Embedded systemppt2343

Embedded System
Embed Everywhere
Chen-Wei Chang
Lee-Kuo Chen

Agenda
Introduction
 History
 Characteristics
 Architecture & Design
 Applications
 Summary


An embedded system is a special-purpose
computer system designed to perform one or
a few dedicated functions, often with real-time
computing constraints. It is usually embedded
as part of a complete device including
hardware and mechanical parts. In contrast, a
general-purpose computer, such as a
personal computer, can do many different
tasks depending on programming. Embedded
systems control many of the common devices
in use today.
-- Wikipedia

Definition
Hard to define
 Computing systems embedded within
electronic devices
 Nearly any computing system other than a
desktop computer


Examples
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Air conditioner
ATM machine
Battery charger
Digital camera
DVD player
Fax machine
Home security system
Mobile phone
Modem

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Navigation system
PDA
Photocopier
Printer
Router
Scanner
TV
Video game console
Wearable computer

Legolas
Elvish language
Josh
English
You know who
Parseltounge

Leo
Lame English

Lieutenant Worf
Klingon Language

Market is here!

Source: BCC, Inc

History


In the earliest years of
computers in 1930 – 40s,
computers were
sometimes dedicated to a
single purpose task.



One of the first
recognizably modern
embedded system was
the
Apollo Guidance Computer
, developed by
Charles Stark Draper at
the MIT Instrumentation
Laboratory.

History


Since these early applications
in the 1960s, embedded
systems have come down in
price and there has been a
dramatic rise in processing
power and functionality. The
first microprocessor for
example, the Intel 4004 was
designed for calculators and
other small systems but still
required many external
memory and support chips.

History


By the mid-1980s, most of the
common previously external
system components had been
integrated into the same chip
as the processor and this
modern form of the
microcontroller allowed an
even more widespread use,
which by the end of the
decade were the norm rather
than the exception for almost
all electronics devices.

Characteristics (1/4)


Special-purpose
 Typically,

is designed
to execute a single
program, repeatedly
 It used to be singlepurpose
 Now, multi-functioned,
but single-purpose
 Tactic and Strategy



Tightly constrained
 Low

cost
 Simple systems
 Fewer components
based
 Performs functions
fast enough
 Minimum power



Reactive and realtime
 Reactive:

Continually
reacts to external
events
 Real-time: Must
compute certain
results in real-time



Hardware and
software co-exist
 The

software written
for embedded systems
is often called
firmware
 Is stored in read-only
memory or Flash
memory chips rather
than a disk drive

Differences from usual
computer programs
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Several components of
vastly different functionalities
are found in embedded
system software



Response time constraint
and strict deadlines



All components must use the
memory optimally

Differences from usual computer
programs


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Each software
component execution
speed must be optimum
Software must have
controlled complexity and
must be thoroughly
tested and debugged for
errors

Architecture
Real-time programming:



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programming the processes or instruction set with
constraints of time for its response, process with
latencies, and process with deadlines.
Procedure-oriented C and object-oriented
programming C++ and Java languages are used in
most embedded systems programming.
Embedded programming is such that methods to
optimize the system memory requirements are also
used.

Real-Time Operating System


An RTOS is an OS for response time-controlled and eventcontrolled processes. It is very essential for large scale
embedded systems.

Real-Time Operating System


Function
1. Basic OS function
2. RTOS main functions
3. Time Management
4. Predictability
5. Priorities Management
6. IPC Synchronisation
7. Time slicing
8. Hard and soft real-time operability



When do we need RTOS?

When is RTOS necessary?


Software for a large number of small-scale embedded
system use no RTOS and these functions are
incorporated into the application software.



For small-scaled systems, RTOS’s function can be
replaced by C.

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For example, instead of the memory allocation and deallocation functions of RTOS, the C function , melloc and
free can be used.



Software can directly handle inter-process
communication

When is RTOS necessary?
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However, RTOS is essential when…
A common and effective way of handling of the hardware
source calls from the interrupts
I/O management with devices, files, mailboxes becomes
simple using an RTOS
Effectively scheduling and running and blocking of the
tasks in cases of many tasks
More…..
In conclusion, an RTOS may not be necessary in a
small-scaled embedded system. An RTOS is necessary
when scheduling of multiple processes and devices is
important.

CPU Platforms
Different from desktop computer
 CPU Architectures: 65816, 65C02,
68HC08, 68HC11, 68k, 8051, ARM, AVR,
Blackfin, C167, Coldfire, COP8, eZ8,
eZ80, FR-V, H8, HT48, M16C, M32C,
MIPS, MSP430, PIC, PowerPC, R8C,
SHARC, ST6, SuperH, TLCS-47, TLCS870, TLCS-900, Tricore, V850, x86,
XE8000, Z80, etc.


Operating System
Usually there is no operating system
 Embedded operating system: designed to
be very compact and efficient, forsaking
many functions that non-embedded
computer operating systems provide
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System on chip (SoC)
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Integrating all components of a computer or
other electronic system into a single integrated
circuit (chip).
It may contain digital, analog, mixed-signal, and
often radio-frequency functions – all on one chip.
A typical application is in the area of embedded
systems.
SiP (System in Package)

Software Development
The software development process can be
represented by lifecycle, also called a
waterfall or linear incremental model.
 Analysis, design, implementation and
maintenance are four stages of this
model.
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User Interface


Embedded systems range from
no user interface at all —
dedicated only to one task — to
full user interfaces similar to
desktop operating systems in
devices such as PDAs.

Application
Lover’s Cup
 Lego Mindstorms NXT
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Applications
Lover’s Cup
 Two cups are wireless
connected to each other
with sip sensors and LED
illumination. The Lover's
cups will glow when your
lover is drinking.
 Lover's Cups can let you
share a drink remotely
with someone you care.
When both of you are
drinking, the glowing
Lover's Cups represents
a celebration of the
shared drinking moment.

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LED, Wi-Fi, liquid
sensor
It can be used in
medical field.

Lego Mindstorms
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Programmable Logic Device
Lego sets combining programmable bricks with
electric motors, sensors, Lego bricks, and Lego
Technic pieces (such as gears, axles, and
beams)
First released in 1998
Created by Lego and MIT Media Laboratory

Lego Mindstorms NXT Technical
specifications
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32-bit ARM7 microcontroller
256 Kbytes FLASH, 64 Kbytes RAM
8-bit AVR microcontroller
4 Kbytes FLASH, 512 Byte RAM
Bluetooth wireless communication (Bluetooth Class II V2.0 compliant)
USB full speed port (12 Mbit/s)
4 input ports, 6-wire cable digital platform (One port includes a IEC 61158
Type 4/EN 50 170 compliant expansion port for future use)
3 output ports, 6-wire cable digital platform
100 x 64 pixel LCD graphical display
Loudspeaker - 8 kHz sound quality. Sound channel with 8-bit resolution and
2-16 KHz sample rate.
Power source: 6 AA batteries

Lego Mindstorms NXT features
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The NXT
Touch Sensor, Sound Sensor, Light Sensor,
Ultrasonic Sensor
Servo motors
Bluetooth, USB
NXT Software
Gears, axles, and beams
Lego bricks

Serve the need for the
customers

Reference
Embedded Systems: Architecture,
Programming, and Design by Raj Kamal
 Embedded Systems Handbook by Richard
Zurawski
 Wikipedia.org
 Lego.com
 web.media.mit.edu/~jackylee/cups.htm


Embedded systemppt2343

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