Training Report On "Embedded System Design"

A

PRACTICAL TRAINING SEMINAR

REPORT

ON

“EMBEDDED SYSTEM DESIGN”

(ARMbedded Electronics Pvt. Ltd. Jaipur)

Submitted in partial fulfillment for the award of the degree of

BACHELOR OF TECHNOLOGY

IN

ELECTRONICS & COMMUNICATION ENGINEERING

2014-15

Submitted To:- Submitted By:-

Mr. VISHNU KR. SHARMA NEERAJ KUMAR

Asst. Prof. (E.C.E.) B.Tech ,VIISEM.

JIT, Jaipur 11EJJEC028

RAJASTHAN TECHNICAL UNIVERSITY, KOTA

DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING

JAIPUR INSTITUTE OF TECHNOLOGY, Group of Institution, Jaipur

RAJASTHAN TECHNICAL UNIVERSITY, KOTA

JAIPUR INSTITUTE OF TECHNOLOGY, JAIPUR

(GROUP OF INSTITUTION)

DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING

CERTIFICATE

This is to certify that the Practical Training Seminar report for Practical

Training taken at “ARMbedded Electronics Pvt. Ltd. Jaipur” From (2-Jun-

2014) To (15-Jul-2014) submitted by “Neeraj Kumar” in partial fulfillment

for the award of degree of Bachelor of Technology in Electronics &

Communication Engineering has been found satisfactory and is approved for

submission.

Mr. Vishnu Kr. Sharma Mr. Vishnu Kr. Sharma

(PTS Coordinator) (PTS Guide)

Assistant Professor Assistant Professor

Dept. of ECE Dept. of ECE

JIT, Jaipur JIT, Jaipur

Ms. Priyanka Agrawal

Head, Dept. of Electronics & Communication Engineering,

JIT, Jaipur

II

CERTIFICATE

I

AKNOWLEDGEMENT

I am deeply thankful to “ARM bedded Electronics Pvt. Ltd. Jaipur” As it

has given me golden opportunity to go through remarkable training on

“Embedded System Design”. Here I have got valuable and detailed knowledge

on real time projects. I owe my gratitude to my faculty cum trainer “Mr.Lalit

Sharma” for his unmatched supports, guidance and inspirations without which I

wouldn’t have learned so many new & innovative things in such a short span of

time.

I would also like to thanks my department i.e. Department of Electronics

& Communication Engineering of my college especially my HOD

“Mrs.Priyanka Agrawal” and all teachers who have suggested me to join this

beneficial summer training. I am highly obliged that I have received all of your

support in such a good way.

Neeraj Kumar

11EJJEC028

ECE, VII Sem.

III

ABSTRACT

The objective of my practical training is to learn something about industries,

practically and to be familiar with the working style of a technical worker to adjust

simply according to industry environment.

As a part of academic syllabus of four years degree course in electronics and

communication engineering, every student is required to undergo a practical training

for 45 days. We are student of fourth year electronics and communication and this

report is written on the basis of practical knowledge acquired by me during the period

of practical training taken at “ARM bedded Electronics Pvt. Ltd. Jaipur”.

This report deals with equipment their relation and their general operating

principle.

We hope that this report will be useful for a person to get the basic knowledge

about the “Embedded System Design”.

IV

LIST OF CONTENTS

CHAPTER NAME PAGE NO.

CERTIFICATE FROM TRAINING I

CERTIFICATE FROM COLLEGE II

ACKNOWLEDGEMENT III

ABSTRACT IV

LIST OF FIGURE V

LIST OF TABLE VI

1. COMPANY PROFILE 1-3

1.1 Introduction 1

1.2 Training & Skill Development 1

1.3 Products 2

1.4 Organizational Structure 2

1.5 Objective 3

1.6 Highlights 3

2. EMBEDDED SYSTEM 4-10

2.1 Introduction 4

2.2 Scope 5

2.3 Components 7

2.3.1 Hardware Components 7

2.3.2 Software Components 7

2.3.3 Real Time Operating System 7

2.4 Classification of Embedded System 8

2.4.1 Small Scale Embedded System 8

2.4.2 Medium Scale Embedded System 9

2.4.3 Sophisticated Embedded System 9

2.5 The Embedded Environment 10

2.5.1 Reliability 10

2.5.2 Efficiency 10

3. MICROCONTROLLER 11-26

3.1 Introduction 11

3.1.1 Microcontroller 12

3.1.2 Microprocessor 13

3.2 Microprocessor v/s Microcontroller 14

3.3 Types of Microcontroller 15

3.3.1 Microcontroller 8031 15

3.3.2 Microcontroller 8051 15

3.3.3 Microcontroller AT89C51 16

3.4 Pin Description of AT89C51 17

3.5 Memory Space Allocation in AT89C51 19

3.5.1 On chip ROM 20

3.5.2 on chip RAM 20

3.5.3 External Code Memory 21

3.5.4 External RAM 21

3.5.5 Code Memory 22

3.5.6 Registers 22

3.5.7 Program Counter & Data Pointer 23

3.5.8 Flag Bits & PSW Registers 23

3.6 Memory Addressing In AT89C51 23

3.6.1 RAM 24

3.6.2 ROM 24

3.6.3 PROM 24

3.6.4 EPROM 25

3.6.5 EEPROM 25

3.6.6 Flash Memory 25

3.6.7 Registers 26

3.7 Fabrication Techniques Of AT89C51 26

3.7.1 CMOS Technology 26

3.7.2 PMP Technology 26

4. ELECTRONICS COMPONENTS 27-42

4.1 Introduction 27

4.1.1 Registers 27

4.1.2 Capacitors 28

4.1.3 Inductor 28

4.1.4 Diode 28

4.1.5 Transistor 29

4.1.6 Potentiometer 29

4.1.7 Switches & Push Button 29

4.1.8 Solenoid 30

4.1.9 Motor 30

4.1.10 Relay 30

4.1.11 Buzzer 31

4.1.12 Light Emitting Diode 31

4.1.13 Photo resistor 31

4.1.14 Photodiode 32

4.1.15 Phototransistor 32

4.1.16 7-segement Led Display 33

4.1.17 Transformer 34

4.1.18 IC7805 voltage Regulator IC 34

4.1.19 LM324 IC 35

4.1.20 555 Timers IC 37

4.1.21 RF Module 39

4.1.22 LCD 41

5. “C” PROGRAMMING 43-51

5.1 Introduction 43

5.2 Statement Types 43

5.3 Basic Structure 43

5.4 Statements in “C” 44

5.4.1 Switch Statement 45

5.4.2 WHILE Loop Structure 45

5.4.3 DO-WHILE Loop Structure 45

5.4.4 FOR Loop Structure 45

5.5 Function 47

5.6 Program 49

5.6.1 WAP to Perform Table of Two 49

5.6.2 WAP To ON & OFF Relay 50

6. PROJECT OVERVIEW 52-59

6.1 Introduction 52

6.2 Circuit Components 52

6.3 Circuit Block Diagram 53

6.4 Circuit Flow Chart 54

6.5 Circuit Design 54

6.6 Circuit Description 55

6.6.1 Transmitter Circuit (Infrared) 56

6.6.2 Receiver Circuit (sensors) 57

6.7 Operation 57

6.8 Applications 58

6.9 Limitations 58

6.10 Project Program 58

7. CONCLUSION 60-61

7.1 Introduction 60

7.2 Lesson Learned 60

7.3 Knowledge Gain 60

7.4 Suitability of Organization 61

8. REFERENCE 62-62

LIST OF FIGURE

FIGURE NO. PAGE NO.

Fig.1.1Company Banner 1

Fig.1.2 Microcontroller Applications Kit 2

Fig.1.3 Recognition of ARMbedded Electronics Pvt. Ltd, Jaipur 3

Fig.2.1 Embedded System Applications 4

Fig.2.2 Function Diagram of Embedded System 5

Fig.2.3 Real-Life Examples of Embedded System 7

Fig.2.4 Hardware Component of Embedded System 8

Fig.2.5 Small Scale Level IC 8

Fig.2.6 Medium Scale Level IC 9

Fig.2.7 Sophisticated Level IC 9

Fig.3.1 Block Diagram of Microcontroller 11

Fig.3.2 Block Diagram of Microprocessor 12

Fig.3.3 Pin diagram & architecture of AT89C51 15

Fig.3.4 ROM & RAM Memory in 8051 Microcontroller 19

Fig.3.5 Some 8-bit & 16-bit Registers 20

Fig.4.1 Resistor Color coding 27

Fig.4.2 Charging, Charged & Discharging Of Capacitor 28

Fig.4.3 Inductor & its Circuit Symbol 28

V

Fig.4.4 Diode & its Circuit symbol 28

Fig.4.5 Transistor & its circuit symbol 29

Fig.4.6 Potentiometer & its circuit symbol 29

Fig.4.7 Switches & its circuit symbol 29

Fig.4.8 Solenoid & its circuit symbol 30

Fig.4.9 Motor & its circuit symbol 30

Fig.4.10 Relays & its circuit symbol 30

Fig.4.11 Buzzer Circuit Symbol 31

Fig.4.12 Various Types of LED’s 31

Fig.4.13 Infrared Detector 31

Fig.4.14 Photo resistor & its symbol 32

Fig.4.15 Photodiode & its symbol 32

Fig.4.16 Phototransistor & its Symbol 33

Fig.4.17 7-segement led display &it’s Pin out Diagram 34

Fig.4.18 Transformer & its Circuit Symbol 34

Fig.4.19 LM7805 IC & its Pin out Diagram 35

Fig.4.20 LM324 IC & Its Pin out Diagram 36

Fig.4.21 555Timer IC & Its Pin out Diagram 37

Fig.4.22 RF Transmitter & Receiver circuit 39

Fig.4.23 LCD & Its Pin out Diagram 41

Fig.6.1 Circuit Description of BDVC 52

Fig.6.2 Block Diagram of BDVC 53

Fig.6.3 Flow Chart of BDVC 54

Fig.6.4 PCB Layout of BDVC 55

Fig.6.5 Transmitter Circuit of BDVC 56

Fig.6.6 Receiver Circuit of BDVC 57

LIST OF TABLE

TABLE NO. PAGE NO.

Tab.1 Embedded System Scope 6

Tab.2 Microcontroller v/s Microprocessor 13

Tab.3Pin Description of 7805 IC 35

Tab.4 Pin Description of LM 324 IC 37

Tab.5 Pin Description of 555 Timers IC 38

Tab.6 Pin Description of RF Transmitter 40

Tab.7 Pin Description of RF Receiver 40

Tab.8 Pin Description Of LCD Display 42

VI

ARMbedded Electronics Pvt. Ltd.

JIT/DOEC/2014-15/PTS/1

CHAPTER 1

COMPANY PROFILE

1.1 Introduction

Fig.1.1 Company Banner

ARMbedded Electronics Pvt.Ltd. is an embedded design house. It provides out-of-the-

box solution from concept to reality. It is registered under company act. 1956 and ISO

9001:2008 Certified Company.The Company is one of the innovations, dedication and

diversification in the field of Embedded, Advanced Embedded System Design,

Embedded Wireless VLSI, and MATLAB

1.2 Training & Skill Development

Training is imparted in all the four domains. Training is such that it equips an

engineer/student to use the practical knowledge gained here, fully in the field. We also

undertake training for corporate in all the respective domains. Company has a team of

professional service engineers equipped with latest communication system for aneffective

after sales service. Periodical checks are also carried out as preventive maintenance.

Company has state-of-the-art computerized design facilities and a team of design

engineers to develop any equipment as per the customer’s need.



1.3 Product

ARMbedded Electronics Pvt.Ltd. is Manufacture and Deliver Technical Goods as per

customer Requirements and Needs. We develop industrial products and protoboards in

the respective domains, which are used in educational institutes. These protoboards are so

designed that a student working on it develops a complete knowledge from firmware

development to interfacing to various active and passive components.

Fig.1.2 8051 Microcontroller Applications Kit

1.4 Organizational Structure

ARM bedded Electronics Pvt. Ltd., channelizes the formidable global project expertise of

embedded projects, tailored to match industry needs. ARM bedded Electronics Pvt. Ltd

offers job ready training programs for the beginners & skill enhancement program for those

who are already employed in industry. Sample practicing on Real Time Projects makes

participants productive in their jobs. At ARM bedded Electronics Pvt. Ltd we create Global

Professionals.

ARMbedded Electronics Pvt. Ltd.Jaipur employs highly qualified professionals with PhD’s,

M.Tech. &, B.Tech.'s,. We havewell disciplinary team comprising education experts,

subject matter experts, instructional designers, quality experts, Academic advisors,

experienced placement officers, project Managers & team leaders.



Fig.1.3 Recognition of ARMbedded Electronics Pvt. Ltd, Jaipur

1.5 Objective

Gain appropriate knowledge of latest technologies.

Ability to understand embedded technology and evaluates the required projects

and components.

Develop a road map/career plan/strategy for campus placement.

Understanding and support for overall development to address these challenges.

And much more…..

1.6 Highlights

Biggest center in Jaipur in terms of area.

Recipient of best embedded training centre by brand academy.

Experienced and globally certified faculties.

Well equipped class room & labs.



CHAPTER 2

EMBEDDED SYSTEM

2.1 Introduction

Fig.2.1 Embedded System Applications

An Embedded System is one that has computer hardware with software embedded in it as

one of its important components.

An Embedded system is any electronic device that incorporates a computer in its

implementation. The user of an embedded device is often not even aware that a computer

is present in the device. The computer is used primarily to provide flexibility and to

simplify the system design. Unlike PC, program code is usually stored in ROM and not a

hard disk drive. Typically, the end user does not develop new software for the embedded



device. With advances in VLSI technology, embedded systems have become so

inexpensive that they are found in most of today's electronic devices.

Fig.2.2 Function Diagram of Embedded System

2.2 Scope

Aircraft & Military Systems

Aircraft autopilots, avionics and

navigation systems, automatic landing

systems, guidance systems, engine

controls.

Biomedical Systems

CT scan and Ultrasound imaging systems,

patient monitors, heart pacers.

Cars

Engine control, anti-lock braking systems,

traction control systems, air bag controls,

heating and air conditioning controls, GPS

mapping, Satellite Radio, On-board



Diagnostics.

Communications

Communication Satellites, network routers,

switches, hubs.

Consumer Electronic TVs, ovens, dishwashers, DVD players,

stereos, security systems, lawn sprinkler

controls, thermostats, cameras, clock

radios, answering machines, set top boxes,

other appliances.

Computer Input Keyboards, mice, printers, scanners, displays,

modems, hard

Output Devices disk drives, DVD drives, graphics cards, USB devices

Electronic

Instrumentation

Data acquisition systems, oscilloscopes,

voltmeters, signal generators, logic analyzers.

Industrial Devices

Elevator controls, surveillance systems,

robots, CNC machines, Programmable

Logic Controllers, industrial automation

and control systems.

Office Machines

FAX machines, copiers, telephones,

calculators, cashregisters.

Personal Devices

Cell phones, portable MP3 players, Video

players, Personal

Digital Assistants (PDAs), electronic

wrist watches,

Robots

Industrial robots, autonomous vehicles,

space exploration robots (i.e. Mars robots)

Tab.1 Embedded System Scope



Fig.2.3 Real-Life Examples of Embedded System

2.3 Components

2.3.1 Hardware Components:-Processor, Timers, Interrupt controller, I/O Devices,

Memories, Ports, etc.

2.3.2 Software Components: -It has main Application Softwarewhich may perform

concurrently the series of tasks or multiple tasks.

2.3.3 Real Time Operating System:-RTOS defines the way the system work. Which

supervise the application software? It sets the rules during the execution of the application

program. A small scale embedded system may not need an RTOS.



Fig.2.4 Hardware Component of Embedded System

2.4 Classification of Embedded System

2.4.1 Small Scale Embedded System

Fig.2.5 Small Scale Level IC

Single 8 bit or 16bit Microcontroller.

Little hardware and software complexity.

They May even be battery operated.

Usually “C” is used for developing this system.

The need to limit power dissipation when system is running continuously.



Programming tools: Editor, Assembler and Cross Assembler.

2.4.2 Medium Scale Embedded system

Fig.2.6 Medium Scale Level IC

Single or few 16 or 32 bit microcontrollers or Digital Signal Processors (DSP) or

Reduced Instructions Set Computers (RISC).

Both hardware and software complexity.

Programming tools: RTOS, Source code Engineering Tool & Simulator.

2.4.3 Sophisticated Embedded System

Fig.2.7 Sophisticated Level IC

Enormous hardware and software complexity.

Which may need scalable processor or configurable processor and programming logic

arrays?

Constrained by the processing speed available in their hardware units.

Programming Tools: For these systems may not be readily available at a reasonable cost



or may not be available at all. A compiler or retarget able compiler might have to be

developed for this.

2.5 The Embedded Environment

Microcontrollers used in development projects have very limited resources. We are working

close to our target machine and we must be familiar with our target hardware construction

and operation. A good quality C development environment incorporates tools which allow

us to concentrate primarily on our applications and not on the hardware which runs them.

However, we cannot ignore low-level details of our target hardware. The better we

understand our run-time environment, the better we can take advantage of its limited

capabilities and resources.

There are many aspects of embedded systems development which must be considered.

These are as follows:-

2.5.1 Reliability

Embedded systems must be reliable. Personal computer programs such as word processors

and games do not need to achieve the same standard of reliability that a microcontroller

application must. Errors in programs such as word processors may result in errors in a

document or loss of data. An error in a microcontroller application such as a television

remote control or compact disc player will result in a product that does not work and

consequently does not sell. An error in a microcontroller application such as an antilock

braking system or autopilot could be fatal.

2.5.2 Efficiency

Issues of efficiency must be considered in real time applications. A real time application is

one in which must be able to act at a speed corresponding with the occurrence of an actual

process. Many embedded systems must compete in a consumer market and cost is an

important issue in project development.



CHAPTER 3

MICROCONTROLLER

3.1 Introduction

3.1.1 Microcontroller

Fig.3.1 Block Diagram of Microcontroller

A microcontroller is a single-chip computer. Micro suggests that the device is small, and

controller suggests that it is used in control applications. Another term for microcontroller is

embedded controller, since most of the microcontrollers are built into (or embedded in) the

devices they control. All microcontrollers operate on a set of instructions (or the user

program) stored in their memory. A microcontroller fetches the instructions from its

program memory one by one, decodes these instructions, and then carries out the required

operations. Microcontrollers have traditionally been programmed using the assembly

language of the target device. Although the assembly language is fast, it has several

disadvantages. An assembly program consists of mnemonics, which makes learning and

maintaining a program written using the assembly language difficult. Also, microcontrollers

manufactured by different firms have different assembly languages, so the user must learn a



new language with every new microcontroller he or she uses.

Examples- INTEL

8031, 8032, 8051,8052,8751,8752

PIC

8-bit PIC16, PIC18,

16-bit DSPIC33 / PIC24,

PIC16C7x

Motorola

MC68HC11

3.1.2 Microprocessor

Fig.3.2 Block Diagram Of Microprocessor

A microprocessor differs from a microcontroller in a number of ways. The main distinction

is that a microprocessor requires several other components for its operation, such as

program memory and data memory, input-output devices, and an external clock circuit. A

microcontroller, on the other hand, has all the support chips incorporated inside its single

chip.



Examples-

Intel

4004, 4040

8080, 8085

8086, 8088,

80186, 80188

80286, 80386

X86-64

Motorola

6800

6809

68000

G3, G4, G5

Zilog

Z80, Z180, eZ80

Z8, eZ8

3.2Microprocessor V/s Microcontroller

Microprocessor Microcontroller

The functional blocks are ALU, registers,

timing & control units.

It is more faster as compare to

microcontroller

It includes functional blocks of

microprocessors & in addition has timer,

parallel i/o, RAM, EPROM, ADC &DAC.

Rapid movements of code and data

between external memory & MP.

Many type of bit handling instruction.

It is used for designing general purpose

digital computers system.

They are used for designing application

specific dedicated systems.



A microprocessor is a single chip semi

conductor device also which is a computer

on chip, but not a complete computer.

A microcontroller is a functional computer

system-on-a-chip. It contains a processor,

memory, and programmable input/output

peripherals.

Its CPU contains an ALU, a program

counter, a stack pointer, some working

register, a clock timing circuit and

interrupts circuit on a single chip.

Microcontrollers include an integrated

CPU, memory (a small amount of RAM,

program memory, or both) and peripherals

capable of input and output.

Tab.2 Microcontroller v/s Microprocessor

3.3 Types of Microcontroller


It is Intel's product. Neither a microprocessor nor a microcontroller.

It is a 8-bit controller. Internally no ROM is provided.


It is a first complete 8-bit microcontroller.

It is a name of a family in which the instruction set, pin configuration, architecture

are same, only memory storage capacity is different.

Internally PROM (programmable read only memory) is provided so it called one

time programmable (OTP).

3.3.3 Microcontroller AT89C51



It is ATMEL's product. It is a similar to 8051 microcontroller i.e., having same

instruction set, pin configuration, architecture

It is a also 8-bit microcontroller. Its cost is only Rs10 more than 8051.

It uses EPROM or FLASH memory.

It is multiple time programmable (MTP) i.e., 1000 times.

In "AT89C51", C‟ stands for CMOS technology used in themanufacturing of the

I.C.

64KB Program Memory address space

4K bytes of on-chip Program Memory

128 bytes of on-chip Data RAM

Fig.3.3 Pin diagram & architecture of AT89C51

3.4 Pin Description of AT89C51

VCC

Supply Voltage

GND

Ground



Port 0

Port 0 is an 8-bit open drain bidirectional I/O port. As an output port each pin can sink

eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high

impedance inputs. Port 0 may also be configured to be the multiplexed low order

address/data bus during accesses to external program and data memory. In this mode P0

has internal pull ups. Port 0 also receives the code bytes during Flash programming, and

outputs the code bytes during program verification. External pull ups are required during

program verification.

Port 1

Port 1 is an 8-bit bidirectional I/O port with internal pull ups. The Port 1 output buffers can

sink/source four TTL inputs. When 1s are written to Port 1 pins they are pulled high by the

internal pull ups and can be used as inputs. As inputs, Port 1 pins that are externally being

pulled low will source current (IIL) because of the internal pull ups. Port 1 also receives the

low-order address bytes low-order address bytes during Flash programming and

verification.

Port 2




pulled low will source current (IIL) because of the internal pull ups. Port 2 emits the high-

order address byte during fetches from external program memory and during accesses to

external data memory that uses 16-bit addresses (MOVX @DPTR). In this application it

uses strong internal pull ups when emitting 1s.

Port 3






pulled low will source current (IIL) because of the pull ups. Port 3 also serves the functions

of various special features of the AT89C51 as listed below.

Port Pin Alternate Functions

P3.0 RXD (serial input port)

P3.1 TXD (serial output port)

P3.2 INT0 (external interrupt 0)

P3.3 INT1 (external interrupt 1)

P3.4 T0 (timer 0 external input)

P3.5 T1 (timer 1 external input)

P3.6 WR (external data memorywrite)

P3.7 RD (external data memory read)

RST

Reset input. A high on this pin for two machine cycles while the oscillator is running resets

the device.

ALE/PROG

Address Latch Enable output pulse for latching the low byte of the address during accesses

to external memory. This pin is also the program pulse input (PROG) during Flash

programming. In normal operation ALE is emitted at a constant rate of 1/6 the oscillator

frequency, and may be used for external timing or clocking purposes. Note, however, that

one ALE pulse is skipped during each access to external Data Memory. If desired, ALE

operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is

active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled

high. Setting the ALE-disable bit has no effect if the microcontroller is in external

execution mode.

PSEN

Program Store Enable is the read strobe to external programmemory. When the AT89C51



is executing code from external program memory, PSEN is activated twice each machine

cycle, except that two PSEN activations are skipped during each access to external data

memory.

EA/VPP

External Access Enable. EA must be strapped to GND in order to enable the device to fetch

code from external program memory locations starting at 0000H up to FFFFH. Note,

however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA

should be strapped to VCC for internal program executions. This pin also receives the 12-

volt programming enable voltage (VPP) during Flash programming, for parts that require

12-volt VPP.

XTAL1

Input to the inverting oscillator amplifier and input to the internal clock operating circuit.

XTAL2

Output from the inverting oscillator amplifier.

3.5 Memory space Allocation in AT89C51

The AT89C51 has three very general types of memory. To effectively program the 8051 it

is necessary to have a basic understanding of these memory types. The memory types are

illustrated in the following graphic. They are: On-Chip Memory, External Code Memory,

and External RAM.

3.5.1 on chip ROM

The AT89C51 has 4K bytes of on-chip ROM. This 4K bytes ROM memory has memory

addresses of 0000 to 0FFFh. Program addresses higher than 0FFFh, which exceed the

internal ROM capacity, will cause the microcontroller to automatically fetch code bytes

from external memory. Code bytes can also be fetched exclusively from an external

memory, addresses 0000h to FFFFh, by connecting the external access pin to ground. The



program counter doesn't care where the code is: the circuit designer decides whether the

code is found totally in internal ROM, totally in external ROM or in a combination of

internal and external ROM.

3.5.2 on chip RAM

The 1289 bytes of RAM inside the 8051 are assigned addresses 00 to 7Fh. These 128

bytes can be divided into three different groups as follows: A total of 32 bytes from

locations 00 to 1Fh are set aside for register banks and the stack. A total of 16 bytes from

locations 20h to 2Fh are set aside for bit addressable read/write memory and instructions.

A total of 80 bytes from locations 30h to 7Fh are used for read and write storage, or what

is normally called a scratch pad.

Fig.3.4 ROM & RAM Memory in 8051 Microcontroller

3.5.3 External Code Memory

External Code Memory is code (or program) memory that resides off-chip. This is often in

the form of an external EPROM.

3.5.4 External RAM

External RAM is RAM memory that resides off-chip. This is often in the form of standard

static RAM or flash refers to any memory (Code, RAM, or other) that physically exists on

the microcontroller itself. On- chip memory can be of several types, but we'll get into that

shortly. External RAM As an obvious opposite of Internal RAM, the 8051 also supports



what is called External RAM. As the name suggests, External RAM is any random access

memory which is found off-chip. Since the memory is off-chip it is not as flexible in terms

of accessing, and is also slower. For example, to increment an Internal RAM location by 1

requires only 1instruction and 1 instruction cycle. To increment 1-byte value stored in

External RAM requires 4 instructions and 7 instruction cycles. In this case, external

memory is 7 times slower.

3.5.5 Code Memory

Code memory is the memory that holds the actual 8051 program that is to be run. This

memory is limited to 64K and comes in many shapes and sizes: Code memory may be

found on-chip, either burned into the microcontroller as ROM or EPROM. Code may also

be stored completely off-chip in an external ROM or, more commonly, an external

EPROM. Flash RAM is also another popular method of storing a program. Various

combinations of these memory types may also be used--that is to say, it is possible to have

4K of code memory on-chip and 64k of code memory off-chip in an EPROM.

3.5.6 Registers

Fig.3.5 Some 8-bit & 16-bit Registers

In the CPU, registers are used to store information temporarily. That information could be

a byte of data to be processed, or an address pointing to the data to be fetched. In the 8051



there is only one data type: 8 bits. With an 8- bit data type, any data larger than 8 bits has

to be broken into 8-bit chunks before it is processed. The most commonly used registers of

the 8051 are A (accumulator), B, R0, R1, R2, R3, R4, R5, R6, R7, DPTR (data pointer)

and PC (program counter). All the above registers are 8-bit registers except DPTR and the

program counter. The accumulator A is used for all arithmetic and logic instructions.

3.5.7 Program Counter & Data Pointer

The program counter is a 16- bit register and it points to the address of the next instruction

to be executed. As the CPU fetches op-code from the program ROM, the program counter

is incremented to point to the next instruction. Since the PC is 16 bit wide, it can access

program addresses 0000 to FFFFH, a total of 64K bytes of code. However, not all the

members of the 8051 have the entire 64K bytes of on-chip ROM installed.The DPTR

register is made up of two 8-bit registers, DPH and DPL, which are used to furnish memory

addresses for internal and external data access. The DPTR is under the control of program

instructions and can be specified by its name, DPTR. DPTR does not have a single internal

address; DPH and DPL are assigned an address each.

3.5.8 Flag Bits & PSW Registers

Like any other microprocessor, the 8051 have a flag register to indicate arithmetic

conditions such as the carry bit. The flag register in the 8051 is called the program status

word (PSW) register. The program status word (PSW) register is an 8-bit register. It is also

referred as the flag register. Although the PSW register is 8-bit wide, only 6 bits of it are

used by the microcontroller. The two unused bits are user definable flags. Four of the flags

are conditional flags, meaning they indicate some conditions that resulted after an

instruction was executed. These four are CY (carry), AC (auxiliary carry), P (parity), and

OV (overflow). The bits of the PSW register are shown below: CY PSW.7 Carry flag AC

PSW.6 Auxiliary carry flag -- PSW.5 Available to the user for general purpose RS1 PSW.6

Register bank selector bit 1 RS0 PSW.3 Register bank selector bit 0 OV PSW.2 Overflow

flag F0 PSW.1 User definable bit P PSW.0 Parity flag



CY, the carry flag

This flag is set whenever there is a carry out from the d7 bit. This flag bit is affected after

an 8-bit addition or subtraction. It can also be set to 1 or 0 directly by an instruction such as

"SETB C" and "CLR C" where "SETB C" stands for set bit carry and "CLR C" for clear

carry.

AC, the auxiliary flag

If there is carry from D3 to D4 during an ADD or SUB operation, this bit is set: otherwise

cleared. This flag is used by instructions that perform BCD arithmetic.

P, the parity flag

The parity flag reflects the number of 1s in the accumulator register only. If the register A

contains an odd number of 1s, then P=1. Therefore, P=0 if Ahas an even number of 1s.

OV, the overflow flag

This flag is set whenever the result of a signed number operation is too large, causing the

high order bit to overflow into the sign bit. In general the carry flags are used to detect

errors in unsigned arithmetic operations.

3.6 Memory Addressing in AT89C51

Each microcontroller has a specific addressing range. An addressing range is the number

of addresses a microcontroller can access. The addressing scheme used to access to these

spaces varies from processor to processor, but the underlying hardware is similar.

3.6.1 RAM

Random access memory or RAM consists of memory addresses. The CPU can both read

from and write to RAM is used for data memory and allows the CPU to create and modify

data as it executes the application program. RAM is volatile; it holds its contents only as

long as it has a constant power supply. If power to the chip is turned off, the contents of

RAM are lost. This does not mean that RAM contents are lost during a chip reset. Vital

state information or other data can be recorded in data memory and recovered after an



interrupt or reset. Some chips provide an alternate RAM power supply so that memory

contents can be maintained even when the rest of the chip is without power. This does not

make RAM any less volatile, without a backup power source the contents would still be

lost. This type of RAM is called battery backed-up static RAM.

3.6.2 ROM

ROM, read only memory, is typically used for program instructions. The ROM in a

microcontroller usually holds the final application program. Mask able ROM is memory

space that must be burned in by the manufacturer of the chip as it is constructed. To do

this, we must provide the chip builder with the ROM contents we wish the chip to have.

The manufacturer will then mask out appropriate ROM blocks and hardware the

information you have provided. Since recording chip ROM contents is part of the

manufacturing process, it is a costly one-time expense. If we intend to use a small number

of parts, we may be better off using chips with PROM. If we intend to use a large number

of parts for our application, then the one-time expense of placing our program in ROM is

more feasible.

3.6.3 PROM

Programmable ROM, or PROM, started as an expensive means to prototype and test

application code before burning ROM. In recent years PROM has gained popularity to the

point where many developers consider it a superior alternative to burning ROM. As

microcontroller applications become more specialized and complex, needs for

maintenance and support rise. Many developers use PROM devices to provide software

updates to customers without the cost of sending out new hardware. There are many

programmable ROM technologies available which all provide a similar service. A special

technique isused to erase the contents of programmable ROM then a special method is

used to program new instructions into the ROM. Often, the developer uses separate

hardware to perform each of these steps.



3.6.4 EPROM

EPROM (erasable programmable ROM) is not volatile and is read only. Chips with

EPROM have a quartz window on the chip. Direct exposure to ultra-violet radiation will

erase the EPROM contents. EPROM devices typically ship with a shutter to cover the

quartz window and prevent ambient UV from affecting the memory. Often the shutter is a

sticker placed on the window. Developers use an EPROM eraser to erase memory contents

efficiently. The eraser bombards the memory with high-intensity UV light. To reprogram

the chip, an EPROM programmer is used, a device which writes instructions into EPROM.

The default, blank state for an EPROM device has each block of memory set. When we

erase an EPROM we are really setting all memory blocks to 1. Reprogramming the device

resets or clears the appropriate EPROM bits to 0. Because of the way EPROM storage is

erased, we can't selectively delete portions of EPROM - when we erase the memory we

must clear the entire storage space.

3.6.5 EEPROM

EEPROM (electrically erasable programmable ROM) devices have a significant advantage

over EPROM devices as they allow selective erasing of memory sections. EEPROM

devices use high voltage to erase and re-program each memory block. Some devices

require an external power source to provide the voltage necessary for erasing and writing

and some have an onboard pump which the chip can use to build up a charge of the

required voltage. Developers can reprogram EEPROM devices while the chip is operating.

However, EEPROM that can be rewritten is usually restricted to data memory storage.

EEPROM storage used as program memory typically requires the use of an external power

source and a programmer just like EPROM storage. The most common use for EEPROM is

recording and maintaining configuration data vital to the application. For example, many

modems use EEPROM storage to record the current configuration settings. This makes the

configuration available to the modem user after cycling the power on the modem. Often the

default or factory configuration settings are stored in ROM and the user can issue a

command to restore default settings by overwriting the current contents of EEPROM with

the default information. Sometimes chip manufacturers build EEPROM blocks into the



chip for last-minute configuration options. This saves manufacturers money as they can

design and fabricate a single chip and then set the EEPROM blocks to provide special

purpose versions with specific capabilities. This method is often used to produce

microcontroller versions for use on an evaluation board where chip access to its own

onboard ROM is turned off and replaced with external EPROM or EEPROM storage. This

allows developers to test application code in cycles by downloading it to the board,

programming the code into the EPROM or EEPROM, and debugging it as it executes in

the target hardware.

3.6.6 Flash Memory

Flash memory is an economical compromise between EEPROM and EPROM technology.

As with EEPROM high voltage is applied to erase and rewrite flash memory. However,

unlike EEPROM, you cannot selectively erase portions of flash memory - you must erase

the entire block as with EPROM devices. Many manufacturers are turning to flash

memory. It has the advantages of not requiring special hardware and being inexpensive

enough to use in quantity. Manufacturers often provide customers with microcontroller

products whose ROM is loaded with a boot or configuration kernel where the application

code is written into flash memory. When the manufacturer wants to provide the customer

with added functionality or a maintenance update, the hardware can be reprogrammed on

site without installing new physical parts. The hardware is placed into configuration mode

which hands control to the kernel written in ROM. This kernel then handles the software

steps needed to erase and re-write the contents of the flash memory. Another useful

implementation of flash memory includes a device which can connect electronically to a

computer owned by the manufacturer. The configuration kernel connects to the

manufacturer's computer, downloads the latest version of the control application and writes

this application to flash memory. Such elaborate applications are typically beyond the

resources of an 8 bit microcontroller; we mention the example to show the advantage of

programmable ROM technologies.



3.6.7 Registers

The CPU maintains a set of registers which it uses to store information. Registers are used

to control program execution and maintain intermediate values needed to perform required

calculations. Some microcontrollers provide access to CPU registers for temporary storage

purposes. This can be extremely dangerous as the CPU can at any time overwrite a register

being used for its designated purpose. 8 bit microcontrollers do not often provide resources

for register memory outside the CPU. This means that the C register keyword is

meaningless because the compiler cannot dedicate a CPU register for data storage. Some C

implementations will set aside RAM for special purpose pseudo-registers to use when your

application attempts certain operations. For example, if you attempt a 16 bit math

operation, the compiler can dedicate a portion of base page RAM for 16 bit pseudo-

registers which store values during math operations.

3.7 Fabrication Techniques of AT89C51

3.7.1 CMOS Technology

Complementary Metal Oxide Semiconductor (CMOS) is a technique commonly used to

fabricate microcontrollers. CMOS requires less power and CMOS chips can be static which

allows the implementation of a sleep mode. CMOS microcontrollers must have all inputs

connected to something.

3.7.2 PMP Technology

Post Metal Programming (PMP) allows ROM to be programmed after final metallization.

This allows ROM to be programmed very late in the productions cycle.



CHAPTER 4

ELECTRONICS COMPONENTS

4.1 Introduction

Electronic Components are the major building blocks of all electronic circuits which make up

complete & desirable circuits. Without this we cannot think about electronic circuits design

&development. it is also responsible for size & cost of electronics devices &circuits. There

are some basic electronics components which are very important for about all the electronics

circuits which are as follows:-

4.1.1 Resistor

Resistors restrict the flow of electric current, for example a resistor is placed in series with a

light emitting diode(LED) to limit the current passing through the LED.

Fig.4.1 Resistor Color coding



4.1.2 Capacitor

As the name suggests tend to store electricity like a minibattery.measured in

faradays(F).0.00000F=0.000000001=1pf.also need to note rated voltages.

Fig.4.2Charging, Charged& Discharging Of Capacitor

4.1.3 Inductor

Inductor is used to produce a magnetic field when a certain current is passed through a

coil of wire. The wire is coiled on a soft iron core. Have applications in motors, and tank

circuits. Abbreviated as ‘L’.

Fig.4.3 Inductor & its Circuit Symbool

4.1.4 Diode

A diode is used to allow electric current to flow in only one direction. Abbreviated as

‘D’.

Fig.4.4 Diode & its Circuit symbol

http://www.circuitstoday.com/wp-content/uploads/2011/11/Inductor-Circuit-Symbol.jpg



4.1.5 Transistor

It is three terminal semiconductor device developed to switching and amplifying the

electronics circuits. it comes in a large number of different varieties, shapes& sizes.

Fig.4.5 Transistor & its circuit symbol

4.1.6 Potentiometer

It is variable resistors have a resistance that varies according to themechanical position of

one of its wiper.

Fig.4.6 Potentiometer & its circuit symbol

4.1.7 Switches & Push Button

It is used to Connect and disconnect circuits.

Fig.4.7 Switches & its circuit symbol



4.1.8 Solenoid

In solenoid if current is passed through the coil a magnetic field is created. it is used to

release latches, lock parts in place, etc.

Fig.4.8 Solenoid & its circuit symbol

4.1.9 Motor:-

A Family of components that uses sequence electricity and magnetism to make

movement. Voltage, Current, Torque & RPM often specified.

Fig.4.9 Motor & its circuit symbol

4.1.10 Relay

It is a electromechanical switches. on applying a current to the coil the connected

switches are connected and disconnected. Cars use relays to switch 12V, 500A!Silicon

relays also available with no movingparts.

Fig.4.10 Relays & its circuit symbol



4.1.11 Buzzer

It is used to produce an output sound corresponding to the electrical energy in the input.

Fig.4.11 Buzzer Circuit Symbool

4.1.12 Light Emitting Diode (LED)

Led is used to emit light when a current is passed through the device. It is abbreviated as

Led.

Fig.4.12Various Types Of LED’s

Fig.4.13 Infrared Detector

http://www.circuitstoday.com/wp-content/uploads/2011/11/Buzzer-Circuit-Symbol.jpg



4.1.13 Photo resistor

It is Light sensitive variable resistors. Its resistance depends on the intensity of light

incident upon it. Under dark condition, resistance is quite high. and Under bright

condition, resistance is lowered.

Fig.4.14 Photo resistor& its symbol

4.1.14 Photodiode

• Photodiode is a 2 lead semiconductor device that transforms light energy to electric

current.

• Suppose anode and cathode of a photodiode are wired to a current meter.

-When photodiode is placed in dark, the current meter displays zero current flow.

– When the photodiode is expose to light, it acts a a current source, causing current flow

from cathode to anode of photodiode through the current meter.

• Photodiodes have very linear light v/s current characteristics.

– Commonly used as light meters in cameras.

Fig.4.15 Photodiode & its symbol



4.1.15 Phototransistor

• Phototransistor is a light sensitive transistor.

• In one common type of phototransistor, the base lead of a BJT is replaced by a

lightsensitive surface.

• When the light sensitive surface @ the base is kept in darkness, the collector-emitterpair

of the BJT does not conduct.

• When the light sensitive surface @ the base is exposed to light, a small amount ofcurrent

flows from the base to the emitter. The small base-emitter current controlsthe larger

collector-emitter current.

• Alternatively, one can also use a field-effect phototransistor (Photo FET).

• In a photo FET, the light exposure generates a gate voltage which controls adrain source

current.

Fig.4.16 Phototransistor & its Symbool

4.1.16 7-Segement Led Display

• Used for displaying numbers and other characters.

• 7 individual LEDs are used to make up the display.

• When a voltage is applied across one of the LEDs, a portion of the 8 lights up.

• Unlike liquid crystal displays (LCD), 7-segment LED displays tend to be

morerugged, but they also consume more power.



Fig.4.17 7-segement led display & its Pin out Diagram

4.1.17 Transformer

It is used as an ac power supply. Consists of two coils, the primary and secondary that are

linked together through an iron core. There is no physical connection between the two

coils. The principle of mutual inductance is used to obtain power. Abbreviated as ‘T’.

Fig.4.18 Transformer & its Circuit Symbool

4.1.18 IC 7805 Voltage Regulator IC

7805 is a voltage regulator integrated circuit. It is a member of 78xx series of fixed linear

voltage regulator ICs. The voltage source in a circuit may have fluctuations and would not

give the fixed voltage output. The voltage regulator IC maintains the output voltage at a

constant value. The xx in 78xx indicates the fixed output voltage it is designed to provide.

7805 provides +5V regulated power supply. Capacitors of suitable values can be connected

at input and output pins depending upon the respective voltage levels.

http://www.circuitstoday.com/wp-content/uploads/2011/11/Transformer-Circuit-Symbol.jpg



Fig.4.19 LM7805 IC & its Pin out Diagram

Pin Description

Tab.3 Pin Description of 7805 IC

4.1.19 LM324 IC

LM324 is a 14pin IC consisting of four independent operational amplifiers (op-amps)

compensated in a single package. Op-amps are high gain electronic voltage amplifier with

differential input and, usually, a single-ended output. The output voltage is many times

higher than the voltage difference between input terminals of an op-amp. These op-amps

are operated by a single power supply LM324 and need for a dual supply is eliminated.

They can be used as amplifiers, comparators, oscillators, rectifiers etc. The conventional op-

Pin No Function Name

1 Input

voltage

(5v-18v)

input

2 Ground

(0v)

ground

3 Regulated

Output(4.

8v-5.2v)

output



amp applications can be more easily implemented with LM324.

Fig.4.20 LM324 IC& Its Pin out Diagram

Pin description


1 Output of 1st t

comparator

Output1

2 Inverting input of

1st comparator

Input1-

3 No inverting input

of 1st comparator

Input1+

4 Supply voltage 5v

(up to 32v)

vcc


of 2nd

comparator

Input2+


2nd

comparator

Input2-

7 Output of 2nd

comparator

Output2

8 Output of 3rd

Output3



comparator


3rd

comparator

Input3-


of 3rd

comparator

Input3+

11 Ground (0v) Ground


of 4th

comparator

Input4+


4th

comparator

Input4-

14 Output of 4th

comparator

Output4

Tab.4 Pin Description Of LM 324 IC

4.1.20 555 Timers IC

555 is a very commonly used IC for generating accurate timing pulses. It is an 8pin timer IC

and has mainly two modes of operation: monostable and a stable. In monostable mode time

delay of the pulses can be precisely controlled by an external resistor and a capacitor

whereas in a stable mode the frequency & duty cycle are controlled by two external resistors

and a capacitor. 555 is very commonly used for generating time delays and pulses.

Fig.4.21 555Timer IC & Its Pin out Diagram



Pin Description


1 Ground

(0V)

Ground

2 Voltage below 1/3 Vcc

to trigger the pulse

Trigger

3 pulsating

output

output

4 Active low; interrupts the

timing interval at Output

Reset

5 Provides access to the

internal voltage divider;

default 2/3 Vcc

Control voltage

6 The pulse ends when the

voltage is greater than

Control

Threshold

7 Open collector output; to

discharge the capacitor

Discharge

8 Supply voltage; 5V (4.5V -

16 V)

Vcc

Tab.5 Pin Description Of 555 Timer IC



4.1.21 RF Module

The RF module, as the name suggests, operates at Radio Frequency. The corresponding

frequency range varies between 30 kHz & 300 GHz. In this RF system, the digital data is

represented as variations in the amplitude of carrier wave. This kind of modulation is

known as Amplitude Shift Keying (ASK). Transmission through RF is better than IR

(infrared) because of many reasons. Firstly, signals through RF can travel through larger

distances making it suitable for long range applications. Also, while IR mostly operates

in line-of-sight mode, RF signals can travel even when there is an obstruction between

transmitter & receiver. Next, RF transmission is more strong and reliable than IR

transmission. RF communication uses a specific frequency unlike IR signals which are

affected by other IR emitting sources. This RF module comprises of an RF Transmitter

and an RF Receiver. The transmitter/receiver (Tx/Rx) pair operates at a frequency of 434

MHzan RF transmitter receives serial data and transmits it wirelessly through RF

through its antenna connected at pin4. The transmission occurs at the rate of 1Kbps -

10Kbps.The transmitted data is received by an RF receiver operating at the same

frequency as that of the transmitter. The RF module is often used along with a pair of

encoder/decoder. The encoder is used for encoding parallel data for transmission feed

while reception is decoded by a decoderHT12E-HT12D. HT640-HT648, etc. are some

commonly used encoder/decoder pair ICs.

Fig.4.22 RF Transmitter & Receiver circuit



Pin Description


1 Ground (0V) Ground

2 Serial data input pin Data

3 Supply voltage; 5V Vcc

4 Antenna output pin ANT

Tab.6 Pin Description of RF Transmitter



2 Serial data output pin Data

3 Linear output pin;

not connected

NC

4 Supply voltage; 5V VCC

5 Supply

voltage;

5V

VCC



8 Antenna

input

pin

ANT

Tab.7 Pin Description Of RF Receiver



4.1.22 LCD

LCD (Liquid Crystal Display) screen is an electronic display module and find a wide

range of applications. A 16x2 LCD display is very basic module and is very commonly

used in various devices and circuits. These modules are preferred over seven segments and

other multi segment LEDs. The reasons being: LCDs are economical; easily

programmable; have no limitation of displaying special & even custom characters (unlike

in seven segments), animations and so on. A 16x2 LCD means it can display 16 characters

per line and there are 2 such lines. In this LCD each character is displayed in 5x7 pixel

matrix. This LCD has two registers, namely, Command and Data. The command register

stores the command instructions given to the LCD. A command is an instruction given to

LCD to do a predefined task like initializing it, clearing its screen, setting the cursor

position, controlling display etc. The data register stores the data to be displayed on the

LCD. The data is the ASCII value of the character to be displayed on the LCD.

Fig.4.23 LCD & Its Pin out Diagram



Pin Description


1 Ground

(0V)

Ground

2

3

Supply voltage; 5V (4.7V -

5.3V)

Contrast adjustment; through a variable

resistor

VCC

Vcc

4 Selects command register when low; and data register

when high

Vee

5 Low to write to the register; High to read from the

register

Register Select

6 Sends data to data pins when a high to low pulse is

given

Read/Write

7 8-bit data pins

Enable

8 DB0

9 DB1

10 DB2

11 DB3

12 DB4

13 DB5

14 DB6

15 DB7

16 Backlight

VCC (5V) Led+

17 Backlight

Ground (0V) Led-

Tab.8Pin Description Of LCD Display



CHAPTER 5

“C’’PROGRAMMING

5.1 Introduction

“C” is a general purpose, high-level programming language developed by Kernighan and

Ritchie at& T Bell labs between 1969 and 1973.Several programmer preferred C to other

programming language of that time like PL/1,ALGOL,COBOL,FORTRAN,Pascal,and

APL.soon C become the most popular programming language because it is

reliable,simple,and easy to use. In Embedded system design It is very Important language

for programming of various microcontroller IC’s.The overall working & processing of

Embedded system is only depends upon the program run on its controller IC’s.

5.2 “C” Statement Type

.Simple Variable Assignment

include input/output data transfers

Arithmetic Operations

Logical/Shift Operations

Control Structure

- IF, WHEN, FOR, SELECT

- Function Calls

- User-defined and /or library functions

5.3 Basic Structure

#include<reg51.h>

Intcount, bob;

Intfunction1 (char x)

{

Int i, j;

}



Voidmain ()

{

5.4 Statements in “C”

5.4.1 Switch Statement

Compact alternative to ELSE-IF structure, formultiday decision that tests one

variable or expression for a number of constant values.

/* example equivalent to that on preceding slide */

Switch (n) { //n is the variable to be tested

Case 0: statement1; //do if n==0



Default: statement4; //if for any other n value

}

5.4.2 WHILE loop Structure

Repeat a set of statements (a “loop”) as long as some condition is met.

While (a<b)

{

Statement s1;

Statement s2;

…..

}

Example-

/* add two 200-element arrays.*/



Int M [200]; N [200]; P [200];

Int k;

/*method 1-using DO_WHILE */

K=0;

Do

{

M[k]=N[k]+P[k];

K=k+1;

}

While (k<200);

/* method 2-using WHILE loop*/

K=0;

While (k<200);

M[k]=N[k]+P[k];

K=k+1

}

5.4.3 DO-WHILE loop Structure

Repeat a set of statements (one “loop”) until some condition is met.

Do

Statement s1;

Statement s2;

…While (a<b);

Example-



#define MAX_ALLOWED 128

#define LIGHT_ON1

#define LIGHT_OFF0

Do

{

LIGHT_PORT=LIGHT_ON;

Delay ();

LIGHT_PORT=LIGHT_OFF;

Delay ();

}

While (AD_PORT<=MAX_ALLOWED);

5.4.4 FOR loop structure

Repeat a set of statements (one “loop”) while some condition is met.

For (m=0; m<200; m++)

{

Statement s1;

Statement s2;

}

Examples-

/* Nested FOR loops to create a time delay*/

For (i=0; i<100; i++)

{

For (j=0; j<1000; j++)



{

}}

5.5 Function

- Calling Program can pass information to a function in two ways

- -By value: pass a constant or a variable value

Function can use, but not modify the value

- -By reference: pass the address of the variable

Function can both read and update the variable

- -values/addresses are typically passed to the function by pushing them

onto the system stack.

Example (Pass by value)-

/* Function to calculate x2 */

Int square (int x)

{

Int y;

Y=x*x;

Return(x);

}

Void main ()

Int k,n;

N=5;

K=square (n);



N=square (5);

}

Example (pass by reference)-

/* Function to calculate x2 */

Int square (int x,int * y)

{

*y=x*x;

}

Void main ()

{

Int k, n;

N=5;

Square (n, &k);

Square (5, &n);

}

Int rcv_data [10];

Int rcv_count;

Void SCI_receive ()

{

While (SCISR1 & 0x20)==0)

{

}



5.6 Program

5.6.1 WAP to Perform Table of Two

#include<reg51.h>

Char arr [10]={0xbf,0x86,0xdb,0xcf,0xe6,0xed,0xfd,0x87,0xff,0xef};

Void delay ()

{

Int f;

For (f=0; f<500; f++);

}

Void main ()

{

Int a, b, c;

For (a=0; a<2; a++)

{

For (b=0; b<10; b=b+2)

{

For (c=0; c<50; c++)

{

P1=0x01;

P2=arr[b];

Delay();

P1=0x02;

P2=arr[a];

Delay();\



}}}

For (a=2;a<3;a++)

{

For (b=0;b<1;b++)

{

For (c=0;c<50;c++)

{

P1=0x01;

P2=arr[b];

Delay();

P1=0x02;

P2=arr[a];

Delay ();

}}}

5.6.2 WAP To ON & OFF Relay

#include<reg51.h>

Sbit relay1=p1^0;

Sbit relay2=p1^1;

Void delay ()

{

Int I;

For (i=0;i<=30000;i++);

}



Void main ()

{

While (1)

{

Relay1=1; //Relay1 ON

Relay2=1; //Relay2 ON

Delay ();

Relay1=0; //Relay1 is OFF

Relay2=0; //Relay2 is OFF

Delay ();

}}



CHAPTER 6

PROJECT OVERVIEW

6.1 Introduction

Project title is “Automatic Room Light Controller With Bidirectional Visitor

Counter”.The objective of this project is to make a controller based model to count

number of persons visiting particular room and accordingly light up the room. Here we

can use sensor and can know present number of persons in today’s world, there is a

continuous need for automatic appliances. With the increase in standard of living, there is

a sense of urgency for developing circuits that would ease the complexity of life. Also if

at all one wants to know the number of people present in room soaps not to have

congestion, this circuit proves to be helpful.

This project "automatic room light controller with visitor counter using microcontroller"

is a reliable circuit that takes over the task of persons/visitor in the room very accurately.

When somebody enters into the room will be switched ON and when any one. The light

in room will be only switched OFF until all the persons in the room go out. The total

number of person inside the room also displayed on the seven segment displays.

Fig .6.1 Circuit Description of BDVC

6.2 Circuit Components

5 Resistor of 330 ohms

2 Variable Resistor of 20K ohms



2 Variable Resistor of 50Kohms

2 Electrolytic Capacitor

4 Ceramic Capacitor 104

2 Ceramic Capacitor 33 pF

11.0592 MHz crystal Oscillator

AT89S52

7805

7812

3 LED

Reset Key

2 Relay

ULN2803 Relay Driver IC

LM324 IC

IR LED

IR Phototransistor

6.3 Circuit Block Diagram

Fig.6.2 Block Diagram of BDVC



6.4 Circuit Flow Chart

Fig.6.3 Flow Chart Of BDVC

6.5 Circuit Design

The heart of the circuit design lies in designing the microcontroller interface. Here we

use the microcontroller AT89S52.The microcontroller AT89S52 is interfaced to the IR

sensor pairs at two ports pins - P1.0 and P1.1 respectively. The 7 segment display is

interfaced to the microcontroller at port P2.Another important aspect of the design

involves designing the oscillator circuit and the reset circuit. The oscillator circuit is

designed by selecting a 11.0592MHz quartz crystal and two ceramic capacitors- each

33pF. The reset circuit is designed by selecting an electrolyte capacitor of 10uF to ensure

a reset pulse width of 100ms and reset pin voltage drop of 1.2V.The sensor circuit is

designed by selecting appropriate value of resistors for both the LED and the

phototransistor.



Fig.6.4 PCB Layout Of BDVC

6.6 Circuit Description

There are mainly two parts of the circuits:-

6.6.1 Transmitter Circuit (Infrared)

This circuit diagram shows a 555 timer IC, configured to function as a basic actable

multivibrator.The stable multivibratorgenerates square wave, the period of which is

determined by the circuit it external to IC 555. The stable multivibrator does not require

any external trigger to change the state of the output. Hence the name free running

oscillator. The time during which the output is either high or low is determined by the

two resistors or a capacitor which are externally connected to the 555 timer. In this

circuit, a negative pulse applied at pin 2 triggers an internal flip-flop that turns off pin 7's

discharge transistor, allowing C1 to charge up throughR1. At the same time, the flip-flop

brings the output (pin 3) level to 'high’. When capacitor C1 as charged up to about 2/3

Vcc, the flip-flop is triggered once again, this time making the pin 3 output 'low' and

turning on pin 7's discharge transistor, which discharges C1 to ground. This circuit, in

effect, produces a pulse at pin 3 whose width t is just the product of R1 and C1, i.e.,

t=R1C1.IR Transmission circuit is used to generate the modulated 36 kHz IR signal. The

IC555 in the transmitter side is to generate 36 kHz square wave. Adjust the preset in the



transmitter to get a 38 kHz signal at the o/p. Then you point it over the sensor and its o/p

will go low when it senses the IR signal of 38 kHz.

Fig.6.5 Transmitter Circuit of BDVC

6.6.2 Receiver Circuit (Sensors)

The IR transmitter will emit modulated 38 kHz IR signal and at the receiver we use

TSOP1738 (Infrared Sensor). The output goes high when there is an interruption and it

return back to low after the time period determined by the capacitor and resistor in the

circuit i.e. around 1 second. CL100 is to trigger theIC555 which is configured as

monostable multivibrator. Input is given to the Port 1of the microcontroller. Port 0 is

used for the 7-Segment display purpose. Port 2 is used for the Relay Turn On and Turn

off Purpose.LTS 542 (Common Anode) is used for 7- Segment display and that time



Relay will get voltage and triggered, so light will get voltage and it will turn on and

when counter will be 00 and at that time Relay will be turned off. Reset button will reset

the microcontroller.

Fig.6.6 Receiver Circuit Of BDVC

6.7 Operation

When the system is powered, the compiler initially initializes the stack pointer and all

other variables. It then scans the input ports (PortP1.0 first). In the meantime, when there

is no interruption between the IR LED and the phototransistor of the first sensor pair, the

output of the phototransistor is always at low voltage. In other words port P1.0 is at logic

low level. Now when a transition takes place, i.e. a logic high level is received at port

P1.0, the compiler sees this as an interruption to sense the passage of a person or an

object between the IR LED and the phototransistor. As per the program, the count value



is increased and this value is displayed on the Counter. Now the compiler starts scanning

the other input pin-P1.1. Similar to the first sensor pair, for this sensor pair also the

phototransistor conducts in absence of any interruption and P1.1 is at logic low level. In

case of an interruption, the pin P1.1 goes high and this interruption is perceived by

decreasing the value of count. The program ensures that the scanning of both the port

pins is done at certain delays so as to avoid confusion of reading. For instance port P1.0 is

scanned for two or three interruptions so as to ensure the count value is above 1 or 2.

6.8 Applications

This circuit can be used domestically to get an indication of number of persons

entering a party.

It can be used at official meetings.

It can be used at homes and other places to keep a check on the number of persons

entering a secured place.

It can also be used as home automation system to ensure energy saving by switching

on the loads and fans only when needed.

6.9 Limitations

It is a theoretical circuit and may require few changes in practical implementation.

It is a low range circuit and cannot be implemented at large areas.

With frequent change in the count value, after a certain time the output may look

confusing.

6.10 Project Program

#include<reg51.h>

Sbit IR=p1^0;

Void delay ()

{

Int I;

For (i=0;i<=30000;i++);

}



Void main()

{

While (!)

{

IR=0;

If (IR==1)

{

P0=0xff;

Delay ();

P0=0xoo;

Delay ();

}]

Int I;

Char arr [] = (‘’0xff…ffx0)

TMOD=0x20;

SCON=0x50;

TH1=0xfd;

TR1=1;

While (1)

{

For (i=0;i<21;i++)

{

SBUF=array[i];

While (T1==0);

T1=0;

}}}

Mov R1=0xff

Mov R2=ffx0

}}

END.



CHAPTER 7

CONCLUSION

7.1 Introduction

This part of the report describes the overall result and conclusion made during the training

period.

7.2 Lesson Learned

Basics Of Embedded System

Medium Level Circuit Designing

Faults Diagnosis in Circuits

PCB Designing &Embedded C Programming

Introduction Of Various Electronics Components

Key Learning

Enhancement in Technical knowledge

Work Experience With Professionals

Industrial Exposure

7.3 Knowledge Gained

The training at”ARmbedded Electronics Pvt. Ltd.”, Jaipur provided me an insight on

embedded system technology and recent trends in industry. This training also helped me

in my overall personality development by interaction with many trainees and the staff

members. It provided me Industrial Exposure, and the working experience with real life

professionals which will certainly help me in my career ahead.



7.4 Suitability of Organization

The organization is suitable for any product based on an embedded system. The whole

staff is very co- operative. This organization provides a healthy environment for trainees

that help them to develop a sense of professionalism in relation to job skills. ARM bedded

Electronics Pvt. Ltd., channelizes the formidable global project expertise of embedded

projects, tailored to match industry needs. ARM bedded Electronics Pvt. Ltd offers job

ready training programs for the beginners & skill enhancement program for those who are

already employed in industry. Sample practicing on Real Time Projects makes participants

productive in their jobs. At ARM bedded Electronics Pvt. Ltd we create Global

Professionals.ARMbedded Electronics Pvt. Ltd.Jaipur employs highly qualified

professionals with PhD’s, M.Tech. &, B.Tech.'s,. We havewell disciplinary team comprising

education experts, subject matter experts, instructional designers, quality experts,

Academic advisors, experienced placement officers, project Managers & team leaders.



CHAPTER 8

REFERENCE

Reference Books

1. Programming in ANSI C: E BALAGURUSAMY

2. The 8051 and embedded systems: MUHAMMAD ALI MAZIDI

3. Electronics Devices &Circuits: RAJEEV TIWARI

4. The 8051 microcontroller: KENNETH J. AYALA

Reference Websites

1. www.google.com

2. www.enclopedia.com

3. www.wikipedia.com

4. www.electronicsforyou.com

5. www.armbeddedindia.org

6. www.datasheets4u.com

http://www.google.com/

http://www.enclopedia.com/

http://www.wikipedia.com/

http://www.electronicsforyou.com/

http://www.armbeddedindia.org/

http://www.datasheets4u.com/







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