UnI

Embedded Systems

an embedded
sys is the combination of computerhardware and software
designed for a specificfun
Hitmobilephones consists of GUI software hardware
and operatingsystems camera microphone andother sensors

2 Automobile airbagsystems cruisecontrol navigation sensors backupsystems

3 Medicalequipments sensors controlmechanisms complex601,0s

4 Industrial machines sensors controlsystems can perform as an embeddedsys

itself
Characteristics
IMP
Z
1 consists hardware software
of firmware
2 can be embedded in a larger system to perform a specificformsastheyarebuilt
for specialized taskswithin thesystem not various tasks
3 Task specific
4 can be either microprocessor based on microcontroller based both are
integrated circuits
5 Sophisticatedfunctionality notwoembedded system applications issame ex The functionality a
of
washingmachineis difffrommicrowave
6 realtimeoperationThey are usedforsensing realtime computing in IOT devices
7 Tightdesignconstraints Thereare manyconstraints to consider performancepowersizetimeTheyarereg
toperform theirtuneunder a time constraint
8 lowmanufalcostsas it aimstoperform a singletasklesspower toperform operations
ComponentsStructure
1 Sensor convertphysicalsensed data to electrical signal
2 Actuator compare actualoutput to memory stored output chooses the correct one
3 memory store dataprocessedbyprocessor
4 processor process dig signals store in memory
5 Analog digconvertor on analogsignalsentbythesensorintodigsignal
6 Dig analog convertorcontdigdatafedbyprocessor into analogdata

Senhor will
generate some analog data this analog data will be convertedto
digitaldata with thehelpof A D convertor
 proceksson
That digital data is treatedas input to the
The processor will eitherstore the dig data into the merkory or the data will be
processed in the same processor and that data is given to the D A Fomenterwhich
counts it into analogdata is givento the Actuator
SENSOR ANAIOS DIGCon

o
fEE
ALPetc

FEE FEE
Structure
Hardware
Software firmware
real time 0 Sys RTOS
Based around microprocessors and microcontrollers
microprocessor CPVcentralprocessing unit itself not on achip
needsexternal components like mem devicesed
req highcomputational power
more powerful and faster
used in Gen purer computers

iagh.TT
zeiEg videogames A I

microcontrollers complete system on achip Sol that ingratesCPU mumperipend

cheaper
compact size ee automotive sys medical devices etc

If pwie diathesis high endcode that runs on hardware toperformfunctie

firmware refers to low level software that is permanently programmed into
hardware
Both are crucial forproper functioning the Emsys
of
usedto manage hardware resources
run applications
defineshow the sys worksby supervising the software setting
rules during program application
 Embedded Sop V S
general computers

E Sys G CompSys INF

used to perform specific tasks designed to perform wide range
eewashing machine microwave elz tasks
ofwordprocessors webbrowsers
ex gaming

embedded with larger systems operate independently not embedded

into other systems standalone devices
many design constrains are neg
low no resource constraintsrear
limited processingpower mem toreduce
cost size and powerconsumption powerful CPU ample amtofRAM
significant storage to support wide
CustomHardware Built with specific range ofapplications
microcontrollers minoprocessorsfortask
Standard Hardware Usesstandonet
Often run firmware RTOS hardware components like intel AMDprocessors
tailored to the specificapplication
run gamal purpose 0 sys like windows
minimalistic software withminimal macos linux to support wide

are challenging
range ofapplications
software updates
frequent compensoftware with rich U I

low power consumption lessmemory frequentsoftware updates patchesare comm

high powerconsumption vastmemory

I
Advantage Disadvantages
high developmenteffort
IEasitiustomizable largertime to market
low powerconsumption
enhancedperformance
Classification
motive
Types
of embedded systems
1
Based on functionalrequirements of
shhh fhdf homeffian
I
scale scale
networked mg
fne Issue

real time embedded systems

renren.ie a
follow timedeadlines
iiiiisiiiii
provide quick response in critical situations
That's timeembedded systems are used indefence sector medicalhealth
why real coma
where output in the right time is given more importance
further dir into 2types
Softreal timesystems timedeadline isnotreq or it isnotfollowed
evenifthe deadline
oftaskis passed still theoutputisaccepted
EEin microwaves we can customizetimedelaysasperrequirement
Hard real timesysfollowsdeadlinestrictly
task mustbecompleted in b w timeframe ortheoutputwillnotbe accepted
EETrafficlightcontrol
examples are Traffic control system
Militaryuse in defence sector
medical use in health care
Standaloneemb
sys
independent systemswhichcan work
bythemselves do notdependonahostsys
lesscomplex
IttakesinputindiganalogformEeprovidesoutput I doorbell calculator mp3player
 network em sys
these systems are connectedto a networkwhichmay be wired or wireless to
provide output to the attached device
they communicate with embedded web server throughanetwork interface LAN
examples ATM cardswipemachine weathermonitoring sys WANetc

mobile emb sys

small portable easytocarry

requires less resources
work on restrictedmemory space
Constantly evolving togeta miniation model
mostpreferredend systems
e mobilephones
digitalcameras
Mp3player

Small scale systems

entry level embeddedsys with no designcomplexity

designed using8 bit on16 bit microcontroller
These
sys are battery operated powered by battery controllers
hardware software complexity is very low due to small size ofmicro
processor uses less resources processing speed as it deals with small amt of
data
easy to program using assemblylanguage or C programming
example robotic arm controller
electronic toys
thermometers

Medium scale
designed using an 16 bit or 32 bit microcontroller
faster than small scale sys wrt speed
hardware software complexity is present
requires more memory power
Jana C Ctt are used to develop these sys
along with microcontrollers application specific 0 Sys are alsoused
Ed routers pagers music systems

Sophisticated complex
usemffueb.int or 64bit microcontrollers and multi core processors
requires very high memorypower
developed to performlargescale complexfunctions
thigh hardware and software complexities
 highestpowerconsumption
some applications use RTOS too
example washing machines
digital watches
multimedia systems

Microproessa Architecture

Case RISC
complex instance set comp reduced insture set lamp
requires less ram requires more from
emphasis on hardware emphasis on software
Less pipelinedprocessors highly pipelined processors
no of instructions is more 0 9 are less
instance
instants are execin n'cycles instant are exec in one cycle
consumes highpower consumed less power
Compeen design simple design
expensive inexpensive
one resister set isused multiple res sets are used
supports arrays doesnot support arrays
conditioncodes are used no conditioncodes are used
more addressing modes less addressingmodes
Variable lengthencodings ofthe fixed length encoding ofthe
instructions instants

Hey
1983
offRI
ARMproject began with ACORNCOMPUTERS tocreate a new microprocessor
1990 ARM Ltd wasfounded as a jointventure b w Acorn Apple VLSI technology
1991 ARMO processor was released enteringinto the microprocessor market
1998 ARM holdings went public listingon the london stock exchange
2000 ARMgained dominance in mobilephonemarket withARM7 ARM11families
2016 ARM was acquired by Japanese conglomerate SoftBank group
202.3 ARM returned to the public markets through an IPO initial public
offering
ARMP
ROCESSORS
AI arm is a family
of RISC instant set architectures to compprocessors
it is a 32 bit processor
Advanced RISC machine
ARM
TAX
FEATURES

RISK architecture is used

simplified instructions
higher performance

Energy Efficiency
consumes less power
ideal for mobile devices other applications

Safftitasilitective
varies from low power microcontrollers to high
provides solus to a wide range of computing needs

Pipelining
instrus is donein 11ᵗʰ
processing of using pipelines
increases throughput rate ofprocessing

Cycles
has clock per instani
most insturs exec only
CPI
in oneclie cycle
IF.es uion inaeetoms
Afatisyche Chateau
Thumb 2 Technology
introduced in 2003
allowstoswitch b w 32 bit 16bit architecture haknIptfftjeoat.mg
2 modes ARM
MILTHUMB 14 point computation
Registers

large no Of registers are

avoids mem shortage
used in ARM processorst
Records store data addressesand theseact as a local mem statefor all
operations
Mem Management
has MMU mem management unit
MPU mem protec unit
these management systems are impfor mem efficiency
 ating
AI
Ag
architecture V.us ormodes

A 0

Threesome control

Bus

a instant
Bus
By made
control
V
ALU

I
Interested data in resister

DEI 0

functional units are connected bydata buses

data enters the processor core through data bus
The data maybe an instant to be executed by
processor
The instant decoder translatesthe instructionsb4 theyare executed
uses load store architecture Load copydata from memto registers
Hagar HIS
copy data from registersto mom
data is placed in a my bank made of 32 bit registers
The ALU takes the negvalues from bus A B E computestheresult
The address by holds the address ofthe data tobeaccessed
incrementer increases the value of P C

ALV 32bits
regs 32 bits
0perating Modes of ARM
User Mode
generalmode for the
running application
is not privileged Cannot
access memory Ilo tagsetc
default mode which runs all userprogrammers
cannotchangethe mode directly
uses general purpose regs
Systemmode
Has full accesstosysresources Uses same as user
privileged instrucs
regs
TypicallyusedbyopsysKernales
The usermode mayuse this modeto access all the resources
A programmerneedstobeverycautious while using this mode as if theprogram
crashes the entire sys crashes But this is not the case inusermode
through asyscall usermode system mode
de uses user mode reg set
EYE
fastinterrupt questmode Elfdevices causing F Ids are
used to handle highpriority instous floppy disks serialPatty
it is a periviledgedmode
we make use of only specialregs not general purposeregs
fast interruptprocessing Treserved
suitable fortime sensitizes regs RB B12 To
cohhnetsuyfgh.is
us
IR Q
interrupt requestmode big devices
used to handle low peri instance keyboard
harddish else
it is a periniledged mode too
works similar to user mode as it is used to general purpose interrupt
no special regs are used It shares regsy handling
with other prinidedged modes erupt FIO specific regs
for
Superneamode SVC
on a software request ARM enterthismode when a software interrupt
or it enters this mode on reset instantis excel
an 0 sys kernal Operates in this mode
it has additional privileges that allow greater controlof the sys
 Aborts
used to handle mem access violations ex illegal men access
entered whenever an attempt access memoryfails
used to perform appropriate error handling

Undefined mode
handles undefined unimplemented instructions
a privileged mode
also used to emulate unsupported instructions

Register Ro usermode RO Ris

CPSR
Sysmode Ro Ris
CPSR
Ftd Ro Rt

Éfn
R 8 Riz reserved
purpose R13 Ris SPSR
regs IRO
s
SPSR
ftp fgagg sameto
around
CPSR is shared to
RB SP tack pointer All modes
link register each perinideged mode
is
page county has its own SPSR

2 special purpose regs other than Ro Ris

CPSR current perg Statusregister

holds the current statusof theregsincluding condition flags
control bits modebits

R Saved pay status register

saves the status of the neg used to save the CPSR's value when
an exception occurs allowing the processor to return to its
original state oncethe exception is handled
Landonpays N night P C setto 1
carry it 4shared.com
2
opinfant
3 overflow set last
it opeatqyea.mg
 Control BI

BE EEEiEiEEEiEE Ei state
ms
using 16 bit instant set
Mode Bits indicate the current processor mode of user
SPSR for
off
There is no user a
Sysmodes
SP stack pointer even though
there is stack in the
no
ARM architecture
PC add of the nextisland
LR saves copy of PC when
subroutine is called

Sys mode user user model regs

Thumb is a 76 bit instantset

as all applications do not need
the full power 32 bit
ARM instants of

7 30 8 27 07 06 Ds o 4
N v1 undefined
IT mode
I H
Fast
EE i
tinier
Sys enters F 10 mode Do alwayshigh
sys enters IRO mode D4 alwayshigh
carry flag works wot D3 bit
if result is going beyond bit 31 overflowflag 1
if result is 0 zeroflag is high
EÉ ÉÑmEtnntE
Pl
iim WE
ht i.tt
instancs must be halfword
puffany Ff after g qigong is stored in bits

www.mmyt 17andbitEdiszero
Arm Corten A R M families
ARMZ 1st one to be commercially produced
ARM 7 dominant in the 32 bit embedded processor market
ARM9 10,11 mon computing powers
COR has architecture v7 version
gg
Arm Cortex A Arma A
A stands for advanced performance
meant for high end applications
handles complex applications with high end embedded 0Sys
Ce mobile phones
video systems

ARE later Arma r

designed for high end applications that req real time capabalities
ee automatic braking systems
other safety critical applications

Arr ARMA M
designed for deeply embedded microcontroller type systems
E industrial control applications
 microcontroller

LPCIKI
dates
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office messed
12MY
crystal
ftp.mail.eaeffe
Adama Taffhdfff is used to
ammmm
drive the
MAMMA
LPC 2148

step
LPC2148 is manufactured by NXP belongs to Philips

CPC 148 falls under ARM family

It is a 32 bit processor can process 32 bitsofdata

Features

7
FEEL cognisstffing allowing high processing power

WIRD LENIN 32 bits

faffing programmablememory KB to storingpongand

const data

RAMEN data memory 32 UB to storingvariables tempdata

implement stack

PARALLEL PITS
I
4spinsCGP10
I p.ge

TIERS 2 32 bittimers Éditions

foulcapture joincomparechannelseach supportingvarious timing E
counting operations

RE realtimeclock HH MM SS to run real time application

hasa separatepowersupplypin to keeptimeevenwhenthe main power is off
 WATCHDOGTIMER D programmable timer
resets the microcontroller if it failsto operate correctly
used for hanging theperg

UART 2 universal asynchronousreceivertransmitter interface

used for serial communication b w devices
it is a hardware commprotocol

Pulse width modulation

PWI provides upto 6 outputs
generates signal can beused to controlvarioustypes
of hardwaresuchas
motors LED
etc
3
Busses AMBA
AUB
VPB

10 bit converters
ADIDAS analog
dig dig analog
2 Iz interface sets
SPI E SSPinterfaces

AMI microcontroller Bus architecture

If fyay.mg buses with diff protocols
Local Bus fastest bus highspeed used to interface the mem
connects processor core with memory as the memory
accesses have to be fast

Anew advanced high performancebus interconnects high speed

usedto interface localbuswith AUB Bus components

VISIBI aka VPB peripheral bus

performance based on custom design application requirements
CPU clock E Peripheral clock
LE
Iff am Cpu core ohdeffffastfflett
Peripheralclock
PER
drivesvariousperipherals
PICK is derivedfrom CLK
Type gyp typesof PLLmodules
 peripheralclock runs quarter 14 speedoftheCCLK

Interfacing and programming GPO

LPC2148 provides 2 ports
each port of 32 bits LP 2148 is a 64 pinIC 32 32 64
Led to interface LCD relays LED etc
BE p Itstated to input and output 29 pins are available
PO 31 used only to output
PO24 Po26 Po 27 are reserved not available These
PORTI 32 bit Ilo port
Pl16 P1 31 are availablefor Ilo 16 pins
First 15 pins 0 15 notused
Total 16 29
E pins are usable out of 64pins
Eachpinhas multiplefunctions
Porto

2148 porto
PortI Canadcon
s supply as

In
port 1
PINSEL registers are used to clonfigities particular
selected pins Each pin has many functions the PINSEL registers
are used to determine which fun the particular pin is
responsible for
PINSEL 0 PO 0 By default all 45 pins are
PO 15 I P pins Wehave to changethe
particular pin to 0 P to use itas
p'YEE 81 I 88 s an O P pin

Bydefault all 45 are GP10

II Plo directionregister
configuresdirection ofeach GPIOpin as inputoroutput
O'forinput and I foroutput set

IET grio set resister white.ms iiiseiisfi iiiiiiipi ish

 IDR clearregister
clean it
Kite issuing S lajpiitoiiiw.to
IIIN reads the current state of the pins
returns high low ofthe pins

every pin has 32 bits

the last bit decides if the pinworks as an O Ppin
I a rin
EE fi i
Every pin has a pin selectMuse
est to PO 5 the pinsel misereceives 4 I P
i e GPio SPIOMatch0 1 AD 0.7
Timer UART

The programmer selects which fun isreq

for PORT 0 12ᵗʰpin
I no

i 0

IEEE
UART

PINEL Function Tnf bitsonly areusedHere 1061 areused

toconfigure PO
5

I
7 1st twobits 091 are usedto
configure PO0 pin
00 Plo default reset
01 VART
10 PWM
11 reserved

3aenassmnetpotno
IE.EE with 2 to
getpinno
 16 31 16 31

Since its starting from16 how do we know which 2 pinsto use

16 16 0 2 0 071
0,1ns
19 16 3 6 and 6 1
2 6,71in

15 0 Set pin POS to Pin June 1 first alternate fund

S
first identify the pinselregister and identify thebits corresponding tothe P

E EE iiiEiEi.n.i
Is I 1 a
I I I I I21 to notdisturb the otherbits

1,1 l tm't
men
include Ipc 14am
intmann 0
Ent
pin 5
18 0000010000

3 is 11 which is mould 5 2 times i e 10times

PISEL 8 It 0 3 is 11 we have to make only 10 00
while i
if we invert the wholevalue everywhere else
3 said Theist futilesuitt0158 henpins

Why do we use AND E OR l