Embedded Systems Reading Group

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Embedded Systems Reading Group

• Tulika Mitra
• Department of Computer Science
• tulika_at_comp.nus.edu.sg

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Motivation

• To learn the state-of-the-art in embedded systems
  research
• Provide interaction among people interested in
  this exciting emerging area
• For graduate students
• How to perform effective literature survey
• Presentation skills
• How to participate in small group discussions

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Computing Systems

• Most of us think of desktop computers
• PC
• Laptop
• Mainframe
• Server
• Maybe at most handheld computer (PDA)
• Now we will look at another type of computing
  system which is far more common that you ever
  imagined ?

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Embedded System What ?

• Computing system embedded within electronic
  devices
• Any device or collection of devices that contain
  one of more dedicated computers, microprocessors,
  or micro-controllers
• Combination of computer hardware and software
  designed to perform a specific function
• Broad definition Any computing system that is
  not a desktop computer

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Embedded System Examples
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Embedded System Types

• General purpose computing
• Control systems
• Signal processing
• Communication Networking

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Embedded System Market

• Average household uses about 225 embedded
  processors about 35 for the automobile itself
• Estimated 5 billion embedded processor in use ---
  94 share of world market Intel Pentium,
  Motorola PowerPC, etc. combined is only 6
• source World Semiconductor Trade Statistics
  Bluebook

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Embedded systems characteristics Users
viewpoint

• Single function
• Dedicated to a task or tasks
• Tight constraints
• Size, power, cost, time-to-market
• Real time and reactive
• Respond to environment in real time
• Safety critical
• Failure of hw/sw can be life threatening

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Embedded systems characteristicsDevelopers
viewpoint

• Concurrent development of hardware and software
  hardware/software codesign
• Variety of microprocessors
• Variety of operating systems mostly real time
  (RTOS)
• May not even have any OS services like printf
• Fewer system resources than desktop system
• Requires specialized development tools
• Debugging extremely difficult
• Hardware and software should be extremely robust

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A typical embedded system
Source Arnold S. Berger
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Elements of an embedded system
Key Point Although vastly different in
complexity and design, common architectural
traits allow us to design and debug a wide
variety of systems
Source Arnold S. Berger
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Design Choices
Technology Performance/ Cost Time until running Time to high performance Time to change code functionality
ASIC Very High Very Long Very Long Impossible
FPGA Medium Medium Long Medium
ASIP/ DSP High Long Long Long
Generic Low-Medium Very Short Not Attainable Very Short
Flexibility
Speed
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Driving Factor

• Moores Law
• Predicted by Intel co-founder Gordon Moore 65
• IC transistor capacity has doubled roughly every
  18 months for the past several decades
• Process technology can put more and more
  functionality on the same chip as CPU at reduced
  cost

Source Intel
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System-on-a-chip (SOC)

• A microprocessor plus additional peripheral
  support devices integrated into a single chip
• Example Intel StrongARM

Source Intel
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Liming Factor

• Design productivity gap
• Growing design gap between what technology can
  offer and our ability to design in that
  technology

Source ITRS99
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Core based SOC design

• Intellectual Property (IP) circuits or cores are
  pre-designed and pre-verified functional units
• IP s are reusable implying lower design cost
• Core examples
• Processors ARM, PowerPC, ..
• Memory RAM, memory controller,
• Peripherals PCI, DMA controller,
• Multimedia MPEG/JPEG encoder/decoder
• Digital Signal Processor (DSP)
• Telecommunication Ethernet controller, router,
  ..

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Hardware/Software Co-design

• In the past
• Hardware and software design technologies were
  very different
• At present
• Recently matured synthesis technique enables a
  unified view of hardware and software

The choice of hardware versus software for a
particular function is simply a tradeoff among
various design metrics, like performance, power,
size, cost, and especially flexibility there is
no fundamental difference between what hardware
or software can implement.
Source Vahid/Givargis
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Embedded Systems Faculty

• Tulika Mitra
• Computer architecture, real time systems
• Abhik Roychoudhury
• Modeling, validation of embedded real-time sys
• P. S. Thiagarajan
• Specification, verification, synthesis
• Wong Weng Fai
• Compilers, computer architecture

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Our research

• Formal specification, verification and synthesis
  methods
• Compilers and Architectures for Embedded Systems
• Real time systems
• Power Aware Computing
• http//www.comp.nus.edu.sg/embsys

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Reading group topics

• Case Study
• Specification
• Verification
• Custom processors
• Re-configurable logic
• Design space exploration
• Real time systems
• Low power
• Code compression
• Code generation
• Memory optimization

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Format

• Each week one of you will be responsible for a
  topic or a sub-topic
• Please prepare one page summary about the topic
  including the references
• Presentation can be in any format
• You will lead the discussions through your
  presentation
• Others should read the references before or after
  the presentation (preferably before)