Transcript Embedded systems

Embedded Systems
By Sushant Kumar
Structure of the seminar
Introduction
History of embedded systems
Characteristics
Embedded systems for meters
Introduction
Part 1
What is an Embedded System ?
An embedded system is a
special-purpose computer system
designed to perform a dedicated
function
An Embedded system
A generic embedded system
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. 10,000,000
units
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
Embedded System
Microprocessor
Micro controller
Micro controllers have built in peripherals and memory
which reduces the size of the system
Application Areas
Signal processing systems
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Real-time video, DVD players, Medical equipment.
Distributed control
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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
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Engine control unit
ABS systems (Anti Lock Brake systems)
Emissions control
Diagnostics and Security systems
Accessories (doors, windows etc)
History of Embedded Systems
Part 2
Apollo Guidance computer
The Apollo Guidance Computer, the first recognizable
modern embedded system developed by Charles Stark
Draper at the MIT Instrumentation Laboratory
Minuteman Missile
1966
First mass-produced embedded system
Autonetics D-17 guidance computer
Built from transistor logic
Reduced 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
Other developments
First Microprocessor
Intel 4004
Required external
memory and support
chips
cost of a
microcontroller fell
below $1
By mid 1980’s micro
controllers came into
existence
By the end of the 80s,
embedded systems
were the norm rather
than the exception
Moore’s law
Characteristics of Embedded
Systems
Part 2
Characteristics of Embedded Systems
1.
2.
3.
4.
5.
6.
7.
Interface
Complexity
Platform
Peripherals
Tools
Reliability
Volume
1. Interface
Interface
No User
Interface
Full User
Interface
Dedicated to one
Task
Performing userdefined
Missile guidance
system
PDA’s
2. Complexity
Complexity
Simple systems
Complex systems
•Use buttons,small
character/ digit-only
displays
•Connected to a network
•simple menu system
•Real time constraints
•Touch screen
•Part of a critical operation
3. CPU Platform
Many different CPU architectures used
in embedded designs such as ARM,
MIPS, x86, PIC, 8051 etc…
Desktop computer market is limited to
just a few architectures
CPU Platform…
PC/104 is a typical base for small, lowvolume embedded system design.
Uses an embedded real-time operating
system such as MicroC/OS-II, QNX or
VxWorks
CPU Platform…
Very-high-volume embedded systems
use the system on a chip (SoC), an
application-specific integrated circuit
(ASIC)
CPU core was purchased and added as
part of the chip design.
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)
5. Tools
Embedded system designers use
compilers, assemblers, and debuggers
Utilities to add a checksum or CRC to a
program
Emulator replaces the microprocessor
with a simulated equivalent
6. Reliability issues
System cannot be shut down for repair
Solutions involve subsystems with
spares
system must be kept running for safety
and monetary reasons
7. Volume
Volume
High Volume
Minimizing cost is
usually the primary
design consideration
Low Volume
Used when cost is
not a major factor
Performance and
reliability
constraints
Embedded systems for Meters
Part 4
Electric power consumption
Electric power consumption is not
constant whole day
Peak period is between 1 pm and 4 pm
System must be engineered to meet
peak power
Limitations of the meter
Mechanical device
Prone to wear,shock
Maintains no record of time
Only Counts the number of rotations of
the wheel
Demand Curve
Real power limitation
Ideally current and voltage are in phase
Every volt-ampere delivered becomes a
watt of power used
Induction motors and lamp ballasts
cause current to flow out of phase
Fewer actual watts are used than
delivered
Ideal power curve
When current and voltage are not inphase
Power factor penalty
Industrial customers must by contract
maintain power factor
Power factor=Ratio of real power used
to volt amperes delivered
Pay penalty if above some agreed upon
values
Multi function meter
Extend for smaller commercial customer
Even for residences
Contract can be varied
Billing
Networked system can facilitate
automation
No need to send personnel
Better accuracy and lesser burden
Design Fundamentals
1.
2.
3.
4.
5.
6.
Means of taking samples
Display
Communication subsystem
Non-volatile memory
Power supply
Stored program micro-controller
Hardware design
Choosing a micro-controller
Feature set
Code space
Data Space
Data converter
Real-time clock
Conclusion
A quiet revolution is in progress in the
utility industry.
Static metering devices, have been in
use for the better part of a century
Gradually being replaced with multirate, multifunction meters
Capable of more accurately accounting
for utility usage.
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
For detailed report
www.sushantkumar.wordpress.com/tech
Thank You 