Analog and Digital C - Introduction to Digital Electronics, Study notes of Digital & Analog Electronics

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Introduction

to

Digital

Electronics

Suplementary Reading

• (^) Digital Design by - John F. Wakerly
• (^) www.ddpp.com - you will find some solutions at this site.
• (^) www.xilinx.com - Xlinix Web site
• (^) Logic and Computer Design Fundamentals by - M. Morris Mano & Charles R. Kime
• (^) Digital Design by - M. Morris Mano
• (^) Digital Logic Circuit Analysis and Design by - Victor P. Nelson, H. Troy Nagle, J. David Irwin & Bill D. Carrol

Analog versus Digital

• (^) Analog systems process time-varying signals that can take on any value across a continuous range of voltages (in electrical/electronics systems).
• (^) Digital systems process time-varying signals that can take on only one of two discrete values of voltages (in electrical/electronics systems). - (^) Discrete values are called 1 and 0 (ON and OFF, HIGH and LOW, TRUE and FALSE, etc.)

Representing Information Electronically

• (^) A light bulb has to represent 4 different information: Bulb off - no student inside Bulb 1/3 lit - 1 student inside Bulb 2/3 lit - 2 student inside Bulb Full lit - 3 student inside
• (^) A light bulb has to represent 10 different information: - (^) Is it possible to differentiate the ten different light intensity?

Representing Information Electronically

• (^) “Analog electronics” deals with non-discrete values
• (^) “Digital electronics” deals with discrete values

Benefits of Digital over Analog

• (^) Reproducibility
• (^) Not effected by noise means quality
• (^) Ease of design
• (^) Data protection
• (^) Programmable
• (^) Speed
• (^) Economy

Digital Devices

• Gates
• Flip-Flops
• PLDs
• FPGAs

Gates

• (^) The most basic digital devices are called gates.
• (^) Gates got their name from their function of allowing or blocking (gating) the flow of digital information.
• (^) A gate has one or more inputs and produces an output depending on the input(s).
• (^) A gate is called a combinational circuit.
• (^) Three most important gates are: AND, OR, NOT

AND, OR, NOT Gates

What is the

Basic Digital Element

in Electronics

a Switch

Using Switch to represent digital information

Real Switches to represent digital information

5v 5v 1k 10k 5v 4.5v Output Output

Logic levels

• (^) Undefined region is inherent digital, not analog
• (^) Switching threshold varies with voltage, temp need “noise margin”
• (^) Logic voltage levels decreasing with new processors. 5 , 3.3 , 2.5 , 1.8 V