Like in the classical functional decomposition approach, the generic architectural approach starts with the definition of the system context. In this case it is called the “Extended System Context” because it captures the operational interfaces between data sources/sinks and the System Under Design (SUD) together with the respective hard-ware interface attributes (hardwired signals/bus, see the following figure). This is needed because I/O data processing will form an essential part of the SUD top-level functions
By starting from the extended system context level, Rapid Prototyping and the later integration of the different subsystems to the overall system model will also be facilitated.