Embedded SystemsEmbedded SystemsMicrocontrollers & Embedded ProcessorsMicrocontrollers & Embedded Processors

An OverviewAn Overview

Embedded SystemsEmbedded SystemsWhat is an Embedded System?Where are Embedded Systems

used?Typical Embedded Systems

HardwareEmbedded OS and SoftwareReferences

What is and Embedded What is and Embedded System?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 What is and Embedded System?System?

ES, Other definitionsES, 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 definitionsES, 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 & ES Types & CharacteristicsCharacteristicsES Characteristics:

◦Efficiently◦Cost effective ◦Power efficiently◦Real-time◦Predictability

Where are Embedded Systems Where are Embedded Systems used?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 CELL PHONE –Block DiagramDiagram

Typical Embedded Systems Typical Embedded Systems HardwareHardwareCommercial 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: SolutionsES: Solutions

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

New trends in ES HWNew 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/802.11 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 SoftwareEmbedded 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 Embedded Operating Systems: Systems: Office-style OSes

◦ PalmOS◦ WindowsCE

RTOSes◦ VxWorks◦ QNX

Linux◦ Linux is already ubiquitous

Hundreds of different devices are using it http://www.linuxdevices.com/articles/AT4936596231.html

◦ Numerous commercial + open source products Mobile OS

◦ Symbian Others

◦ TinyOS

ReferencesReferences Web References:

◦ www.google.com◦ http://www.embedded.com◦ http://www.wikipedia.org/wiki/Embedded_system◦ http://www.linuxdevices.com◦ Mani Srivastava’s EE202A class

http://nesl.ee.ucla.edu/courses/ee202a/2002f◦ Edward Lee, “Embedded Software”

http://citeseer.nj.nec.com/497408.html

◦ Microprocessors: Uffenbeck, john Books:

◦ The 8051 Microcontroller and Embedded Systems: Mazidi, M.A.

◦ ، ف. خاکپور، 8051مدار عملی با میکروکنترولر 201انتشارات صفار