COMP1321COMP1321

Digital InfrastructureDigital Infrastructure

Richard HensonRichard Henson

DecemberDecember 20132013

Week 9: Devices and Week 9: Devices and Embedded SystemsEmbedded Systems

Objectives:Objectives:Explain what an embedded system is and Explain what an embedded system is and

what it consists ofwhat it consists ofExplain the diversity of use of embedded Explain the diversity of use of embedded

systems in modern day life, and how this systems in modern day life, and how this has transformed our societyhas transformed our society

What is an “Embedded What is an “Embedded System?System?

““A computer on a chip”A computer on a chip” Could be an i/o control deviceCould be an i/o control device Needs programming to control a Needs programming to control a

peripheralperipheral Requirements:Requirements:

CPU and RAMCPU and RAMROM to store control program(s)ROM to store control program(s)

Embedded Digital Systems Embedded Digital Systems for controlfor control

No longer a simulation of reality…No longer a simulation of reality…parameters need to be controlled IN parameters need to be controlled IN

REAL TIMEREAL TIME Been happening for centuries in Been happening for centuries in

analogue systems such as steam analogue systems such as steam engine, petrol engine, etc.engine, petrol engine, etc.http://

www.youtube.com/watch?v=W94iksaQwUo

Feedback LoopsFeedback Loops

Biggest challenge in a control system is Biggest challenge in a control system is to get data transferred quickly enough to get data transferred quickly enough to change parameters in sufficient timeto change parameters in sufficient time

Obviously not possible to control a Obviously not possible to control a rocket remotely if out in space…rocket remotely if out in space…embedded systems the only way…embedded systems the only way…

Early SciFi view of a “control” Early SciFi view of a “control” computer: HALcomputer: HAL

http://www.youtube.com/watch?v=OuEN5TjYRCE

History of Embedded History of Embedded Digital SystemsDigital Systems

Not possible before integrated circuits went into production (mid-1960s)

Started with Apollo Project:President Kennedy’s plan to land a man on

the moon by end of 1969…first commercial production for US defence

(1966)…» “Minuteman” intercontinental ballistic missile

Programming of Apollo guidance system

Written in Fortran languageFormula Translationmost popular engineering/technology

language before “C” Later showed to have an almost fatal

flawApollo 13 near catastrophe…

“Moon Lander” Program

Retro rockets of falling LEM vehicle Balanced against moon gravity Limited amount of fuel… Version written for BASIC Most popular early microcomputer

game

What happened to “Moon Lander”?

In reality…start of the embedded system revolution“A small step for man… a giant step for

mankind” can be interpreted more broadly In virtual reality…

versions available to present daygreat introduction to real-time control

Economics of Embedded Systems

Huge initial development cost!! Once “chips” go into production, cost

falls dramatically…e.g. First Apollo guidance program cost

$1000 per chip to implementas soon as mass production started, unit

cost was $3economic driving force behind “Silicon

Valley”….

Early Microprocessors

Two main rival companies:Intel (world’s first, 4004)Motorola (pushed efficiency, through larger

bus size…)

CPU not much of a system on its own…still needed lots of “external” support

MicrocontrollersMicrocontrollers

Mass produced in late 1980sresponsible for “computerisation” of

electrical appliancesprograms held on ROM

Further development of microprocessor & components…

Whole system on a chip…truly an embedded system

Programming a Programming a MicrocontrollerMicrocontroller

Assembly language cumbersomeAssembly language cumbersome Fortran shown to be deficientFortran shown to be deficient

Apollo 13 failure caused by variable not Apollo 13 failure caused by variable not being reinitialised to zero – other being reinitialised to zero – other languages enable this by defaultlanguages enable this by default

““C” seen as the way forward:C” seen as the way forward:perfected by 1978perfected by 1978

Components of a Components of a MicrocontrollerMicrocontroller

e.g. Intel 8048 (1977):e.g. Intel 8048 (1977):CPUCPURAMRAMTimer chipTimer chipROM of some kindROM of some kindi/o capabilityi/o capability

Uses of MicrocontrollersUses of Microcontrollers Automatically controlled products and Automatically controlled products and

devices:devices:car engine control systemscar engine control systemsimplantable medical devicesimplantable medical devicesremote controlsremote controlsoffice machinesoffice machinesAppliancesAppliancespower tools, toys, etc.power tools, toys, etc.

Why are embedded systems Why are embedded systems so popular now?so popular now?

Reduced the size and cost compared to designs that uses a separate microprocessor, memory, and input/output devices

Therefore economical to digitally control ever more devices and processes

» if have a comms module, embedded systems configurable via network…

“Intelligent” products now leave the factory with an IP address…

The Internet of thingsThe Internet of things

A logical extension of giving digital devices IP addresses

» is this wise with intelligent devices?» especially with 3D printers

Is this wise… (lol)» http://www.youtube.com/watch?v=LRq_SAuQD

ec

Linking of DevicesLinking of Devices

Two fundamentally different Two fundamentally different arrangements:arrangements:Peer-peerPeer-peerClient-serverClient-server

The latter is better for centralised The latter is better for centralised control…control…

The Internet uses peer-peerThe Internet uses peer-peer