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forestevanescentElectronics - Devices

Nov 2, 2013 (3 years and 7 months ago)

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Definition of Embedded


Systems

1.Embedded system
:
is a system whose principal function is not computational,


but which is controlled by a computer embedded within it.

2. A general computer is defined not to be an embedded system.

3. An Embedded system is some combination hardware and software ,either


fixed in capability or programmable ,that is specifically designed for a particular


function.

4.Any hardware system which is intended to do a specific task can be called as

embedded system









1.The situation we find ourselves today in the field of microcontroller


had its beginnings in the development of technology of integrated


circuit.

2.This development has enabled us to store hundreds of thousands


of transistors into one chip.

3.The first computers were made by adding external peripherals such


as memory ,input /output line, timers and others to it.

4. Further increasing of package density resulting in creating an


integrated circuit which contained processor & peripherals .That


is how the first chip containing a microcomputer later known as


MICROCONTROLLER has developed.



1. In 1981,Intel corporation introduced an 8
-
bit microcontroller known as 8051.

2. It had 128bytes RAM,4Kbytes ROM,2timers,1 serial port & 4 ports on a single


chip.

3. It was referred as “System on a chip”.

4. Intel's original MCS
-
51 family was developed using



NMOS technology.

5. Later versions, identified by a letter C in their name (e.g., 80C51) used

CMOS



technology and were less power
-
hungry than their NMOS predecessors.



:

1.4 KB on chip program memory.(ROM)

2.128 bytes on chip data memory(RAM).

3. 4 register banks.

4. 8
-
bit data bus

5.16
-
bit address bus.

6.16 bit timers (usually 2, but may have more, or less).

7.3 internal and 2 external interrupts.

8.Four 8
-
bit ports, (short models have two 8
-
bit ports).

9. 16
-
bit program counter and data pointer.

10.1 Microsecond instruction cycle with 12 MHz Crystal.


Home Automation, Networking, and
Entertainment Lab

Dept. of Computer Science and Information
Engineering

National Cheng Kung University, TAIWAN

Chung
-
Ping Young

楊中平

8051
MICROCONTROLLERS

The 8051 Microcontroller and Embedded

Systems: Using Assembly and C

Mazidi
,
Mazidi

and
McKinlayDepartment

of
Computer Science and Information
Engineering

National Cheng Kung University, TAIWAN 2

HANEL

OUTLINES

‰ Microcontrollers and embedded

processors

‰ Overview of the 8051
familyDepartment

of
Computer Science and Information
Engineering

National Cheng Kung University, TAIWAN 3

HANEL

MICROCONTROLLERS

AND

EMBEDDED

PROCESSORS

Microcontroller

vs.
GeneralPurpose


Microprocessor

‰ General
-
purpose microprocessors

contains

¾ No RAM

¾ No ROM

¾ No I/O ports

‰ Microcontroller has

¾ CPU (microprocessor)

¾ RAM

¾ ROM

¾ I/O ports

¾ Timer

¾ ADC and other
peripheralsDepartment

of
Computer Science and Information
Engineering

National Cheng Kung University, TAIWAN 4

HANEL

MICROCONTROLLERS

AND

EMBEDDED

PROCESSORS

Microcontroller

vs.
GeneralPurpose


Microprocessor

(cont’)

Serial

COM

Port

I/O Timer

CPU RAM ROM

Microcontroller

CPU

RAM

Address bus

Data bus

ROM

I/O

Port

Serial

COM

Port

Timer

Generalpurpose


MicroProcessorDepartment

of Computer
Science and Information Engineering

National Cheng Kung University, TAIWAN 5

HANEL

MICROCONTROLLERS

AND

EMBEDDED

PROCESSORS

Microcontroller

vs.
GeneralPurpose


Microprocessor

(cont’)

‰ General
-
purpose
microprocessorsgarage

door
openers, answering machines, fax

machines, home computers, TVs, cable TV
tuner,

VCR, camcorder, remote controls, video games,

cellular phones, musical instruments, sewing

machines, lighting control, paging, camera,
pinball

machines, toys, exercise equipment

‰ Office

¾ Telephones, computers, security systems, fax

machines, microwave, copier, laser printer,
color


printer, paging

‰ Auto

¾ Trip computer, engine control, air bag, ABS,

instrumentation, security system, transmission

control, entertainment, climate control,
cellular

phone, keyless
entryDepartment

of Computer
Science and Information Engineering

National Cheng Kung University, TAIWAN 8

HANEL

MICROCONTROLLERS

AND

EMBEDDED

PROCESSORS

x86 PC

Embedded

Applications

‰ Many manufactures of general
-
purpose

microprocessors have targeted their

microprocessor for the high end of the

embedded market

¾ There are times that a microcontroller is

inadequate for the task

‰ When a company targets a
generalpurpose

microprocessor for the

embedded market, it optimizes the

processor used for embedded systems

‰ Very often the terms embedded

processor and microcontroller are used

interchangeablyDepartment

of Computer
National Cheng Kung University, TAIWAN 9

AND

EMBEDDED

PROCESSORS

x86 PC

Embedded Serial
er

ƒ UV
-
EPROM eraser takes 20 min to erase

‰ AT89C51 from Atmel Corporation

CPU

On
-
chip
RAM

On
-
chip
ROM for
program
code

4 I/O Ports

Timer 0

Serial
Port

OSC

Interrupt
Control

External interrupts

Timer 1

Timer/Counter

Bus
Control

TxD RxD

P0 P1 P2 P3

Address/Data

Counter
Inputs

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

40

39

38

37

36

35

34

33

32

31

30

29

28

27

26

25

24

23

22

21

P1.0

P1.1

P1.2

P1.3

P1.4

P1.5

P1.6

P1.7

RST

(RXD)P3.0

(TXD)P3.1

(T0)P3.4

(T1)P3.5

XTAL2

XTAL1

GND

(INT0)P3.2

(INT1)P3.3

(RD)P3.7

(WR)P3.6

Vcc

P0.0(AD0)

P0.1(AD1)

P0.2(AD2)

P0.3(AD3)

P0.4(AD4)

P0.5(AD5)

P0.6(AD6)

P0.7(AD7)

EA

ALE

PSEN

P2.7(A15)

P2.6(A14)

P2.5(A13)

P2.4(A12)

P2.3(A11)

P2.2(A10)

P2.1(A9)

P2.0(A8)


8051


In this project the robot, is controlled by a mobile phone that makes call to
the mobile phone attached to the robot in the course of the call, if any
button is pressed control corresponding to the button pressed is heard at
the other end of the call. This tone is called
dual tone multi frequency tone
(DTMF)
robot receives this DTMF tone with the help of phone stacked in the
robot




The received tone is processed by the microcontroller with the help of
DTMF decoder MT8870 the decoder decodes the DTMF tone in to its
equivalent binary digit and this binary number is send to the
microcontroller, the microcontroller is pre programmed to take a decision
for any given input and outputs its decision to motor drivers in order to
drive the motors for forward or backward motion or a turn.



The mobile that makes a call to the mobile phone stacked in the
robot acts as a remote. So this simple robotic project does not
require the construction of receiver and transmitter units.


DTMF signalling is used for telephone signalling over the line in
the voice frequency band to the call switching centre. The version
of DTMF used for telephone dialling is known as touch tone.


DTMF assigns a specific frequency (consisting of two separate
tones) to each key s that it can easily be identified by the
electronic circuit. The signal generated by the DTMF encoder is
the direct
alzebric

submission, in real time of the amplitudes of
two sine(cosine) waves of different frequencies, i.e. ,pressing 5
will send a tone made by adding 1336hz and 770hz to the other
end of the mobile.

CIRCUIT DIAGRAM OF DTMF ROBO CAR

when you press 2 the robot will move forward


when you press 4 the robot will move left


when you press 8 the robot will move backwards


when you press 6 the robot will move right


when you press 5 the robot will stop.



APLLICATIONS

1
)

Scientific


Remote

control

vehicles

have

various

scientific

uses

including

hazardous


environments,

working

in

the

deep

ocean

,

and

space

exploration
.

The

majority


of

the

probes

to

the

other

planets

in

our

solar

system

have

been

remote

control


vehicles,

although

some

of

the

more

recent

ones

were

partially

autonomous
.


The

sophistication

of

these

devices

has

fueled

greater

debate

on

the

need

for


manned

spaceflight

and

exploration
.


2
)
Military

and

Law

Enforcement


Military

usage

of

remotely

controlled

military

vehicles

dates

back

to

the

first


half

of

20
th

century
.

Soviet

Red

Army

used

remotely

controlled

Tele

tanks

during


1930
s

in

the

Winter

War

and

early

stage

of

World

War

II
.


3
)

Search

and

Rescue



UAVs

will

likely

play

an

increased

role

in

search

and

rescue

in

the

United

States
.

This

was

demonstrated

by

the

successful

use

of

UAVs

during

the

2008

hurricanes

that

struck

Louisiana

and

Texas
.




4
)
Recreation

and

Hobby



See

Radio
-
controlled

model
.

Small

scale

remote

control

vehicles

have

long

been

popular

among

hobbyists
.

These

remote

controlled

vehicles

span

a

wide

range

in

terms

of

price

and

sophistication
.

There

are

many

types

of

radio

controlled

vehicles
.

These

include

on
-
road

cars,

off
-
road

trucks,

boats,

airplanes,

and

even

helicopters
.

The

"robots"

now

popular

in

television

shows

such

as

Robot

Wars,

are

a

recent

extension

of

this

hobby

(these

vehicles

do

not

meet

the

classical

definition

of

a

robot
;

they

are

remotely

controlled

by

a

human)
.

FURTHER IMROVEMENTS &
FUTURE SCOPE




1
.

IR

Sensors
:



IR

sensors

can

be

used

to

automatically

detect

&

avoid

obstacles

if

the

robot

goes

beyond

line

of

sight
.

This

avoids

damage

to

the

vehicle

if

we

are

maneuvering

it

from

a

distant

place
.






2
.

Password

Protection
:



Project

can

be

modified

in

order

to

password

protect

the

robot

so

that

it

can

be

operated

only

if

correct

password

is

entered
.

Either

cell

phone

should

be

password

protected

or

necessary

modification

should

be

made

in

the

assembly

language

code
.

This

introduces

conditioned

access

&

increases

security

to

a

great

extent
.






3
.

Alarm

Phone

Dialer
:



By

replacing

DTMF

Decoder

IC

CM
8870

by

a

'DTMF

Transceiver

IC’

CM
8880
,

DTMF

tones

can

be

generated

from

the

robot
.

So,

a

project

called

'Alarm

Phone

Dialer'

can

be

built

which

will

generate

necessary

alarms

for

something

that

is

desired

to

be

monitored

(usually

by

triggering

a

relay)
.

For

example,

a

high

water

alarm,

low

temperature

alarm,

opening

of

back

window,

garage

door,

etc
.



When

the

system

is

activated

it

will

call

a

number

of

programmed

numbers

to

let

the

user

know

the

alarm

has

been

activated
.

This

would

be

great

to

get

alerts

of

alarm

conditions

from

home

when

user

is

at

work
.







4
.

Adding

a

Camera
:




If

the

current

project

is

interfaced

with

a

camera

(e
.
g
.

a

Webcam)

robot

can

be

driven

beyond

line
-
of
-
sight

&

range

becomes

practically

unlimited

as

GSM

networks

have

a

very

large

range
.