Introduction

1. Introduction • What is an embedded system? • Embedded system market trends • Characteristics of embedded systems • Embedded system requirements • Design of embedded systems • Trend of embedded systems

2. What Is an Embedded System? • What is a system? • A set or arrangement of things so related or connected as to form a unity or organic whole. • What is embedded? • To be set or fixed firmly in a surrounding mass. • What is an embedded system? • An electronic system embedded within a given plant or external process to perform a specific function, which has to respond to certain inputs within a prescribed time constraint. • The external process comprises both a physical system and also humans performing some supervising or parameter setting tasks.

4. Components of an Embedded System • Software • Operating systems, device drivers, application programs that Provide system features and flexibility • Hardware • Processor cores, DSP cores, ASICs, Memorys, I/O devices, SOCs (system-on-chip), communication ICs, ADC/DAC, …, are used for achieving the required performance and sometimes the security.

5. Characteristics • Perform a single or tightly knit set of functions, which is not usually general purpose, i.e., application specific • Increasingly high-performance and real-time constraints • Reactive, i.e., an embedded system (ES) must respond to an input stimulus • Distributed, i.e., many correlated components (processors) are coordinated to react the input stimuli coming from the various positions of an ES. • Cost, reliability(long life), power are important attributes in design decision, usually under the constraints of limited hardware resource.

6. Real-Time Requirements • A real-time system consists of tasks under deadline constraints • Notion of time typically is global • Hard real-time versus soft real-time systems • Hard real-time: the tasks must complete by specified deadlines, e.g., flight control, collision alert, the warning coming from most of the medical equipment, etc. • Soft real-time: task execution may go beyond specified deadlines without catastrophic failures, .e.g., display update, ...

7. Applications • Consumer electronics, e.g., cameras, camcorders, …. • Home appliance, e.g., washers, microwave ovens, …. • Medical instruments, e.g., heart-beat monitor for new-born, contraction monitor for womb,…. • Automobiles, e.g., anti-lock braking, engine control, …. • Industrial process controllers • Avionics and defense systems • Computer/communication products, e.g., network printers, fax, PDA, cellular phones, software modem, …. • Multimedia applications, e.g., interactive game boxes, TV set-top-box, ...

8. Diversified Computing Requirements • Infrared remote controller • Required least amount of computing power, but optimized for code size and power • Pocket remote control RF transmitter • 100 KIPS, optimized for code size and power • Industrial equipment controller • 1 MIPS, 1 MB memory • safety-critical • Military signal processing and multimedia applications • 1 GFLOPS, 1 GB/sec IO, 32 MB • Software for high performance

9. Embedded System Market • Market size for embedded systems: US$ 31 B • General purpose computing: US$ 46.5 B • Micro-controller market: US$4.6 B, +18% annual growth rate • Versus +10% annual growth rate for general purpose processors • Embedded system market will finally surpass computing marketing.

10. Driving Forces • Computing technologies are proliferating to non-computing domains • portable devices, medical instrumentation and imaging, information appliance • Increasing the need for product personalization • Hand-held devices • Increasing the need for entertainment • Game boxes • Advance in semiconductor technologies and design methodologies • reducing manufacturing and design costs

11. Embedded System Design • Defining Specifications • Modeling the system to be designed algorithmically; • Refining the function to be implemented into smaller interacting pieces; • HW-SW partitioning by allocating elements in the refined model to either (1) HW units, or (2) SW running on custom hardware or a general processor; • Scheduling the times at which the functions are executed; • Mapping a functional description into (1) software that runs on a processor, or (2) a collection of custom, semi-custom, or commodity HW.

12. Diversified Design Requirements • Cost • Size • Power • Reliability • safety-critical • viable for a harsh environment • Performance • Real-time constraint • Product differentiation • Time to market pressure • Combination of HW and SW • New design paradigms, techniques, and tools

13. Embedded System Design • Defining Specifications • Modeling the system to be designed algorithmically; • Refining the function to be implemented into smaller interacting pieces; • HW-SW partitioning by allocating elements in the refined model to either (1) HW units, or (2) SW running on custom hardware or a general processor; • Scheduling the times at which the functions are executed; • Mapping a functional description into (1) software that runs on a processor, or (2) a collection of custom, semi-custom, or commodity HW.

14. What is HW/SW Co-design? • The act of bridging the gap between the HW and SW. • Traditional design approach • SW and HW partitioning is decided at an early stage, and designs proceed separately from then onward. • HW/SW co-design • A flexible design strategy, wherein the HW/SW designs proceed in parallel, with feedback and interaction occurring between the two as the design progresses. • Final HW/SW partitioning and allocation is made after evaluating trade-offs and performance of options.

15. CAD for Embedded System Design • Co-design: Joint optimization of hardware and software • Cost-performance tradeoffs as a part of product implementation, as opposed to product specification. That is, we can perform design space exploration across the HW and SW boundary • Co-synthesis: Synthesis assisting co-design • Design derived from (formal) specifications • Rapid exploration of design alternatives

16. Disciplines in Embedded System Design • The design of embedded systems spans several different disciplines in CS and EE • Application domain (Signal processing,….) • Software engineering (Programming languages, compilers, …) • VLSI (computer aided) design • Parallel/distributed system design • Networking and communications • Real-time systems (Real-time OS) • Computer organization and architecture • Input/output, sensor and actuators technologies, etc.

17. Trends in Embedded Systems • Increasing code size • Average code size: 16K~64KB in 1992, 64K~512KB in 1996 • Migration from assembling coding to high-level languages • Reuse of hardware and software components • Processors (micro-controllers, DSPs) • Software components (drivers) • Increasing integration and system complexity • integration of RF, DSP, networking interface • 32-bit processors, IO processors, Network processors • Increasing more intelligent

18. Digital Signal Processing in ES • Continued digitalization of signals increasing the role of DSP • Signals are represented digitally as sequence of samples • ADCs are moving closer to signals • Even RF, IF processing in digital domain • Typical DSP processing • Filtering, averaging, FFT, device control, etc. • Speech: codec, processing, user interface, etc • Communications: modulation, demodulation, noise/echo cancellation, encoding, decoding, equalization, etc.

19. Example 1 • Nike psa • Delivers up to 120 minutes of digital music. • Plays either MP3 or WMA digital audio formats downloaded from the Internet. • Universal Information Appliance

20. Summary • What is an embedded system? • Embedded system market trends • Characteristics of embedded systems • Embedded system requirements • Design of embedded systems • Trend of embedded systems