except the CMD). The VFSM object list contains by definition a command (CMD) object as it is assumed that a VFSM should have a command. In practice, when specifying simple examples we design also state machines without a command — this is accepted by the runtime system. State machines designed for a system of state machines have commands as the commands realize the interface among them.
