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CS M51A/EE M16 Winter05 Section 1 Logic Design
of Digital SystemsLecture 1
January 10

• Yutao He
• yutao_at_cs.ucla.edu
• 4532B Boelter Hall
• http//courseweb.seas.ucla.edu/classView.php?term
  05Wsrs187154200

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Outline

• Welcome
• Chapter 1 - Class Overview
• Summary

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Why Are We Here?

• Because the computer is everywhere!

Welcome to the class!
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Course Administration

• Instructor Yutao He (yutao_at_cs.ucla.edu)
• Office Hours MW 6-7pm (4750 BH)
• TA Kenneth Leung (kyleung_at_ucla.edu)
• Office Hours TTh 1-2pm (4428 BH)
• Textbook
• Introduction to Digital Systems
• by Ercegovac, Lang, and Moreno
• John Wiley Sons, 1999
• Course Website
• http//courseweb.seas.ucla.edu/classView.php?term
  05Wsrs187154200

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Course Structure
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Homework

• Available on-line every Monday before the class
• Due at 4pm on the following Monday
• Drop off in the class mailbox in Room 4428BH
• Each homework hand-in should attach a cover sheet
• Solution is available on-line Tuesday
• 9 Homework in total

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Quizzes

• To get you acquainted with Midterm and Final
• To have you keep up with the class progress
• 3 quizzes in total
• Given every two weeks at the end of Friday
  session
• Closed-book and Closed-note
• 30 minutes
• Test class materials covered in the past two weeks

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Projects

• To get hands-on experiences on current industry
  practice (EDA tools dominated)
• 2 or 3 small projects
• Design simple digital systems in VHDL
• Use the Altera MAXPLUS II toolkit
• May team up with your fellow classmates
• SEASNET accounts are required unless you have PC
  at home

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Midterm and Final

• Goal is to test knowledge not to test speed
  writing
• Midterm
• Date 2-350pm Friday, February 18
• Location in the lecture room
• Closed-book/Closed-note but allows a cheat-sheet
• Final
• Date 8-11am Monday, March 18
• Location TBD
• Closed-book/Closed-note but allows a cheat-sheet

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Academic Integrity

• Studying in groups is encouraged
• Actual work must be your own
• Common cheating scenarios
• running out of time on an assignment and then
  cut-and-paste from your buddys work
• cross-talking and cross-eyeing during exams
• Will be reported to Deans Office if catch any
  violation

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Course Problems

• Cant make quizzes or exams
• should ask for permission ahead of time
• the score would be zero unless some unexpected
  emergencies
• Forget to turn in homework or your pet dog ate it
• Only one time is allowed

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Course Protocols

• Please do not have small talk
• Please do not read newspapers
• Please do not wear the headphone
• Please put your cell phone in a non-disturbing
  mode
• Sleep is ok as long as you make sure not to snore
• Quiet food is allowed
• Dont be shy to ask any questions occur to your
  mind
• Dont get intimidated if some fellow students
  happen to know better than you in the beginning
• Thats why you take the class

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What You Need to Do Well

• You have common sense
• There are 12 months in a year
• You can count properly
• 11 ?
• You can do logic reasoning
• if I miss one lecture, then Ill fail the class
• You have the positive motivation
• Ill shoot for an A
• You know how to work smart

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What We will Learn

• Language of logic design
• Boolean algebra, logic minimization, state,
  timing, CAD tools
• Concept of state in digital systems
• Analogous to variables in software systems
• How to design/analysis digital systems
• Contrast with software design
• Both map well-posed problems to physical devices
• Both must be flawless

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Applications of Logic Design

• Conventional computer design
• CPUs, memories, busses, peripherals
• Networking and communications
• Phones, modems, NICs, routers
• Embedded products
• Cars, PDAs, entertainment devices
• Scientific equipments
• Testing, measuring, sensing, reporting
• World of computing much bigger than just PCs!

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A Brief Historic Flashback

• 1850 George Boole invents Boolean algebra
• Maps logical propositions to symbols
• Permits manipulation of logic statements using
  mathematics
• 1938 Claude Shannon links Boolean algebra to
  switches
• His Masters thesis
• 1945 John von Neumann develops first stored
  program computer
• Its switching elements are vacuum tubes
• 1947 Shockley, Brittain, and Bardeen invent the
  transistor
• enable integration of multiple devices into one
  package
• gateway to modern electronics

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Follow-on Courses

• CS152A (Lab)
• CS151B (Computer Architecture)
• CS152B (Lab)

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Questionnaire

• Help us better know your background and thus
  teach the course more effectively.

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Hardware Systems

• A simple model of a hardware system is a unit
  with inputs and outputs

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Analog vs. Digital

• Digital It has only discrete input/output values
• In computer systems, only 0 and 1 are used
• Analog It has continuous input/output values
• In reality, real electronic components exhibit
  analog behavior

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Combinational vs. Sequential

• Combinational
• a digital circuit is combinational if its current
  output valuesonly depend on its current input
  values
• means "memory-less
• AND, OR gates
• Sequential
• Exhibit behaviors (output values) that depend not
  only on the current input values, but also on
  previous input values
• In reality, all circuits are sequential

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Synchronous vs. Asynchronous

• Synchronous
• The outputs can only change at prescribed time
  instant
• Asynchronous
• The outputs can change at any time instant

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Systems Studied in the Class

• Digital
• Both Combinational and Sequential
• Synchronous

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Big Picture of Digital Systems Design
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Course At-A-Glance

• Specification
• Spec. of combinational systems Ch. 2 and 4
• Spec. of sequential systems Ch. 7
• Implementation
• Physical level Ch. 3
• Combinational Systems
• at the gate level Ch. 5 and 6
• at the module level Ch. 9, 10, and 12
• Sequential systems
• elementary Ch 8

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An Example

• Calendar subsystem number of days in a month (to
  control watch display)
• used in controlling the display of a wrist-watch
  LCD screen
• inputs month, leap year flag
• outputs number of days

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Implementation in Software

• int number_of_days (month,leap_year_flag)
• switch (month)
• case 1 return (31)
• case 2 if (leap_year_flag 1)
• return (29)
• else return (28)
• case 3 return (31)
• ...
• case 12 return (31)
• default return (0)

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Implementation in Hardware

• Encoding
• how many bits for each input/output?
• binary number for month
• four wires for outputs 28, 29, 30, and 31
• Behavior
• combinational
• truth tablespecification

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Specification Truth Table
month leap d28 d29 d30 d310000
0001 0 0 0 10010 0 1 0 0 00010 1 0 1 0 00011
0 0 0 10100 0 0 1 00101 0 0 0 10110 0
0 1 00111 0 0 0 11000 0 0 0 11001 0 0 1 0
1010 0 0 0 11011 0 0 1 01100 0 0 0 11101
111
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Boolean Expression

• Truth-table to logic to gates
• d28 1 when month0010 and leap0
• d28 m8'm4'm2m1'leap'
• d31 1 when month0001 or month0011 or ...
  month1100
• d31 (m8'm4'm2'm1) (m8'm4'm2m1) ...
  (m8m4m2'm1')
• d31 can we simplify more?

symbol for or
symbol for and
symbol for not
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Implementation in Gate networks

• d28 m8'm4'm2m1'leap
• d29 m8'm4'm2m1'leap
• d30 (m8'm4m2'm1') (m8'm4m2m1')
  (m8m4'm2'm1) (m8m4'm2m1)
• d31 (m8'm4'm2'm1) (m8'm4'm2m1)
  (m8'm4m2'm1) (m8'm4m2m1)
  (m8m4'm2'm4') (m8m4'm2m1')
  (m8m4m2'm1')

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Summary

• That was what the entire course is all about
• Converting solutions to problems into
  combinational and sequential networks effectively
  
• Organizing the design hierarchically and
  systematically
• Taking advantage of optimization opportunities
• Analyze a digital system
• Now let us do it again
• This time we'll take the rest of the quarter!

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Next Lecture

• Section 2.3 - Data Representation and Coding
• Class Note 1