EMBEDDED SYSTEMS

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Study Of flow Of Electrons

Nothing Without Current

Basically A Branch Of Science Which Have No Limits

Full Of Creativity.

Transforming Ideas Into Reality

Only Limit Is Imagination

Embedded Systems Are Heart Of Electronics

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Also Known As Potential Difference

Because Represents The Potential Gap Between Two Points

Always Measured With A Reference Point

Root Cause Of Flow Of Current

Determines Total Electromotive Force Acting Between Charges

Basically The Amount Of Charge Determines The Potential Of A

Point

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Flow Of Electrons

Generally From Higher Potential To Lower Potential

Similar Behavior To that Of Water

Makes Its Own Way Itself

Usually Follows The Least Resistance Path

In Two Parallel Branches Divided According To The

Inverse Proportion Of Their Resistances

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A system is a way

of working,

organizing or

doing one or many

tasks according to

a fixed plan,

program or set of

rules.

• A system is also an

arrangement in which

all its units assemble

and work together

according to the plan

or program.

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SOFTWARE PROGRAM

#include <16f876a.h>#use delay (clock=20000000)#byte PORTB=6main(){set_tris_b(0);portb=255; //decimaldelay_ms(1000);portb=0x55; //hexadecimaldelay_ms(1000);portb=0b10101010; //binarydelay_ms(500);}

An embedded system is a special-purpose computer system designed to perform certain dedicated functions. It is usually embedded as part of a complete device including hardware and mechanical parts…………………………..………. (Wikipedia)

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We can say that it is “A combination of computer

hardware and software, and perhaps additional

mechanical or other parts, designed to perform a

dedicated function.

Embedded software is a part of almost every electronic

device in the use today.

Each embedded System is unique, and the hardware is

highly specialized to the application domain.

Its software embeds in ROM (Read Only Memory) &

does not requires secondary memories as in a computer.

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Embedded systems span all aspects of modern life and thereare many examples of their use.

a)Biomedical Instrumentation – ECG Recorder, Blood cell recorder,patient monitor system.

b)Communication systems – pagers, cellular phones, cable TV terminals,fax and transreceivers, video games and so on.

c)Peripheral controllers of a computer – Keyboard controller,DRAM controller, DMA controller, Printer controller, LAN controller,disk drive controller.

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d) Industrial Instrumentation – Process controller, DC motor

controller, robotic systems, CNC machine controller, close loop

engine controller, industrial moisture recorder cum controller.

e) Scientific – digital storage system, CRT display controller,

spectrum analyser.

f) Defence - machine guns, GPS, tanks, wireless, missiles,

Submarines, Aircrafts & All Other Latest Equipments

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Every embedded system consists of custom-built hardwarebuilt around a Central Processing Unit (CPU). Thishardware also contains memory chips onto which thesoftware is loaded. The software residing on the memorychip is also called the ‘firmware’.

The operating system runs above the hardware, andthe application software runs above the operatingsystem. The same architecture is applicable to anycomputer including a desktop computer.However,there are some significant differences. Itis not compulsory to have an operating system inevery embedded system.

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EMBEDDED SYSTEM14

•POWER

•SUPPLY

•CAPACITORS

MICRO

CONTROLLERRESISTORS

DIODESTRANSISTORS

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A microcontroller is a single silicon chip with memory and all Input/Output peripherals on it. Hence a microcontroller is also popularly known as a single chip computer. Normally, a single microcomputer has the following features :

Memory for storing program Arithmetic and logic unit EEPROM for nonvolatile data storage RAM for storing variables and special function registers Input/output ports Timers and counters Analog to digital converter Circuits for reset, power up, serial programming, debugging Instruction decoder and a timing and control unit.

So it is no wonder to say that: ’’Microcontrollers Are The Heart Of Embedded Systems.”

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Microcontroller architecture

Pin Description: Made by microchip

40 pin DIP

5 i/o ports

2 analog ports

3 Digital Ports

Inbuilt ADC

Operates at +5 V.

Based on CMOS

technology

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Use of microcontroller always involves someinterfacing.

Interfacing is nothing but connecting an i/o device orsome other device with our microcontroller.

Basically it is the effective interfacing whichcompletes the embedded system

Various components like LCD, Switch, Led, Relayetc. will have to be interface with the microcontroller.

In the next few slides we will explain theseinterfacings.

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VERY SIMILAR TO THAT OF THE INTERFACING OF THE

LED

REMEMBER SWITCH IS AN INPUT DEVICE WHILE LED IS

AN OUTPUT

HENCE THE PORT AT WHICH WE ARE INTERFACING THE SWITCH MUST BE MADE AN

INPUT PORT .

If we want to make port B as input Port & Port C as output Port. Then write:

TRISB=0XFF

TRISC=0X00

All this programming for PIC16F877A is done in embedded C by using “MPLAB” software.

The MPLAB is designed and developed by ‘microchip’.

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The type of LCD display generally used for interfacingPIC16f877A is a 16*2 display as shown here.

It has total 16 pins out of which 8 pins are data pins(D0-D7).

Like LED , LCD is also an input device.

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A relay is generally a 5 pin device as shown :

1 COIL Coil Terminal 1

2 COIL Coil Terminal 2

3 POLE Common Terminal

4 NC Normally Connected

5 NO Normally Open

1.) Common point is connected to the supply

12V relay

2) Output is taken at NO Terminal w.r.t. ground

3.)Pole is normally connected to NC terminal

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1) Password Based Security System:

The project was made by using a pic16f877a, a 16*2 LCD display,5

push/pull switches, and a 5V power supply along with basic

electronic components

The program code was written in embedded c language using

MPLAB software. And burning of the program on pic

microcontroller was done using pic burner with the help of pic kit2

software.

A particular password for the system was set.

Reset switch erases the previous content and allows the user to

again enter the password

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If the password enter by the user is correct then the LCD display shows the message ‘password matched.’

However if the password entered is incorrect thenthe LCD display shows the massage ‘Unauthorised User’.

Next slide shows the design of this circuit in Proteus software.

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Consist of an RF transmitter/reciever module (BX- R433a)

Transmitter contains IC HT-12E as encoder.

Reciever contains IC HT-12D as decoder.

The driving section contains a dc motor having atleast 1000

rpm

The motor is driven by the motor driver IC L293D

By getting commands from the reciever output.

Switches are provided on transmitter section to control the motor.

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SOUND TRANSMISSION THROUGH LASER

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TRANSMITTER:

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