COMP1321COMP1321

Digital InfrastructureDigital Infrastructure

Richard HensonRichard Henson

NovemberNovember 20152015

Week 7: Devices and Week 7: 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 of

Explain 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)

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…

Embedded Digital Systems Embedded Digital Systems for controlfor control

To control movement in machinesTo control movement in machinesparameters for feedback loops need to parameters for feedback loops need to

be controlled IN REAL TIMEbe controlled IN REAL TIME

Nothing new… been happening for Nothing new… been happening for centuries in analogue systemscenturies in analogue systems

Analogue Control…Analogue Control… The Steam Engine… control of Steam The Steam Engine… control of Steam

to move piston. Feedback loop?to move piston. Feedback loop?https://

www.youtube.com/watch?v=ESfSG2OlQYQ https://www.youtube.com/watch?v=73txXT21aZU

The Petrol Engine… control of Spark for The Petrol Engine… control of Spark for Igniting Petrol. Feedback loop?Igniting Petrol. Feedback loop?http://www.youtube.com/watch?v=W94iksaQwUo

Digital Control…Digital Control…

The same effect can be created digitally The same effect can be created digitally using a transistor as electronic switch:using a transistor as electronic switch:https://www.youtube.com/watch?v=H2J0lS

TYVhQ

What is the feedback loop in this digital What is the feedback loop in this digital system?system?

History of Embedded History of Embedded Digital SystemsDigital Systems

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

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

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

(1966)…(1966)…» ““Minuteman” intercontinental ballistic missileMinuteman” intercontinental ballistic missile

Early SciFi view of a “control” Early SciFi view of a “control” computer: HAL (1968)computer: HAL (1968)

One that controls a space ship, and One that controls a space ship, and gets “out of control…”gets “out of control…”

https://www.youtube.com/watch?v=ARJ8cAGm6JE

And has to be turned off…And has to be turned off…

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

Programming of Programming of Apollo guidance systemApollo guidance system

Written in Written in Fortran Fortran languagelanguageForFormula mula TranTranslationslationmost popular engineering/technology most popular engineering/technology

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

flawflawApollo 13 near catastrophe…Apollo 13 near catastrophe…

““Moon Lander” ProgramMoon Lander” Program

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

gamegame

What happened to What happened to “Moon Lander”?“Moon Lander”?

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

mankind” can be interpreted more broadlymankind” can be interpreted more broadly In virtual reality…In virtual reality…

versions available to present dayversions available to present daygreat introduction to real-time controlgreat introduction to real-time control

Economics of Economics of Embedded SystemsEmbedded Systems

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

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

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

cost was $3cost was $3economic driving force behind “Silicon economic driving force behind “Silicon

Valley”….Valley”….

BBC, 1977 BBC, 1977 “The Chips are Down”… “The Chips are Down”… Silicon Valley, CaliforniaSilicon Valley, California

https://www.youtube.com/watch?v=HW5Fvk8FNOQ

Early MicroprocessorsEarly 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 1980sMass produced in late 1980sresponsible for “computerisation” of responsible for “computerisation” of

electrical applianceselectrical appliancesprograms held on ROMprograms held on ROM

Further development of microprocessor Further development of microprocessor & components…& components…

Whole system on a chip…Whole system on a chip…truly an embedded systemtruly 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?so popular?

Reduced size/cost compared to designs Reduced size/cost compared to designs that using separate microprocessor, that using separate microprocessor, memory, and input/output devicesmemory, and input/output devicesbecame economical to digitally control ever became economical to digitally control ever

more devices and processesmore devices and processes» embedded systems networkableembedded systems networkable» even configurable via network…even configurable via network…» ““intelligent” products now leave the factory with intelligent” products now leave the factory with

an IP address…an IP address…

The Internet of thingsThe Internet of things

Networks often have embedded systemsNetworks often have embedded systems Why not the Internet…?Why not the Internet…?

logical extension of giving each digital device logical extension of giving each digital device or system a MAC addressor system a MAC address» generate IP address from this!generate IP address from this!

is this wise with intelligent devices?is this wise with intelligent devices?especially with 3D printers?especially with 3D printers? http://www.youtube.com/watch?v=LRq_SAuQDec http://www.youtube.com/watch?v=LRq_SAuQDec

Networking Embedded Networking Embedded DevicesDevices

Two ways to network:Two ways to network:Peer-peerPeer-peer

» Internet uses peer-peerInternet uses peer-peer

Client-serverClient-server» better for centralised control…better for centralised control…

How about IoT?How about IoT?» https://www.youtube.com/watch?v=6chnIdEsUeI https://www.youtube.com/watch?v=6chnIdEsUeI