Introduction to embedded Systems

actuallyabandonedΗλεκτρονική - Συσκευές

15 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

124 εμφανίσεις

Embedded Systems Design: A Unified
Hardware/Software Introduction

1

Introduction to embedded Systems

3

Embedded systems overview


Computing systems are everywhere


Most of us think of “desktop” computers


PC’s


Laptops


Mainframes


Servers


But there’s another type of computing system


Far more common...


4

Embedded systems overview


Embedded computing
systems


Computing systems embedded
within electronic devices


Hard to define. Nearly any
computing system other than a
desktop computer


Billions of units produced
yearly, versus millions of
desktop units


Perhaps 50 per household and
per automobile


Computers are in here...

and here...

and even here...

Lots more of
these, though they
cost a lot less each.

5

A “short list” of embedded systems

And the list goes on and on

Anti
-
lock brakes

Auto
-
focus cameras

Automatic teller machines

Automatic toll systems

Automatic transmission

Avionic systems

Battery chargers

Camcorders

Cell phones

Cell
-
phone base stations

Cordless phones

Cruise control

Curbside check
-
in systems

Digital cameras

Disk drives

Electronic card readers

Electronic instruments

Electronic toys/games

Factory control

Fax machines

Fingerprint identifiers

Home security systems

Life
-
support systems

Medical testing systems

Modems

MPEG decoders

Network cards

Network switches/routers

On
-
board navigation

Pagers

Photocopiers

Point
-
of
-
sale systems

Portable video games

Printers

Satellite phones

Scanners

Smart ovens/dishwashers

Speech recognizers

Stereo systems

Teleconferencing systems

Televisions

Temperature controllers

Theft tracking systems

TV set
-
top boxes

VCR’s, DVD players

Video game consoles

Video phones

Washers and dryers


6

2.08.02
CS4272 Lecture1
14
Automotive Electronics.


More than 30% of the car is now in electronics.

90% of innovations will be based on electronics
.
7

Automotive embedded systems


Today’s high
-
end automobile may have lots of
microcontrollers:


checks seat belt;


run dashboard devices;


controls engine;


controls automatic transmission; etc.

8

BMW 850i brake and stability control system


Anti
-
lock brake system (ABS):

pumps brakes to
reduce skidding.


Automatic stability control + Traction (ASC+T):

controls engine to improve stability.


ABS and ASC+T communicate.


ABS was introduced first
---
needed to interface to existing
ABS module.

9

ABS

brake

sensor

brake

sensor

brake

sensor

brake

sensor

ABS

hydraulic

pump

10

Some common characteristics of embedded
systems


Single
-
functioned


Executes a single program, repeatedly


Tightly
-
constrained


All computing systems have constraints on design metrics,
but embedded systems are especially tight.


Low cost, low power, small (must fit in a small space), fast,
etc.


Reactive and real
-
time


Continually reacts to changes in the system’s environment


Must compute certain results in real
-
time without delay


11

An embedded system example
--

a digital
camera

Microcontroller

CCD preprocessor

Pixel coprocessor

A
2
D

D
2
A

JPEG codec

DMA controller

Memory controller

ISA bus interface

UART

LCD ctrl

Display ctrl

Multiplier/Accum

Digital camera chip

lens

CCD


Single
-
functioned
--

always a digital camera


Tightly
-
constrained
--

Low cost, low power, small, fast


Reactive and real
-
time
--

only to some extent

12

Design challenge


optimizing design metrics


Obvious design goal:


Construct an implementation with desired functionality


Key design challenge:


Simultaneously optimize numerous design metrics


Design metric



A measurable feature of a system’s implementation


Optimizing design metrics is a key challenge

13

Design challenge


optimizing design metrics


Common metrics


Unit cost:
the monetary cost of manufacturing each copy of the system,
excluding NRE cost


NRE cost (Non
-
Recurring Engineering cost):
The one
-
time
monetary cost of designing the system


Size:
the physical space required by the system


Performance:
the execution time or throughput of the system


Power:
the amount of power consumed by the system


Flexibility:
the ability to change the functionality of the system without
incurring heavy NRE cost

14

Design challenge


optimizing design metrics


Common metrics (continued)


Time
-
to
-
prototype:
the time needed to build a working version of the
system


Time
-
to
-
market:
the time required to develop a system to the point that it
can be released and sold to customers


Maintainability:
the ability to modify the system after its initial release


Correctness, safety, many more



15

Microprocessor varieties


Microcontroller:

includes I/O devices, on
-
board
memory.


Digital signal processor (DSP):

microprocessor
optimized for digital signal processing.


Typical embedded word sizes:
8
-
bit,
16
-
bit,
32
-
bit.

16

Application examples


Simple control: front panel of microwave oven, etc.


Canon EOS
3
has three microprocessors.


32
-
bit RISC CPU runs autofocus and eye control systems.


Analog TV: channel selection, etc.


Digital TV: programmable CPUs + hardwired logic.

In the
21
st

Century, internet
-
enabled
appliances will dominate the
technology space
-

paving the way
for electronic maintenance.

and beyond

Technology Overview

Decade

Predominant Technology


60
s


Mainframes


70
s


Mini Computers


80
s


Personal Computers

’90s


Internet for people

2000


Internet for Devices

e
-
Vending

Vending Management

from the Desktop




Internet




Stock Level Report

Machine Status Report

Dispatch Activity Log

Vending Activity Log

Devices.net Server

Operator’s Office




Internet



Automatic Alerts !

Pager

Phone

Email

e
-
Vending

Vending Management

from the Desktop

Internet

Gateway

Cold Drink Vendor

Snack Food Vendor

Hot Drink Vendor

Internet

Gateway

Slave

Slave



Interne
t



Telephone

Line



GSM



One

Gateway


16
Machines

1000
m

Apart

Devices.net


e
-
Vending

Vending Management

from the Desktop

20

Internet

Gateway


Built
-
in Modem


Digital Inputs


Analogue Inputs


Digital Outputs

Slave


Plug & Play


Digital Inputs


Analogue Inputs


Digital Outputs

Hardware Features

e
-
Vending


Event
-

driven Dialup


Automatic Health Check


On Demand Connection


Password Protection


Automatic Configuration


Local Data Logging


Data Encryption

21

Summary


Embedded systems are everywhere


Key challenge: optimization of design metrics


Design metrics compete with one another


A unified view of hardware and software is necessary to
improve productivity


Three key technologies


Processor: general
-
purpose, application
-
specific, single
-
purpose


IC: Full
-
custom, semi
-
custom, PLD


Design: Compilation/synthesis, libraries/IP, test/verification