01 Notes on Digital Systems

Hierarchical Approach- II• We now split the system into discrete blocks which have(typically) a single function (termed highly cohesive) andidentify the way in which they are interconnected• An example of this is presented in schematic 1 where thehierarchy of our ‘phone has been taken down a level togive the internal details of the telephone IC– The system is now comprised of 5 blocks which perform asingle function within the whole system (e.g. display control)– Could further decompose design– Note that the inputs and outputs are the same as the previouslevel (i.e. keybd[6..0] etc.)19