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ECSE-2610ECSE-2610Computer Components Computer Components & Operations (COCO)& Operations (COCO)

Today:

• General Course Information

• First Hour: Introduction to Design– Section 1.1 of Katz’s Textbook

– In-class Activity #1

• Second Hour: Digital Systems– Section 1.2 of Katz

– In-class Activity #2

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Course InformationCourse Information• Lectures (DCC 308) twice a week

– First hour: Lecture + in-class activity– Second hour: Lecture + in-class activity– For each class, need to

» Read ahead» Bring the Katz textbook

• 2-hr Studio sessions (JEC 6309/6314) once a week.– Points for advance preparation!

• All course material and info is on WebCT– Go to RPINFO, Click on WebCT courses, ECSE Dept, COCO.– Login ID same as RCS– Initial password is your birthdate in “mmddyy” format. Change it!

• Adds, Drops, Section Changes…– Contact Ms. Jeanne Denue for all administrative matters– JEC 6049, Phone: 276 - 6313

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The Digital WorldThe Digital World

PCs

printer

Scanner

TelephoneFax

Data

Mainframe/supercomputer

PDA

Laptop computer

Router

Router

Router

Television

CRT projector

smartcards

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The Digital WorldThe Digital World• Information Processing Systems, especially

computers, are driving the world economy.– The Internet is changing the way we communicate, shop, learn,

invest, and entertain ourselves.

• This is an amazingly fast moving business!!– Processors double in speed every 18 months

– The Internet doubles in size every year

• Computers are the most amazing and complex things ever built by mankind

– The Intel Pentium III has 28 million transistors

– It runs at 1.3 billion cycles per second

COCO is about:

1. Computer building blocks

2. How the building blocks are assembled to build the computer

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Sheer ComplexitySheer Complexity

• 28 million transistors

• 1.3 billion cycles/sec clock

• Just one part of a computer

• Overall, a computer can have a billion transistors.

Intel Pentium III Chip

The Design Process is a systematic way to cope with all this complexity.

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Basic IdeasBasic Ideas

• To design is to represent• Divide and conquer• Successive Refinement• Use Math Tools:

Combinational LogicSequential Logic

• Use Software tools

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Traffic Signal ExampleTraffic Signal ExampleN

S

EW

N - S E - W

Lights for N & S are the same, call them N-S

Similarly, we have E-W

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What the System DoesWhat the System Does

• Cycles through the sequence GREEN-YELLOW-RED

• N-S and E-W never GREEN or YELLOW at the same time

• GREEN stays on for 45 seconds, YELLOW for 15, RED for 60

N

S

EW

N - S E - W

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System RequirementsSystem Requirements

• speed: compute changes in under 100 ms

• power: consume less than 20 watts

• board area: implement in less than 20 square cm

• cost: less than $20 to manufacture

N

S

EW

N - S E - W

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"To Design Is to Represent""To Design Is to Represent"

1. English language specificationnot precise, can be ambiguous

2. Functional descriptionmore preciseflow charts, program fragments

3. Structural descriptionmodules decomposed into simpler components

4. Physical descriptionIn terms of logic gates or transistors

Start

after 45 seconds

after 15 seconds

after 45 seconds

after 15 seconds

N-S RedE-W Yellow

N-S RedE-W Green

N-S YellowE-W Red

N-S GreenE-W Red

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Going from One Going from One Representation to AnotherRepresentation to Another

Top Down: Complex functions replaced by more primitive functions

Bottom Up: Build more and more complex assemblies out of smaller parts,

respecting the rules of composition

Rules of Composition: Electrical RulesTiming Rules

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TrafficSubsystem

StartN-S Green

E-W Red

N-S YellowN-S Red

E-W GreenE-W Yellow

45 secs

TimerStart Light Sequencer

15 secs

N-S Green

E-W Red

N-S YellowN-S Red

E-W GreenE-W Yellow

Start Timer

15 secs

N-S Lights

E-W Lights

Counter

45 secs

Decoder

N-S Green

E-W Red

N-S YellowN-S Red

E-W GreenE-W Yellow

Top-Down Design ExampleTop-Down Design Example

Refine

Refine again

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The Process of BuildingThe Process of Building

E.g., a group of flip flops form a counter

groups of gates form flip flops, timers, sequencers etc.

a group of transistors form a gate

Gates

Transistors

Modules

System

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Representations & TechnologiesRepresentations & Technologies

Word description

Functional Description

Blocks

Waveforms

Truth Tables

Boolean Algebra

Gates

Transistors

Rapid PrototypingTechnologies

ChipDesign

ComputerSynthesisTools

Computer Simulation

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Debugging the SystemDebugging the System

• Design FlawsImplementation does not meet functional specification

Logic design is incorrect (wrong function implemented)

• Implementation Flaws

Individual modules function correctly but their compositions do not

Misunderstanding of interface and timing behavior

Wiring mistakes

• Component Flaws

What Can Go Wrong

• Design Flaws

• Implementation Flaws

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Systematic testingSystematic testing

Simulate before constructing

Use lab Instruments, e.g., Logic Analyzers

Debugging MethodsDebugging Methods

Divide and conquerDivide and conquer

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Design

Recap Of Design ProcessRecap Of Design Process

DesignInitial concept: what is the function performed by the object?Constraints: How fast? How much area? How much cost?Refine abstract functional blocks into more concrete realizations

Implementation

Assemble primitives into more complex building blocksComposition via wiringChoose among alternatives to improve the design

DebugFaulty systems: design flaws, composition flaws, component flawsDesign to make debugging easierHypothesis formation and troubleshooting skills

ImplementationIteration

Debug

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Do Activity #1 NowDo Activity #1 Now

• Reference: –Section 1.1 of Katz Textbook

–Bring the book to each class from now on

• If you are on the wait list, put “W” for the section number.

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Digital Hardware SystemsDigital Hardware Systems

Analog: values vary over a broad range continuously

Digital: only discrete values

+5

V

–5

1 0 1

Time

+5 V

–5

Time

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Analog systems:

• Limited precision, errors accumulate, drift

• Interface circuits (i.e., sensors & actuators) often analog

Why Prefer Digital ? Why Prefer Digital ?

Digital systems:

• More accurate and reliable

• Readily available as self-contained, easy to cascade building blocks

• Computers use digital circuits internally

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• Just two discrete values: yes/on/5 volts/current flowing/magnetized North/true/"1" no/off/0 volts/no current flowing/magnetized South/false/"0"

• Two kinds of systems:

1. Combinational: Described by Boolean Logic

2. Sequential: Described by State Machine Theory

Binary Digital SystemsBinary Digital Systems

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Boolean variable: assume values 0 or 1Boolean equation: also called “logic expression”

If a logic expression is false, it has value 0 If a logic expression is true, it has value 1

Basic Boolean Operations: AND, OR, NOT

X AND Y 0 0 1 1

X Y

0 1 0 1

0 0 0 1

X OR Y X Y

0 0 1 1

0 1 0 1

0 1 1 1

X NOT X

0 1

1 0

Boolean Logic OperationsBoolean Logic Operations

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Traffic Light ExampleTraffic Light Example

IF N-S is green

AND E-W is red

AND 45 seconds has elapsed since the last light change

THEN we can advance to the next light configuration

IF N-S is green

AND E-W is red

AND 45 seconds has elapsed since the last light change

THEN we can advance to the next light configuration

Start

after 45 seconds

after 15 seconds

after 45 seconds

after 15 seconds

N-S RedE-W Yellow

N-S RedE-W Green

N-S YellowE-W Red

N-S GreenE-W Red

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Variables, Equation, and CircuitVariables, Equation, and Circuit

IF N-S is green

AND E-W is red

AND 45 seconds has elapsed since the last light change

THEN we can advance to the next light configuration

IF N-S is green

AND E-W is red

AND 45 seconds has elapsed since the last light change

THEN we can advance to the next light configuration

Boolean variables:

NSG (1 Green), EWR (1 Red), T45 (1 Elapsed), NEXT (1 Go to next)

Logic Equation: NEXT = NSG AND EWR AND T45

LOGICCIRCUIT

NSG

EWR

T45

NEXT

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Combinational LogicCombinational Logic

For this circuit, the outputs are a pure, instant function of the inputs

• Combinations of inputs define the output• Also called “memoryless” logic

For this circuit, the outputs are a pure, instant function of the inputs

• Combinations of inputs define the output• Also called “memoryless” logic

LOGICCIRCUIT

NSG

EWR

T45

NEXT

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Start

after 45 seconds

after 15 seconds

after 45 seconds

after 15 seconds

N-S RedE-W Yellow

N-S RedE-W Green

N-S YellowE-W Red

N-S GreenE-W Red

Combinational Logic cannot describe the

entire system!!

Why??

Traffic Light ExampleTraffic Light Example

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Traffic light controller sequences infinitely through four states

Inputs and outputs overlap

Outputs depend on inputs and the entire history of execution!

That is, the circuit has memory Circuit only needs a summary representation of

the past: a limited number of unique configurations called state

Sequential LogicSequential Logic

Need: storage elements to remember the current stateNeed: storage elements to remember the current state

Start

after 45 seconds

after 15 seconds

after 45 seconds

after 15 seconds

N-S RedE-W Yellow

N-S RedE-W Green

N-S YellowE-W Red

N-S GreenE-W Red

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New component: storage elements to remember the current state

Circuit has feedback connections

output and new state is a function of the inputs and the old state

So, the fed back outputs are the state!

Sequential Logic Block DiagramSequential Logic Block Diagram

- - -

X 1 X 2 X n

LogicCircuit

Z 1 Z 2 Z m

- - -

Feedback connection!

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Traffic Light ExampleTraffic Light Example

Current Traffic Light Controller Configuration

Other Inputs, Like Timer Signals

New Traffic Light Controller Configuration

Traffic Light Controller

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Traffic Light DetailsTraffic Light Details

Maps current state and alarm events into the next state

IF controller in state N-S green, E-W redAND the 45 second timer alarm is on,THEN the next state becomes N-S yellow, E-W red at the next clock tick

IF controller in state N-S green, E-W redAND the 45 second timer alarm is on,THEN the next state becomes N-S yellow, E-W red at the next clock tick

Next StateCombinational

Logic

S T A T E

Output Combinational

Logic

Clock Timer

Alarms

Current State

Detailed Light Control Signals

Binary Storage devices replaced by next statewhen the clock signal arrives

Current StateCurrent state mapped into control signalsto change the lights and to start the eventtimers

Output LogicNext State Logic

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Do Activity #2 NowDo Activity #2 NowDue: End of Class Today

RETAIN THE LAST PAGE (#3)!!

For Next Class:• Bring Randy Katz Textbook

• Required Reading:– Sec 1.1, 1.2, and 1.3 of Katz

– Omit Sec 1.3.5 - 1.3.7, and Sec 1.4

• This reading is necessary for getting points in the Studio Activity!

• Studio Session #1 Tuesday/Wednesday