Design Recipes for FPGAs, 2nd Edition

Chapter 24

Counters

Abstract

One of the most commonly used applications of flip-flops in practical systems is counters. They are used in microprocessors to count the program instructions (program counter or PC), for accessing sequential addresses in memory (such as ROM) or for checking progress of a test. Counters can start at any value, although most often they start at zero and they can increment or decrement. Counters may also change values by more than one at a time, or in different sequences (such as grey code, binary or binary coded decimal (BCD) counters).

Keywords

BCD

Counters

Grey code

Binary counters

24.1 Introduction

One of the most commonly used applications of flip-flops in practical systems is counters. They are used in microprocessors ...