Circuit Design: Know It All

Chapter 11

Sequential Logic Design

Ian Grout

11.1 Introduction

Sequential logic circuits are based on combinational logic circuit elements (AND, OR, etc.) working alongside sequential circuit elements (latches and flip-flops). A generic sequential logic circuit is shown in Figure 11.1. Here, the circuit inputs are applied to and the circuit outputs are derived from a combinational logic block. The sequential logic circuit elements store an output from the combinational logic that is fed back to the combinational logic input to constitute the present state of the circuit. The output from the combinational logic that forms the inputs to the sequential logic circuit elements constitutes the next state of the circuit. These sequential logic circuit elements ...