Embedded Systemsnew

8/22/2019 Embedded Systemsnew

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Embedded Systems

By Sushant Kumar


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Structure of the seminar

Introduction

History of embedded systems

Characteristics

Embedded systems for meters


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Introduction

Part 1


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What is an Embedded System ?

Anembedded systemis a

special-purposecomputer systemdesigned to perform adedicatedfunction


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An Embedded system

A generic embedded system


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Why Embedded system ?Performance Technology Advances

CMOS VLSI dominates older technologies (TTL, ECL)

Computer architecture improvements RISC, superscalar, RAID,

Price Simpler development

CMOS VLSI: smaller systems, fewer components Higher volumes

CMOS VLSI : same device cost 10,000 vs. 10,000,000units


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Embedded system vs General Computer

Performs one or a few pre-defined tasks

Very specific requirements

Task-specific hardware and mechanical parts

Often mass-produced

Design engineers can optimize it


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Embedded System

Microprocessor Micro controller

Micro controllershave built in peripherals and memory

which reduces the size of the system


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Application Areas

Signal processing systems Real-time video, DVD players, Medical equipment.

Distributed control Network routers, switches, firewalls,

Small systems Mobile phones, home appliances, toys, smartcards, MP3 players,

PDAs, digital cameras, sensors, pc keyboard & mouse

Modern cars: Up to 100 or more processors Engine control unit ABS systems (Anti Lock Brake systems) Emissions control Diagnostics and Security systems Accessories (doors, windows etc)


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History of Embedded Systems

Part 2


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Apollo Guidance computer

The Apollo Guidance Computer, the first recognizablemodern embedded system developed by Charles StarkDraperat the MIT Instrumentation Laboratory


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Minuteman Missile 1966

First mass-producedembedded system

Autonetics D-17guidance computer

Built from transistor logicReduced prices on nand gate ICs from$1000/each to $3/each

Medicinal appliances

Avionics, such as inertial guidance systems,flight control systems

Cellular telephones and telephone switches

Home automation products


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Other developments

First Microprocessor

Intel 4004

Required externalmemory and supportchips

By mid 1980s microcontrollers came intoexistence

cost of amicrocontroller fellbelow $1

By the end of the 80s,embedded systemswere the norm ratherthan the exception


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Moores law


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Characteristics of EmbeddedSystems

Part 2


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Characteristics of Embedded Systems

1. Interface

2. Complexity

3. Platform

4. Peripherals

5. Tools

6. Reliability

7. Volume


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1. Interface

Interface

No UserInterface

Full UserInterface

Performing user-defined

PDAs

Dedicated to oneTaskMissile guidancesystem


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2. Complexity

Complexity

Simple systems Complex systems

Use buttons,smallcharacter/ digit-only

displays

simple menu system

Connected to a network

Touch screen

Real time constraints

Part of a critical operation


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3. CPU Platform

Many different CPU architectures usedin embedded designs such as ARM,

MIPS, x86, PIC, 8051 etc

Desktop computer market is limited to

just a few architectures


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CPU Platform

PC/104 is a typical base for small, low-volume embedded system design.

Uses an embedded real-time operatingsystem such as MicroC/OS-II, QNX or

VxWorks


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CPU Platform

Very-high-volume embedded systemsuse the system on a chip (SoC), an

application-specific integrated circuit(ASIC)

CPU core was purchased and added aspart of the chip design.


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4. Peripherals

Serial Communication Interfaces

Universal Serial Bus (USB)

Networks: Ethernet, Controller Area Network

Timers:PLL(s), Capture/Compare and Time Processing Units

General Purpose Input/Output (GPIO)

Analog to Digital/Digital to Analog (ADC/DAC)


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5. Tools

Embedded system designers usecompilers, assemblers, and debuggers

Utilities to add a checksum or CRC to aprogram

Emulator replaces the microprocessor

with a simulated equivalent


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6. Reliability issues

System cannot be shut down for repair

Solutions involve subsystems withspares

system must be kept running for safetyand monetary reasons


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7. Volume

Volume

High Volume Low Volume

Minimizing cost is

usually the primary

design consideration

Used when cost isnot a major factor

Performance andreliabilityconstraints


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Embedded systems for Meters

Part 4


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Electric power consumption

Electric power consumption is notconstant whole day

Peak period is between 1 pm and 4 pmSystem must be engineered to meetpeak power


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Limitations of the meter

Mechanical device

Prone to wear,shock

Maintains no record of time

Only Counts the number of rotations ofthe wheel


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Demand Curve


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Real power limitation

Ideally current and voltage are in phase

Every volt-ampere delivered becomes a

watt of power usedInduction motors and lamp ballastscause current to flow out of phase

Fewer actual watts are used thandelivered


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Ideal power curve


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When current and voltage are not in-phase


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Power factor penalty

Industrial customers must by contractmaintain power factor

Power factor=Ratio of real power usedto volt amperes delivered

Pay penalty if above some agreed upon

values


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Multi function meter

Extend for smaller commercial customer

Even for residences

Contract can be varied


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Billing

Networked system can facilitateautomation

No need to send personnelBetter accuracy and lesser burden


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Design Fundamentals

1. Means of taking samples

2. Display

3. Communication subsystem4. Non-volatile memory

5. Power supply

6. Stored program micro-controller


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Hardware design


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Choosing a micro-controller

Feature set

Code space

Data Space

Data converter

Real-time clock


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Conclusion

A quiet revolution is in progress in theutility industry.

Static metering devices, have been inuse for the better part of a century

Gradually being replaced with multi-rate, multifunction meters

Capable of more accurately accountingfor utility usage.


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References

www.maxim-ic.com

www.electronicsforu.com

www.refdesign.techonline.com

www.wikipedia.org

www.powerelectronics.com

www.ucpros.com

www.pdfserv.maxim-ic.com
http://www.maxim-ic.com/http://www.electronicsforu.com/http://www.refdesign.techonline.com/http://www.wikipedia.org/http://www.powerelectronics.com/http://www.ucpros.com/http://www.pdfserv.maxim-ic.com/http://www.pdfserv.maxim-ic.com/http://www.pdfserv.maxim-ic.com/http://www.pdfserv.maxim-ic.com/http://www.ucpros.com/http://www.powerelectronics.com/http://www.wikipedia.org/http://www.refdesign.techonline.com/http://www.electronicsforu.com/http://www.maxim-ic.com/http://www.maxim-ic.com/http://www.maxim-ic.com/


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For detailed report

www.sushantkumar.wordpress.com/tech
http://www.sushantkumar.wordpress.com/techhttp://www.sushantkumar.wordpress.com/tech


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Thank You

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