TABLE OF CONTENTS Objective: Chapters 1 to 10 introduced fundamental concepts, indispensable devices, basic circuits, and several applications of digital electronics. From this chapter on, we focus exclusively on circuit analysis, design, and simulation.
Digital circuits can be divided into two main groups, called combinational and sequential. The former is further divided into logical and arithmetic, depending on the type of function (i.e., logical or arithmetic) that the circuit implements. We start by studying combinational logic circuits in this chapter, proceeding to Combinational arithmetic circuits in the next, and then sequential circuits in the chapters that follow. This type of design (combinational logic) will be further illustrated using VHDL in Chapter 20.
Chapter Contents
| 11.1 | Combinational versus Sequential Logic |
| 11.2 | Logical versus Arithmetic Circuits |
| 11.3 | Fundamental Logic Gates |
| 11.4 | Compound Gates |
| 11.5 | Encoders and Decoders |
| 11.6 | Multiplexer |
| 11.7 | Parity Detector |
| 11.8 | Priority Encoder |
| 11.9 | Binary Sorter |
| 11.10 | Shifters |
| 11.11 | Nonoverlapping Clock Generators |
| 11.12 | Short-Pulse Generators |
| 11.13 | Schmitt Triggers |
| 11.14 | Memories |
| 11.15 | Exercises |
| 11.16 | Exercises with VHDL |
| 11.17 | Exercises with SPICE |
By definition, a combinational logic circuit is one in which the outputs depend solely on its current inputs. Thus the system is memory less and has no feedback loops, as in the model of Figure 11.1(a). In contrast, a sequential logic circuit is one in which the output does depend on previous system states, so storage elements are necessary, as well as a clock signal that...
