79.

Throw theory into the fire;
it only spoils life.

-M. A. Bakunin

We must use time as a tool, not as a couch.

-J. F. Kennedy

Introduction

In this chapter, we illustrate some of the operational characteristics of sequential circuits by examining three particularly useful sequential logic components: registers, counters, and memories. Registers contain groups of storage elements that are read or written as a unit. Register files are multiple registers within a single integrated component. -Random-access memories are generalizations of register files with very many storage elements. Shift registers contain logic to circulate the contents of the storage elements among themselves. Counters are registers with additional logic that cycle the register's contents through a predefined sequence of states. If these states are interpreted as a binary or BCD number, the state sequence may increase (an up-counter) or decrease (a down-counter). In particular, we shall cover:

Construction of various kinds of registers and counters. Starting with the flip-flop building blocks introduced in the previous chapter, we show how to build registers and counters.
Counter design procedure. We develop a procedure for mapping a behavioral description of a counter into an implementation based on flip-flops and combinational logic. This is a primitive form of the more general finite-state machine design procedure we describe in the next chapter.
Counters available as packaged parts. We will examine catalog counters and some of the pitfalls in their use.
Random-access memories. We describe the function and timing behavior of logic components with very many storage elements.

1. Kinds of Registers and Counters
2. Counter Design Procedure
3. Self-Starting Counters
4. Implementation with Different Kinds of Flip-Flops
5. Asynchronous Versus Synchronous Counters
6. Random-Access Memories
Chapter Review
Exercises

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Introduction

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This file last updated on 07/14/96 at 16:36:05. randy@cs.Berkeley.edu;

This file last updated on 07/14/96 at 16:36:05.
randy@cs.Berkeley.edu;