Implementation of Digital System

Prerequisite – Introduction to Digital Systems
Implementation means how the system is constructed from smaller and simpler components called modules. The modules can vary from simple Gates to complex processors. Digital system follows some Hierarchical implementation.

Hierarchical implementation :
It is a modular design system which uses divide and conquer technique which simplifies implementation and debugging. Modules are designed and built separately and then assembled to form the system. One of the major factors for cost effectiveness of Digital Systems.

Top – Down Design :
It starts at the top (root) and works down by successive refinement. This design decomposes the system into sub-system and then sub-system into simpler and smaller sub-system and so on. It stops when sub-system can be realized by directly module.

Bottom – Up Design :
It starts at the leaves and puts pieces together to build up the design. Sub-systems are assembled to form a bigger sub-system. It stops when required functional specification is achieved.

In practice, both Top – Down and Bottom – Up design approaches are needed and used. Designers need a Top – Down approach to divide and conquer to handle the complexity and designers need Bottom – Up because in a well designed system, the structure is designed influenced by what primitives are available.