Digital Logic Design, 4th Edition

5

Combinational logic design with MSI circuits

5.1 Introduction

Since the introduction of MSI and LSI circuits, the traditional methods of logic design have largely been superseded. Traditionally, the design engineer has developed a Boolean equation as the solution to a particular problem. This function has then been minimised and implemented using SSI circuits.

In practice, many combinational circuits may have a large number of inputs and outputs, and consequently the use of truth tables in the design of such circuits is impractical. Furthermore, it is not economical to provide sufficient pins on an IC package to allow access to each of the gates that can be provided on a single chip. Many functions such as counting, adding and parity checking ...