Unit 20 – Digital Principles

While the broad field of electronics covers many aspects, it is digital electronics that now has the greatest impact. This is immediately evident in the mobile phone, laptop, and numerous other everyday devices and systems. Digital electronics allows us to process, store, and transmit data in digital form in robust ways, which minimises data degradation.

This Module includes:

  • 1 Workbook
  • 4 Assignments
  • 2 Worked Solutions
  • 3 Simulation Files
  • 1 Software
  • 31 Tutorial Videos

Description

The unit introduces the two main branches of digital electronics, combinational and sequential. Thus, the student gains familiarity in the fundamental elements of digital circuits, notably different types of logic gates and bistables. The techniques by which such circuits are analysed, introduced and applied, including Truth Tables, Boolean Algebra, Karnaugh Maps, and Timing Diagrams.

The theory of digital electronics has little use unless the circuits can be built – at low cost, high circuit density, and in large quantity. Thus the key digital technologies are introduced. These include the conventional TTL (Transistor-Transistor Logic) and CMOS (Complementary Metal Oxide Semiconductor). Importantly, the unit moves on to programmable logic, including the Field Programmable Gate Array (FPGA). Finally, some standard digital subsystems, which become important elements of major systems such as microprocessors, are introduced and evaluated.

On successful completion of this unit students will have a good grasp of the principles of digital electronic circuits, and will be able to proceed with confidence to further study.


Learning Outcomes

By the end of this unit students will be able to:

1. Explain and analyse simple combinational logic circuits.

Concepts of combinational logic:
Simple logic circuits implemented with electro-mechanical switches and transistors. Circuits built from AND, OR, NAND, NOR, XOR gates to achieve logic functions, e.g. majority voting, simple logical controls, adders
Number systems, and binary arithmetic:
Binary, Decimal, Hexadecimal number representation, converting between, applications and relative advantages. Addition and subtraction in binary, range of n-bit numbers
Analysis of logic circuits:
Truth Tables, Boolean Algebra, de Morgan’s theorem, Karnaugh Maps
Simplification and optimisation of circuits using these techniques

2. Explain and analyse simple sequential logic circuits.

Sequential logic elements and circuits:
SR latch built from NAND or NOR gates
Clocked and edge-triggered bistables, D and JK types
Simple sequential circuits, including shift registers and counters
Timing Diagrams
Memory technologies:
Memory terminology, overview of memory technologies including Static RAM, Dynamic RAM and Flash memory cells
Relative advantages in terms of density, volatility and power consumption
Typical applications, e.g. in memory stick, mobile phone, laptop

3. Describe and evaluate the technologies used to implement digital electronic circuits.

Logic values represented by voltages:
The benefit of digital representation of information
The concept of logic input and output values and thresholds
Digital technologies:
Introduction to discrete logic families, CMOS and TTL, relative advantages in terms of speed, power consumption, density
Programmable logic, FPGAs, relative advantages and applications

4. Describe and analyse a range of digital subsystems, hence establishing the building blocks for larger systems.

User interface:
Examples to include switches, light emitting diodes and simple displays
Digital subsystems:
Examples to be drawn from adders (half, full, n-bit), multiplexers and demultiplexers, coders and decoders, counters applied as timers, shift registers applied to serial data transmission, elements of the ALU (Arithmetic Logic Unit).
Emphasis on how these can be applied, and how they might fit into a larger system

Additional information

Workbooks

1

Assignments

4

Worked Solutions

2

Simulation Files

3

Tutorial Videos

31 Tutorial Videos included in the cost of the module

Logic and Truth Tables (25:13)
Boolean Algebra and DeMorgans Theorem (21:37)
Karnaugh Maps (28:25)
Transient Analysis and MicroCap (28:25)
AND3 Analysis and Simulation (16:46)
OR3 Analysis and Simulation (14:48)
NAND3 Analysis and Simulation (14:33)
NOR3 Analysis and Simulation (11:55)
XOR2 Analysis and Simulation (18:41)
Gate Minimisation with Karnaugh Maps (19:53)
SR Latch Analysis and Simulation (17:03)
D Type Flip-Flop (15:28)
JK Flip-Flop (21:43)
Shift Register (11:15)
Counter (16:04)
State Diagrams, State Tables and State Machines (24:07)
Sequential Design Example (32:17)

Casio Scientific Calculator Demo (37:24)
Dimensions of Frequency (08:26)
Getting started with the MicroCap Simulator (21:59)
Graph Simulator – Advanced (12:46)
Graph Simulator – Beginner (23:17)
Graph Simulator – Intermediate (15:12)
Kirchoff's Voltage and Current Laws (14:59)
MicroCap – Parallel AC RC Circuit (13:41)
MicroCap – Parallel AC RL Circuit (15:38)
MicroCap – Series RC Low-Pass Filter (15:46)
MicroCap – Series RL High-Pass Filter (36:50)
MicroCap – Series RLC Tuned Circuit (16:12)
Resistors in Series and Parallel (27:50)
Thevenin and Norton Equivalents (17:52)

Software

1

Workbook Sample

Tutorial Video Sample