This document provides information about a digital electronics course syllabus, including:
1. The course is titled EC8392 Digital Electronics and covers topics such as digital fundamentals, combinational and sequential circuit design, memory devices, and digital integrated circuits.
2. The syllabus is divided into 5 units that cover these topics in more detail over 45 class periods.
3. The objectives of the course are to present digital fundamentals, design digital circuits, explain sequential circuits and memory technology, and introduce electronic circuit implementation.
Introduction to IEEE STANDARDS and its different types.pptx
Digital Electronics Fundamentals Guide
1. EC8392 – DIGITAL ELECTRONICS
Unit1
Digital ElectronicsGeneral View
Subject Name : EC 8392 – Digital Electronics
Department : Electronics and Communication
Engineering
Class : III year ECE
Dr.M.A.Raja
Professor
ECE Department
NEHRU INSTITUTE OF ENGINEERING AND TECHNOLOGY
T. M. Palayam, Coimbatore-641 105
(Approved by AICTE, New Delhi and Affiliated to Anna UniversityChennai)
Accredited by NAAC, Recognized by UGC under Section 2(f) and 12, (B)
2. EC8392 – DIGITAL ELECTRONICS
SYLLABUS
EC8392 DIGITAL ELECTRONICS L T P C 3 0 0 3 TOTAL:45 PERIODS
OBJECTIVES:
To present the Digital fundamentals, Boolean algebra and its applications in digital systems
To familiarize with the design of various combinational digital circuits using logic gates
To introduce the analysis and design procedures for synchronous and asynchronous sequential circuits
To explain the various semiconductor memories and related technology
To introduce the electronic circuits involved in the making of logic gates
UNIT I DIGITAL FUNDAMENTALS 9
Number Systems – Decimal, Binary, Octal, Hexadecimal, 1‘s and 2‘s complements, Codes – Binary, BCD, Excess 3, Gray, Alphanumeric codes, Boolean theorems, Logic
gates, Universal gates, Sum of products and product of sums, Minterms and Maxterms, Karnaugh map Minimization and Quine-McCluskey method of minimization.
UNIT II COMBINATIONAL CIRCUIT DESIGN 9
Design of Half and Full Adders, Half and Full Subtractors, Binary Parallel Adder – Carry look ahead Adder,
BCD Adder, Multiplexer, Demultiplexer, Magnitude Comparator, Decoder, Encoder, Priority Encoder.
UNIT III SYNCHRONOUS SEQUENTIAL CIRCUITS 9
Flip flops – SR, JK, T, D, Master/Slave FF – operation and excitation tables, Triggering of FF, Analysis and
design of clocked sequential circuits – Design – Moore/Mealy models, state minimization, state assignment, circuit implementation – Design of Counters- Ripple Counters,
Ring Counters, Shift registers, Universal Shift Register.
UNIT IV ASYNCHRONOUS SEQUENTIAL CIRCUITS 9
Stable and Unstable states, output specifications, cycles and races, state reduction, race free assignments, Hazards, Essential Hazards, Pulse mode sequential circuits,
Design of Hazard free circuits.
UNIT V MEMORY DEVICES AND DIGITAL INTEGRATED CIRCUITS 9
Basic memory structure – ROM -PROM – EPROM – EEPROM –EAPROM, RAM – Static and dynamic RAM – Programmable Logic Devices – Programmable Logic Array
(PLA) – Programmable Array Logic (PAL) – Field Programmable Gate Arrays (FPGA) – Implementation of combinational logic circuits using PLA, PAL.
Digital integrated circuits: Logic levels, propagation delay, power dissipation, fan-out and fan-in, noise
margin, logic families and their characteristics-RTL, TTL, ECL, CMOS
OUTCOMES:
At the end of the course:
Use digital electronics in the present contemporary world
Design various combinational digital circuits using logic gates
Do the analysis and design procedures for synchronous and asynchronous sequential circuits
Use the semiconductor memories and related technology
Use electronic circuits involved in the design of logic gates
3. 1. DIGITAL ELECTRONICS GENERAL
VIEW
Introductionto DigitalElectronics
Digitalelectronicsisabranchof electronicswhichdealswith digitalformat of dataandcodes.
Digitalstandfor digit,digital electronicsbasicallyhastwo conditionswhicharepossible, 0
(low logic)and1(highlogic).
Digital electronic systemsuseadigital signalthat arecomposedofmathematical features to
work.
"1" astrue and"0" asfalsearecalledbit andthe groupof bitsarenamedbyte.
Digitalelectronic circuitsareusuallymadefrom largeassembliesof logicgates.
Digitaldescribeselectronic technology that generates,stores, andprocessesdata in termsof two
states:1andnumber0.
Amodemisusedto convertthe digitalinformation in yourcomputerto analogsignalsfor
your deviceandto convertanalog signalsto digital information for yourcomputer.
4. and
(ICs)
ited on
Digital ElectronicsQuick History
Priorto digital technology, electronic transmission waslimited toanalogtechnology, which
conveysdata aselectronic signalsof varyingfrequencyoramplitude.
• 1930'sthe prototypes of the computer were
constructed from mechanicalswitches(vacuum
tubes) andrelays.Thesewere comparativelyslow,
large, produced agreat dealofheat.
• Thenext stagein the 1940'swasthe useofelectronic
diodes,andwhile thesewerebetter but theywere
unreliable.
• Thenext stagewasthe result of the development in 1947
of the transistor which wasmuchsmaller,faster and
cooler.
• Simpletransistors were replacedbyintegrated
circuits andthat got smaller andsmallerand
finallydepossilicon to beput intoa"chip".
1. DIGITAL ELECTRONICS GENERAL
VIEW
6. Digital systemscanprocess,store, andtransmit datamore efficiently butcanonly assign
separatevaluesto eachpoint.
1. DIGITAL ELECTRONICS GENERAL
VIEW
AnalogQuantities
Most natural quantities (suchastemperature, pressure,light intensity)
areanalog quantities that varycontinuously.
7. AnalogandDigital Systems
Many systems useamaximum of analog and digital electronics to takeadvantage of
eachtechnology.
Example: Atypical CDplayer accepts digital data from the CDdrive and converts it to an
analog signal for amplification.
CDdrive
Digital data
10110011101
Analog
reproduction
of musicaudio
signal
Speaker
Sound
waves
Digital-to-analog
converter
Linearamplifier
1. DIGITAL ELECTRONICS GENERAL
VIEW
8. 1. DIGITAL ELECTRONICS GENERAL
VIEW
Analogueto DigitalConversion
Although somesignalsare originallydigital.
A continuous signal canbe first converted toaproportional
voltage waveform by asuitable transducer, the analogue
signal is generated, andthen for adapting digital processor,
the signal hasto be converted into digital form. The
diagrams showsan analogue signal and its digital signal.
Theupper is the analogue signal and the lower is the digital
signal.
9. TheDigital Revolution
Recently, many types of devices have been converted from analog to digital.
In all of these digital devices, info is processed, transmitted and received aslong strings
of 1sand0s.
1. DIGITAL ELECTRONICS GENERAL
VIEW
10. Advantagesof Digital Electronics
• Computer-controlled digital systems canbe controlled by software, allowing
new functions to be added withoutchanging hardware.
• Information storage can be easier in digital systems than in analog ones.
• The noise-immunity of digital systems permits data to be stored and retrieved
without noise.
• In adigital system are easier to design and more precise representation of asignalcan
be obtained by using more binary digits torepresent it.
• More digital circuitry canbe fabricated onICchips.
• Error management method can be inserted into the signal path. Todetect errors,
and then either correct the errors, or at least askfor anew copy of the data.
1. DIGITAL ELECTRONICS GENERAL
VIEW
11. Disadvantagesof DigitalElectronics
Conversion to digital format and re-conversion to analog format is needed, which always
include the lost ofinformation.
In somecases,digital circuits usemore energy than analog circuits and producemore
heat and need heatsinks.
Digital circuits are sometimes moreexpensive,
especially in smallquantities.
1. DIGITAL ELECTRONICS GENERAL
VIEW
13. Types of NumberingSystems
Manynumberingsystemsarein usein digital technology. Themost commonarethe:
Decimal 537 10
Binary 1010012
Octal 148 8
Hexadecimal 4BAF16
Toavoid confusion while using different numeral systems,
the baseof eachindividual number maybe
asspecified by writing it asasubscript of thenumber.
2. NUMBERING
SYSTEM
18. ConvertingDecimalto Binary
• To convert from adecimal integer numeral to binary, the number is divided by
two and the remainder is the least-significant bit(LSD).
• The result is again divided by two, and its remainder is the next least significant
bit.
• The processis repeated until theresult cannot be divided anymore and the last
result is the most-significant bit(MSD).
2. NUMBERING
SYSTEM
22. CONVERTING FRACTIONARY DECIMALS TO BINARY
• If it is afactionary decimal number the integer is converted using the previous
method and the factionary part is multipliedby 2;
• Theinteger part of that product is the MSDof the factionary part of the number;
• If the fractionary part is not zero, it is once more multiplied by 2 and the integer part
of that product is the next significant digit and soon until we reach zero for the
fractionary part.
2. NUMBERING
SYSTEM
24. BINARYCODEDDECIMALBCD
Onthe BCD(Binary CodedDecimal) system the digits aregrouped in
4 bits nibbles, eachnibble representing adecimaldigit;
Therepresentation of the decimals 10, 11, 12, 13, 14 and 15is
excluded.
TheBCDis usually usedin frequency counters, digital counters
and calculators.
2. NUMBERING
SYSTEM
42. Introduction to BooleanAlgebra
• Much of what we will be discussing wasformalized by George Boole (1815–1864) inhis
paper An Investigation of the LawsofThought.
• Thebranch of mathematics involving digital logic is aptly named BooleanAlgebra.
• Developedto investigate the fundamental laws of the human mind ´s operations relating
to reasoning.
• Its purpose is to define symbols to represent phenomenon's that will originate more
complex mathematical expressions– Boolean Functions or BooleanExpressions;
• But unlike traditional Algebra, instead of dealing with quantities, BooleanAlgebra deals
with Logic.
• Symbolslike (+) or (x) represent logic relations between signals and pules, instead of sum
and multiplication algorithms.
• Thesymbols 0 and 1 represent LogicStates and not quantities (0 is Low or Falseand 1 is
High or True).
4. BOOLEAN
ALGEBR
A
44. Productof TwoStates
Multiplication of twostates:
- There are only twopossibilities: true or false;
-Asquare wave with High value multiplying to
another results in asquare wave with Highvalue.
It doesnot matter how many or few terms we
multiply together.
4. BOOLEAN
ALGEBR
A
46. What isLogicGate?
Digital gate is aDigital Deviceusedto perform thelogic operation
Logicgates (or simply gates) are the fundamental building blocks of digital circuitry
Electronic gates require apower supply.
GateINPUTSare driven by voltages having two nominalvalues,
e.g. 0Vand 5Vrepresenting logic 0 and logic 1respectively.
TheOUTPUTof agate provides two nominal values of voltageonly,
e.g. 0Vand 5V representing logic 0 and logic 1respectively.
In general, there is only one output to alogic gate except in some special cases.
5. BASIC LOGIC
OPERATION
47. 5. BASIC LOGIC
OPERATION
TruthTable
Truth table are usedto help show the function of alogic gate.
Relation between outputs andinputs.
Number of entries on thetable is with n
being the number of entries and base2because
it is related to the binary numbering 0 and 1.
48. Typesof LogicGate
NOTGate
– Output is the invert of the input;
– Always one input.
ORGate
– Output is the binary sum of theinputs.
ANDGate
– Output is the binary multiplication of the inputs.
5. BASIC LOGIC
OPERATION
49. NOTGate
The NOTgate is an electronic circuit that produces an inverted version of the input at its
output. It is also known asan inverter. If the input variable is X,the inverted output is
known asNOTX. Thisis also shown asX', or Xwith abar over the top, asshown at the
outputs.
5. BASIC LOGIC
OPERATION
52. ORGate
The ORgate is an electronic circuit that gives ahigh output (1) if one or more of its inputs
are high. Aplus (+) is usedto show the ORoperation.
X+Y= Z
Equivalent circuit:
5. BASIC LOGIC
OPERATION
53. ORGate
The ORgate is an electronic circuit that gives ahigh output (1) if one or more of its inputs
are high. Aplus (+) is usedto show the ORoperation.
X+Y= Z
Equivalent circuit:
5. BASIC LOGIC
OPERATION
58. ANDGate
TheANDgate is an electronic circuit that gives ahighoutput (1) only if all its inputsare
high. Adot (.) is usedto show the ANDoperation (X.Y), Bearin mind that this dot is
sometimes omitted (XY).
X Y = Z
5. BASIC LOGIC
OPERATION
63. NORGate
This is a NOT-OR gate which is equal to an OR gate followed by a NOT gate. The outputs of
all NOR gates are low if any of the inputs are high. The symbol is an OR gate with a small circle
on the output. The small circle represents inversion.
5. BASIC LOGIC
OPERATION
66. NAND Gate
Thisis aNOT-ANDgate which is equal to anANDgate followed by aNOTgate.
The outputs of all NANDgates are high if any of the inputs are low. Thesymbol is anAND
gate withasmall circle on the output. Thesmall circle represents inversion.
5. BASIC LOGIC
OPERATION
70. ComplexOperations
Upuntil now we remembered the followinglogic gates:
NOT
, OR, AND, NOR, NAND
There are two more gates available to do more complex operations:
- XOR(Exclusive-OR),and its output is HIGHonly if the number of HIGHinputs isODD.
- XNOR(Exclusive-NOR),and its output is HIGHonly if the number of HIGHinputs isEVEN.
5. BASIC LOGIC
OPERATION
71. ComplexOperations
XORGate
The 'Exclusive-OR' gate isacircuit which will give ahigh output if its two inputs are
different.
An encircled plus sign ( ) is usedto show the EORoperation.
5. BASIC LOGIC
OPERATION
78. ComplexOperations
XNORGate: The 'Exclusive-NOR' gate circuit does the opposite to the XORgate. It will
give a low output when its two inputs are different. The symbol is an EXORgate with a
small circle on the output. Thesmall circlerepresents inversion.
5. BASIC LOGIC
OPERATION
82. Simplificationof LogicCircuits
Theprevious Boolean identities and proprieties are usedto simplify complexdigital
circuits in order to obtain more direct ways of circuit implementation.
The circuit will have the samefunction but with fewer components, and consequently
more liability at alower cost ofproduction.
Like in normalAlgebra, the useof Theorems defines the way to simplify digital circuits
using BooleanAlgebra.
5. BASIC LOGIC
OPERATION