Embedded Systems Microcontrollers & Embedded Processors An Overview

Embedded Systems What is an Embedded System? Where are Embedded Systems used? Typical Embedded Systems Hardware Embedded OS and Software References

What is and Embedded System? A specialized computer system that is part of a larger system or machine. Typically, an embedded system is housed on a single microprocessor board with the programs stored in ROM. Virtually all appliances that have a digital interface -- watches, microwaves, VCRs, cars -- utilize embedded systems. Some embedded systems include an operating system, but many are so specialized that the entire logic can be implemented as a single program. (Definition from wikipedia.com)

What is and Embedded System?

ES, Other definitions A special purpose computer built into a larger device. Special purpose: - Embedded systems have a (more or less) well-defined purpose - Contrast with: general purpose computers (PCs etc) - Both hardware and software is tailored to application(s), which are well defined - However, re-programmability is a requirement Built into a larger device: ESs are (usually) part of a larger device, augmenting its capabilities

ES, Other definitions Any device that includes a programmable computer but is not itself a general-purpose computer. Anything that uses a computer but does not look like one. The microprocessor in an embedded system is like an electric motor in a washing machine.

ES Types & Characteristics ES Characteristics: Efficiently Cost effective Power efficiently Real-time Predictability

Where are Embedded Systems used? Signal processing systems Real-time video, DVD players, Medical equipment. Distributed control Network routers, switches, firewalls, mass transit systems, Elevators Small systems Mobile phones, pagers, home appliances, toys, smartcards, MP3 players, PDAs, digital cameras, sensors, pc keyboard & mouse Modern cars: Up to 100 or more processors Engine control unit ABS systems (Anti Lock Brake systems) Emissions control Diagnostics and Security systems Accessories (doors, windows etc)

CELL PHONE –Block Diagram

Typical Embedded Systems Hardware Commercial off-the-shelf components (COTS) e.g. wireless radios, sensors, I/O devices Cheap Application-Specific ICs (ASICs) ICs tailored to meet application needs Good performance for their intended task(s) Original ESs were ASICs only Domain-specific processors DSPs Microcontrollers Microprocessors General Purpose Processors

ES: Solutions Embedded Systems Solutions: Microcontrollers Embedded Processors Digital Signal processors

New trends in ES HW Systems-on-chip Usual (or desired) specs: 32-bit RISC CPU Built-in interfaces to RAM and ROM Built-in DMA, interrupt and timing controllers Built-in interfaces to disk or flash memory Built-in Ethernet/ interfaces Built-in LCD/CRT interfaces New SOCs appearing almost every week! Examples Intel StrongARM SA-1110 Motorola PowerPC MPC823e NEC VR4181 Many, many more

Embedded OS and Software Principal role: Not transformation of data but interaction with physical world Acquires properties of physical world Takes time Consumes power Does not terminate (unless it fails)

Embedded Operating Systems: Office-style OSes PalmOS WindowsCE RTOSes VxWorks QNX Linux Linux is already ubiquitous Hundreds of different devices are using it Numerous commercial + open source products Mobile OS Symbian Others TinyOS

References Web References: Mani Srivastavas EE202A class Edward Lee, Embedded Software Microprocessors: Uffenbeck, john Books: The 8051 Microcontroller and Embedded Systems: Mazidi, M.A. 201 مدار عملی با میکروکنترولر 8051 ، ف. خاکپور، انتشارات صفار