Embedded System Industrial Trainng Report

SIX MONTHS INDUSTRIAL TRAINING REPORTDUCAT,NOID

A

SIX MONTHS INDUSTRIAL TRAINING TRAINING REPORT

UNDERTAKEN AT

DUCAT, NOIDA

IN

EMBEDDED SYSTEM TECHNOLOGIES

ON

EMBEDDED HARDWARE & SOFTWARE

SUBMITTED IN PARTIAL FULFILLMENT OF THE DEGREE

OF

BACHELOR OF TECHNOLOGY

IN

ELECTRONICS AND COMMUNICATION ENGINEERING

Under the Guidance of: Submitted By: Name: Mr. Sonu Verma Name: Mr. Surinder SinghDesignation: Sr. Embedded Sys. Consultant College Roll No.: EC/06/6306Department: Embedded H/w(R&D) University Roll No.: 6170406213

INSTITUTE OF ENGINEERING AND TECHNOLOGY-BHADDALPO : MIANPUR, District: Ropar, Punjab

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1.EMBEDDED SYSTEMS

1.1 What are embedded systems?

• Embedded System is a system which takes some inputs and Process them based on some

s/w written on it and output the Corresponding results. It is a part of large system.

• It is a system that has computer hardware with software embedded in it as one of its most

important component.

Figure 1.1 Embedded system

• Embedded systems are computer systems that monitor, respond to, or control an external

environment.

• Environment connected to system through sensors, actuators and other I/O interfaces.

• Embedded systems must meet timing & other constraints imposed on it by environment .

• “Any sort of device which includes a programmable computer, but itself is not intended

to be a general-purpose computer” (Wayne Wolf)

• It does not need secondary memories as in computers.

• It has one single dedicated operation

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1.2 Embedded System Composition

Figure1. 2 Embedded System Composition

1.3 Classification of Embedded Systems

• It is classified in to 3 types:

1.3.1 Small scale (8 to16 Bit )

Little S/W and H/W complexity on board.

Battery operated,editor,compiler specific to processor,assembler are the basic tools.

Less s/w ,limiting power dessipation.

1.3.2 Medium Scale(16 to 32 bit)

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Contains RISC processors with h/w and s/w complexity.

Tools, debuggers, simulators, IDE in addition.

1.3.3 Sophesticated embedded systems(16 to 32 bit)

More s/w and h/w complexity that medium as it contains scalable processors, have

processing speed constraints.

1.4 Embedded Systems components

• The hardware for an embedded system can come in many styles and flavours. It can be as

complex as a Linux system with 64 megabytes of memory, a disc, specialty input/output

devices Internet or other communications capability.It can be as simple as a single

microprocessor with the requisite input/output devices integrated on the microprocessor

integrated circuit.

• Microprocessors (µP)

– The “engine” that processes instructions

– These instructions are stored in Read Only Memory (ROM)

– No real time capability.

• Busses (data, address, Input/Output)

• System clock - steps µP through each instruction

• Read Only Memory (ROM):

– Permanently loaded with instructions (firmware):Basic Input Output System

(BIOS) - primitive operating system that allows chips to interface with each other.

Also known as micro kernel. Application code (provides functionality)

• Random Access Memory (RAM)

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– Stores Data in Processing (eg: Temperature Readings)

– Shares data with external partners (eg: Sensors)

• Real Time Clock RTC

– Required for keeping long times and for operation with Real Time Operating

System (RTOS), which controls the coordinated Operations of multiple systems.

• Communication Circuitry

– Ethernet Port, Printer Port

– Communication Port (RS232C, RS422, IEEE488)

1.5 Von-Neumann architecture

Fig.1.3 Von-Neumann architecture

1.6 Harvard Architecture

Fig.1.4 Harvard Architecture

1.7 Examples of embedded systems

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Keyboard and other controllers for computers, CD players and consumer electronics, Timing

and control electronics in microwave ovens, coffee makers. Controllers for vacuum cleaners

and washing machines for sensing dirt loads. Control of the dashboard, ignition, fuel

injection, suspension stiffness and environmental temperature and noise in automobiles.

Parking meter controllers. Elevator, environmental and security systems in buildings,

Internal operation of medical instrumentation such as infusion pumps, pulse ox meters, Disc

controllers for computer systems, Control of data communications routers for wide-band

communications and many more. Ibo, the Robotic Dog of Sony Corp., incorporates Emotion-

Detecting Sensors, Voice Recognition System, a CCD Camera, and Distance Measurement

Sensor. It has 18 Joints that can generate different types of movements.LG Electronics has

introduced Refrigerators that can check E-Mail, Surf the Web, Watch TV, and make

Videophone Calls. Users have access to information like Real-Time Grocery Prices and

Stock Prices. Carrier and IBM are developing Air-conditioners that can be controlled over

the Internet.

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2.COMPONENTS OF A COMPUTER SYSTEM

Fig.2.1 Components of a computer system

2.1 Types of computer

• Microcomputers- desktop, laptop, notebook and palmtop personal computers (PCs)- used in businesses, schools/colleges and homes- cost from a few hundred pounds to a few thousand

• Minicomputers- often used as multi-user systems, with 100’s of workstations or terminals attached to central minicomputer, e.g. EPOS.- cost from £10,000 to about £150,000.

• Mainframe computers- used by large organisations which may have 1000’s of terminals, often remote- cost ££ hundreds of thousands

• Supercomputers- largest category of computer used mostly by scientific & industrial research departments, NASA, the Weather Centre, stock exchanges- cost ££ millions

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2.2 CPU

Controls the transmission of data from input devices to memoryProcesses the data held in main

memory.Controls the transmission of information from main memory to output devices. A

microprocessor -- also known as a CPU or central processing unit -- is a complete computation

engine that is fabricated on a single chip. Using its ALU (Arithmetic/Logic Unit), a

microprocessor can perform mathematicaloperations like addition, subtraction, multiplicationand

division. Modern microprocessors contain complete floating point processors that can perform

extremely sophisticated operations on large floating point numbers. A microprocessor can move

data from one memory location to another. A microprocessor can make decisions and jump to a

new set of instructions based on those decisions.

Figure 2.1 CPU

2.2.1 Clock Speed

To synchronize the steps of the fetch-decode,execute cycle, All processors have an internal

clock which generates regularly timed pulses. All activities of the fetch-decode-execute cycle

must begin on a clock pulse.

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2.2.2 Word Size

The number of bits that the CPU can process simultaneously. Normally groups of 8, 16, 32, 64,

128 bit words are processed as a unit during input, output and logic instructions.Word size is a

major factor in determining the speed of a processor.

2.2.3 Bus Size

Buses are the lines along which data is transmitted. This data can be in the form of data and

instructions as well the addresses of the data and the instructions.The width of a data bus

determines how many bits can be transmitted simultaneously and the maximum address which

can be referenced. For 8 bits 28 – 1 = 255 i.e. 0 to 255 which is 256 locations. An address bus

(that may be 8, 16 or 32 bits wide) that sends an address to memory. A data bus (that may be 8,

16 or 32 bits wide) that can send data to memory or receive data from memory An RD (read) and

WR (write) line to tell the memory whether it wants to set or get the addressed location. A clock

line that lets a clock pulse sequence the processor. A reset line that resets the program counter to

zero (or whatever) and restarts execution

2.2.4 Instruction Set

Instructions in machine language are in the form of binary codes, with each different processor

using different codes for the instruction set supported by its hardware. The instruction set for a

typical computer includes the following types of instructions:

• Data Transfer

• Arithmetic Operations

• Logical Operations

• Test and Branch Instructions

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2.3 Memory

2.3.1 Main memory

Instructions and data are held in main memory, which is divided into millions of individually-

addressable storage units called bytes. One byte can hold one character, or it can be used to hold

a code representing, for example, a tiny part of a picture, a sound, or part of a computer program

instruction. The total number of bytes in main memory is referred to as the computer’s memory

size. Computer memory sizes are measured as follows:

1 Kilobyte (Kb) = 1000 bytes (to be exact, 1024 bytes)

1 Megabyte (Mb) = 1,000,000 (1 million) bytes

1 Gigabyte (Gb) = 1,000,000,000 (1 billion) bytes

1 Terabyte (Tb) = 1,000,000,000,000 (1 trillion) bytes

2.3.2 Random Access Memory (RAM)

It is an ‘Ordinary’ memory. Used for storing programs which are currently running and data

which is being processed. This type of memory is volatile - it loses all its contents as soon as the

machine is switched off.

2.3.3 Read Only Memory (ROM)

It is a non-volatile memory with contents permanently etched into the memory chip at the

manufacturing stage. Used for example to hold the bootstrap loader, the program which runs as

soon as the computer is switched on and instructs it to load the operating system from disk into

memory.

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2.3.3 Programmable read only memory(PROM)

Short for programmable read-only memory, a memory chip on which data can be written only

once. Once a program has been written onto a PROM, it remains there forever. Unlike RAM,

PROMs retain their contents when the computer is turned off. The difference between a PROM

and a ROM (read-only memory) is that a PROM is manufactured as blank memory, whereas a

ROM is programmed during the manufacturing process. To write data onto a PROM chip, you

need a special device called a PROM programmer or PROM burner. The process of

programming a PROM is sometimes called burning the PROM. An EPROM (erasable

programmable read-only memory) is a special type of PROM that can be erased by exposing it to

ultraviolet light. Once it is erased, it can be reprogrammed. An EEPROM is similar to a PROM,

but requires only electricity to be erased.

2.3.4 Erasable Programmable read only memory(EPROM)

EPROM(Erasable Programmable Read Only Memory) can be programmed and erased enabling

them to be re-used. Erasure is accomplished using an UV (Ultra Violet) light source that shines

through a quartz erasing window in the EPROM package. Acronym for erasable programmable

read-only memory, and pronounced ee-prom, EPROM is a special type of memory that retains its

contents until it is exposed to ultraviolet light. The ultraviolet light clears its contents, making it

possible to reprogram the memory. To write to and erase an EPROM, you need a special device

called a PROM programmer or PROM burner. An EPROM differs from a PROM in that a

PROM can be written to only once and cannot be erased. EPROMs are used widely in personal

computers because they enable the manufacturer to change the contents of the PROM before the

computer is actually shipped. This means that bugs can be removed and new versions installed

shortly before delivery.Pronounced double-ee-prom or e-e-prom, short for electrically erasable

programmable read-only memory. EEPROM is a special type of PROM that can be erased by

exposing it to an electrical charge. Like other types of PROM, EEPROM retains its contents

even when the power is turned off. Also like other types of ROM, EEPROM is not as fast as

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RAM. EEPROM is similar to flash memory (sometimes called flash EEPROM). The principal

difference is that EEPROM requires data to be written or erased one byte at a time whereas

flash memory allows data to be written or erased in blocks. which makes flash memory faster.

2.3.5 Flash EPROM

A flash EPROM is similar to an EEPROM except that flash EPROMs are erased all at once

while a regular EEROMs can erase one byte at a time. In- circuit writing and erasing is possible

because no special voltages are required. To accomplish in-circuit operation, you have to write

special application software routines. Flash EPROMs are also called nonvolatile memory.

2.3.6 Cache Memory

Ita a very fast memory used to improve the speed of a computer, doubling it in some cases. Acts

as an intermediate store between the CPU and main memory. Stores the most frequently or

recently used instructions and data for rapid retrieval Generally between 1Kb and 512Kb. It is

much more expensive than normal RAM.

Figure 3 Cache Memory

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2.3.7 Virtual memory

Figure 4.3 Virtual Memory

2.3.8 Auxiliary Storage

Hard disks

- all standalone PCs have in-built hard disk

- typical capacity for Pentium PC is >= 40 Gb

- used for storing software including the operating system,

other systems software, application programs and data

Floppy disks

- thin sheet of mylar plastic in hard 3½” casing

- capacity 1.44Mb

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CD-ROM

- holds about 700Mb

Zip disks

- hold up to 250Mb

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3. ‘C’ LANGUAGE

3.1 Machine Language through High-Level Languages and C

Compilers turn high level languages into object code, and the linker changes the object code into

machine code. In many IDE's the compile and link steps are done with one command. On the

command line, it is normally a 2 step process. High level languages are usually only platform

dependant after compiling, and assuming you do not use specific OS or compiler functions. If

you stick to the language standards, nearly every language is platform independant. If you write

a standard C or C++ programm the only thing you have to do is recompile it for a different

platform.

The C and C++ compiliation is done in 3-stages.

Stage 1. The source files are processed by the pre-processor, whose job it is to combine

all the include files and source files into one file. It also strips all comments and expands

all defines and other macros.

Stage 2. the compiler takes the ourput of the pre-processor to produce the *.obj file.

Stage 3. The linker combines all the *.obj files in the project with *.lib libraries to

produce a *.exe program, or a DLL.

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How is a program converted into a form that a computer can use?

What is the form of data that the computer uses?

– All data is converted into a set of binary codes, strings of 1s and 0s

– Binary codes are distinguished by the manner in which the computer uses them.

– Machine language

Machine language to High-level languages

Machine language

o made up binary-coded instructions used directly by the computer

o tedious and error prone

o programs were difficult to read and modify

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Assembly language

o Low-level programming language in which a mnemonic is used to represent each

of the machine language instructions for a particular computer

Assembly Language Machine Language

ADD 100101

SUB 010011

Assembly language

– Computer not able to process instructions directly hence a program, written in

machine language, was used to translate from assembly language to machine

language: Assembler

– Easier for humans to use than machine language however programmers still

forced to think in terms of individual machine instructions

High-level languages

– Closer to English, and other natural languages, than assembly and machine

languages.

3.1.1 Language-Processing System

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3.1.2 Memory model

• Whilst near pointers simplify memory access in the segmented memory of Intel

processors by allowing direct arithmetic on pointers, they limit accessible memory to 64

kilobytes.

• Far pointers can be used to access multiple code segments, each 64K, up to 1 megabyte,

by using segment and offset addressing.

• The cost is that the programmer cannot use the simple pointer arithmetic that is possible

with near pointers.

• The default model is Small, which is effective for the majority of applications.

• The Tiny model is specifically designed for the production of TSR (memory-resident)

programs, which must fit into one code segment and be compiled as .COM rather

than .EXE files.

• The remaining models are selectable in the compilation process, through the IDE or in

the make file.

• Careful use of alternative memory models is one the hallmarks of thoughtful C

programming.

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3.2 Cygwin

Cygwin is free software that provides a Unix-like environment and software tool set to users of

any modern version of MS-Windows for x86 CPUs (95/98/NT/2000/ME/XP). Cygwin consists

of a Unix system call emulation library, cygwin1.dll, together with a vast set of GNU and other

free software applications organized into a large number of optional packages. Among these

packages are high-quality compilers and other software development tools, a complete X11

development toolkit, GNU emacs, TeX and LaTeX, OpenSSH (client and server), and much

more, including everything needed to compile and use PhysioToolkit software under MS-

Windows.Cygwin does not provide a means for running GNU/Linux or other Unix binary

executables under MS-Windows. In order to run such software using Cygwin, that software must

be compiled from its sources. Cygwin provides all of the components needed to do this in most

cases; most POSIX-compliant software, including X11 applications, can easily be ported to MS-

Windows using Cygwin. Cygwin is a UNIX-compatible environment that runs on Windows

systems. It consists of cygwin1.dll, a library that takes POSIX calls and translates them into

Win32 calls (kind of like winelib in reverse); a shell (GNU BASH, the shell used on most Linux

systems, is the default); an implementation of the X Window System and, of course, GCC.

3.3 C Data Types

All C variables are defined with a specific type. C has the following built-in types.

char - characters

int - integers (whole numbers)

float - real numbers

void - valueless

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3.4 Data Modifiers

• Data Modifiers enable you to have greater control over the data:

1. signed 2. unsigned 3. short 4. long

• The signed Modifier:

• Used to enable the sign bit.

• Used to indicate to the compiler that the int or char data type uses the sign bit.

• All int variables in C are signed by default.

• The unsigned Modifier:

• used to tell the C compiler that no sign bit is needed in the specified data type.

• Like the signed modifier, the unsigned modifier is meaningful only to the int and

char data types

• By default, ‘unsigned’ means ‘unsigned int’.

• The short Modifier:

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• A data type can be modified to take less memory by using the short modifier.

• By default, a short int data type is a signed number.

• %hd, %hi or % hu is to specify that the corresponding number is a short int or

unsigned short int.

• The long modifier :

• It is used to define a data type with increased storage space.

• The ANSI standard allows you to indicate that a constant has type long by

suffixing l or L to the constant.

• %ld or %Ld specifies that the corresponding datum is long int. %lu or %Lu is

then used for the long unsigned int data.

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3.5 Control Flow statements

• The if statement

• The if-else statement

• The switch statement

• The break statement

• The continue statement

• The goto statement

3.6 Call by Value and Call by Reference

• The arguments passed to function can be of two types namely

• 1.Values passed

2. Address passed

• The first type refers to call by value and the second type refers to call by reference.

3.7 Array

• An array is a collection of variables that are of the same data type. Each item in an array

is called an elemen t . All elements in an array are referenced by the name of the array and

are stored in a set of consecutive memory slots.

• The general form to declare an array:

data-type Array-Name[Array-Size];

eg. int array_int[8];

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• In C Array subscripts start at 0 and end one less than the array size.

• In above example the size of array_int starts with 0 and ends with 7.

• Indexing the Arrays all arrays in C are indexed starting at 0.

3.8 Pointers

• We can make a pointer that refers to the first element of an array by simply assigning the

array name to the pointer variable.

– A pointer is said to refer to an array when the address of the first element in the

array is assigned to the pointer. The address of the first element in an array is also

called the start address of the array.

– To assign the start address of an array to a pointer, you can either put the

combination of the address-of operator (&) and the first element name of the

array, or simply use the array name, on the right side of an assignment operator

(=).

3.9 Sorting Algorithm

One of the fundamental problems of computer science is ordering a list of items. There's a

plethora of solutions to this problem, known as sorting algorithms. Some sorting algorithms are

simple and intuitive, such as the bubble sort. Others, such as the quick sort are extremely

complicated, but produce lightening-fast results.The common sorting algorithms can be divided

into two classes by the complexity of their algorithms.

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• Algorithmic complexity

• It is generally written in a form known as Big-O notation, where the O represents

the complexity of the algorithm and a value n represents the size of the set the

algorithm is run against.

• Relative Effeciency

• The run times on your system will almost certainly vary from these results, but

the relative speeds should be the same - the selection sort runs in roughly half the

time of the bubble sort.

There are four types of sorting techniques:-

1. Bubble sort

2. Insertion sort

3. Selection sort

4. Quick Sort

3.9.1 Bubble sort

The bubble sort is the oldest and simplest sort in use. Unfortunately is the slowest.The bubble

sort works by comparing each item in the list with the item next to it, and swapping them if

required. The algorithm repeats this process until it makes a pass all the way through the list

without swapping any items (in other words, all items are in the correct order). This causes larger

values to "bubble" to the end of the list while smaller values "sink" towards the beginning of the

list. The bubble sort is generally considered to be the most inefficient sorting algorithm in

common usage.

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3.9.2 Insertion Sort

The insertion sort works just like its name suggests - it inserts each item into its proper place in

the final list. The simplest implementation of this requires two list structures - the source list and

the list into which sorted items are inserted.To save memory, most implementations use an in-

place sort that works by moving the current item past the already sorted items and repeatedly

swapping it with the preceding item until it is in place. Although it has the same complexity, the

insertion sort is a little over twice as efficient as the bubble sort.And almost 40% faster than the

selection sort.The insertion sort is a good middle-of-the-road choice for sorting lists of a few

thousand items or less. The algorithm is significantly simpler than the shell sort, with only a

small trade-off in efficiency.The insertion sort shouldn't be used for sorting lists larger than a

couple thousand items or repetitive sorting of lists larger than a couple hundred items.

3.9.3 Selection Sort

The selection sort works by selecting the smallest unsorted item remaining in the list, and then

swapping it with the item in the next position to be filled. It is simple and easy to implement. It

yields a 60% performance improvement over the bubble sort, but the insertion sort is over twice

as fast as the bubble sort and is just as easy to implement as the selection sort. In short, there

really isn't any reason to use the selection sort - use the insertion sort instead. If at all made in

use, try to avoid sorting lists of more than a 1000 items.

3.9.4 Quick Sort

The quick sort is an in-place, divide-and-conquer, massively recursive sort. As a normal person

would say, it's essentially a faster in-place version of the merge sort.The quick sort algorithm is

simple in theory, but very difficult to put into code (computer scientists tied themselves into

knots for years trying to write a practical implementation of the algorithm, and it still has that

effect on university students). The efficiency of the algorithm is majorly impacted by which

element is choosen as the pivot point. The worst-case efficiency of the quick sort occurs when

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the list is sorted and the left-most element is chosen. Randomly choosing a pivot point rather

than using the left-most element is recommended if the data to be sorted isn't random.

The recursive algorithm consists of four steps (which closely resemble the merge sort):

• If there are one or less elements in the array to be sorted, return immediately.

• Pick an element in the array to serve as a "pivot" point. (Usually the left-most

element in the array is used.)

• Split the array into two parts - one with elements larger than the pivot and the

other with elements smaller than the pivot.

• Recursively repeat the algorithm for both halves of the original array.

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4.8051 MICROCONTROLLER

The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 8K bytes of

Flash programmable and erasable read only memory (PEROM). The device is manufactured

using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-

standard MCS-51 instruction set and pin out. The on-chip Flash allows the program memory to

be reprogrammed in-system or by a conventional nonvolatile memory programmer. The Atmel

AT89C51 is a powerful microcomputer, which provides a highly flexible and cost-effective

solution to many embedded control applications. It also provides 32 I/O lines, 256bytes of RAM

for data storage.

Microprocessor, by-itself, completely useless . It does not have RAM,ROM and no I/O ports on

the chip itself. Must have external peripherals to Interact with outside world. Makes system

bulkier and expensive. A Microcontroller has a CPU along with fixed amount of RAM, ROM

and I/O ports and timer on a single chip.

• There are four major 8 bit microcontrollers.

» Freescale-68111

» Intel's -8051

» PIC 16x

» Microchip.

Each one has its own instruction set and register set so not compatible with each other.

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4.1 Features Of Microcontroller

8051 is an 40 pin IC.

8051 is an 8-bit Microcontroller.

128 byes of RAM

4KBytes of inbuilt ROM.

It have one serial port i.e. UART

Four parallel ports i.e. P0,P1,P2&P3.

It have two 16-bit Timers i.e. Timer0 ,Timer1.

It have five sources and six Interrupts.

It have four Register Banks (Bank0-3) .

16-bit Program Counter.

DPTR(16-bit).

8-bit stack pointer (sp).

External code and data memory up to 64KB.

8-bit PSW (program status word).

On chip Oscillator.

8K Bytes of In-System Reprogrammable Flash Memory

Low-power Idle and Power-down Modes

4v to 5.5v operating range.4.2 8051 Architecture

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PIN Configuration

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4.2.1 Pin configuration of AT89C51

• VCC -Supply voltage.

• GND- Ground.

• RST -Reset input.

– A high on this pin for two machine cycles while the oscillator is running resets the

device.

• Port 0

– Port 0 is an 8-bit open drain bidirectional I/O port.

– 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.

– Port 0 also receives the code bytes during Flash programming, and outputs the

code bytes during program verification.

– External pullups are required during program verification.

• Port 1

– Port 1 is an 8-bit bidirectional I/O port with internal pullups .

– When 1s are written to Port 1 pins they are pulled high by the internal pullups

and can be used as inputs.

– It also receives the low-order address bytes during Flash programming and

verification.

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• Port 2

– Port 2 is an 8-bit bidirectional I/O port with internal pullups.

– When 1s are written to Port 2 pins they are pulled high by the internal pullups and

can be used as inputs.

– Port 2 emits the high-order address byte during fetches from external program

memory and during accesses to external data memory that use 16-bit addresses

(MOVX @DPTR).

– During accesses to external data memory that use 8-bit addresses (MOVX @ RI),

Port 2 emits the contents of the P2 Special Function Register.

– Port 2 also receives the high-order address bits and some control signals during

Flash programming and verification.

• Port 3

– Port 3 is an 8-bit bidirectional I/O port with internal pullups.

– When 1s are written to Port 3 pins they are pulled high by the internal pullups and

can be used as inputs.

– Port 3 also receives some control signals for Flash programming and verification.

– Port 3 also receives some control signals for Flash programming and

programming verification. RST Reset input. A high on this pin for two machine

cycles while the oscillator is running resets the device.

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• 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 memory write strobe)

– P3.7 RD (external data memory read strobe)

• ALE/PROG:

– Address Latch Enable is an 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 program memory. When the

AT89C52 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: A 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

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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 when 12-volt programming is selected.

• XTAL1:

– Input to the inverting oscillator amplifier and input to the Internal clock operating

circuit.

• XTAL2:

– Output from the inverting oscillator amplifier.

4.2.2 Memory Organisation

MCS-51 devices have a separate address space for program and data memory up to 64k

bytes each of external program and data memory can be addressed.

Program Memory:

If the EA pin is connected to GND, all program fetches are directed to external memory.

In the AT89C51RC if EA is connected to Vcc, program fetches the addresses 0000H

through 7FFFH are directed to internal memory and fetches to addresses memory.

Data Memory:

The AT89C51RC has internal data memory that is mapped into four separate segments.

The lower 128 bytes of RAM, upper 128 bytes special function register (SFR) and 256

bytes expanded RAM (ERAM).

The four segments are:

1. The lower 128bytes of RAM (addresses 00H to 7FH) are directly and indirectly addressable.

2. The upper 128 bytes of RAM (addresses 80H to FFH) are indirectly addressable only.

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3. The special function registers, (SFR’s) (addresses 80H to FFH) are directly addressable only.

4. 256 bytes expanded RAM (ERAM, 00H-FFH) is indirectly accessed by MOVX instruction

and with the EXTRAM bit cleared.

Either direct or indirect addressing can access the lower 128 bytes. The upper 128 bytes

can be accessed indirect addressing only. The upper 128 bytes occupy the same address but are

physically separate from the SFR space. When an instruction accesses an internal location above

address 7FH, the CPU knows whether the accesses is to the upper 128 bytes of data RAM or to

SFR space by the direct addressing mode used in the instruction. Instructions that use direct

addressing access SFR space. For example MOV OAOH, #data.

SFR (Special Function Register):

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A map of the on-chip memory area is called the special function registers (SFR) space. Note

that in the SFR's not all the addresses are occupied. Unoccupied addresses are not implemented

on the chip. Read accesses to these addresses will in general return random data and write

accesses will have no-effect. The functions of SFR's are described as follows:

Accumulator:

Acc is the accumulator register. The mnemonics for accumulator, specific Instructions.

However, refer to the accumulator simply as "A".

PSW (Program Status Register):

The PSW contains several status bits that reflect the current state of the cpu.the psw resides

in the SFR space.

Stack Pointer:

This is of 8-bit wide. It is incremented before data is stored during PUSH and CALL

executions. While the stack pointer may any where in on chip RAM the stack pointer is

initialized to 07h after a reset. This causes the stack to begin at location 08h.

Data Pointer (DPTR):

This consists of a high type and a low byte. Its intended function is to hold a 16-bit address.

It may be manipulated as a 16-bit register or as two independent 8-bit registers.

Ports 0 to 3:

P0, P1, P2, and P3 are the SFR of ports 0,1,2 & 3 respectively. Writing a one of a port SFR

causes the port output pin to switch low. When used as an input, the external state of a pin will

be held in the port SFR.

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Serial Data Buffer:

The serial buffer is actually two separate registers transmit buffer and a receive buffer. When

data is involved to SBUF. It goes to transmit buffer and is held for serial transmission. When

data is moved from SBUF. It comes from SBUF. It comes the receive buffer.

Timer Register Basic to 89C51:

Register pins (TH0, TL0), (TH1, TL1), (TH2, TL2) are 16-bit counting registers for

timer/counters 0,1&2, respectively.

Control Register For The 89C51:

SFR, IP, IE, TMOD, SCON and PCON contain and status bits for the interrupt system. The

timer/counters and the serial port.

4.3.3 Instruction Set:

The 89C52 instruction set has 111 instructions. It includes

Arithmetic

Logical

Data transfer

Boolean and

Branching instructions

4.4.4 Addressing Modes:

There are five addressing modes in the 89C52 instruction set explained as follows:

Direct addressing

Indirect addressing

Register instructions

Immediate addressing

Indexed addressing

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5.SERIAL COMMUNICATION PROTOCOL

Different Serial Communication Protocols

o USB.

o CAN.

o FIREWIRE.

o SPI - Serial Peripheral Interface.

5.1 Introduction to USB

USB stands for universal serial bus

• Complex, hierarchical standard

• Requires software layers both on the host computer and on the USB device

• Serial Protocol and Physical Link

• Hierarchy: PC is the host

– Upstream points towards the host

– Downstream points away from the host

• Data transmitted serially

• Data transmitted differentially on a pair of wires (D+ and D-)

• 2 other wires are used to supply power to USB devices

• USB devices may be Bus Powered or Self-Powered

• USB includes specs on power consumption and voltage drops etc.

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• Data transmitted serially

• Data transmitted differentially on a pair of wires (D+ and D-)

• 2 other wires are used to supply power to USB devices

• USB devices may be Bus Powered or Self-Powered

• USB includes specs on power consumption and voltage drops etc .

• Evolution

– USB 1.0 (1996)

– USB 1.1 (1998)

– USB 2.0 (2000)

• Advantages of serial buses:

– Signal Integrity

Fewer coinciding signal transitions. Less crosstalk. Less noise. Less inter-signal

skew.

– Cost

Drivers, connectors, cables, receivers

• Disadvantage of serial buses:

– Higher clock-rates required for given bandwidth

5.1.1 Types of USB Cable

• High Speed Cables

– Shielded, jacketed - use twisted pair wiring

– Support max data rates of 12Mb/s

– Support Cable lengths of 5m

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• Low Speed cables

– Not shielded, pairs not twisted, cheaper

– Support 1.5Mb/s

– Support Cable lengths of 3m

5.1.2 USB Connectors

Connectors

– 4-Position with shielded housing

– Positive Retention

– Blind Mating Capabilities

Cables

– 28 AWG twisted pair for signalling

– 20-28 AWG pair for power

– Shielding for fully rated segments

Type A Connector connects to Upstream Ports

Type B Connector connects to Downstream Ports

Each USB Cable has a Type A & Type B Connector

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5.1.3 USB Bandwidth

• USB 1.0 / 1.1

– 12 Mb/s Full Speed (FS) bit rate

– 1.5 Mb/s Low Speed (LS) bit rate

• USB 2.0 (May 2000)

– additionally: 480 Mb/s High Speed (HS)

– Applications: USB HDD. Video

5.1.4 USB Pipes

USB Communication uses the idea of a Pipe. The USB connection consists of a big pipe

(12Mb/s) and up to 127 small pipes. Each of the small pipes connects to a USB device. Each

small pipe can connect to a smaller pipe (tiny pipe) – up to 16 tiny pipes per small pipe.

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5.2 CAN

The Controller Area Network (CAN) is a serial communications protocol which efficiently

supports distributed real time control. Used in high speed networks to low cost multiplex wiring.

In automotive electronics, engine control units, sensors, anti-skid-systems, etc. are connected

using CAN with bitrates up to 1 Mbit/s. It is cost effective to build into vehicle body electronics,

e.g. lamp clusters, electric windows etc. to replace the wiring harness otherwise required.

• CAN has been subdivided into different layers.

– the (CAN-) object layer

– the (CAN-) transfer layer

– the physical layer

The object layer and the transfer layer comprise all services and functions of the data link layer

defined by the ISO/OSI model. The scope of the object layer includes finding which messages

are to be transmitted deciding which messages received by the transfer layer are actually to be

used, providing an interface to the application layer related hardware. The scope of the transfer

layer mainly is the transfer protocol, i.e. controlling the framing, performing arbitration, error

checking error signalling and fault confinement.

5.2.1 Layered Structure of a CAN

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5.3 Firewire Bus

The 1394 protocol is a peer-to-peer network with a point to point signaling environment. Nodes

on the bus may have several ports on them, each of these ports act as repeaters, retransmitting

any packets that are received by other ports within the node.

1394 is a peer to peer implementation, no need for specific host required, such as a PC in USB.

Digital Camera could easily stream data to both the Digital VCR and the DVD-RAM without

any assistance from other devices on the bus. There is the concept of a Cycle Master and Root

Node. The determination of what device plays the Cycle Master role is determined dynamically

and can change whenever a new device is added or a bus reset occurs. Configuration of the bus

occurs automatically whenever a new device is plugged in. Configuration proceeds from leaf

nodes (those with only one other device attached to them) up through the branch nodes. A bus

that has three or more devices attached will have a branch node as the Root Node. A 1394 bus

appears as a large memory mapped space with each node occupying a certain address range.

Each node supports up to 48 bits of address space (256 TeraBytes ). Each bus can support up to

64 nodes and the 1394 serial bus specification supports up to 1024 busses.

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5.3SPI - Serial Peripheral Interface

The Serial Peripheral Interface is used primarily for a synchronous serial communication of host

processor and peripherals. However, a connection of two processors via SPI is just as well

possible . In the standard configuration for a slave device two control and two data lines are

used. The data output SDO serves on the one hand the reading back of data, offers however also

the possibility to cascade several devices. The data output of the preceding device then forms the

data input for the next IC.

There is a MASTER and a SLAVE mode. The MASTER device provides the clock

signal and determines the state of the chip select lines, i.e. it activates the SLAVE itwants

to communicate with. CS and SCKL are therefore outputs. The SLAVE device receives

the clock and chip select from the MASTER, CS and SCKL are therefore inputs. This

means there is one master, while the number of slaves is only limited by the number of

chip selects. A SPI device can be a simple shift register up to an independent subsystem.

The basic principle of a shift register is always present. Command codes as well as data

values are serially transferred, pumped into a shift register and are then internally

available for parallel processing. The length of the shift registers is not fixed, but can

differ from device to device. Normally the shift registers are 8Bit or integral multiples of

it. Of course there also exist shift registers with an odd number of bits. For example two

cascaded 9Bit EEPROMs can store 18Bit data. A SPI device can be a simple shift register

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up to an independent subsystem. The basic principle of a shift register is always present.

Command codes as well as data values are serially transferred, pumped into a shift

register and are then internally available for parallel processing. The length of the shift

registers is not fixed, but can differ from device to device. Normally the shift registers are

8Bit or integral multiples of it. Of course there also exist shift registers with an odd

number of bits. For example two cascaded 9Bit EEPROMs can store 18Bit data. A SPI

device can be a simple shift register up to an independent subsystem. The basic principle

of a shift register is always present. Command codes as well as data values are serially

transferred, pumped into a shift register and are then internally available for parallel

processing. The length of the shift registers is not fixed, but can differ from device to

device. Normally the shift registers are 8Bit or integral multiples of it. Of course there

also exist shift registers with an odd number of bits. For example two cascaded 9Bit

EEPROMs can store 18Bit data.

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• Serial communication uses a single data line is used instead of the 8-bit data line of

parallel communication.

• It is cheaper and also makes it possible for two computers located in two different cities

to communicate over telephone.

• At the transmitter bytes of data is converted to serial bits using a parallel-in-serial-out

shift register.

• At the receiver serial data is packed in to bytes by serial-in-parallel-out shift register

• Data is transferred through the telephone line by converting 0s and 1s to audio tones

(sinusoidal shaped signal), by a peripheral device called Modem

(Modulator/Demodulator).

• Serial communication uses two methods:

• Asynchronous.

• Synchronous.

• Synchronous: Transfers a block of data (characters) at a time.

• Asynchronous: Transfers single byte at a time.

• There are special IC chip made by many manufacturers for serial data communications.

• UART (Universal Asynchronous Receiver-Transmitter ).

• USART (Universal Synchronous –Asynchronous Receiver-Transmitter).

• In data transmission if the data can be transmitted and received, it is a duplex

transmission.

• Half duplex: data is transmitted one way at a time.

• Full duplex: data is transmitted both ways at the same time.

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• Each character is placed between a start bit and a stop bits.

• Start bit is always a 0(low) and the stop bit is always 1(high).

• Baud rate: The rate of data transfer in serial data communication. Also stated as bps (bits

per second).

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RS-232 Standards:

• To allow compatibility among data communication equipment made by various

manufacturers, an interfacing standard called RS232 was set by the electronics industries

association (EIA) in 1960.

• In RS232, a 1 is represented by -3 to -25v, while a 0 bit is +3 to 25v, making -3 to +3

undefined.

Data Communication Classification

Current terminology classifies data communication as DTE (Data Terminal Equipment) or DCE (Data Communication Equipment).

• DCE refer to communication equipment, such as modems.• DTE refer to terminals and computers that send and receive data

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MAX232 .:

•

• 8051 has two pins that are used specifically for transferring and receiving data serially.

• These pins are called TXD and RXD.

• These pins are TTL compatible;

• They require a line driver to make them RS232 compatible.

• One such driver is the MAX232 chip.

BAUD RATE

8051 transfers and receives data serially at many different baud rates.

• The baud rate in the 8051 is programmable.

• 8051 divides the crystal frequency by 12 to get the machine cycle frequency.

• UART circuitry divides the machine cycle frequency by 32 before it is used by timer 1 to

set the baud rate.

SBUF Register

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• SBUF is an 8-bit register used solely for serial communication in the 8051.

• For a byte of data to be transferred via the TXD line, it must be placed in the SBUF

register.

• Similarly SBUF holds the byte of data when it is received by the 8051’s RXD line.

• The moment a byte is written into SBUF, it is framed with the start and stop bit and

transferred serially via the TXD pin.

SCON REGISTER

SM0,SM1: Mode select register

SM0 SM1

0 0 mode0

0 1 mode1

1 0 mode2

1 1 mode3

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6. Real Time Clock DS1307 (RTC)

The DS1307 serial real-time clock (RTC) is a low-power, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV SRAM. Address and data are transferred serially through an I2C™, bidirectional bus. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24- hour or 12-hour format with AM/PM indicator. The DS1307 has a built-in power-sense circuit that detects power failures and automatically switches to the battery supply. The DS1307 is a low-power lock/calendar with 56 bytes of battery-backed SRAM. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The DS1307 operates as a slave device on the I2C bus. Access is obtained by implementing a START condition and providing a device identification code followed by a register address. Subsequent registers can be accessed sequentially until a STOP condition is executed. When VCC falls below 1.25 x VBAT, the device terminates an access in progress and resets the device address counter. Inputs to the device will not be recognized at this time to prevent erroneous data from being written to the device from an out-oftolerance system. When VCC falls below VBAT, the device switches into a low-current battery-backup mode. Upon power-up, the device switches from battery to VCC when VCC is greater than VBAT +0.2V and recognizes inputs when VCC is greater than 1.25 x VBAT. The block diagram in Figure 1 shows the main elements of the serial RTC.

6.3.1 Features

Real-Time Clock (RTC) Counts Seconds,

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Minutes, Hours, Date of the Month, Month,

Day of the week, and Year with Leap-Year

Compensation Valid Up to 2100

56-Byte, Battery-Backed, Nonvolatile (NV)

RAM for Data Storage

I2C Serial Interface

Programmable Square-Wave Output Signal

Automatic Power-Fail Detect and Switch

Circuitry

Consumes Less than 500nA in Battery-

Backup Mode with Oscillator Running

Optional Industrial Temperature Range:

-40°C to +85°C

Available in 8-Pin DIP or SO

Underwriters Laboratory (UL) Recognized

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7.RS232:

RS-232 (Recommended standard-232) is a standard interface approved by the Electronic

Industries Association (EIA) for connecting serial devices. In other words, RS-232 is a long

established standard that describes the physical interface and protocol for relatively low-speed

serial data communication between computers and related devices. An industry trade group, the

Electronic Industries Association (EIA), defined it originally for teletypewriter devices. In 1987,

the EIA released a new version of the standard and changed the name to EIA-232-D. Many

people, however,still refer to the standard as RS-232C, or just RS-232. RS-232 is the interface

that your computer uses to talk to and exchange data with your modem and other serial devices.

The serial ports on most computers use a subset of the RS-232C standard.

RS232 on DB9 (9-pin D-type connector):

There is a standardized pinout for RS-232 on a DB9 connector, as shown below

Pin No

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Signal Description

1 DCD Data carrier detect

2 RxD Receive Data

3 TxD Transmit Data

4 DTR Data terminal ready

5 GND Signal ground

6 DSR Data set ready

7 RTS Ready to send

8 CTS Clear to send

9 RI Ring Indicator

Signal Description:

TxD: - This pin carries data from the computer to the serial device

RXD: - This pin carries data from the serial device to the computer

DTR signals: - The computer to signal that it is ready to communicate with the serial device like

modem uses DTR. In other words, DTR indicates to the Dataset (i.e., the modem or DSU/CSU)

that the DTE (computer) is ON.

DSR: - Similarly to DTR, Data set ready (DSR) is an indication from the Dataset that it is ON.

DCD: - Data Carrier Detect (DCD) indicates that carrier for the transmit data is ON.

RTS: - This pin is used to request clearance to send data to a modem

CTS: - The serial device to acknowledge the computer’s RTS Signal uses this pin.

In most situations, RTS and CTS are constantly on throughout the communication session. Clock

signals (TC, RC, and XTC): - The clock signals are only used for synchronous communications.

The modem or DSU extracts the clock from the data stream and provides a steady clock signal to

the DTE. Note that the transmit and receive clock signals do not have to be the same, or even at

the same baud rate.

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CD: - CD stands for Carrier Detect. Carrier Detect is used by a modem to signal that it has a

made a connection with another modem, or has detected a carrier tone. In other words, this is

used by the modem to signal that a carrier signal has been received from a remote modem.

RI: - RI stands for Ring Indicator. A modem toggles (keystroke) the state of this line when an

incoming call rings your phone. In other words, this is used by an auto answer modem to signal

the receipt of a telephone ring signal. The Carrier Detect (CD) and the Ring Indicator (RI) lines

are only available in connections to a modem. Because most modems transmit status information

to a PC when either a carrier signal is detected (i.e. when a connection is made to another

modem) or when the line is ringing, these two lines are rarely used.

7.4.2 Limitations of RS-232:

RS-232 has some serious shortcomings as an electrical interface. Firstly, the interface

presupposes a common ground between the DTE and DCE. This is a reasonable assumption

where a short cable connects a DTE and DCE in the same room, but with longer lines and

connections between devices that may be on different electrical busses, this may not be true. We

have seen some spectacular electrical events causes by "uncommon grounds". Secondly, a signal

on a single line is impossible to screen effectively for noise. By screening the entire cable one

can reduce the influence of outside noise, but internally generated noise remains a problem. As

the baud rate and line length increase, the effect of capacitance between the cables introduces

serious cross talk until a point is reached where the data itself is unreadable. Using low

capacitance cable can reduce cross talk. Also, as it is the higher sequences that are the problem,

control of slew rate in the signal (i.e., making the signal more rounded, rather than square) also

decreases the cross talk. The original specifications for RS-232 had no specification for

maximum slew rate. Voltage levels with respect to ground represent the RS 232 signals. There is

a wire for each signal, together with the ground signal (reference for voltage levels). This

interface is useful for point-to-point communication at slow speeds. For example, port COM1 in

a PC can be used for a mouse, port COM2 for a modem, etc. This is an example of point-to-point

communication: one port, one device. Due to the way the signals are connected, a common

ground is required. This implies limited cable length - about 30 to 60 meters maximum. (Main

problems are interference and resistance of the cable.) Shortly, RS 232 was designed for

communication of local devices, and supports one transmitter and one receiver.

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Converters:

Converters in general can be used to change the electrical characteristic of one communications

standard into another, to take advantage of the best properties of the alternate standard selected.

For example, an Automatic RS232<=>RS485 converter, could be connected to a computer’s

RS232, full-duplex port, and transform it into an RS485 half-duplex, multi-drop network at

distances up to 4000ft. Converters in most instances, pass data through the interface without

changing the timing and/or protocol. While the conversion is "transparent" the software must be

able to communicate with the expanded network features. An "Automatic Converter"

(RS232<=>RS485) will turn on the RS485 transmitter when data is detected on the RS232 port,

and revert back into the receive mode after a character has been sent. This avoids timing

problems (and software changes) that are difficult to deal with in typical systems. When full

duplex is converted into half-duplex only one device at a time can transmit data. Automatic

Converters take care of the timing problems and allow fast communications without software

intervention.

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8. LIQUID CRYSTAL DISPLAY (LCD)

Liquid Crystal Displays have materials, which combine the properties of both liquids and

crystals. LCD consists of two glass panels, with the Liquid Crystal material sand witched in

between them. The inner surfaces of the glass plates are coated with transparent electrodes,

which define the character, symbols or patterns to be displayed.The LCDs are lightweight with

only a few millimeters thickness. Since the LCDs consume less power, they are compatible with

low power electronic circuits and can be powered for long durations.The LCDs don’t generate

light and so light is needed to read the display. By using backlighting, reading is possible in the

dark. The LCDs have long life and wide operating temperature range. A brighter display can be

obtained by providing backlighting.

LCD has single line display, Two-line display, four line display

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Single line display

Two-line display

Registers

The Controller has two 8-bit registers. Instruction Registers (IR) and Data Registers (DR). The

IR stores the instruction codes and address instruction for Display Data RAM (DD RAM) and

Character Generator RAM (CG RAM). The DR temporarily stores data to be written to/read

from DD RAM or CG RAM. When an address code is written to IR, the data (of the specified

address) is automatically transferred from the DD RAM or CG RAM to the DR

Display Data RAM (DD RAM)

The characters to be displayed are written into the Display Data RAM (DDRAM) in the form of

8-bit character codes.

Character Generator ROM (CG ROM)

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80 8F

C0 CF

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The character generator ROM generates 5x8 dot or 5x10 dot character patterns from 8-bit

character codes. It can generate 208, 5x8 dot character patterns and 32, 5x10 dot character

patterns.

Hardware Configuration

The initial equates are

RS EQU P0.0 (PORT-0)

EN EQU P0.1

DATA0 EQU P0.2

DATA1 EQU P0.3

DATA2 EQU P0.4

DATA3 EQU P0.5

PIN DETAILS

Pin No. Symbol Description

1 VSS Ground Terminal, 0V

2 VDD Supply Terminal, +5V

3 VLCD Power supply to control

Contrast

4 RS Register Select:

RS = 0-Instrution Register

RS = 1-Data Register

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5 R/W Read/Write:

R/W = 0 – Write

R/W = 1 – Read

6 EN Enable

7-14 DB0-DB7 8-bit Data Bus

15 LED+ Supply Terminal,+5V

16 LED- Ground Terminal,0V

9. Stepper Motors

A stepper motor is a permanent magnet or variable reluctance dc motor that has the following performance characteristics:

1. rotation in both directions,

2. precision angular incremental changes,

3. repetition of accurate motion or velocity profiles,

4. a holding torque at zero speed, and

5. capability for digital control.

A stepper motor can move in accurate angular increments knows as steps in response to the

application of digital pulses to an electric drive circuit from a digital controller. The number and

rate of the pulses control the position and speed of the motor shaft. Generally, stepper motors are

manufactured with steps per revolution of 12, 24, 72, 144, 180, and 200, resulting in shaft

increments of 30, 15, 5, 2.5, 2, and 1.8 degrees per step.

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Stepper motors are either bipolar, requiring two power sources or a switchable polarity power

source, or unipolar, requiring only one power source. They are powered by dc current sources

and require digital circuitry to produce the coil energizing sequences for rotation of the motor.

Feedback is not always required for control, but the use of an encoder or other position sensor

can ensure accuracy when it is essential. The advantage of operating without feedback is that a

closed loop control system is not required. Generally, stepper motors produce less than 1

horsepower(746W) and are therefore frequently used in low-power position control applications.

10.PROJECT UNDER TAKEN:

Cell phone Operated Land Rover Robot

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10.1INTRODUCTION: Conventionally,Wireless-controlled robots use rf circuits, which have the drawbacks of limited working range, limited frequency range and the limited control. Use of a mobile phone for robotic control can overcome these limitations. It provides the advantage of robust control, working range as large as the coverage area of the service provider, no interference with other controllersand up to twelve controlles.

Although the appearance and the capabilities of robots vary vastly, all robots share the feature of a mechanical, movable structure under some form of control. The Control of robot involves three distinct phases: perception, processing and action. Generally, the preceptors are sensors mounted on the robot , processing is done by the on-board microcontroller or processor, and the task is perfomed using motors or with some other actuators.

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10.2PROJECT PREFACE:

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 tome (DTMF) robot receives this DTMF tone with the help of phone stacked in the robot The received tone is processed by the atmega16 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 preprogrammed to take a decision for any give 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 ofreceiver and transmitter units. DTMF signaling is used for telephone signaling over the line in the voice frequency band to the call switching center. The version of DTMF used for telephone dialing 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 al-gebric 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. The tones and assignments in a dtmf system shown below .

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10.3.TECHNOLOGY USED:

Dual-Tone Multi-Frequency (DTMF) Dual-tone multi-frequency (DTMF) signaling is used for telecommunication signaling over analog telephone lines in the voice-frequency band between telephone handsets and other communications devices and the switching center. The version of DTMF used for telephone tone dialing is known by the trademarked term Touch-Tone (canceled March 13, 1984), and is standardized by ITU-T Recommendation Q.23. It is also known in the UK as MF4. Other multi-frequency systems are used for signaling internal to the telephone network.

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10.4.HARDWARE DESCRIPTION:

This project contains mainly four modules which encapsulates the working of whole project and these are as follows:

10.4.0 Block Diagram

10.4.1 Power Supply Unit

10.4.2 Microcontoller Unit

10.4.3 MAX232 Unit

10.4.4 DTMF 8870

10.4.5 L57404 (Inverting IC)

10.4.6 L293D (motor driving IC)

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10.4.0 BLOCK DIAGRAM:

STEPPER MOTORS

L293D

Microco-ntroller

8

0

5

1

Power Supply Unit

DTMF

8870

L57404

CELL PHONE

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10.4.1. POWER SUPPLY UNIT (+5V)

Power supplies are designed to convert high voltage AC mains electricity to a suitable

low voltage supply for electronics circuits and other devices. A power supply can by broken

down into a series of blocks, each of which performs a particular function.

For a 5V regulated supply :

Fig. 2

Each of the block has its own function as described below

1. Transformer – steps down high voltage AC mains to low voltage AC.

2. Rectifier – converts AC to DC, but the DC output is varying.

3. Smoothing – smooths the DC from varying greatly to a small ripple.

4. Regulator – eliminates ripple by setting DC output to a fixed voltage.

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TRANSFORMER

Transformers convert AC electricity from one voltage to another with little loss of

power. Transformers work only with AC and this is one of the reasons why mains electricity

is AC. The two types of transformers

Step-up transformers increase voltage,

Step-down transformers reduce voltage.

Fig. 3 Transformer

Most power supplies use a step-down transformer to reduce the dangerously

high mains voltage (230V in UK) to a safer low voltage. The input coil is called the

primary and the output coil is called the secondary. There is no electrical connection

between the two coils, instead they are linked by an alternating magnetic field created in

the soft-iron core of the transformer. The two lines in the middle of the circuit symbol represent

the core.

Transformers waste very little power so the power out is (almost) equal to the power in.

Note that as voltage is stepped down current is stepped up. The ratio of the number of turns

on each coil, called the turns ratio, determines the ratio of the voltages. A step-down

transformer has a large number of turns on its primary (input) coil which is connected to the

high voltage mains supply, and a small number of turns on its secondary (output) coil to

give a low output voltage.

Turns ratio = Vp = Np Vs Ns

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And

Power Out = Power In Vs Is Vp Ip

Where

Vp = primary (input) voltage

Np = number of turns on primary coil

Ip = primary (input) current

Ns = number of turns on secondary coil

Is = secondary (output) current

Vs = secondary (output) voltage

RECTIFIER

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A bridge rectifier can be made using four individual diodes, but it is also available in

special packages containing the four diodes required. It is called a full-wave rectifier because

it uses all the AC wave (both positive and negative sections). 1.4V is used up in the bridge

rectifier because each diode uses 0.7V when conducting and there are always two diodes

conducting, as shown in the diagram below. Bridge rectifiers are rated by the maximum current

they can pass and the maximum reverse voltage they can withstand (this must be at least

three times the supply RMS voltage so the rectifier can withstand the peak voltages). Please

see the DIODES page for more details, including pictures of bridge rectifiers. In this alternate

pairs of diodes conduct, changing over the connections so the alternating directions of AC are

converted to the one direction of DC.

Fig. 4 OUTPUT – Full-wave Varying DC

Smoothing

Smoothing is performed by a large value electrolytic capacitor connected across the DC

supply to act as a reservoir, supplying current to the output when the varying DC voltage from

the rectifier is falling. The diagram shows the unsmoothed varying DC (dotted line) and the

smoothed DC (solid line). The capacitor charges quickly near the peak of the varying DC,

and then discharges as it supplies current to the output.

Fig. 5 Capacitor Voltage

Note that smoothing significantly increases the average DC voltage to almost the

peak value (1.4 × RMS value). For example 6V RMS AC is rectified to full wave DC of

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about 4.6V RMS (1.4V is lost in the bridge rectifier), with smoothing this increases to

almost the peak value giving 1.4 × 4.6 = 6.4V smooth DC.

Smoothing is not perfect due to the capacitor voltage falling a little as it discharges,

giving a small ripple voltage. For many circuits a ripple which is 10% of the supply voltage

is satisfactory and the equation below gives the required value for the smoothing capacitor. A

larger capacitor will give less ripple. The capacitor value must be doubled when smoothing half-

wave DC.

Smoothing capacitor for 10% ripple, C = 5 × Io

Vs × f

Where,

C = smoothing capacitance in farads (F)

Io = output current from the supply in amps (A)

Vs = supply voltage in volts (V), this is the peak value of the unsmoothed DC

f = frequency of the AC supply in hertz (Hz), 50Hz in the UK

REGULATOR

Fig. 6 Regulator

Voltage regulator ICs are available with fixed (typically 5, 12 and 15V) or variable

output voltages. They are also rated by the maximum current they can pass. Negative voltage

regulators are available, mainly for use in dual supplies. Most regulators include some automatic

protection from excessive current ( 'overload protection') and overheating ( 'thermal

protection'). Many of the fixed voltage regulator ICs have 3 leads and look like power

transistors, such as the 7805 +5V 1A regulator shown on the right. They include a hole for

attaching a heatsink if necessary.

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Working Of Power Supply

Transformer

Fig. 7 Transformer Output

The low voltage AC output is suitable for lamps, heaters and special AC motors. It is not

suitable for electronic circuits unless they include a rectifier and a smoothing capacitor.

Transformer + Rectifier

Fig. 8 Rectifier Stage Output

The varying DC output is suitable for lamps, heaters and standard motors. It is not

suitable for electronic circuits unless they include a smoothing capacitor.

Transformer + Rectifier + Smoothing

Fig. 9 Filtered Output

The smooth DC output has a small ripple. It is suitable for most electronic circuits.

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Transformer + Rectifier + Smoothing + Regulator

D 2

C 1

1000uf

1N4007 +5V

V

L M 7 8 0 5

1 2

3

V I N V O U T

GND

J 1

123

D 3

gnd

D 4

D 1

Fig. 10 Power Supply

The regulated DC output is very smooth with no ripple. It is suitable for all electronic

circuits.

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10.4.2 MICROCONTROLLER UNIT

VARIOUS TYPE OF MICROCONTOLLERS:

First microcontroller is ‘8031’

FEATURES

(i) It is Intel’s product. Neither a microprocessor nor a microcontroller.

(ii) It is a 8-bit controller.

(iii) Internally no ROM is provided i.e. code is outside the chip.

Second microcontroller is ‘8051’

FEATURES

(i) It is a first complete 8-bit microcontroller.

(ii) It is a name of a family. In which the instruction set, pin configuration,

architecture are same, only memory storage capacity is different.

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

time programmable (OTP).

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Third microcontroller is ‘AT89C51’

FEATURES

(ii) It is ATMEL’s product.

(iii) It is a similar to 8051 microcontroller i.e. having same instruction set, pin

configuration, architecture.

(iv)It is a also 8-bit microcontroller. It’s cost is only Rs10 more than 8051.

(v) It uses EPROM (erasable programmable read only memory) or FLASH memory.

(vi)It is Multiple time programmable (MTP) i.e. 1000 times. So it is better than

8051.

(vii) In ‘AT89C51’, ‘C’ stands for CMOS technology used in the manufacturing

of the I.C.

ATMEL89C52DescriptionThe AT89C52 is a low-power, high-performance CMOS 8-bit microcomputer with 8Kbytes of Flash programmable and erasable read only memory (PEROM). The deviceis manufactured using Atmel’s high-density nonvolatile memory technology and iscompatible with the industry-standard 80C51 and 80C52 instruction set and pinout.The on-chip Flash allows the program memory to be reprogrammed in-system or by aconventional nonvolatile memory programmer. By combining a versatile 8-bit CPUwith Flash on a monolithic chip, the Atmel AT89C52 is a powerful microcomputerwhich provides a highly-flexible and cost-effective solution to many embedded controlapplications.

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PIN DISCRIPTION

The ATMEL89C52 have a total of 40 pins that are dedicated for various functions such as I/O, RD, WR, address and interrupts. Out of 40 pins, a total of 32 pins are set aside for the four ports P0, P1, P2, and P3, where each port takes 8 pins. The rest of the pins are designated as Vcc, GND, XTAL1, XTAL, RST, EA, and PSEN. All these pins except PSEN and ALE are used by all members of the 8051 and 8031 families. In other words, they must be connected in order for the system to work, regardless of whether the microcontroller is of the 8051 or the 8031 family. The other two pins, PSEN and ALE are used mainly in 8031 based systems.

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10.4.3Max 232 UNIT:

The MAX232 is an electronic circuit that converts signals from a serial port to signals suitable for usage in e.g. microprocessor circuits. When communicating with various micro processors one needs to convert the RS232 levels down to lower levels, typically 3.3 or 5.0 Volts. Serial RS-232 communication works with voltages -15V to +15V for high and low. On the other hand, TTL logic operates between 0V and +5V . Modern low power consumption logic operates in the range of 0V and +3.3V or even lower. Thus the RS-232 signal levels are far too high TTL electronics, and the negative RS-232 voltage for high can’t be handled at all by computer logic. To receive serial data from an RS-232 interface the voltage has to be reduced. Also the low and high voltage level has to be inverted. The level converter uses a Max232 and five capacitors.

MAX 232 (communication interface)

This chip is used when interfacing micro controller with PC to check the Baud rate and

changes the voltage level because micro controller is TTL compatible whereas PC is CMOS

compatible. The MAX 232 IC contains the necessary driverstwo and receivers two, to adapt

the RS- 232 signal voltage levels to TTL logic.It became popular,because it just needs one

voltage+5V and generates the necessary RS-232 voltage levelsapprox -10V AND +10V

internally.This greatly simplified the design of circuitry.And this made the IC so

popular.MAX232 is just a driver/receiver.It does not generate the necessary RS-232 sequence of

marks and spaces with the right timing,it does not decode RS-232 signal, it does not provide a

serial /parallel conversion.All it does is to convert signal voltage levels.

Fig. 15 PIN DIAGRAM

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General Description

The MAX220–MAX249 family of line drivers/receivers is intended for all EIA/TIA-

232E and V.28/V.24 communications interfaces, particularly applications where ±12V is not

available. These parts are especially useful in battery-powered systems, since their low-power

shutdown mode reduces power dissipation to less than 5µW.

Applications

Portable Computers

Low-Power Modems

Interface Translation

Battery-Powered RS-232 Systems

Multidrop RS-232 Networks

Features1. Superior to bipolar

2. Low-power receive mode in shutdown

3. Meet all EIA/TIA-232E and v.28 specifications.

4. 3-state driver and receiver output.

The MAX220–MAX249 contain four sections: dual charge-pump DC-DC voltage

converters, RS-232 drivers, RS-232 receivers, and receiver and transmitter enable control inputs.

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Dual Charge-Pump Voltage Converter

The MAX220–MAX249 have two internal charge-pumps that convert +5V to ±10V

(unloaded) for RS-232 driver operation. The first converter uses capacitor C1 to double the +5V

input to +10V on C3 at the V+ output. The second converter uses capacitor C2 to invert +10V to

-10V on C4 at the V- output. A small amount of power may be drawn from the +10V (V+) and -

10V (V-) outputs to power external circuitry except on the MAX225 and MAX245–MAX247,

where these pins are not available. V+ and V- are not regulated, so the output voltage drops with

increasing load current. Do not load V+ and V- to a point that violates the minimum ±5V

EIA/TIA-232E driver output voltage when sourcing current from V+ and V- to external circuitry.

When using the shutdown feature in the MAX222, MAX225, MAX230, MAX235, MAX236,

MAX240, MAX241, and MAX245–MAX249, avoid using V+ and V to power external

circuitry. When these parts are shut down, V- falls to 0V, and V+ falls to +5V. For applications

where a +10V external supply is applied to the V+ pin (instead of using the internal charge pump

to generate +10V), the C1 capacitor must not be installed and the SHDN pin must be tied to

VCC. This is because V+ is internally connected to VCC in shutdown mode.

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RS-232 Drivers

The typical driver output voltage swing is ±8V when loaded with a nominal 5kΩ RS-232

receiver and VCC = +5V. Output swing is guaranteed to meet the EIA/TIA- 232E and V.28

specification, which calls for ±5V minimum driver output levels under worst-case conditions.

These include a minimum 3kΩ load, VCC = +4.5V, and maximum operating temperature.

Unloaded driver output voltage ranges from (V+ -1.3V) to (V- +0.5V). Input thresholds are both

TTL and CMOS compatible. The inputs of unused drivers can be left unconnected since 400kΩ

input pull-up resistors to VCC are built in (except for the MAX220). The pull-up resistors force

the outputs of unused drivers low because all drivers invert. The internal input pull-up resistors

typically source 12µA, except in shutdown mode where the pull-ups are disabled. Driver outputs

turn off and enter a high-impedance state—where leakage current is typically microamperes

(maximum 25µA)—when in shutdown mode, or when in three-state mode, device power is

removed. Outputs can be driven to ±15V. The power supply current typically drops to 8µA in

shutdown mode.

The MAX220 does not have pull-up resistors to force the outputs of the unused drivers

low. Connect unused inputs to GND or VCC. The MAX239 has a receiver three-state control

line, and the MAX223, MAX225, MAX235, MAX236, MAX240, and MAX241 have both a

receiver three-state control line and a low-power shutdown control. The receiver TTL/CMOS

outputs are in a high-impedance, three-state mode whenever the three-state enable line is high

(for the MAX225/MAX235/MAX236/MAX239– MAX241), and are also high-impedance

whenever the shutdown control line is high. When in low-power shutdown mode, the driver

outputs are turned off and their leakage current is less than 1µA with the driver output pulled to

ground. The driver output leakage remains less than 1µA, even if the transmitter output is back

driven between 0V and (VCC + 6V). Below -0.5V, the transmitter is diode clamped to ground

with 1kΩ series impedance. The transmitter is also zener clamped to approximately VCC + 6V,

with a series impedance of 1kΩ. The driver output slew rate is limited to less than 30V/µs as

required by the EIA/TIA-232E and V.28 specifications. Typical slew rates are 24V/µs unloaded

and 10V/µs loaded with 3Ω and 2500pF.

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10.4.4DTMF (M-8870): Dual-tone multi-frequency signaling (DTMF) is used for telecommunication signaling over analog telephone lines in the voice-frequency band between telephone handsets and other communications devices and the switching center. The version of DTMF that is used in push-button telephones for tone dialing is known as Touch-Tone, first used by AT&T in commerce as a registered trademark The Touch-Tone system, using the telephone keypad, gradually replaced the use of rotary dial starting in 1963, and since then DTMF or Touch-Tone became the industry standard for both cell phones and landline service.

#, *, A, B, C, and D

DTMF keypad layout.DTMF keypad frequencies (with sound clips)

1209 Hz 1336 Hz 1477 Hz 1633 Hz697 Hz 1 2 3 A770 Hz 4 5 6 B852 Hz 7 8 9 C941 Hz * 0 # D

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Description of DTMF decoder IC: The M-8870 is a full DTMF Receiver that integrates both bandsplit filter and decoder functions into a single 18-pin DIP or SOIC package. Manufactured using CMOS process technology, the M-8870 offers low power consumption (35 mW max) and precise data handling. Its filter section uses switched capacitor technology for both the high and low group filters and for dial tone rejection. Its decoder uses digital counting techniques to detect and decode all 16 DTMF tone pairs into a 4-bit code.

PIN DIAGRAM:

TONE DECODING:

Applications:• Telephone switch equipment• Remote data entry• Paging systems• Personal computers• Credit card systems

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http://upload.wikimedia.org/wikipedia/commons/e/e7/DtmfStar.ogg

http://upload.wikimedia.org/wikipedia/en/9/96/DtmfC.ogg

http://upload.wikimedia.org/wikipedia/en/5/59/Dtmf9.ogg

http://upload.wikimedia.org/wikipedia/en/f/f7/Dtmf8.ogg

http://upload.wikimedia.org/wikipedia/en/9/9f/Dtmf7.ogg

http://upload.wikimedia.org/wikipedia/en/5/5a/DtmfB.ogg

http://upload.wikimedia.org/wikipedia/en/7/7b/Dtmf6.ogg

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http://upload.wikimedia.org/wikipedia/en/9/9f/Dtmf4.ogg

http://upload.wikimedia.org/wikipedia/en/d/d5/DtmfA.ogg

http://upload.wikimedia.org/wikipedia/en/2/28/Dtmf3.ogg

http://upload.wikimedia.org/wikipedia/en/7/7d/Dtmf2.ogg

http://upload.wikimedia.org/wikipedia/en/b/bf/Dtmf1.ogg

http://en.wikipedia.org/wiki/Landline

http://en.wikipedia.org/wiki/Mobile_phone

http://en.wikipedia.org/wiki/Rotary_dial

http://en.wikipedia.org/wiki/Telephone_keypad

http://en.wikipedia.org/wiki/Push-button_telephone

http://en.wikipedia.org/wiki/Automatic_telephone_exchange

http://en.wikipedia.org/wiki/Telephone

http://en.wikipedia.org/wiki/Signalling_(telecommunications)

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10.4.5 L57404 (HEX Inverting IC):In digital logic, an inverter or NOT gate is a logic gate which implements logical negation.

Shown above:The NOT gate on lines 3 and 4 will be put into an astable mode where no definite state can be resolved. Consequently, the LED will blink on and off at a rate dependent on the response time of the inverter gate (NOT gate) and prorogation delays. With adequate support electronics, the blink rate can be precisely controlled. Performing similar experiments can also allow the simple construction of AM radio transmitters, since the speed of most 7404 chips is well beyond the range of standard AM radios. Outputs of one gate can be connected to inputs of another within the same chip or to another chip as long as they share the same ground. The figure to the left illustrates a basic circuit showing how to wire inputs and using LEDs to display outputs.

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10.4.6 L293D:

Whenever a robotics hobbyist talk about making a robot, the first thing comes to his mind is making the robot move on the ground. And there are always two options in front of the designer whether to use a DC motor or a stepper motor. When it comes to speed, weight, size, cost... DC motors are always preffered over stepper motors. There are many things which you can do with your DC motor when interfaced with a microcontroller. For example you can control the speed of motor, you can control the direction of rotation, you can also do encoding of the rotation made by DC motor i.e. keeping track of how many turns are made by your motors etc. So you can see DC motors are no less than a stepper motor.

In this,l we will learn to interfacing a DC motor with a microcontroller. Usually H-bridge is preffered way of interfacing a DC motor. These days many IC manufacturers have H-bridge motor drivers available in the market like L293D is most used H-Bridge driver IC. H-bridge can also be made with the help of trasistors and MOSFETs etc. rather of being cheap, they only increase the size of the design board, which is somtimes not required so using a small 16 pin IC is preffered for this purpose.

Working The name "H-Bridge" is derived from the actual shape of the switching circuit which control the motoion of the motor. It is also known as "Full Bridge". Basically there are four switching elements in the H-Bridge as shown in the figure below.

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As you can see in the figure above there are four switching elements named as "High side left", "High side right", "Low side right", "Low side left". When these switches are turned on in pairs motor changes its direction accordingly. Like, if we switch on High side left and Low side right then motor rotate in forward direction, as current flows from Power supply through the motor coil goes to ground via switch low side right. This is shown in the figure below.

Similarly, when you switch on low side left and high side right, the current flows in opposite direction and motor rotates in backward direction. This is the basic working of H-Bridge. We can also make a small truth table according to the switching of H-Bridge explained above.

Truth TableHigh Left High Right Low Left Low Right DescriptionOn Off Off On Motor runs clockwiseOff On On Off Motor runs anti-clockwiseOn On Off Off Motor stops or deceleratesOff Off On On Motor stops or decelerates

As already said, H-bridge can be made with the help of trasistors as well as MOSFETs, the only thing is the power handling capacity of the circuit. If motors are needed to run with high current then lot of dissipation is there. So head sinks are needed to cool the circuit.

Now you might be thinkin why i did not discuss the cases like High side left on and Low side left on or high side right on and low side right on. Clearly seen in the

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diagra, you don't want to burn your power supply by shorting them. So that is why those combinations are not discussed in the truth table

L293D is a dual H-Bridge motor driver, So with one IC we can interface two DC motors which can be controlled in both clockwise and counter clockwise direction and if you have motor with fix direction of motion the you can make use of all the four I/Os to connect up to four DC motors. L293D has output current of 600mA and peak output current of 1.2A per channel. Moreover for protection of circuit from back EMF ouput diodes are included within the IC. The output supply (VCC2) has a wide range from 4.5V to 36V, which has made L293D a best choice for DC motor driver.A simple schematic for interfacing a DC motor using L293D is shown below.

As you can see in the circuit, three pins are needed for interfacing a DC motor (A, B, Enable). If you want the o/p to be enabled completely then you can connect Enable to VCC and only 2 pins needed from controller to make the motor work.

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10.5 CIRCUIT DIAGRAM:

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10.6 PCB LAYOUT:

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10.7 MICROCONTROLLER CODE:Hardware declarationlcdport equ p1rs equ p2.6en equ p2.5buzzer bit p0.1led bit p0.0enm bit p2.0ma1 bit p2.1mb1 bit p2.2ma2 bit p2.3mb2 bit p2.4s1 bit p0.2s2 bit p0.3s3 bit p0.4s4 bit p0.5

ORG 0030HPOWERON: MOV SP,#70H ; Move the stack pointer at 70h location MOV IE,#00H ; Disable all the interrupts MOV IP,#00H ; Dissable the interrupt priority register MOV P0,#0FFH ; Move 0FFH in in port 0 MOV P1,#0FFH ; Move 0FFH in in port 1 MOV P2,#0FFH ; Move 0FFH in in port 2 MOV P3,#0FFH ; Move 0FFH in in port 3RAM CLEARANCE MOV R0,#7FHRAM_CLR: MOV @R0,#00H ; Clear the RAM from 00 to 7FH DJNZ R0,RAM_CLR

MAINPROGmov lcdport,#38hacall commandacall delaymov lcdport,#01hacall commandacall delaymov lcdport,#0ch

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acall commandacall delaymov lcdport,#80hacall commandacall delaymov dptr,#200hmov r4,#19acall display

main: acall indicator

acall keysensesjmp main

indicator: clr buzzer acall delay setb buzzer acall delay ret

keysense:

mov a,p0 anl a,#11110000b cjne a,#11110000b,check1 acall forward acall delay mov lcdport,#80h acall command acall delay mov dptr,#220h mov r4,#10 acall display acall indicator sjmp keysensecheck1: mov a,p1 anl a,#00110000b cjne a,#00110000b,check2 acall left acall delay mov lcdport,#80h acall command acall delay mov dptr,#240h mov r4,#10 acall display acall indicator sjmp main

check2: mov a,p1

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anl a,#11000000b cjne a,#11000000b,exit acall right acall delay mov lcdport,#80h acall command acall delay mov dptr,#260h mov r4,#10 acall display acall indicator sjmp keysenseexit: acall stop acall delay mov dptr,#280h mov r4,#10 mov lcdport,#80h acall command acall delay acall display ljmp main ret

backward:

setb p2.3setb p2.4sjmp keysenseret

forward:setb enmsetb ma1clr mb1setb enmsetb ma2clr mb2ret

left:setb enmsetb ma1clr mb1setb enmclr ma2setb mb2ret

right:setb enmclr ma1

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setb mb1setb enmsetb ma2clr mb2ret

stop:setb enmsetb ma1setb mb1setb enmsetb ma2setb mb2

ret

command:data:setb rssetb ennopnopnopnopclr enret

delay:mov r1,#10dgo2:mov r2,#100dgo3:mov r3,#100dgo:djnz r3,godjnz r2,go3djnz r1,go2ret

org 200hdb 'CELLPHONE OPERATED LAND ROVER ROBOT'org 220hdb 'FORWARD'org 260hdb 'RIGHT TURN'org 240hdb 'LEFT TURN'org 280hdb 'STOP'end

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10.8 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 CM8870 by a 'DTMF Transceiver IC’ CM8880, 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.

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10.9 INDUSTRIAL APPLICATIONS:

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 20th century. Soviet Red Army used remotely controlled Teletanks during 1930s 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.

3) 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).

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10.10 TOOLS/SOFTWARES /COMPONENTS REQUIRED KEIL µ Vision2 Software for programming of Microcontroller.

I.C Programmer and Software for the burning of the Microcontroller.

PC and line driver circuit.

Microphone and audio speaker.

Components for designing of the embedded part.

Components used:- " MT8870 DTMF DECODER - 1 " AT89S52 – 1 " L293d motor driver ic - 1 " Cd7004 not gate ic - 1 " 1n4007 diode - 1 " 100k resistances - 2 " 10 k resistances - 5 " 330 k resistances - 1 " 0.47mf capacitors - 1 " 0.1mf capacitors - 1 " 22pf capacitors - 4 " 3.57mhz crystal - 1 " 12mhz crystal - 1 " Push to on switch - 1 " 2 geared motors (6v, 50 rpm) - 2 (4 for four wheel drive) " Battery 6v – 1 wheels - 4 cellphone - 2 (one urs and one can be ur frnds)

handsfree - 1 (for the phn on the rover)

Soldering kit.

Measuring Instruments (Multi-meter), etc.

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10.11 BIBLIOGRAPHY/ REFERENCES:

1. 8051 Microcontroller and Embedded Systems, by Muhammad Ali Mazidi.

2. The 8051 Microcontroller, Kenneth J. Ayala.

3. Programming & Customizing The 8051 Microcontroller, by Predko M

4. www.google.com .

5. www.wikipedia.com .

6. www.electrosoftwiz.com .

7. www.electronics.com .

8. www.datasheets.com 9. www.8051projects.info 10. www.instructables.com 11. “DTMF Tester” , ‘Electronics For You’ Magazine , Edition (June 2003) 12. www.alldatasheet.com

13. www.datasheet4u.com

14. www.datasheetcatalog.com

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http://www.electrosoftwiz.com/

http://www.wikipedia.com/

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Embedded System Industrial Trainng Report

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Transcript of Embedded System Industrial Trainng Report