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[attachment=3647]
Embedded Systems
Theory and Design
Anupam Basu
2
Course overview
Tentative contents:
Introduction to Embedded Computing
Embedded System Hardware
Embedded Computing Platform
Programming Embedded Systems
Embedded System Development
6. Case Study and Assignments for Designing a Complete System
3
Course Overview
Evaluation criteria:
Term papers / Seminars/ Projects : 40% (20% will be clubbed with end term marks and 20% will contribute as Teacher's Assessment)
Mid Term (written): 20%
End Term (written): 40%
4
What is an Embedded System
An Embedded System is a microprocessor based system that is embedded as a subsystem, in a larger system (which may or may not be a computer system).
O
I
5
Application areas
Automotive electronics
Aircraft electronics
Trains
Telecommunication
6
Application areas
Authentication
Military applications
Medical systems
7
Application areas
Consumer electronics
Smart buildings
Fabrication equipment
\
8
Essential Components
Microprocessor / DSP
Sensors
Converters (A-D and D-A)
Actuators
Memory (On-chip and Off chip)
Communication path with the interacting environment
9
Embedded System Structure
(Generic)
Memory
Processor & ASICs
A-D
Sensor
D-A
Actuator
10
Essential Considerations
Response Time -- Real Time Systems
Area
Cost
Portability
Low Power (Battery Life)
Fault Tolerance
11
Design Issues
(Hardware-Software Co-design)
System Specification
o Functions, Real Time Constraints, Cost and Power Constraints
Hardware Software Partitioning
Hardware Synthesis
Software Synthesis and Code Generation
Simulation
Implementation
\
12
ES, MS and RTS
All embedded systems are microprocessor based systems, but all microprocessor basedsystems may not be amenable to embedding (Area, Power, Cost, Payload parameters).
Most of the embedded systems have real time constraints, but there may be ES which are not hard RTS (for example off line Palm tops)
There may be RTS which are not embedded (e.g. Separate Process Control Computers in a network)
Embedded Systems are not GPS; they are designed for dedicated applications with specific interfaces with the sphere of control
13
General Characteristics of Embedded Systems
Perform a single task
o Usually not general purpose
Increasingly high performance and real time constrained
Power, cost and reliability are important considerations
HW-SW systems
o Software is used for more features and flexibility
o Hardware (processors, ASICs, memory etc. are used for performance and security
14
General Characteristics of Embedded Systems (contd.)
ASIC s
Processor Cores
ASIPs and ASICs form a significant component
o Adv: customization lower power, cost and enhanced performance
o Disadv: higher development effort (debuggers, compilers etc.) and larger time to market
Mem
Analog IO
Digital
15
Classification of Embedded Systems
Distributed and Non distributed
Reactive and Transformational
Control dominated and Data dominated
16
Application Specific Characteristics
Application is known before the system is designed
System is however made programmable for
o Feature upgrades
o Product differentiation
Often application development occurs in parallel to system development
o Hw-Sw partitioning should be as delayed as possible
For upgrades design reuse is an important criterion
o IP reuse, object oriented development
17
DSP Characteristics
Signals are increasingly being represented digitally as a sequence of samples
ADCs are moving closer to signals; RFs are also treated digitally
Typical DSP processing includes:
o Filtering, DFT, DCT etc.
o Speech and image: Compression, decompression, encryption, decryption etc.
o Modems: Equalization, noise and echo cancellation, better SNR
o Communication channel: encoding, decoding, equalization etc.
18
Distributed Characteristics
Components may be physically distributed
Communicating processes on multiple processors
Dedicated hw connected through communicating channels
Often economical
o 4 x 8 Bit controllers may be cheaper than a 32 bit microcontroller
o Multiple processors can perform multiple time critical tasks
o Better logistics devices being controlled may be physically distributed
19
Design Metrics
Unit cost the $ cost for each unit excluding development cost
NRE cost: $ cost for design and development
Size: The physical space reqd. determined by bytes of sw, number of gates and transistors in hw
Performance: execution time or throughput of the system
Power: lifetime of battery, cooling provisions
Flexibility: ability to change functionality without heavy NRE cost
20
Design Metrics (contd.)
Time to market = Time to prototype + Time to refine + Time to produce in bulk
Correctness: Test and Validation
Safety:
Often these metrics are contradictory hence calls for optimization
Processor choice, partitioning decisions, compilation knowledge
Requires expertise in hw and sw both
21
Major Subtasks of Embedded System Design
Modeling the system to be designed and constraints
o Experimenting with different algorithms and their preliminary evaluation
o Factoring the task into smaller subtasks and modeling their interaction
Refinement
HW-SW partitioning
o Allocating the tasks into hw, sw running on custom hw or general purpose hw
Scheduling allocation of time steps for several modules sharing the same resource
Implementation: Actual hw binding and sw code generation
Simulation and Validation
Iterate if necessary
22
What is Co-design
Traditional design
o SW and HW partitioning done at an early stage and development henceforth proceeds independently
CAD tools are focussed towards hardware synthesis
For embedded systems we need several components
o DSPs, microprocessors, network and bus interface etc.
HW-SW codesign allow hw and sw design to proceed in parallel with interactions and feedback between the two processes
Evaluation of trade offs and performance yields ultimate result
23
CAD for Embedded Systems
Co-design: Joint optimization of hw and sw to optimize design metrics
Co-synthesis: Synthesizes designs from formal specifications
Rapid prototyping and design space exploration
Many of the tasks are interrelated
Intermediate evaluation is not easy as a later decision in one path affects the other
24
A Mix of Disciplines
Application Domain (Signal processing, control )
Software Engg. ( Design Process plays an important role)
Programming Language
Compilers and Operating System
Architecture Processor and IO techniques
Parallel and Distributed Computing
Real Time Systems
Importance of Embedded Software
and Embedded Processors
.. the New York Times has
estimated that the average
American comes into contact with about 60 micro-processors every day.. [Camposano, 1996]
Latest top-level BMWs
contain over 100 micro-
processors
[Personal communication]
Most of the functionality
of embedded systems
will be implemented in software!
26
It is estimated that each year embedded software is written five times as much as 'regular' software
The vast majority of CPU-chips produced world-wide today are used in the embedded market .. ; only a small portion of CPU's is applied in PC's
.. the number of software-constructors of Embedded Systems will rise from 2 million in 1994 to 10 million in 2010;
.. the number of constructors employed by software-producers 'merely' rises from 0.6 million to 1.1 million.
[Department of Trade and Industry/ IDC Benelux BV: Embedded software research in the Netherlands. Analysis and results, 1997
(according to: scintilla.utwente.nl/shintabi/engels/thema_text.html)]
Views on embedded System
27
Some problems
How can we capture the required behaviour of complex
systems
How do we validate specifications
How do we translate specifications efficiently into
implementation
Do software engineers ever consider electrical power
How can we check that we meet real-time constraints
How do we validate embedded real-time software
(large volumes of data, testing may be safety-critical)
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[attachment=8431]
HARI BABU YADAV
UNDERGUIDNESS PROF. RAJENDRA SINGH KUSHWAH
Course overview
Tentative contents:
Introduction to Embedded Computing
Embedded System Hardware
Embedded Computing Platform
Programming Embedded Systems
Embedded System Development
6. Case Study and Assignments for Designing a Complete System
Evaluation criteria:
Term papers / Seminars/ Projects : 40% (20% will be clubbed with end term marks and 20% will contribute as Teacher's Assessment)
Mid Term (written): 20%
End Term (written): 40%
What is an Embedded System
An Embedded System is a microprocessor based system that is embedded as a subsystem, in a larger system (which may or may not be a computer system).
Essential Components
Microprocessor / DSP
Sensors
Converters (A-D and D-A)
Actuators
Memory (On-chip and Off chip)
Communication path with the interacting environment
Essential Considerations
Response Time -- Real Time Systems
Area
Cost
Portability
Low Power (Battery Life)
Fault Tolerance
Design Issues (Hardware-Software Co-design)
System Specification
Functions, Real Time Constraints, Cost and Power Constraints
Hardware Software Partitioning
Hardware Synthesis
Software Synthesis and Code Generation
Simulation
Implementation
ES, MS and RTS
All embedded systems are microprocessor based systems, but all microprocessor based systems may not be amenable to embedding (Area, Power, Cost, Payload parameters).
Most of the embedded systems have real time constraints, but there may be ES which are not hard RTS (for example off line Palm tops)
There may be RTS which are not embedded (e.g. Separate Process Control Computers in a network)
Embedded Systems are not GPS; they are designed for dedicated applications with specific interfaces with the sphere of control
General Characteristics of Embedded Systems
Perform a single task
Usually not general purpose
Increasingly high performance and real time constrained
Power, cost and reliability are important considerations
HW-SW systems
Software is used for more features and flexibility
Hardware (processors, ASICs, memory etc. are used for performance and security
ASIPs and ASICs form a significant component
Adv: customization lower power, cost and enhanced performance
Disadv: higher development effort (debuggers, compilers etc.) and larger time to market
Classification of Embedded Systems
Distributed and Non distributed
Reactive and Transformational
Control dominated and Data dominated
Application Specific Characteristics
Application is known before the system is designed
System is however made programmable for
Feature upgrades
Product differentiation
Often application development occurs in parallel to system development
Hw-Sw partitioning should be as delayed as possible
For upgrades design reuse is an important criterion
IP reuse, object oriented development
DSP Characteristics
Signals are increasingly being represented digitally as a sequence of samples
ADCs are moving closer to signals; RFs are also treated digitally
Typical DSP processing includes:
Filtering, DFT, DCT etc.
Speech and image: Compression, decompression, encryption, decryption etc.
Modems: Equalization, noise and echo cancellation, better SNR
Communication channel: encoding, decoding, equalization etc.
Distributed Characteristics
Components may be physically distributed
Communicating processes on multiple processors
Dedicated hw connected through communicating channels
Often economical
4 x 8 Bit controllers may be cheaper than a 32 bit microcontroller
Multiple processors can perform multiple time critical tasks
Better logistics devices being controlled may be physically distributed
Design Metrics
Unit cost the $ cost for each unit excluding development cost
NRE cost: $ cost for design and development
Size: The physical space reqd. determined by bytes of sw, number of gates and transistors in hw
Performance: execution time or throughput of the system
Power: lifetime of battery, cooling provisions
Flexibility: ability to change functionality without heavy NRE cost
Time to market = Time to prototype + Time to refine + Time to produce in bulk
Correctness: Test and Validation
Safety:
Often these metrics are contradictory hence calls for optimization
Processor choice, partitioning decisions, compilation knowledge
Requires expertise in hw and sw both
Major Subtasks of Embedded System Design
Modeling the system to be designed and constraints
Experimenting with different algorithms and their preliminary evaluation
Factoring the task into smaller subtasks and modeling their interaction
Refinement
HW-SW partitioning
Allocating the tasks into hw, sw running on custom hw or general purpose hw
Scheduling allocation of time steps for several modules sharing the same resource
Implementation: Actual hw binding and sw code generation
Simulation and Validation
Iterate if necessary
What is Co-design?
Traditional design
SW and HW partitioning done at an early stage and development henceforth proceeds independently
CAD tools are focussed towards hardware synthesis
For embedded systems we need several components
DSPs, microprocessors, network and bus interface etc.
HW-SW codesign allow hw and sw design to proceed in parallel with interactions and feedback between the two processes
Evaluation of trade offs and performance yields ultimate result
CAD for Embedded Systems
Co-design: Joint optimization of hw and sw to optimize design metrics
Co-synthesis: Synthesizes designs from formal specifications
Rapid prototyping and design space exploration
Many of the tasks are interrelated
Intermediate evaluation is not easy as a later decision in one path affects the other
A Mix of Disciplines
Application Domain (Signal processing, control )
Software Engg. ( Design Process plays an important role)
Programming Language
Compilers and Operating System
Architecture Processor and IO techniques
Parallel and Distributed Computing
Real Time Systems
Importance of Embedded Software and Embedded Processors
.. the New York Times has
estimated that the average
American comes into contact with about 60 micro-processors every day.. [Camposano, 1996]
Latest top-level BMWs
contain over 100 micro-
processors
[Personal communication]
Views on embedded System
It is estimated that each year embedded software is written five times as much as 'regular' software
The vast majority of CPU-chips produced world-wide today are used in the embedded market .. ; only a small portion of CPU's is applied in PC's
.. the number of software-constructors of Embedded Systems will rise from 2 million in 1994 to 10 million in 2010; .. the number of constructors employed by software-producers 'merely' rises from 0.6 million to 1.1 million.
Some problems
How can we capture the required behaviour of complex systems ?
How do we validate specifications?
How do we translate specifications efficiently into implementation?
Do software engineers ever consider electrical power?
How can we check that we meet real-time constraints?
How do we validate embedded real-time software? (large volumes of data, testing may be safety-critical)
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[attachment=14145]
ABSTRACT
Embedded systems have virtually entered every sphere of our lives
Embedded systems encompass a variety of hardware and software components, which perform specific functions in host systems, for example, satellites, washing machines, hand-held telephones and automobiles. Embedded systems have become increasingly digital with a non-digital periphery (analog power) and therefore, both hardware and software co-design are relevant. The vast majority of computers manufactured are used in such systems. They are called embedded' to distinguish them from standard mainframes, workstations, and PCs. Although the design of embedded systems has been used in industrial practice for decades, the systematic design of such systems has only recently gained increased attention. Advances in microelectronics have made possible applications that would have been impossible without an embedded system design.
Embedded System Applications describes the latest techniques for embedded system design in a variety of applications. This also includes some of the latest software tools for embedded system design. Embedded System Applications will be of great interest to researchers and designers working in the design of embedded systems for industrial applications.
Embedded systems have virtually entered every sphere of our lives, right from the time we work out on trade mills in the gym, to the cars we drive today. Embedded systems cover a broad range of products that generalization is difficult.
INTRODUCTION:
Breathtaking developments in microelectronics, processor speeds, and memory elements, accompanied with dropping prices, have resulted in powerful embedded systems with a number of applications.
An embedded system is a microprocessor based system that is incorporated into a device to monitor and control the functions of the components of the device. They are used in many devices ranging from a microwave oven to a nuclear reactor. Unlike personal computers that run a variety of applications, embedded systems are designed for performing specific tasks. An embedded system used in a device (for instance the embedded system in washing machine that is used to cycle through the various states of the washing machine) is programmed by the designers of the system and generally cannot be programmed by the end user.
Definition :
An embedded system is various type of computer system or computing device that performs a dedicated function and/or is designed for use with a specific embedded software application.
Embedded systems posses the following distinguishing qualities.
Reliability:
Embedded system should be very reliable as they perform critical functions. For instance, consider the embedded system used for flight control. Failure of the embedded system could have disastrous consequences. Hence embedded system programmers should take into consideration all possibilities and write programs that do not fail.
Responsiveness:
Embedded systems should respond to events as soon as possible. For example, a patient monitoring system should process the patient s heart signals quickly and immediately notify if any abnormality in the signals is detected.
Specialized hardware:
Since embedded systems are used for performing specific functions, specialized hardware is used. For example, embedded systems that monitor and analyze audio signals use signal processors.
Low cost:
As embedded systems are extensively used in consumer electronic systems, they are cost sensitive. Thus their cost must be low.
Robustness:
Embedded systems should be robust since they operate in a harsh environment. They should endure vibrations, power supply fluctuations and excessive heat.
EMBEDDED SYSTEM AND REAL TIME SYSTEM:
Embedded systems are confused with real-time systems. A real time system is one in which the correctness of the computations not only depends on the accuracy of the result, but also on the time when the result is produced. Figure 1 shows the relationship between embedded and real time systems.
Fig: Embedded And real-time systems
COMPONENTS OF AN EMBEDDED SYSTEM:
Embedded systems have the following components.
PROCESSOR:
A processor fetches instructions from the memory unit and executes the instructions. An instruction consists of an instruction code and the operands on which the instruction should act upon. The format of instruction code and operands of a processor is defined by the processor s instruction set. Each type of processor has its own instruction set. Performance of the system can be improved by dedicated processors, which implement algorithms in hardware using building blocks such as hardware counters and multipliers.
Some embedded processors have special fuzzy logic instructions. This is because inputs to an embedded system are sometimes better represented as fuzzy variables. For instance, the mathematical model for a control system may not exist or may involve expensive computing power. Fuzzy logic can be employed for such control systems to provide a cost-effective solution.
MEMORY:
The memory unit in an embedded system should have low access time and high density. (A memory chip- has greater density if it can store more bits in the same amount of space. Memory in an embedded system consists of ROM and RAM .The contents of ROM are non-volatile while RAM is volatile. ROM stores the program code while RAM is used to store transient input or output data. Embedded systems generally do not possess secondary storage devices such as magnetic disks. As programs of embedded systems are small there is no need of virtual storage.
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[attachment=15867]
Microcontrollers
A Microcontroller is essentially a small and selfsufficient
computer on a chip, used to control devices
It has all the memory and I/O it needs on board
Is not expandable no external bus interface
Characteristics of a Microcontroller
Low cost, on the order of $1
Low speed, on the order of 10 KHz 20 MHz
Low Power, extremely low power in sleep mode
Small architecture, usually an 8-bit architecture
Small memory size, but usually enough for the type of
application it is intended for. Onboard Flash.
Limited I/O, but again, enough for the type of application
intended for
Microprocessors
A Microprocessor is fundamentally a collection of
on/off switches laid out over silicon in order to perform
computations
Characteristics of a Microprocessor
High cost, anywhere between $20 - $200 or more!
High speed, on the order of 100 MHz 4 GHz
High Power consumption, lots of heat
Large architecture, 32-bit, and recently 64-bit architecture
Large memory size, onboard flash and cache, with an
external bus interface for greater memory usage
Lots of I/O and peripherals, though Microprocessors tend
to be short on General purpose I/O
Harvard Architecture
Harvard Architecture refers to a memory structure
where the processor is connected to two different
memory banks via two sets of buses
This is to provide the processor with two distinct data
paths, one for instruction and one for data
Through this scheme, the CPU can read both an
instruction and data from the respective memory
banks at the same time
This inherent independence increases the throughput
of the machine by enabling it to always prefetch the
next instruction
The cost of such a system is complexity in hardware
Commonly used in DSPs
Von-Neumann Machine
A Von-Neumann Machine, in contrast to the Harvard
Architecture provides one data path (bus) for both
instruction and data
As a result, the CPU can either be fetching an
instruction from memory, or read/writing data to it
Other than less complexity of hardware, it allows for
using a single, sequential memory.
Today s processing speeds vastly outpace memory
access times, and we employ a very fast but small
amount of memory (cache) local to the processor
Modern processors employ a Harvard Architecture to
read from two instruction and data caches, when at the
same time using a Von-Neumann Architecture to access
external memory
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[attachment=5099]
embeded system design
Introduction
Single-purpose processors
Performs specific computation task
Custom single-purpose processors
Designed by us for a unique task
Standard single-purpose processors
Off-the-shelf -- pre-designed for a common task
a.k.a., peripherals
serial transmission
analog/digital conversions
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plz send me smart cameras using embedded systems ppt
I WANT SMART CAMERAS USING EMBEDDED SYSTEMS PPT ONLY
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