EEL 3705 / 3705L Digital Logic Design

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EEL 3705 / 3705LDigital Logic Design

• Fall 2006Instructor Dr. Michael Frank

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Lecture Outline

• Overview of the subject area
• Whats Digital Logic Design all about?
• Overview of the course
• Syllabus, policies, procedures
• Administrative matters
• Sign-in sheet, Prereq form, Blackboard, 1st
  assignment

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What do we mean by Digital Logic Design?

• Digital
• Using discrete physical states (e.g., on/off
  transistor, high/low voltage) to represent
  information
• Logic
• Using the basic operations of Booles algebra of
  logic to interpret, manipulate and process
  information
• Design
• To conceive, plan, analyze and construct the
  structure of working systems that will meet
  application requirements

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Applications of Digital Logic Design

• All complex electronic systems today rely heavily
  on components whose design and operation is based
  (almost entirely) on digital logic principles,
  including
• Microprocessors and microcontrollers
• The heart of the modern computer, and also
  embedded within all manner of other consumer and
  industrial electronic devices
• Digital Signal Processors
• Used in cellphones, cameras, networking equipment
• FPGAs (Field-Programmable Gate Arrays)
• Used for prototyping in a wide range of
  equipment
• ASICs (Application-Specific Integrated Circuits)
• Semi-custom, used in many specialized applications

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Electrical Computer Engineeringand the Design
of Electronic Systems

• Although electrical engineering and computer
  engineering are considered different disciplines,
  its important to always remember that any
  complex electronic component includes both
• Physical/electrical characteristics
• Such as power, current, inductance, capacitance,
  etc.
• And computation-related characteristics
• E.g., information content, logical function,
  software, protocols
• To successfully design working systems requires
  multidisciplinary teams that understand and can
  take care of the engineering considerations on
  both sides!

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What does a modernDigital Logic Designer do?
System-levelrequirements
Functional design

• Design engineering, in general, involves taking
  abstract, system-level requirements, and
  translating them into ever more concrete and
  specific designs for technological artifacts.
• Digital Logic Design is no different.
• In modern industrial practice, increasingly many
  of the steps of the design process have been
  automated.
• This is true for digital functions especially.
• See e.g. resources at eda.org
• Today, computer-based tools do most of the grunt
  work and heavy lifting
• But, the designer has to understand what the
  tools are doing in order to use them!

Functional orbehavioralspecification
Structuraldesign
Schematic orstructuralspecification
Logic design
Gate-LevelDesign
Designcompiler
Circuit synthesis
FPGAProgram
Transistor-levelSchematics
Layout
Loading
ConfiguredFPGA
VLSI Mask Layers
Fabrication
Physical chip
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The Basis of Digital Logic todayThe MOSFET

• Nearly all digital systems today (2006) are based
  on an electronic device called the MOSFET
• Metal-Oxide-Semiconductor Field-Effect Transistor
• This device is a voltage-controlled switch
• Two basic types of FET
• nFET The dominant charge carriers are electrons
  (negative)
• Conducts low voltages well
• pFET The dominant charge carriers are holes
  (positive)
• Conducts high voltages well

gate
source
drain
nFET icon used in schematics
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Todays Dominant Logic StyleCMOS

• Most logic today is done in the CMOS
  (Complementary MOS) logic style
• Each logic gate (hardware to do a given logic
  operation) is built using both nFETs and pFETs
• nFETs pull output low, pFETs pull it high
• Uses energy mainly only when switching
• Here are a simple CMOS inverter circuit and its
  logic gate icon
• When input is high (1) output is low (0) and
  vice-versa.
• This and a few other simple gates are sufficient
  to build any digital system!

Vdd (PWR)
Vin
Vout
Vss (GND)
in
out in
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Course Overview

• Go through syllabus posted on Blackboard

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Administrative Matters

• Sign the attendance sheet being passed around
• Clearly print your preferred email address
• Pick up and sign a prerequisite form
• Turn it in at the end of class
• Make sure you are enrolled on Blackboard
• Email Dr. Frank if you arent
• Download the Quartus II software
• Labs begin next week!

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First-Day Homework Assignment

• To be completed by this Wednesdays lecture
• No time to waste!
• The assignment is
• 1. Turn in the signed course prerequisite form to
  Dr. Frank
• Preferably, at the end of todays lecture
• 2. Ensure you are enrolled for the course on
  Blackboard
• Email instructor at mpf_at_eng.fsu.edu immediately
  if not
• 3. On your home or laptop computer, download
  install the Quartus II software (web version)
• Available from altera.com (see link on Blackboard)