1 Embedded Systems Development

transcript

7/31/2019 1 Embedded Systems Development

http://slidepdf.com/reader/full/1-embedded-systems-development 1/82

Embedded Systems

Dr. Y S Rao1

What are Embedded Systems• They are Embedded ‘in’

• They are not desktops

• Not mainframes or mini’s• -

• A heating furnace controller- Thermostat• mo e p one

• Medical device

• DSP based systems

Embedded Processors

Embedded vs. Desktop

Processors

Applications

Advantages:• Lower cost

• Cell phones / pagers / PDAs

• DAQ• Optimized Instruction Set

• Lower Power consumption

• Controls (Automotive,

Industrial)• Smaller footprint

Disadvantages:

• “Smart” Media

Desktop Processors:

• ower c oc spee s• Less Processing power

• es top computers

• Notebook computers / Laptops

Why Use Embedded Systems• ser unc ona y – portability

• User convenience, comfort - HVAC, Auto,

Appliances, GPS, TV remote, DVR, iPod

• Low power and safety – iron, coffee maker, LED

• Commercial/industrial applications

• Replace electro-mechanical systems

• os re uc on• Quality improvement

An Embedded System

Microcontroller

(uC)OutputsInputs

An Embedded Control System

Microcontroller

(uC)Outputs

Inputs

Beware of the computer!

• computers + SoCs = hardware / software mix

• com lete chan e in device interaction

• ever-growing number of critical applications 7

Embedded Systems on Chip

• Many processing units• Lar e embedded software

CPU GLU

RAM FPGAROM

H r w r r f w r ?

Wh Com uterizin Ob ects?1. Simplicity and uniformity of digital information

ex s, mages, soun s, mov es, money, orces,...

count, store, organize, transmit, encrypt, visualize,...

2. The fabulous information engine

Moore : computers => microprocessors => SoCsprogress n e sensor e

3. Advances in numerical methods

control & information theory

algorithmics

numer ca ana ys s

A lications and Constraintsflight-control, engines, brakes, fuel, power, climatesafety-critical => certification

trajectory, attitude, image, telecom- =

telephone, audio, TV, DVD, gamesbusiness critical => time-to market + quality

pacemakers, diabet control, robot surgeonslife-critical => TBD (!)

Microcontroller Manufacturers• ARM – Advanced RISC Machines

• Atmel

• Cypress- programmable blocks• Freescale Semiconductor- uC, DSP

• Microchip

• NEC• Renasas

• Sharp

• croe ec ron cs• Texas Instruments- uC, DSP

• Man others

Microcontrollers S ectrum• $0.15 - $0.20 Far Eastern parts

• - - .

• Musical gift card uC

• 8-bit 8K flash,1K RAM, 16-I/O

• -Bi 2 K fl h 2K RAM 4-I

• 32-Bit, 2M Flash, 64K RAM, TPU

• – GbE, USB HS

• e- reaten ng

• 24/7/365

• Can’t reboot!

• pt m ze ssem y anguage

• Limits, Inaccuracies of Fixed Precision

Design Issues

• Design Methodology• Time To Market• oc pee• Power Consumption•• Consumer Market: Minimize Manufacturing

• No chance for future modification.

A Low End Microcontroller

RAM16 B tes

Microcontroller Functionalit• Core processor - Voltages

• y – as , , , ,

• – n er ace vo age

• Timers• Interrupts

• Serial Communication- SPI, I2C, UART

• USB, CAN-BUS, IR, SD-Cards

– , , ompara or, p-amp

A Typical Microcontroller

RAM Flash EEPROM

I/OClock

CoreReset

Power-On Reset Modules• Internal reset

• Programmable threshold voltage

• Programmable duration

• Pr r mm l r im • Brown-out condition - programmable

•• Watchdog timer

Batter Powered A lications• Sleep mode

• u w

• All kinds of modes available

• Reduced clock frequencies

• r i n• Selective peripherals sleep mode

• – c oc s, t mers, nterrupts

• Watchdog timer

Why Worry About Power ?

Process Technology and Supply

Why Worry About Power ? Portability

Battery industry does not have a Gordon Moore23

A Typical Microcontroller

RAM Flash EEPROM

I/OClock

CoreReset

A High End Microcontroller

JTAG NEXUS

2MB Flash

64KB SRAM

32-BitMPC5554

C h T P U

C h D MA

64-ChI/O

A/D40-Ch

CAN Bus(3)

32-Bit External Bus

Microcontroller Selection Criterion• Speed of operation, complexity – 8/16/32 Bits

• Cost – HW/SW tradeoffs

• Power consumption - TI, Microchip, Freescale• Memory Size – Flash, RAM, EEPROM

• # of I/O

• Analog – A/D, DAC, Comparator, Op-amp• Serial Communication- SPI, I2C, USB, IR, GbE

• Product Family

• eve opmen oo s• Timers – input capture, output compare

Embedded S stems Develo ment• System development

• Electronics•

• Software

• Mechanical

• DFM – design for manufacturability

S stem Develo ment• Architecture

• - requ re

• Sub-systems interface - Master/slave

• Communication - Networking protocols

•• HW/SW tradeoffs

• u se ec on• S stem tests – regulatory agencies

Electronics Develo ment

• Design specs

• es gn or es a y

• uC and components selection

• Worst case analyses

• Schematics – CAD tools, Design rule checks• Simulations

• Proof of concept, Prototyping

• Design validation• Product qualification

Electronics Develo ment Tools

• Schematic capture- Orcad, PADS, Cadence, Mentor

• Analog simulation-pSpice, LTSpice

• Lo ic Simulation- Orcad Cadence Mentor

• VHDL, Verilog

• Worst case analyses- simulations

• Proof of conce t, Protot in - PALs, FPGAs

• DFMEA- UL, agencies approval

• Reliability predictions - MTBF

ASICs & Pro rammable Lo ic

• Application Specific ICs

• , , - uCs with PLDs

• Gate Arrays

• Standard Cells

• Custom ICs• Languages- VHDL, Verilog

• Functional simulation

• Timing simulations• Floor planning

• Back-annotation31

PCB La out

• CAD tools- Orcad, Protel, PADS, Allegro, Mentor

• # of layers•

• 3D fit

• - - -,

• Thermal considerations

• DRC

• Gerber output

• Fabrication

Real -TimeSoftware Development

Hold on there!

What is real time software?

Software Develo ment

• Specs

• SW Design• – ‘ ’, ,

• OS’

•• Tools – compilers, assemblers, programmers, emulators

• Real time as ects - ISRs

• SW/HW tradeoffs• S stem inte ration

Real Time Software Develo ment

• Timers

• Interrupts

• Priorities

Real Time Software

ExternalEvent

Timer 1 Timer n

Micro-

ControllerPrioritized

InputsI/OCore SW

Task 1

Task 2

Task n

Real Time Software Develo ment

• Interrupts – ISRs

• ‘C’ v/s Assembly

• Tasks and priorities• RTOS’

Programming Languages Used in

ew m e e es gns

60.0%1999-2000

Assembly C C++ Java Other

Use of Real-Time Kernels in

New Embedded Designs.

100.0%

4-bit 8-bit 16-bit 32-bit 64-bit Special

they will respond to an external event.

• Real Time systems don’t have to be “real” “.

time”.

guarantee they provide, real time“

time” or “hard real time”.

guarantee, but missing an event is not. ,

decoding used during satellite TV

“frame time”. If this guarantee is missed, – .

but not catastrophic!

missing a timing deadline will lead to. ,

missile guidance system should not miss

S h ft l ti

So why use soft real time

systems at all?•

provide a real time guarantee. But if we,

guaranteed response time can be much

.• Soft real time systems would be used in

-very fast.

I l ti ft

Is real time software any

different•

careful.

scheduling is done at the operating system,

systems should be used.

form of an endless loop, which waits for

occur.

recovery if there is a “hang up” while

Software Develo ment - Tools

• Programmers- development, in-circuit, field

• mu a ors- JTAG

• Simulators

• Assemblers

• Compilers• Linkers

• Loaders

• CASE tools• V r i n n r l

Architecture componentsdimensioning

Word, Excel, Visio

dimensioning

communicationSystem C

Micro-Architectureconcurrencypipeline

resource sharin

Word, Visio

RTL design VHDL, Veriloggates, clocksregisters, RAMs

circuits cells, clock treesarea, speed

Verilog + ...

DFT (test)testabilityscan insertion

Place&Route

Translation of Code on Host : Compiling

C Source File (s)

C Compiler

C Header File (s)Preprocessing

Compiling

C Object File (s)

Linker C System Libraries

Embedded System

ost omputer

Th b ild d l d f

The build and load process fordesktop application programs.

Compiler

O ject Fi es

Executable

AssemblerL i n k

L o a d e

Read-Write

Memory (RAM)

Run-Time Library:

Operating System Image: Boot

Process

The build and load process for

em e e app cat on programs.Object Executable Files Image File

File Compiler

Read-Write

Memory(RAM)

L o c a t o

Assembler

Program

Re-Entrant Library:

i n k e r

Read-Only

Initialization

Real-Time Kernel: ROM"Burner"

Memory(ROM)

What is ISP?• In-System Programmable

(ISP) means :

– The ability toreconfigure the logican unct ona ty o adevice, board orcomplete electronic

– This can be donebefore, during and

and shipment to theend user.

Mobile Phone User Interface

TouchScreen

Freescale

68HC05Radio

Freescale

Dragonball

DriverKeypad Graphics

Battery

68328Micro-

Speaker

Postal Mail Sorting Device

PowerSu l

FreescalePostal Optical FlashOptical

68HCxxPiecesnco er

PLDso at on

PCApplication

Battery

PC/104

Pentium

Processor

PCMCIAGraphics

LCDVideoXilinxFPGA

TouchScreen

Product:Vendo V

Product:Vendo V-

MAX 720 vendingmachine.

Microprocessor:

8-bit Motorola68HC11.

Sonicare Plus toothbrush.

Pro uct: M e edishwashers.

Microprocessor:- o oro a

68HC05.

Product: NASA's

Mars Sojourner

Rover.

Microprocessor:

8-bit Intel 80C85.

P d t C i C

Product: CoinCo

USQ-712 coin

chan er.

Microprocessor:

8-bit Motorola68HC912.

Product: Garmin

StreetPilot GPS

Receiver.

Microprocessor:16-bit.

Product: Palm Vx

handheld.

Microprocessor:

32-bit MotorolaDragonball EZ.

i1000plus iDEN Multi-

Microprocessor:

MP3 Player.

Micro rocessor:32-bit RISC.

Product: RCARC5400P DVD

player.

Microprocessor:

32-bit RISC.

Product: Sony Aibo

64-bit MIPS RISC.

Web Servers… get smaller

PIC 12c508

Classification

. u onomous

. ea - me

. e wor e

. o e a egor es 78

standalone mode.

process control in manufacturing units

.• Ex: Air-conditioner, CD players

• ea – me em e e sys ems are

required to carry out specific tasks ina spec e amoun o me.

• These systems are extensively usedto carry out time critical tasks inprocess control

• Ex: Boiler Plant

3. Networked Embedded

Systems• Monitor plant parameters, such as

temperature, pressure, andhumidity, and the data over thenetwork to a centralized system foronline monitoring.

• Ex: Web camera monitoring the

plant floor transmits its video outputto a remote controlling organization.

4. Mobile``````

• Mobile gadgets need to store data

• These gadgets imbibe powerful

com utin and communicationcapabilities to perform real-time tasksand handle multimedia applications.

• The gadgets embed powerfulprocessor and OS, and a lot of memoryw t m n ma power consumpt on.

1 Embedded Systems Development

Documents