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WRES1103

Introductory Digital Concepts

REKABENTUK DIGITAL

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Analog & Digital

Analog• Having continuous values

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Analog & Digital

Digital• Having discrete values

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Analog & Digital

Digital Advantage• Can be processed & transmitted more

efficiently and reliably• Advantage of storage (e.g. compression,

enhancement etc)

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Analog & Digital

An analog Electronic System

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Analog & Digital

A System using Digital and analog methods

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Logic Levels

Example:• High for TTL => 2V to

5V• Low for TTL => 0V to

0.8V• 0.8V to 2V

unacceptable/ never used

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Digital Waveforms

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A Digital Waveform Carries Binary Information

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A Digital Waveform Carries Binary Information

Data Transfer

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Encoding & Decoding Function

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Multiplexer & Demultiplexer

Mux• Switches from several inputs line onto single

output line in a specified timeDemux• Vice versa

Purpose• Data can be transferred from several sources

over one line to a distant location and redistributed to several destination

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Multiplexer & Demultiplexer

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Storage Functions

Flip-flopsRegisters• Formed by several flip-flops

Semiconductor memories• ROM (permanent), RAM (temporary)

Magnetic memories• Floppy, internal hard disk

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Storage Functions

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Storage Functions

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Fixed Function Integrated Circuit

All components make up circuits (transistor, diode, resistors and capacitors) are integral part of that single chip.Logic function set by manufacturer and cannot be altered

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IC Packages

Through-hole mounted• Dual in-line package (DIP)

Surface-mount technology (SMT)• Save space• Smaller than DIP (pins close together)• Example

• Small-outline integrated circuit (SOIC)• Plastic lead chip carrier (PLCC)• Leadless ceramic chip carrier (LCCC)• Flat Pack (FP)

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IC Packages

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IC PackagesExample of SMT package configurations

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Pin NumberingDot always next to pin 1Number increase going counterclockwise.

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Programmable Logic Device (PLD)

SPLDCPLDFPGAWill be discussed in WRES1102 (VHDL)

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Introduction to Test InstrumentsOscilloscope – Analog, Digital

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Introduction to Test Instruments

• Amplitude = (3 div)(1V/div) = 3V• Period = (4 div)(10 µs/div) = 40 µs• Frequency = f = 1/T = 1/40µs = 25 kHz

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Introduction to Test Instruments

Logic Analyzer• Oscilloscope format

• Display single or dual waveform• Timing diagram format

• Can display up to 32 waveform• State table format

• Display data in tabular form (e.g. hex, octal, BCD, ASCII)

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Introduction to Test InstrumentsLogic Analyzer

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Introduction to Test Instruments

Logic Probe• Detect high-level voltage, low-level voltage, single

pulses, repetitive pulses and opens on PCB

Logic Pulser• Produce repetitive pulse waveform

Current tracer• = current probe• Sense pulsating current – locating shorts on PCB

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Introduction to Test Instruments

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Introduction to Test Instruments

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Introduction to Test Instruments

DC Power Supply• Converts AC from standard wall outlet into regulated DC

voltage.Function Generator• Provides pulse waveforms, sine wave, triangular wave

Digital multimeter (DMM)• Measure DC and AC voltage• Measure DC and AC current• resistance

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Introduction to Test Instruments