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RFID READER BASED Attendance System

Objective :-

• To interface 8051 with Serial devivce

• To Study RFID Reader

FEATURES.

USING MICROCONTROLLER 89S51 ( 40 PIN) MICROCONTROLLERLCD INTERFACE. 2 BY 16 LINE4 VOTE CAST SWITCH.4 INDIVIDUAL VOTE CHECKING MACHINE.1 SWITCH FOR TOTAL VOTE2 SWITCH FOR RESET THE WHOLE DATA.1 SWITCH FOR ELECTION CONTROL.1 ALARNM POINT FOR VAOTE CASTING INDICATION.24C02 FLASH MEMORY

Detail methodology

Methodology of this project Serial Communication Between Reader and Microcntroller. Tag will give 32 character to reader. Reader will give data to 89s52. We will work on serial communication and RFID technology.

In this project we will use UID. UID is unique Identification using RFID reader machine Reader. We will use 125KHz frequency RFID for Reading purpose. Tag will be provided to each for identification. Person will have to show tag. Reader will tag and machine will give serial output. Max232 will be used for communication between RFID machine reader and Microcontroller 89s52. LCD will show each tag Number on LCD.

In this voting machine we use ic 89s52 as a main microcontroller. Lcd available is 2 by 16 line. Eerom is 24c02 . Pin no 40 is connected to the positive supply. Pin no 20 is connected to the negative supply.

Pin 1 to 4 of IC2 is connected with IC1 ‘s port 0. Thsese pins are to mark attendance. Pin 5 to 8 is to check the attendance of Individual candidate.Crystal is connected to the pin no 18 and pin no 19

Pin no 21 is the output pin and buzzer is connected to the pin no 21

Pin no 9 is connected to the reset button to reset the microcontroller automatically when we switch on the power. Power on reset

Eerom of this circuit is 24c02

Pin no 8 is connected to the positive supply. Pin no 1,2,3,4 is connected to the ground pin. Pin no 6,7,8 is the data read and write pins and these pins are connected to the Pin no 22,23,24

In this project firstly we use one step down transformer. Step down

transformer step down the voltage from 220 volt Ac to 12 volt Ac. This Ac

voltage is further converted into DC with the help of rectifier circuit. In

rectifier circuit we use four diode. All the diodes are arranges as a bridge

rectifier circuit. Output of this rectifier is pulsating Dc. To convert this

pulsating DC into smooth dc we use one capacitor as a filter components.

Capacitor converts the pulsating Dc into smooth DC with the help of its

charging and discharging effect.

Output of the rectifier is now regulated with the help of IC regulator circuit.

In this project we use positive voltage regulator circuit. Here we use three

pin regulator. Output of this regulator is regulated voltage. If we use 7805

regulator then its means its is 5 volt regulator and if we use 7808 regulator

then its means that it is 8 volt regulator circuit. In this project we use 5 volt

dc regulated power supply for the complete circuit. Separate 9 volt dc power

supply is used for the relay coil

89s52 microcontroller is a main ic of this project. To drive the lcd,

to check the balance amount and balance comparison all this

activity is done in the this ic. Here we use microcontroller for this

purpose. We wrote a program for this ic. Program is to be written

in the ASM codes and then this code is converted into hex code

with the help of the assembler. In this project we use 8051 ide

software to assemble the asm codes into hex code. Once the code

is converted into hex code then we transfer this code in the blank

ic with the help of program kit connected with the computer. After

transfer the hex code in the blank ic our ic is ready for the

project .

LCD INTERFACE.

In this project we use lcd for output device. Here in this project we use 2 by

16 lcd for the output device. LCD drive by the microcontroller directly

with the port p0. In this project we use 8 data line for the data transfer from

the microcontroller to lcd. Our processor inside the controller is 8 bit

processor, so we use parallel line transfer from microcontroller to lcd. Three

control line R/S, R/W, AND ENABLE is also provided by the

microcontroller itself.

Lcd display welcome message. In the starting, then after show the recharge

value of the money Then display the balance in first line and in the second

line show the unit consumption and pulse counter logic.

COMPONENTS USED IN THE PROJECT VOTING MACHINE:

STEP DWON TRANSFORMER 9-0-9

DIODE IN 4007 (2)

CAPACITOR:

470 MFD, 1000MFD, 10 MFD, 27 PF(2)

IC 89s52 OR 89S51 ( 40 PIN MICROCONTROLLER)

LCD 2BY 16.

MEMORY IC 24C02

PUSH TO ON SWITCHES. 12 SWITCHES.

CRYSTAL 12 MHZ

PULL UP RESISTOR 10 K OHM ( CONNECTED TO PORT 0)

PC B DESIGN

BUZZER ALARM.

Complete PIN LAYOUT of the voting machine.

In this voting machine we use ic 89s52 as a main microcontroller. Lcd

available is 2 by 16 line. Eerom is 24c02 .

Pin no 40 is connected to the positive supply. Pin no 20 is connected to the

negative supply. All the input switches are connected to the pin no 1,2,3,

4,5 6,7,8 ,10,11,12, 13

Pin no 1,4,6,8, is connected to the four different candidate vote enter switch

Pin no 2,3,5,7 is connected to the check the vote of individual candidate

Pin no 10 is connected to the total vote

Pin no 12 is control the voting, After pressing this switch by both controller

we enter the vote on different candidate

Block Diagram:

Description of Project

In this project LCD is connected to Microcntroller port 0. RFID is

connected to MCU at port pins p3.0 and p3.1. when any data card come

contact with RFID reader then our reader give 32 character serial data to

mcuCandidate selection switches

LCD display

Check switch for each candidate & reset sw

Supply circuit5v

buzzer

mcu. MCU pick last 8 bits and save in serial eeprom 24c02. Serial eeprom

is to save data permanently. When switch off power even then eeprom save

RFID tags. Our controller 1 give output at port 0. P0.0 connected to mcu2

port p1.0 respectively. Similarly p0.1 connected to p1.1.

In this controller we will connect lcd at port 1 and switches to check vote at

port1.

Rs , rw , and en of LCD at port p2.5, pp2.4 and p2.3 respectively.

To check total votes at pin p3.0

We used 5v DC power supply for whole circuit.

We used 12v 1A adapter for RFID reader.

About controller used in Circuit.

Look around. Notice the smart “intelligent” systems? Be it the T.V, washing machines, video games, telephones, automobiles, aero planes, power systems, or any application having a LED or a LCD as a user interface, the control is likely to be in the hands of a micro controller!

Measure and control, that’s where the micro controller is at its best.

Micro controllers are here to stay. Going by the current trend, it is obvious that micro controllers will be playing bigger and bigger roles in the different activities of our lives.

These embedded chips are very small, but are designed to replace components much bigger and bulky In size. They process information very intelligently and efficiently. They sense the environment around them. The signals they gather are tuned into digital data that streams through tributaries of circuit lines at the speed of light. Inside the microprocessor collates and calculators. The software has middling intelligence. Then in a split second, the processed streams are shoved out.

What is the primary difference between a microprocessor and a micro controller?

Unlike the microprocessor, the micro controller can be considered to be a true “Computer on a chip”.

In addition to the various features like the ALU, PC, SP and registers found on a microprocessor, the micro controller also incorporates features like the ROM, RAM, Ports, timers, clock circuits, counters, reset functions etc.

While the microprocessor is more a general-purpose device, used for read, write and calculations on data, the micro controller, in addition to the above functions also controls the environment.

8051 micro controller

The 8051

The 8051 developed and launched in the early 80`s, is one of the most popular micro controller in use today. It has a reasonably large amount of built in ROM and RAM. In addition it has the ability to access external memory.

The generic term `8x51` is used to define the device. The value of x defining the kind of ROM, i.e. x=0, indicates none, x=3, indicates mask ROM, x=7, indicates EPROM and x=9 indicates EEPROM or Flash.

A note on ROM

The early 8051, namely the 8031 was designed without any ROM. This device could run only with external memory connected to it. Subsequent developments lead to the development of the PROM or the programmable ROM. This type had the disadvantage of being highly unreliable.

The next in line, was the EPROM or Erasable Programmable ROM. These devices used ultraviolet light erasable memory cells. Thus a program could be loaded, tested and erased using ultra violet rays. A new program could then be loaded again.

An improved EPROM was the EEPROM or the electrically erasable PROM. This does not require ultra violet rays, and memory can be cleared using circuits within the chip itself.

Finally there is the FLASH, which is an improvement over the EEPROM. While the terms EEPROM and flash are sometimes used interchangeably, the difference lies in the fact that flash erases the complete memory at one stroke, and not act on the individual cells. This results in reducing the time for erasure.

Different microcontrollers in market.

• PIC One of the famous microcontrollers used in the industries. It is based on RISC Architecture which makes the microcontroller process faster than other microcontroller.

• INTEL These are the first to manufacture microcontrollers. These are not as sophisticated other microcontrollers but still the easiest one to learn.

• ATMEL Atmel’s AVR microcontrollers are one of the most

powerful in the embedded industry. This is the only microcontroller having 1kb of ram even the entry stage. But it is unfortunate that in India we are unable to find this kind of microcontroller.

Intel 8051

Intel 8051 is CISC architecture which is easy to program in assembly language and also has a good support for High level languages.

The memory of the microcontroller can be extended up to 64k.

This microcontroller is one of the easiest microcontrollers to learn.

The 8051 microcontroller is in the field for more than 20 years. There are lots of books and study materials are readily available for 8051.

Derivatives

The best thing done by Intel is to give the designs of the 8051 microcontroller to everyone. So it is not the fact that Intel is the only manufacture for the 8051 there more than 20 manufactures, with each of minimum 20 models. Literally there are hundreds of models of 8051 microcontroller available in market to choose. Some of the major manufactures of 8051 are

Atmel

Philips

PhilipsThe Philips‘s 8051 derivatives has more number of features than in any

microcontroller. The costs of the Philips microcontrollers are higher than the Atmel’s which makes us to choose Atmel more often than Philips

Dallas

Dallas has made many revolutions in the semiconductor market. Dallas’s 8051 derivative is the fastest one in the market. It works 3 times as fast as a 8051 can process. But we are unable to get more in India.

Atmel These people were the one to master the flash devices. They are the cheapest

microcontroller available in the market. Atmel’s even introduced a 20pin variant of 8051 named 2051. The Atmel’s 8051 derivatives can be got in India less than 70 rupees. There are lots of cheap programmers available in India for Atmel. So it is always good for students to stick with 8051 when you learn a new microcontroller.

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Architecture

Architecture is must to learn because before learning new machine it is necessary to learn the capabilities of the machine. This is some thing like before learning about the car you cannot become a good driver. The architecture of the 8051 is given below.

The 8051 doesn’t have any special feature than other microcontroller. The only feature is that it is easy to learn. Architecture makes us to know about the hardware features of the microcontroller. The features of the 8051 are

4K Bytes of Flash Memory 128 x 8-Bit Internal RAM Fully Static Operation: 1 MHz to 24 MHz 32 Programmable I/O Lines Two 16-Bit Timer/Counters Six Interrupt Sources (5 Vectored) Programmable Serial Channel Low Power Idle and Power Down Modes

The 8051 has a 8-Bit CPU that means it is able to process 8 bit of data at a time. 8051 has 235 instructions. Some of the important registers and their functions are

Let’s now move on to a practical example. We shall work on a simple

practical application and using the example as a base, shall explore the

various features of the 8051 microcontroller.

Consider an electric circuit as follows,

The positive side (+ve) of the battery is connected to one side of a switch. The other side of the switch is connected to a bulb or LED (Light Emitting Diode). The bulb is then connected to a resistor, and the other end of the resistor is connected to the negative (-ve) side of the battery.

When the switch is closed or ‘switched on’ the bulb glows. When the switch is open or ‘switched off’ the bulb goes off

If you are instructed to put the switch on and off every 30 seconds, how would you do it? Obviously you would keep looking at your watch and every time the second hand crosses 30 seconds you would keep turning the switch on and off.

Imagine if you had to do this action consistently for a full day. Do you think you would be able to do it? Now if you had to do this for a month, a year??

No way, you would say!

The next step would be, then to make it automatic. This is where we use the Microcontroller.

But if the action has to take place every 30 seconds, how will the microcontroller keep track of time?

Execution time

Look at the following instruction, clr p1.0

This is an assembly language instruction. It means we are instructing the microcontroller to put a value of ‘zero’ in bit zero of port one. This instruction is equivalent to telling the microcontroller to switch on the bulb.

The instruction then to instruct the microcontroller to switch off the bulb is,

Set p1.0

This instructs the microcontroller to put a value of ‘one’ in bit zero of port one.

Don’t worry about what bit zero and port one means. We shall learn it in more detail as we proceed.

There are a set of well defined instructions, which are used while communicating with the microcontroller. Each of these instructions requires a standard number of cycles to execute. The cycle could be one or more in number.

How is this time then calculated?

The speed with which a microcontroller executes instructions is determined by what is known as the crystal speed. A crystal is a component connected externally to the microcontroller. The crystal has different values, and some of the used values are 6MHZ, 10MHZ, and 11.059 MHz etc.Thus a 10MHZ crystal would pulse at the rate of 10,000,000 times per second.

The time is calculated using the formula

No of cycles per second = Crystal frequency in HZ / 12.

For a 10MHZ crystal the number of cycles would be,

10,000,000/12=833333.33333 cycles.

This means that in one second, the microcontroller would execute

833333.33333 cycles.

Therefore for one cycle, what would be the time? Try it out.

The instruction clr p1.0 would use one cycle to execute. Similarly, the instruction setb p1.0 also uses one cycle.

So go ahead and calculate what would be the number of cycles required to be executed to get a time of 30 seconds!

Getting back to our bulb example, all we would need to do is to instruct the microcontroller to carry out some instructions equivalent to a period of 30 seconds, like counting from zero upwards, then switch on the bulb, carry out instructions equivalent to 30 seconds and switch off the bulb.

Just put the whole thing in a loop, and you have a never ending on-off sequence.

Let us now have a look at the features of the 8051 core, keeping the above example as a reference,

1. 8-bit CPU.( Consisting of the ‘A’ and ‘B’ registers)

Most of the transactions within the microcontroller are carried out through the ‘A’ register, also known as the Accumulator. In addition all arithmetic functions are carried out generally in the ‘A’ register. There is another register known as the ‘B’ register, which is used exclusively for multiplication and division.

Thus an 8-bit notation would indicate that the maximum value that can be input into these registers is ‘11111111’. Puzzled?

The value is not decimal 111, 11,111! It represents a binary number, having an equivalent value of ‘FF’ in Hexadecimal and a value of 255 in decimal.

We shall read in more detail on the different numbering systems namely the Binary and Hexadecimal system in our next module.

2. 4K on-chip ROM

Once you have written out the instructions for the microcontroller, where do you put these instructions?

Obviously you would like these instructions to be safe, and not get deleted or changed during execution. Hence you would load it into the ‘ROM’

The size of the program you write is bound to vary depending on the application, and the number of lines. The 8051 microcontroller gives you space to load up to 4K of program size into the internal ROM.

4K, that’s all? Well just wait. You would be surprised at the amount of stuff you can load in this 4K of space.

Of course you could always extend the space by connecting to 64K of external ROM if required.

3. 128 bytes on-chip RAM

This is the space provided for executing the program in terms of moving data, storing data etc.

4. 32 I/O lines. (Four- 8 bit ports, labeled P0, P1, P2, P3)

In our bulb example, we used the notation p1.0. This means bit zero of port one. One bit controls one bulb.

Thus port one would have 8 bits. There are a total of four ports named p0, p1, p2, p3, giving a total of 32 lines. These lines can be used both as input or output.

5. Two 16 bit timers / counters.

A microcontroller normally executes one instruction at a time. However certain applications would require that some event has to be tracked independent of the main program.

The manufacturers have provided a solution, by providing two timers. These timers execute in the background independent of the main program. Once the required time has been reached, (remember the time calculations

described above?), they can trigger a branch in the main program.

These timers can also be used as counters, so that they can count the number of events, and on reaching the required count, can cause a branch in the main program.

6. Full Duplex serial data receiver / transmitter.

The 8051 microcontroller is capable of communicating with external devices like the PC etc. Here data is sent in the form of bytes, at predefined speeds, also known as baud rates.

The transmission is serial, in the sense, one bit at a time

7. 5- interrupt sources with two priority levels (Two external and three internal)

During the discussion on the timers, we had indicated that the timers can trigger a branch in the main program. However, what would we do in case we would like the microcontroller to take the branch, and then return back to the main program, without having to constantly check whether the required time / count has been reached?

This is where the interrupts come into play. These can be set to either the timers, or to some external events. Whenever the background program has reached the required criteria in terms of time or count or an external event, the branch is taken, and on completion of the branch, the control returns to the main program.

Priority levels indicate which interrupt is more important, and needs to be executed first in case two interrupts occur at the same time.

8. On-chip clock oscillator.

This represents the oscillator circuits within the microcontroller. Thus the hardware is reduced to just simply connecting an external crystal, to achieve the required pulsing rate.

PIN FUNCTION OF IC 89C51.

1 Supply pin of this ic is pin no 40. Normally we apply a 5 volt regulated dc power supply to this pin. For this purpose either we use step down transformer power supply or we use 9 volt battery with 7805 regulator.

2 Ground pin of this ic is pin no 20. Pin no 20 is normally connected to the ground pin ( normally negative point of the power supply.

3 XTAL is connected to the pin no 18 and pin no 19 of this ic. The quartz crystal oscillator connected to XTAL1 and XTAL2 PIN. These pins also needs two capacitors of 30 pf value. One side of each capacitor is connected to crystal and other pis is connected to the ground point. Normally we connect a 12 MHz or 11.0592 MHz crystal with this ic.. But we use crystal upto 20 MHz to this pins

4 RESET PIN.. Pin no 9 is the reset pin of this ic.. It is an active high pin. On applying a high pulse to this pin, the micro controller will reset and terminate all activities. This is often referred to as a power on reset. The high pulse must be high for a minimum of 2 machine cycles before it is allowed to go low.

5. PORT0 Port 0 occupies a total of 8 pins. Pin no 32 to pin no 39. It can be used for input or output. We connect all the pins of the port 0 with the pullup resistor (10 k ohm) externally. This is due to fact that port 0 is an open drain mode. It is just like a open collector transistor.

6. PORT1. ALL the ports in micrcontroller is 8 bit wide pin no 1 to pin no 8 because it is a 8 bit controller. All the main register and sfr all is mainly 8 bit wide. Port 1 is also occupies a 8 pins. But there is no need of pull up resistor in this port. Upon reset port 1 act as a input port. Upon reset all the ports act as a input port

7. PORT2. port 2 also have a 8 pins. It can be used as a input or output. There is no need of any pull up resistor to this pin.

PORT 3. Port3 occupies a totoal 8 pins from pin no 10 to pin no 17. It can be used as input or output. Port 3 does not require any pull up resistor. The same as port 1 and port2. Port 3 is configured as an output port on reset. Port 3 has the additional function of providing some important signals such as interrupts. Port 3 also use for serial communication.

ALE ALE is an output pin and is active high. When connecting an 8031 to external memory, port 0 provides both address and data. In other words, the 8031 multiplexes address and data through port 0 to save pins. The ALE pin is used for demultiplexing the address and data by connecting to the ic 74ls373 chip.

PSEN. PSEN stands for program store eneable. In an 8031 based system in which an external rom holds the program code, this pin is connected to the OE pin of the rom.

EA. EA. In 89c51 8751 or any other family member of the ateml 89c51 series all come with on-chip rom to store programs, in such cases the EA pin is connected to the Vcc. For family member 8031 and 8032 is which there is no on chip rom, code is stored in external memory and this is fetched by 8031. In that case EA pin must be connected to GND pin to indicate that the code is stored externally.

SPECIAL FUNCTION REGISTER ( SFR) ADDRESSES.

ACC ACCUMULATOR 0E0H

B B REGISTER 0F0H

PSW PROGRAM STATUS WORD 0D0H

SP STACK POINTER 81H

DPTR DATA POINTER 2 BYTES

DPL LOW BYTE OF DPTR 82HDPH HIGH BYTE OF DPTR 83H

P0 PORT0 80H

P1 PORT1 90H

P2 PORT2 0A0H

P3 PORT3 0B0H

TMOD TIMER/COUNTER MODE CONTROL 89H

TCON TIMER COUNTER CONTROL 88H

TH0 TIMER 0 HIGH BYTE 8CH

TLO TIMER 0 LOW BYTE 8AH

TH1 TIMER 1 HIGH BYTE 8DH

TL1 TIMER 1 LOW BYTE 8BH

SCON SERIAL CONTROL 98H

SBUF SERIAL DATA BUFFER 99H

PCON POWER CONTROL 87H

INSTRUCTIONS

SINGLE BIT INSTRUCTIONS.

SETB BIT SET THE BIT =1

CLR BIT CLEAR THE BIT =0

CPL BIT COMPLIMENT THE BIT 0 =1, 1=0

JB BIT,TARGET JUMP TO TARGET IF BIT =1

JNB BIT, TARGET JUMP TO TARGET IF BIT =0

JBC BIT,TARGET JUMP TO TARGET IF BIT =1 &THEN CLEAR THE BIT

MOV INSTRUCTIONS

MOV instruction simply copy the data from one location to another location

MOV D,S

Copy the data from(S) source to D(destination)

MOV R0,A ; Copy contents of A into Register R0

MOV R1,A ; Copy contents of A into register R1

MOV A,R3 ; copy contents of Register R3 into Accnmulator.

DIRECT LOADING THROUGH MOV

MOV A,#23H ; Direct load the value of 23h in A

MOV R0,#12h ; direct load the value of 12h in R0

MOV R5,#0F9H ; Load the F9 value in the Register R5

ADD INSTRUCTIONS.

ADD instructions adds the source byte to the accumulator ( A) and place the result in the Accumulator.

MOV A, #25H

ADD A,#42H ; BY this instructions we add the value 42h in Accumulator ( 42H+ 25H)

ADDA,R3 ;By this instructions we move the data from register r3 to accumulator and then add the contents of the register into accumulator .

SUBROUTINE CALL FUNCTION.

ACALL,TARGET ADDRESS

By this instructions we call subroutines with a target address within 2k bytes from the current program counter.

LCALL, TARGET ADDRESS.

ACALL is a limit for the 2 k byte program counter, but for upto 64k byte we use LCALL instructions.. Note that LCALL is a 3 byte instructions. ACALL is a two byte instructions.

AJMP TARGET ADDRESS.

This is for absolute jump

AJMP stand for absolute jump. It transfers program execution to the target address unconditionally. The target address for this instruction must be withib 2 k byte of program memory.

LJMP is also for absoltute jump. It tranfer program execution to the target addres unconditionally. This is a 3 byte instructions LJMP jump to any address within 64 k byte location.

INSTRUCTIONS RELATED TO THE CARRY

JC TARGET

JUMP TO THE TARGET IF CY FLAG =1

JNC TARGET

JUMP TO THE TARGET ADDRESS IF CY FLAG IS = 0

INSTRUCTIONS RELASTED TO JUMP WITH ACCUMULATOR

JZ TARGET

JUMP TO TARGET IF A = 0

JNZ TARGET

JUMP IF ACCUMULATOR IS NOT ZERO

This instructions jumps if registe A has a value other than zero

INSTRUCTIONS RELATED TO THE ROTATE

RL A

ROTATE LEFT THE ACCUMULATOR

BY this instructions we rotate the bits of A left. The bits rotated out of A are rotated back into A at the opposite end

RR A

By this instruction we rotate the contents of the accumulator from right to left from LSB to MSB

RRC A

This is same as RR A but difference is that the bit rotated out of register first enter in to carry and then enter into MSB

RLC A

ROTATE A LEFT THROUGH CARRY

Same as above but but shift the data from MSB to carry and carry to LSB

RET

This is return from subroutine. This instructions is used to return from a subroutine previously entered by instructions LCALL and ACALL.

RET1

THIS is used at the end of an interrupt service routine. We use this instructions after intruupt routine,

PUSH.

This copies the indicated byte onto the stack and increments SP by . This instructions supports only direct addressing mode.

POP.

POP FROM STACK.

This copies the byte pointed to be SP to the location whose direct address is indicated, and decrements SP by 1. Notice that this instructions supports only direct addressing mode.

DPTR INSTRUCTIONS.

MOV DPTR,#16 BIT VALUE

LOAD DATA POINTER

This instructions load the 16 bit dptr register with a 16 bit immediate value

MOV C A,@A+DPTRThis instructions moves a byte of data located in program ROM into register A. This allows us to put strings of data, such as look up table elements.

MOVC A,@A+PC

This instructions moves a byte of data located in the program area to A. the address of the desired byte of data is formed by adding the program counter ( PC) register to the original value of the accumulator. INC BYTE

This instructions add 1 to the register or memory location specified by the operand.

INC AINC RnINC DIRECT

DEC BYTE

This instructions subtracts 1 from the byte operand. Note that CY is unchanged

DEC ADEC RnDEC DIRECT

ARITHMATIC INSTRUCTIONS.

ANL dest-byte, source-byte

This perform a logical AND operation

This performs a logical AND on the operands, bit by bit, storing the result in the destination. Notice that both the source and destination values are byte –size only

` DIV AB

This instructions divides a byte accumulator by the byte in register B. It is assumed that both register A and B contain an unsigned byte. After the division the quotient will be in register A and the remainder in register B.

TMOD ( TIMER MODE ) REGISTER

Both timer is the 89c51 share the one register TMOD. 4 LSB bit for the timer 0 and 4 MSB for the timer 1.

In each case lower 2 bits set the mode of the timer

Upper two bits set the operations.

GATE: Gating control when set. Timer/counter is enabled only while the INTX pin is high and the TRx control pin is set. When cleared, the timer is enabled whenever the TRx control bit is set

C/T : Timer or counter selected cleared for timer operation ( input from internal system clock)

M1 Mode bit 1

M0 Mode bit 0

M1 M0 MODE OPERATING MODE

0 0 0 13 BIT TIMER/MODE

0 1 1 16 BIT TIMER MODE

1 0 2 8 BIT AUTO RELOAD

1 1 3 SPLIT TIMER MODE

PSW ( PROGRAM STATUS WORD)

CY PSW.7 CARRY FLAG

AC PSW.6 AUXILIARY CARRY

F0 PSW.5 AVAILABLE FOR THE USER FRO GENERAL PURPOSE

RS1 PSW.4 REGISTER BANK SELECTOR BIT 1

RS0 PSW.3 REGISTER BANK SELECTOR BIT 0

0V PSW.2 OVERFLOW FLAG

-- PSW.1 USER DEFINABLE BIT

P PSW.0 PARITY FLAG SET/CLEARED BY HARDWARE

PCON REGISATER ( NON BIT ADDRESSABLE)

If the SMOD = 0 ( DEFAULT ON RESET)

TH1 = CRYSTAL FREQUENCY 256---- ____________________

384 X BAUD RATE

If the SMOD IS = 1CRYSTAL FREQUENCY

TH1 = 256--------------------------------------192 X BAUD RATE

There are two ways to increase the baud rate of data transfer in the 8051

1. To use a higher frequency crystal2. To change a bit in the PCON register

PCON register is an 8 bit register . Of the 8 bits, some are unused, and some are used for the power control capability of the 8051. the bit which is used for the serial communication is D7, the SMOD bit. When the 8051 is powered up, D7 ( SMOD BIT) OF PCON register is zero. We can set it to high by software and thereby double the baud rate

BAUD RATE COMPARISION FOR SMOD = 0 AND SMOD =1

TH1 ( DECIMAL) HEX SMOD =0 SMOD =1

-3 FD 9600 19200-6 FA 4800 9600-12 F4 2400 4800-24 E8 1200 2400

XTAL = 11.0592 MHZ

IE ( INTERRUPT ENABLE REGISTOR)

EA IE.7 Disable all interrupts if EA = 0, no interrupts is acknowledged If EA is 1, each interrupt source is individually enabled or disbaledBy sending or clearing its enable bit.

IE.6 NOT implemented

ET2 IE.5 enables or disables timer 2 overflag in 89c52 only

ES IE.4 Enables or disables all serial interrupt

ET1 IE.3 Enables or Disables timer 1 overflow interrupt

EX1 IE.2 Enables or disables external interrupt

ET0 IE.1 Enables or Disbales timer 0 interrupt.

EX0 IE.0 Enables or Disables external interrupt 0

INTERRUPT PRIORITY REGISTER

If the bit is 0, the corresponding interrupt has a lower priority and if the bit is 1 the corresponding interrupt has a higher priority

IP.7 NOT IMPLEMENTED, RESERVED FOR FUTURE USE.

IP.6 NOT IMPLEMENTED, RESERVED FOR FUTURE USE

PT2 IP.5 DEFINE THE TIMER 2 INTERRUPT PRIORITY LELVEL

PS IP.4 DEFINES THE SERIAL PORT INTERRUPT PRIORITY LEVEL

PT1 IP.3 DEFINES THE TIMER 1 INTERRUPT PRIORITY LEVEL

PX1 IP.2 DEFINES EXTERNAL INTERRUPT 1 PRIORITY LEVEL

PT0 IP.1 DEFINES THE TIMER 0 INTERRUPT PRIORITY LEVEL

PX0 IP.0 DEFINES THE EXTERNAL INTERRUPT 0 PRIORITY LEVEL

SCON: SERIAL PORT CONTROL REGISTER , BIT ADDRESSABLE

SCON

SM0 : SCON.7 Serial Port mode specifier

SM1 : SCON.6 Serial Port mode specifier

SM2 : SCON.5

REN : SCON.4 Set/cleared by the software to Enable/disable reception

TB8 : SCON.3 The 9th bit that will be transmitted in modes 2 and 3, Set/cleared By software

RB8 : SCON.2 In modes 2 &3, is the 9th data bit that was received. In mode 1, If SM2 = 0, RB8 is the stop bit that was received. In mode 0 RB8 is not used

T1 : SCON.1 Transmit interrupt flag. Set by hardware at the end of the 8th bit Time in mode 0, or at the beginning of the stop bit in the other Modes. Must be cleared by software

R1 SCON.0 Receive interrupt flag. Set by hardware at the end of the 8th bit Time in mode 0, or halfway through the stop bit time in the other Modes. Must be cleared by the software.

TCON TIMER COUNTER CONTROL REGISTER

This is a bit addressable

TF1 TCON.7 Timer 1 overflow flag. Set by hardware when the Timer/Counter 1 Overflows. Cleared by hardware as processor

TR1 TCON.6 Timer 1 run control bit. Set/cleared by software to turn Timer Counter 1 On/off

TF0 TCON.5 Timer 0 overflow flag. Set by hardware when the timer/counter 0 Overflows. Cleared by hardware as processor

TR0 TCON.4 Timer 0 run control bit. Set/cleared by software to turn timer Counter 0 on/off.

IE1 TCON.3 External interrupt 1 edge flag

ITI TCON.2 Interrupt 1 type control bit

IE0 TCON.1 External interrupt 0 edge

IT0 TCON.0 Interrupt 0 type control bit.

- 8051 Instruction SetArithmetic Operations

Mnemonic Description Size Cycles

ADD A,Rn Add register to Accumulator (ACC). 1 1

ADD A,direct Add direct byte to ACC. 2 1

ADD A,@Ri Add indirect RAM to ACC . 1 1

ADD A,#data Add immediate data to ACC . 2 1

ADDC A,Rn Add register to ACC with carry . 1 1

ADDC A,direct Add direct byte to ACC with carry. 2 1

ADDC A,@Ri Add indirect RAM to ACC with carry. 1 1

ADDC A,#data Add immediate data to ACC with carry. 2 1

SUBB A,Rn Subtract register from ACC with borrow. 1 1

SUBB A,direct Subtract direct byte from ACC with borrow 2 1

SUBB A,@Ri Subtract indirect RAM from ACC with borrow. 1 1

SUBB A,#data Subtract immediate data from ACC with borrow. 2 1

INC A Increment ACC. 1 1

INC Rn Increment register. 1 1

INC direct Increment direct byte. 2 1

INC @Ri Increment indirect RAM. 1 1

DEC A Decrement ACC. 1 1

DEC Rn Decrement register. 1 1

DEC direct Decrement direct byte. 2 1

DEC @Ri Decrement indirect RAM. 1 1

INC DPTR Increment data pointer. 1 2

MUL AB Multiply A and B Result: A <- low byte, B <- high byte. 1 4

DIV AB Divide A by B Result: A <- whole part, B <- remainder. 1 4

DA A Decimal adjust ACC. 1 1

Logical Operations

Mnemonic Description Size Cycles

ANL A,Rn AND Register to ACC. 1 1

ANL A,direct AND direct byte to ACC. 2 1

ANL A,@Ri AND indirect RAM to ACC. 1 1

ANL A,#data AND immediate data to ACC. 2 1

ANL direct,A AND ACC to direct byte. 2 1

ANL direct,#data AND immediate data to direct byte. 3 2

ORL A,Rn OR Register to ACC. 1 1

ORL A,direct OR direct byte to ACC. 2 1

ORL A,@Ri OR indirect RAM to ACC. 1 1

ORL A,#data OR immediate data to ACC. 2 1

ORL direct,A OR ACC to direct byte. 2 1

ORL direct,#data OR immediate data to direct byte. 32

XRL A,Rn Exclusive OR Register to ACC. 1 1

XRL A,direct Exclusive OR direct byte to ACC. 2 1

XRL A,@Ri Exclusive OR indirect RAM to ACC. 1 1

XRL A,#data Exclusive OR immediate data to ACC. 2 1

XRL direct,A Exclusive OR ACC to direct byte. 2 1

XRL direct,#data XOR immediate data to direct byte. 3 2

CLR A Clear ACC (set all bits to zero). 1 1

CPL A Compliment ACC. 1 1

RL A Rotate ACC left. 1 1

RLC A Rotate ACC left through carry. 1 1

RR A Rotate ACC right. 1 1

RRC A Rotate ACC right through carry. 1 1

SWAP A Swap nibbles within ACC. 1 1

Data Transfer

Mnemonic Description Size Cycles

MOV A,Rn Move register to ACC. 1 1

MOV A,direct Move direct byte to ACC.2 1

MOV A,@Ri Move indirect RAM to ACC. 1 1

MOV A,#data Move immediate data to ACC. 2 1

MOV Rn,A Move ACC to register. 1 1

MOV Rn,direct Move direct byte to register. 2 2

MOV Rn,#data Move immediate data to register. 2 1

MOV direct,A Move ACC to direct byte. 2 1

MOV direct,Rn Move register to direct byte. 2 2

MOV direct,direct Move direct byte to direct byte. 3 2

MOV direct,@Ri Move indirect RAM to direct byte. 2 2

MOV direct,#data Move immediate data to direct byte. 3 2

MOV @Ri,A Move ACC to indirect RAM. 1 1

MOV @Ri,direct Move direct byte to indirect RAM. 2 2

MOV @Ri,#data Move immediate data to indirect RAM. 2 1

MOV DPTR,#data16 Move immediate 16 bit data to data pointer register. 3 2

MOVC A,@A+DPTR Move code byte relative to DPTR to ACC (16 bit address).1 2

MOVC A,@A+PC Move code byte relative to PC to ACC (16 bit address).1 2

MOVX A,@Ri Move external RAM to ACC (8 bit address). 1 2

MOVX A,@DPTR Move external RAM to ACC (16 bit address). 1 2

MOVX @Ri,A Move ACC to external RAM (8 bit address). 1 2

MOVX @DPTR,A Move ACC to external RAM (16 bit address). 1 2

PUSH direct Push direct byte onto stack. 2 2

POP direct Pop direct byte from stack. 2 2

XCH A,Rn Exchange register with ACC. 1 1

XCH A,direct Exchange direct byte with ACC. 2 1

XCH A,@Ri Exchange indirect RAM with ACC. 1 1

XCHD A,@Ri Exchange low order nibble of indirect

RAM with low order nibble of ACC 1 1

Boolean Variable Manipulation

Mnemonic Description Size Cycles

CLR C Clear carry flag. 1 1

CLR bit Clear direct bit. 2 1

SETB C Set carry flag. 1 1

SETB bitSet direct bit 2 1

CPL C Compliment carry flag. 1 1

CPL bit Compliment direct bit. 2 1

ANL C,bit AND direct bit to carry flag. 2 2

ANL C,/bit AND compliment of direct bit to carry. 2 2

ORL C,bit OR direct bit to carry flag. 2 2

ORL C,/bit OR compliment of direct bit to carry. 2 2

MOV C,bit Move direct bit to carry flag. 2 1

MOV bit,C Move carry to direct bit. 2 2

JC rel Jump if carry is set. 2 2

JNC rel Jump if carry is not set. 2 2

JB bit,rel Jump if direct bit is set. 3 2

JNB bit,rel Jump if direct bit is not set. 3 2

JBC bit,rel Jump if direct bit is set & clear bit. 3 2

Program BranchingMnemonic Description Size Cycles

ACALL addr11 Absolute subroutine call. 2 2

LCALL addr16 Long subroutine call. 3 2

RET Return from subroutine. 1 2

RETI Return from interrupt. 1 2

AJMP addr11 Absolute jump. 2 2

LJMP addr16 Long jump. 3 2

SJMP rel Short jump (relative address). 2 2

JMP @A+DPTR Jump indirect relative to the DPTR. 1 2

JZ rel Jump relative if ACC is zero. 2 2

JNZ rel Jump relative if ACC is not zero. 2 2

CJNE A,direct,rel Compare direct byte to ACC and jump if not equal. 3 2

CJNE A,#data,rel Compare immediate byte to ACC and jump if not equal.3 2

CJNE Rn,#data,rel Compare immediate byte to register and jump if not equal.32

CJNE @Ri,#data,rel Compare immediate byte to indirect and jump if not equal.32

DJNZ Rn,rel Decrement register and jump if not zero. 2 2

DJNZ direct,rel Decrement direct byte and jump if not zero. 3 2

Other Instructions

Mnemonic Description Size Cycles

NOP No operation. 1 1

component qty rateIC89C051, 1 60

ULN2003, 1 30

Diodes in4001, 4 1

IC 7805 1 15

Optocoupler PC817 4 12

Tr548 4 3

Tr 558 4 3Motors 12v 2 250

IC base 20 pin 1 10Crystal 12 Mhz 1 25Resiatncec 10k 4 .254k 4 .25Cap 10µf 1 5Connecting wires 1 20Ir sensors 3 120

• Software:-Keil compiler or UMPS for programmingWindow xp

Bibliography:

http://www.sciencejoywagon.com/physicszone/lesson/otherpub/wfendt/electricmotor.htm

exists which allows us to communicate with the vast 3 control lines as well as either 4 or

8 I/O lines for the data bus. The user may select whether the LCD is to operate with a 4-

bit data bus or an 8-bit data bus. If a 4-bit data bus is used, the LCD The 44780 standard

requires 3 control lines as well as either 4 or 8 I/O lines for the data bus. The user may

select whether the LCD is to operate with a 4-bit data bus or an 8-bit data bus. If a 4-bit

data bus is used, the LCD will require a total of 7 data lines (3 control lines plus the 4

lines for the data bus). If an 8-bit data bus is used, the LCD will require a total of 11 data

lines (3 control lines plus the 8 lines for the data bus).

The three control lines are referred to as EN, RS, and RW.

will require a total of 7 data lines (3 control lines plus the 4 lines for the data bus). If an

8-bit data bus is used, the LCD will require a total of 11 data lines (3 control lines plus

the 8 lines for the data bus).

The three control lines are referred to as EN, RS, and RW.

The EN line is called "Enable." This control line is used to tell the LCD that you are

sending it data. To send data to the LCD, your program should first set this line high (1)

and then set the other two control lines and/or put data on the data bus. When the other

lines are completely ready, bring EN low (0) again. The 1-0 transition tells the 44780 to

take the data currently found on the other control lines and on the data bus and to treat it

as a command.

The RS line is the "Register Select" line. When RS is low (0), the data is to be treated as

a command or special instruction (such as clear screen, position cursor, etc.). When RS is

high (1), the data being sent is text data which should be displayed on the screen. For

example, to display the letter "T" on the screen you would set RS high.

The RW line is the "Read/Write" control line. When RW is low (0), the information on

the data bus is being written to the LCD. When RW is high (1), the program is effectively

querying (or reading) the LCD. Only one instruction ("Get LCD status") is a read

command. All others are write commands--so RW will almost always be low.

Finally, the data bus consists of 4 or 8 lines (depending on the mode of operation selected

by the user). In the case of an 8-bit data bus, the lines are referred to as DB0, DB1, DB2,

DB3, DB4, DB5, DB6, and DB7.

Fortunately, a very popular standard exists which allows us to communicate with the vast

majority of data from an external source (in this case, the 8051) and communicates

directly with the LCD.

I

atic Showing Column of Laser Light Leaving Optical Oscillator

COMPONENT DESCRIPTION

TRANSFORMER

Transformer works on the principle of mutual inductance. We know that if two coils or

windings are placed on the core of iron, and if we pass alternating current in one winding,

back emf or induced voltage is produced in the second winding. We know that alternating

current always changes with the time. So if we apply AC voltage across one winding, a

voltage will be induced in the other winding. Transformer works on this same principle.

It is made of two windings wound around the same core of iron. The winding to which

AC voltage is applied is called primary winding. The other winding is called as

secondary winding.

Voltage and current relationship:

Let V1 volts be input alternating voltage applied to primary winding. I1 Amp is input

alternating current through primary winding. V2 volt is output alternating voltage

produced in the secondary. I2 amp be the current flowing through the secondary.

Then relationship between input and output voltages is given by

V1/V2 = N1/N2

Relationship between input and output currents is

I1/I2 = N2/N1

(Where N1 is no. of turns of coil in primary and N2 is number of turns in secondary )

We know that Power = Current X Voltage. It is to be noted that input power is

equal to output power. Power is not changed. If V2 is greater than V1, then I2 will

be less than I1. This type of transformer is called as step up transformer. If V1 is

greater than V2, then I1 will be less than I2. This type of transformer is called as

step down transformer.

For step up transformer, N2>N1, i.e., number of turns of secondary winding is

more than those in primary.

For step down transformer, N1>N2, i.e., numbers of turns of primary winding is

more than those in secondary.

RESISTORS

The flow of charge (or current) through any material, encounters an opposing force similar in many respect to mechanical friction. This opposing

force is called resistance of the material. It is measured in ohms. In some electric circuits resistance is deliberately introduced in the form of the

resistor.Resistors are of following types:

1. Wire wound resistors.

2. Carbon resistors.

3. Metal film resistors.

Wire Wound Resistors:

Wire wound resistors are made from a long (usually Ni-Chromium) wound on a ceramic core. Longer the length of the wire, higher is the resistance. So depending on the value of resistor required in a circuit, the wire is cut and wound on a ceramic core. This entire assembly is coated with a ceramic

metal. Such resistors are generally available in power of 2 watts to several hundred watts and resistance values from 1ohm to 100k ohms. Thus wire

wound resistors are used for high currents.

Carbon Resistors:

Carbon resistors are divided into three types:a. Carbon composition resistors are made by mixing carbon grains with

binding material (glue) and moduled in the form of rods. Wire leads are inserted at the two ends. After this an insulating material seals the

resistor. Resistors are available in power ratings of 1/10, 1/8, 1/4 ,

1/2 , 1.2 watts and values from 1 ohm to 20 ohms.b. Carbon film resistors are made by deposition carbon film on a ceramic

rod. They are cheaper than carbon composition resistors.c. Cement film resistors are made of thin carbon coating fired onto a

solid ceramic substrate. The main purpose is to have more precise resistance values and greater stability with heat. They are made in a

small square with leads.

Metal Film Resistors:

They are also called thin film resistors. They are made of a thin metal coating deposited on a cylindrical insulating support. The high resistance

values are not precise in value; however, such resistors are free of inductance effect that is common in wire wound resistors at high frequency.

Variable Resistors:

Potentiometer is a resistor where values can be set depending on the requirement. Potentiometer is widely used in electronics systems. Examples are volume control, tons control, brightness and contrast control of radio or

T.V. sets.

Fusible Resistors:

These resistors are wire wound type and are used in T.V. circuits for protection. They have resistance of less than 15 ohms. Their function is

similar to a fuse made to blow off whenever current in the circuit exceeds the limit.

Resistance of a wire is directly proportional to its length and inversely proportional to its thickness.

R L R 1/A

RESISTOR COLOR CODE

Example: 1k or 1000 ohms

1st 2nd 3rd 4th

Band1

Band 2

Band 3

Band 4

COLOUR CODES

COLOUR NUMBER

MULTIPLIER

COLOUR TOLERANCE

Black Brown

RedOrange YellowGreenBlue

VioletGreyWhiteGoldSilver

0 1 2 3 4 5 6 7 8 9

100

101

102 103

104

105

106

107

108

109

10-1 10-2

GoldSilver

No colour

5% 10% 20%

CAPACITORS

A capacitor can store charge, and its capacity to store charge is called capacitance. Capacitors consist of two conducting plates, separated by an

insulating material (known as dielectric). The two plates are joined with two leads. The dielectric could be air, mica, paper, ceramic, polyester,

polystyrene, etc. This dielectric gives name to the capacitor. Like paper capacitor, mica capacitor etc.

Types of capacitors:

Capacitors can be broadly classified in two categories, i.e., Electrolytic capacitors and Non-Electrolytic capacitors as shown if the figure above.

Electrolytic Capacitor:

Electrolytic capacitors have an electrolyte as a dielectric. When such an electrolyte is charged, chemical changes takes place in the electrolyte. If its

one plate is charged positively, same plate must be charged positively in future. We call such capacitors as polarized. Normally we see electrolytic capacitor as polarized capacitors and the leads are marked with positive or

negative on the can. Non-electrolyte capacitors have dielectric

Capacitor

Fixed capacitor Variable capacitor

Electrolytic Non-Electrolytic

Pape

material such as paper, mica or ceramic. Therefore, depending upon the dielectric, these capacitors are classified.

Mica Capacitor:

It is sandwich of several thin metal plates separated by thin sheets of mica. Alternate plates are connected together and leads attached for outside connections. The total assembly is encased in a plastic capsule or Bakelite case. Such capacitors have small capacitance value (50 to 500pf) and high working voltage (500V and above). The mica capacitors have excellent characteristics under stress of

temperature variation and high voltage application. These capacitors are now replaced by ceramic capacitors.

Ceramic Capacitor:

Such capacitors have disc or hollow tabular shaped dielectric made of ceramic material such as titanium dioxide and barium titanate. Thin coating of silver compounds is deposited on both sides of

dielectric disc, which acts as capacitor plates. Leads are attached to each sides of the dielectric disc and whole unit is encapsulated in a moisture proof coating. Disc type capacitors have very high value up to 0.001uf. Their working voltages range from 3V to 60000V.

These capacitors have very low leakage current. Breakdown voltage is very high.

Paper Capacitor:

It consists of thin foils, which are separated by thin paper or waxed paper. The sandwich of foil and paper is then rolled into a

cylindrical shape and enclosed in a paper tube or encased in a plastic capsules. The lead at each end of the capacitor is internally

attached to the metal foil. Paper capacitors have capacitance

ranging from 0.0001uf to 2.0uf and working voltage rating as high as 2000V.

THE DIODE

Diodes are polarized, which means that they must be inserted into the PCB the correct way round. This is because an electric current

will only flow through them in one direction (like air will only

flow one way trough a tyre valve). Diodes have two connections, an anode and a cathode. The cathode is always identified by a dot,

ring or some other mark.

The PCB is often marked with a +sign for the cathode end. Diodes come in all shapes and sizes. They are often marked with a type

number. Detailed characteristics of a diode can be found by looking up the type number in a data book. If you know how to

measure resistance with a meter then test some diodes. A good one has low resistance in one direction and high in other. They are specialized types of diode available such as the zener and light

emitting diode (LED).

SYMBOLS OF DIFFERENT DIODES anode cathode

simple diode zener diode

+

IC

IC (Integrated Circuit) means that all the components of the circuit are fabricated

on same chip. Digital ICs are a collection of resistors, diodes, and transistors

fabricated on a single piece of semiconductor, usually silicon called a substrate,

which is commonly referred to as ‘wafer’. The chip is enclosed in a protective

plastic or ceramic package from which pins extend out connecting the IC to other

device. Suffix N or P stands for dual-in-line (plastic package (DIP)) while suffix J

or I stands for dual-in-lime ceramic package. Also the suffix for W stands for flat

ceramic package.

The pins are numbered counter clockwise when viewed from the top of the

package with respect to an identity notch or dot at one end of the chip.The

manufacturer’s name can usually be guessed from its logo that is printed on the

IC. The IC type number also indicates the manufacturer’s code. For e.g. DM 408

N SN 7404 indicates National Semiconductor and Texas Instruments.

Other examples are:

Fair Child : UA, UAF

National Semiconductor : DM, LM, LH, LF, and TA.

Motorola : MC, MFC.

Sprague : UKN, ULS, ULX.

Signetic : N/s, NE/SE, and SU.

Burr-Brown : BB.

Texas Instruments : SN.

The middle portion i.e. the IC type number tells about the IC function and also the

family, which the particular IC belongs to.IC’s that belongs to standard TTL series

have an identification number that starts with 74; for e.g. 7402, 74LS04, 74S04

etc. IC’s that belongs to standard CMOS family their number starts with 4, like

4000, 451B, 4724B, 1400. The 74C, 74HC, 74AC & 74ACT series are newer

CMOS series.

Various series with TTL logic family are:-

Standard TTL 74.

Schottky TTL 74s.

Low power Schottky 74LS.

Advance Schottky 74AS.

Advanced Low Power Schottky 74ALs.

Also there are various series with CMOS logic family as metal state CMOS 40 or

140.

Power Supply

For TTL circuits, the power supply pin is labeled Vcc and its nominal value.

For CMOS ICs, the power supply pin is labeled as VDD & its nominal value range

from T3 to 18V.

Unconnected Inputs

An unconnected input is called “floating input”. The floating TTL input acts as

logic 1. High level is applied to it. This characteristic is often used when

testing a TTL circuit. A floating TTL input will measure a DC level between 1.4V

to 1.8V when checked with VOM as oscilloscope. If a CMOS input is left floating,

it may have disastrous results. The IC may become overheated and eventually

destroy itself. For this reason, all inputs to CMOS circuit must be connected to a

LOW or HIGH level or to the output of another IC.

RELAYS

STRIP

OUT N/C

OUT N/O

SPRING

MAGNET

230V P

Error: Reference source not found

A relay is an electrically operated switch. The relay contacts can be made to

operate in the pre-arranged fashion. For instance, normally open contacts close

and normally closed contacts open. In electromagnetic relays, the contacts

however complex they might be, they have only two position i.e. OPEN and

CLOSED, whereas in case of electromagnetic switches, the contacts can have

multiple positions.

NEED FOR THE USE OF RELAY

The reason behind using relay for switching loads is to provide complete electrical

isolation. The means that there is no electrical connection between the driving

circuits and the driven circuits. The driving circuit may be low voltage operated

low power circuits that control several kilowatts of power. In our circuit where a

high fan could be switched on or off depending upon the output from the

telephone.

Since the relay circuit operated on a low voltage, the controlling circuit is quite

safe. In an electromagnetic relay the armature is pulled by a magnetic force only.

There is no electrical connection between the coil of a relay and the switching

contacts of the relay. If there are more than one contact they all are electrically

isolated from each other by mounting them on insulating plates and washers.

Hence they can be wired to control different circuits independently.

Some of the popular contacts forms are described below:

1. Electromagnetic relay

2. Power Relay.

3. Time Delay Relay.

4. Latching Relay.

5. Crystal Can Relay.

6. Co-axial Relay.

1. Electromagnetic relay:

An electromagnetic relay in its simplest form consists of a coil, a DC current

passing through which produces a magnetic field. This magnetic field attracts an

armature, which in turn operates the contacts. Normally open contacts close and

normally closed contacts open. Electromagnetic relays are made in a large variety

of contacts forms.

2. Power relays:

Power relays are multi-pole heavy duty lapper type relays that are capable of

switching resistive loads of upto 25amp.. These relays are widely used for a

variety of industrial application like control of fractional horse power motors,

solenoids, heating elements and so on. These relays usually have button like silver

alloy contacts and the contact welding due to heavy in rush current is avoided by

wiping action of the contacts to quench the arc during high voltage DC switching

thus avoiding the contact welding.

3. Time Delay Relay:

A time delay relay is the one in which there is a desired amount of time delay

between the application of the actuating signal and operation of the load switching

devices.

4. Latching Relay:

In a Latching Relay, the relay contacts remain in the last energized position even

after removal of signal in the relay control circuit. The contacts are held in the last

relay-energized position after removal of energisation either electrically or

magnetically. The contacts can be released to the normal position electrically or

mechanically.

5. Crystal Can Relay:

They are so called, as they resemble quartz crystal in external shapes. These are

high performance hermetically sealed miniature or sub-miniature relay widely

used in aerospace and military application. These relays usually have gold plated

contacts and thus have extremely low contact resistance. Due to low moment of

inertia of the armature and also due to statically and dynamically balanced nature

of armature, these relays switch quite reliably even under extreme condition of

shock and vibration.

6. Co-axial Relay:

A Co-axial Relay has two basic parts, an actuator which is nothing but some kind

of a coil and a cavity, housing the relay contacts. The co-axial relay are

extensively used for radio frequency switching operations of equipment

THE JUNCTION TRANSISTOR

Collector Collector

Base Base

Emitter Emitter

C

C B

B E

E NPN PNP

_ _ _ _ _ _ _ _ _ _

+ + + + + _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + + + + + +

+ + +

+ + + + + + + + + +

+ + + + + -- -- -- --

Junction transistors consists of two junctions made from N-type and P-Junction transistors consists of two junctions made from N-type and P-

type semiconductor materials and are called bipolar transistors (two type semiconductor materials and are called bipolar transistors (two

polarities). They have three connections emitter, base, and collector.polarities). They have three connections emitter, base, and collector.

TRANSISTOR CURRENTSTRANSISTOR CURRENTS

Collector Collector

Current Current IIcc

I Ibb

Base currentBase current

Emitter Emitter IIe e current current

I Ie e = = IIbb++IIcc

The forward biased base/emitter junction causes electrons to be The forward biased base/emitter junction causes electrons to be

attracted from the emitter area towards the base. Arriving in the base attracted from the emitter area towards the base. Arriving in the base

area, most of the negative electrons come under the influence of the area, most of the negative electrons come under the influence of the

more positive collector and are attracted by it. This is shown in the left more positive collector and are attracted by it. This is shown in the left

hand drawing, where the base current plus collector current equals thehand drawing, where the base current plus collector current equals the

emitter current. Alpha gain is collector current divided by emitter emitter current. Alpha gain is collector current divided by emitter

current, and is always less than 1. Beta gain is collector current dividedcurrent, and is always less than 1. Beta gain is collector current divided

by base current and can be fairly high number. Therefore, causing a by base current and can be fairly high number. Therefore, causing a

small base current to flow makes a much larger collector current to small base current to flow makes a much larger collector current to

flow. A small base current controls a large collector current. There is flow. A small base current controls a large collector current. There is

0.6 volts across the base\emitter junction, where it is forward biased 0.6 volts across the base\emitter junction, where it is forward biased

(0.3 volts for germanium).(0.3 volts for germanium).

How to control sensorsWhat is a voltage divider?

You are going to find out but don't be in too much of a hurry. Work through the Chapter and allow the explanation to develop.

The diagram below shows a light dependent resistor, or LDR, together with its circuit symbol:

The light-sensitive part of the LDR is a wavy track of cadmium sulphide. Light energy triggers the release of extra charge carriers in this material, so that its resistance falls as the level of illumination increases.

A light sensor uses an LDR as part of a voltage divider.

The essential circuit of a voltage divider, also called a potential divider, is:

What happens if one of the resistors in the voltage divider is replaced by an LDR? In the circuit below, Rtop is a 10 resistor, and an LDR is used as Rbottom :

Suppose the LDR has a resistance of 500 , 0.5 , in bright light, and 200 in the shade (these values are reasonable).

When the LDR is in the light, Vout will be:

In the shade, Vout will be:

In other words, this circuit gives a LOW voltage when the LDR is in the light, and a HIGH voltage when the LDR is in the shade. The voltage divider circuit gives an output voltage which changes with illumination.

A sensor subsystem which functions like this could be thought of as a 'dark sensor' and could be used to control lighting circuits which are switched on automatically in the evening.

Perhaps this does not seem terribly exciting, but almost every sensor circuit you can think of uses a voltage divider. There's just no other way to make sensor subsystems work.

Here is the voltage divider built with the LDR in place of Rtop :

Temperature sensors

A temperature-sensitive resistor is called a thermistor. There are several different types:

The resistance of most common types of thermistor decreases as the temperature rises. They are called negative temperature coefficient, or ntc, thermistors. Note the -t° next to the circuit symbol. A typical ntc thermistor is made using semiconductor metal oxide materials. (Semiconductors have resistance properties midway between those of conductors and insulators.) As the temperature rises, more charge carriers become available and the resistance falls.

Although less often used, it is possible to manufacture positive temperature coefficient, or ptc, thermistors. These are made of different materials and show an increase in resistance with temperature.

How could you make a sensor circuit for use in a fire alarm? You want a circuit which will deliver a HIGH voltage when hot conditions are detected. You need a voltage divider with the ntc thermistor in the Rtop position:

How could you make a sensor circuit to detect temperatures less than 4°C to warn motorists that there may be ice on the road? You want a circuit which will give a HIGH voltage in cold conditions. You need a voltage divider with the thermistor in place of Rbottom :

This last application raises an important question: How do you know what value of Vout you are going to get at 4°C?

Key point: The biggest change in Vout from a voltage divider is obtained when Rtop and Rbottom are equal in value

Sound sensors

Another name for a sound sensor is a microphone. The diagram shows a cermet microphone:

Cermet' stands for 'ceramic' and 'metal'. A mixture of these materials is used in making the sound-sensitive part of the microphone. To make them work properly, cermet microphones need a voltage, usually around 1.5 V across them. A suitable circuit for use with a 9 V supply is:

The 4.7 and the 1 resistors make a voltage divider which provides 1.6 V across the microphone. Sound waves generate small changes in voltage, usually in the range 10-20 mV. To isolate these small signals from the steady 1.6 V, a capacitor is used.

Signals from switches

When a switch is used to provide an input to a circuit, pressing the switch usually generates a voltage signal. It is the voltage signal which triggers the circuit into action. What do you need to get the switch to generate a voltage signal? . . . You need a voltage divider. The circuit can be built in either of two ways:

The pull down resistor in the first circuit forces Vout to become LOW except when the push button switch is operated. This circuit delivers a HIGH voltage when the switch is pressed. A resistor value of 10 is often used.

In the second circuit, the pull up resistor forces Vout to become HIGH except when the switch is operated. Pressing the switch connects Vout directly to 0 V. In other words, this circuit delivers a LOW voltage when the switch is pressed.

In circuits which process logic signals, a LOW voltage is called 'logic 0' or just '0', while a HIGH voltage is called 'logic1' or '1'. These voltage divider circuits are perfect for providing input signals for logic systems.

What kinds of switches could you use. One variety of push button switch is called a miniature tactile switch. These are small switches which work well with prototype board:

As you can see, the switch has four pins which are linked in pairs by internal metal strips. Pressing the button bridges the contacts and closes the switch. The extra pins are useful in designing printed circuit boards for keyboard input and also stop the switch from being moved about or bent once soldered into position.

There are lots of other switches which you might want to use in a voltage divider configuration. These include magnetically-operated reed switches, tilt switches and pressure pads, all with burglar alarm applications.

Transistor CircuitsThis page explains the operation of transistors in circuits. Practical matters such as testing, precautions when soldering and identifying leads are covered by the Transistors page.

General: Types | Currents | Functional model | Darlington pair Switching: Introduction | Use relay? | IC output | for NPN | and PNP | Sensors | Inverter

Next Page: Analogue and Digital Systems Also See: Transistors (soldering, lead identification)

Types of transistor

There are two types of standard transistors, NPN and PNP, with different circuit symbols. The letters refer to the layers of semiconductor material used to make the transistor. Most transistors used today are NPN because this is the easiest type to make from silicon. This page is mostly about NPN transistors and if you are new to electronics it is best to start by learning how to use these first.

The leads are labelled base (B), collector (C) and emitter (E).These terms refer to the internal operation of a transistor but they are not much help in understanding how a transistor is used, so just treat them as labels!

A Darlington pair is two transistors connected together to give a very high current gain.

In addition to standard (bipolar junction) transistors, there are field-effect transistors which are usually referred to as FETs. They have different circuit symbols and properties and they are not (yet) covered by this page.

Transistor currents

The diagram shows the two current paths through a transistor. You can build this circuit with two standard 5mm red LEDs and any general purpose low power NPN transistor (BC108, BC182 or BC548 for example).

Transistor circuit symbols

The small base current controls the larger collector current.

When the switch is closed a small current flows into the base (B) of the transistor. It is just enough to make LED B glow dimly. The transistor amplifies this small current to allow a larger current to flow through from its collector (C) to its emitter (E). This collector current is large enough to make LED C light brightly.

When the switch is open no base current flows, so the transistor switches off the collector current. Both LEDs are off.

A transistor amplifies current and can be used as a switch.

This arrangement where the emitter (E) is in the controlling circuit (base current) and in the controlled circuit (collector current) is called common emitter mode. It is the most widely used arrangement for transistors so it is the one to learn first.

Functional model of an NPN transistor

The operation of a transistor is difficult to explain and understand in terms of its internal structure. It is more helpful to use this functional model:

• The base-emitter junction behaves like a diode. • A base current IB flows only when the voltage VBE across the base-emitter

junction is 0.7V or more. • The small base current IB controls the large collector current Ic. • Ic = hFE × IB (unless the transistor is full on and saturated)

hFE is the current gain (strictly the DC current gain), a typical value for hFE is 100 (it has no units because it is a ratio)

• The collector-emitter resistance RCE is controlled by the base current IB: o IB = 0 RCE = infinity transistor off o IB small RCE reduced transistor partly on o IB increased RCE = 0 transistor full on ('saturated')

Additional notes: • A resistor is often needed in series with the base connection to limit the base

current IB and prevent the transistor being damaged. • Transistors have a maximum collector current Ic rating. • The current gain hFE can vary widely, even for transistors of the same type! • A transistor that is full on (with RCE = 0) is said to be 'saturated'. • When a transistor is saturated the collector-emitter voltage VCE is reduced to

almost 0V. • When a transistor is saturated the collector current Ic is determined by the supply

voltage and the external resistance in the collector circuit, not by the transistor's

current gain. As a result the ratio Ic/IB for a saturated transistor is less than the current gain hFE.

• The emitter current IE = Ic + IB, but Ic is much larger than IB, so roughly IE = Ic.

There is a table showing technical data for some popular transistors on the transistors page.

Darlington pair

This is two transistors connected together so that the current amplified by the first is amplified further by the second transistor. The overall current gain is equal to the two individual gains multiplied together:

Darlington pair current gain, hFE = hFE1 × hFE2 (hFE1 and hFE2 are the gains of the individual transistors)

This gives the Darlington pair a very high current gain, such as 10000, so that only a tiny base current is required to make the pair switch on.

A Darlington pair behaves like a single transistor with a very high current gain. It has three leads (B, C and E) which are equivalent to the leads of a standard individual transistor. To turn on there must be 0.7V across both the base-emitter junctions which are connected in series inside the Darlington pair, therefore it requires 1.4V to turn on.

Darlington pairs are available as complete packages but you can make up your own from two transistors; TR1 can be a low power type, but normally TR2 will need to be high

Touch switch circuit

power. The maximum collector current Ic(max) for the pair is the same as Ic(max) for TR2.

A Darlington pair is sufficiently sensitive to respond to the small current passed by your skin and it can be used to make a touch-switch as shown in the diagram. For this circuit which just lights an LED the two transistors can be any general purpose low power transistors. The 100k resistor protects the

transistors if the contacts are linked with a piece of wire.

Using a transistor as a switch

When a transistor is used as a switch it must be either OFF or fully ON. In the fully ON state the voltage VCE across the transistor is almost zero and the transistor is said to be saturated because it cannot pass any more collector current Ic. The output device switched by the transistor is usually called the 'load'.

The power developed in a switching transistor is very small:

• In the OFF state: power = Ic × VCE, but Ic = 0, so the power is zero. • In the full ON state: power = Ic × VCE, but VCE = 0 (almost), so the power is very

small.

This means that the transistor should not become hot in use and you do not need to consider its maximum power rating. The important ratings in switching circuits are the maximum collector current Ic(max) and the minimum current gain hFE(min). The transistor's voltage ratings may be ignored unless you are using a supply voltage of more than about 15V. There is a table showing technical data for some popular transistors on the transistors page.

For information about the operation of a transistor please see the functional model above.

Protection diode

If the load is a motor, relay or solenoid (or any other device with a coil) a diode must be connected across the load to protect the transistor from the brief high voltage produced when the load is switched off. The diagram shows how a protection diode is connected 'backwards' across the load, in this case a relay coil.

Current flowing through a coil creates a magnetic field which collapses suddenly when the current is switched off. The sudden collapse of the magnetic field induces a brief high voltage across the coil which is very likely to damage transistors and ICs. The protection diode allows the induced voltage to drive a brief

current through the coil (and diode) so the magnetic field dies away quickly rather than instantly. This prevents the induced voltage becoming high enough to cause damage to transistors and ICs.

When to use a relay

Transistors cannot switch AC or high voltages (such as mains electricity) and they are not usually a good choice for switching large currents (> 5A). In these cases a relay will be needed, but note that a low power transistor may still be needed to switch the current for the relay's coil!

Advantages of relays:

• Relays can switch AC and DC, transistors can only switch DC. • Relays can switch high voltages, transistors cannot. • Relays are a better choice for switching large currents (> 5A). • Relays can switch many contacts at once.

Disadvantages of relays: • Relays are bulkier than transistors for switching small currents. • Relays cannot switch rapidly, transistors can switch many times per second. • Relays use more power due to the current flowing through their coil. • Relays require more current than many ICs can provide, so a low power transistor may be

needed to switch the current for the relay's coil.

Connecting a transistor to the output from an IC

Relays Photographs © Rapid Electronics

Most ICs cannot supply large output currents so it may be necessary to use a transistor to switch the larger current required for output devices such as lamps, motors and relays. The 555 timer IC is unusual because it can supply a relatively large current of up to 200mA which is sufficient for some output devices such as low current lamps, buzzers and many relay coils without needing to use a transistor.

A transistor can also be used to enable an IC connected to a low voltage supply (such as 5V) to switch the current for an output device with a separate higher voltage supply (such as 12V). The two power supplies must be linked, normally this is done by linking their 0V connections. In this case you should use an NPN transistor.

A resistor RB is required to limit the current flowing into the base of the transistor and prevent it being damaged. However, RB must be sufficiently low to ensure that the transistor is thoroughly saturated to prevent it overheating, this is particularly important if the transistor is switching a large current (> 100mA). A safe rule is to make the base current IB about five times larger than the value which should just saturate the transistor.

Choosing a suitable NPN transistor

The circuit diagram shows how to connect an NPN transistor, this will switch on the load when the IC output is high. If you need the opposite action, with the load switched on when the IC output is low (0V) please see the circuit for a PNP transistor below.

The procedure below explains how to choose a suitable switching transistor.

1. The transistor's maximum collector current Ic(max) must be greater than the load current Ic.

load current Ic = supply voltage Vsload resistance RL

NPN transistor switch(load is on when IC output is high)

Using units in calculationsRemember to use V, A and orV, mA and k . For more detailsplease see the Ohm's Law page.

2. The transistor's minimum current gain hFE(min) must be at least five times the load current Ic divided by the maximum output current from the IC.

hFE(min) > 5 × load current Ic max. IC current

3. Choose a transistor which meets these requirements and make a note of its properties: Ic(max) and hFE(min). There is a table showing technical data for some popular transistors on the transistors page.

4. Calculate an approximate value for the base resistor:

RB = Vc × hFE where Vc = IC supply voltage

(in a simple circuit with one supply this is Vs)5 × Ic

5. For a simple circuit where the IC and the load share the same power supply (Vc = Vs) you may prefer to use: RB = 0.2 × RL × hFE

6. Then choose the nearest standard value for the base resistor. 7. Finally, remember that if the load is a motor or relay coil a protection diode is

required.

ExampleThe output from a 4000 series CMOS IC is required to operate a relay with a 100 coil. The supply voltage is 6V for both the IC and load. The IC can supply a maximum current of 5mA.

1. Load current = Vs/RL = 6/100 = 0.06A = 60mA, so transistor must have Ic(max) > 60mA. 2. The maximum current from the IC is 5mA, so transistor must have hFE(min) > 60

(5 × 60mA/5mA).

3. Choose general purpose low power transistor BC182 with Ic(max) = 100mA and hFE(min) = 100. 4. RB = 0.2 × RL × hFE = 0.2 × 100 × 100 = 2000 . so choose RB = 1k8 or 2k2. 5. The relay coil requires a protection diode.

Choosing a suitable PNP transistor

The circuit diagram shows how to connect a PNP transistor, this will switch on the load when the IC output is low (0V). If you need the opposite action, with the load switched on when the IC output is high please see the circuit for an NPN transistor above.

PNP transistor switch(load is on when IC output is low)

The procedure for choosing a suitable PNP transistor is exactly the same as that for an NPN transistor described above.

Using a transistor switch with sensors

The top circuit diagram shows an LDR (light sensor) connected so that the LED lights when the LDR is in darkness. The variable resistor adjusts the brightness at which the transistor switches on and off. Any general purpose low power transistor can be used in this circuit.

The 10k fixed resistor protects the transistor from excessive base current (which will destroy it) when the variable resistor is reduced to zero. To make this circuit switch at a suitable brightness you may need to experiment with different values for the fixed resistor, but it must not be less than 1k .

If the transistor is switching a load with a coil, such as a motor or relay, remember to add a protection diode across the load.

The switching action can be inverted, so the LED lights when the LDR is brightly lit, by swapping the LDR and variable resistor. In this case the fixed resistor can be omitted because the LDR resistance cannot be reduced to zero.

LED lights when the LDR is dark

LED lights when the LDR is bright

Note that the switching action of this circuit is not particularly good because there will be an intermediate brightness when the transistor will be partly on (not saturated). In this state the transistor is in danger of overheating unless it is switching a small current. There is no problem with the small LED current, but the larger current for a lamp, motor or relay is likely to cause overheating.

Other sensors, such as a thermistor, can be used with this circuit, but they may require a different variable resistor. You can calculate an approximate value for the variable resistor (Rv) by using a multimeter to find the minimum and maximum values of the sensor's resistance (Rmin and Rmax):

Variable resistor, Rv = square root of (Rmin × Rmax)

For example an LDR: Rmin = 100 , Rmax = 1M , so Rv = square root of (100 × 1M) = 10k .

You can make a much better switching circuit with sensors connected to a suitable IC (chip). The switching action will be much sharper with no partly on state.

A transistor inverter (NOT gate)

Inverters (NOT gates) are available on logic ICs but if you only require one inverter it is usually better to use this circuit. The output signal (voltage) is the inverse of the input signal:

• When the input is high (+Vs) the output is low (0V). • When the input is low (0V) the output is high (+Vs).

Any general purpose low power NPN transistor can be used. For general use RB = 10k and RC = 1k , then the inverter output can be connected to a device with an input impedance (resistance) of at least 10k such as a logic IC or a 555 timer (trigger and reset inputs).

If you are connecting the inverter to a CMOS logic IC input (very high impedance) you can increase RB to 100k and RC to 10k , this will reduce the current used by the inverter.

List of activities to be carried Out to complete the Project-

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Study PCB design Troubleshooting

Weeks

In First weeks I will collect study material and circuit diagram. I will finalized circuit and detail.In next week I will test circuit on simulation softare proteus or bread board. Proteus is simulation software.In Next we will make PCB on copper clad Board.After it we will do programming and soldering.After soldering we will Test circuit.If there will be any problem then we will do repair of it.After completion of project we will make report.

Applications:1. Attendance System2.electronics voting machine for polls

3.for commercial voting machine 4. for quiz purposes.

5. Access control System

Advantages:

low cost

flexible

portable

easy to make

component easily available

Conclusion:Finally project is working . it was tough to program controller . it was tough to interface to mcu with RFID reader.

Program 1.

#include<reg51.h>

sbit RS=P3^7;sbit EN=P3^6;sbit R=P3^2;sbit bz=P1^7;

void Rxmsg(void);void lcdinit(void);void lcdData(unsigned char l);void lcdcmd(unsigned char k);void DelayMs(unsigned int count); void sucessRx(void);void unknown(void);void display(unsigned char s, t);

void welcome(void); void main(){unsigned char i=0;unsigned int j=0;unsigned char c[15];

TMOD=0x20; // Configure the serial port to 9600 baud rateTH1=0xFD;SCON=0X50;TR1=1;R=0;lcdinit();welcome();bz=1;

while(1){back:

for(i=0;i<15;i++)

//command to recv data{c[i]=0xFF;}

while(RI==0);

for(i=0;i<15;i++)

//command to recv data{j=0;while(RI==0){if(j>=1000)goto timeout;j++;}c[i]=SBUF;RI=0;}

timeout:for(i=0;i<15;i++){if(c[i]=='1' && c[i+1]=='E' && c[i+2]=='0' && c[i+3]=='0' && c[i+4]=='7' && c[i+5]=='C' && c[i+6]=='A' && c[i+7]=='0' && c[i+8]=='3' && c[i+9]=='C'){sucessRx();DelayMs(1000); R=1;bz=0;DelayMs(1000);R=0;bz=1;DelayMs(1000);lcdinit();DelayMs(100);welcome();

goto back;}}unknown();DelayMs(2000); bz=0;DelayMs(2000);

bz=1;DelayMs(1000);lcdinit();DelayMs(100);welcome();}}

void sucessRx(){unsigned int i=0;unsigned char c[]="ACCESS GRANTED ";

lcdcmd(0x01);DelayMs(10);lcdcmd(0x80);DelayMs(10);

while(c[i]!='\0'){lcdData(c[i]);i++;}}

void unknown(void){unsigned int i=0;unsigned char c[]="ACCESS DENIED";

lcdcmd(0x01);DelayMs(10);lcdcmd(0x80);DelayMs(10);

while(c[i]!='\0'){lcdData(c[i]);i++;}

}

//---------------------------------------// Lcd initialization subroutine//---------------------------------------void lcdinit(void){lcdcmd(0x38);DelayMs(250);lcdcmd(0x0E);DelayMs(250);lcdcmd(0x01);DelayMs(250);lcdcmd(0x06);DelayMs(250);lcdcmd(0x80);DelayMs(250);}

//---------------------------------------// Lcd data display//---------------------------------------void lcdData(unsigned char l){P2=l;RS=1;EN=1;DelayMs(1);EN=0;return;}

//---------------------------------------// Lcd command//---------------------------------------void lcdcmd(unsigned char k){P2=k;RS=0;EN=1;

DelayMs(1);EN=0;return;}

//---------------------------------------// Delay mS function//---------------------------------------void DelayMs(unsigned int count) { // mSec Delay 11.0592 Mhz unsigned int i; // Keil v7.5a while(count) { i = 115;

// 115exact

value

while(i>0) i--;

count--; }}

void welcome(void){unsigned int i=0;unsigned char c[]="RFID READER"; unsigned char d[]="SYSTEM";

lcdcmd(0x01);DelayMs(10);lcdcmd(0x80);DelayMs(10);

while(c[i]!='\0'){lcdData(c[i]);

i++;}

lcdcmd(0xc0);

i=0;while(d[i]!='\0'){lcdData(d[i]);i++;}}; ****************************************************************** RS BIT P2.5 RW BIT P2.4 E BIT P2.3 FL BIT P0.7

buzz BIT P3.7 LCD EQU P0 C1 EQU 31H C2 EQU 32H C3 EQU 33H ORG 00H AJMP START ORG 30H START: MOV LCD,#00H MOV C1,#0 MOV C2,#0 MOV C3,#0 MOV A,#38H ;2*16 MATRIX ACALL COMMAND MOV A,#38H ;2*16 MATRIX ACALL COMMAND MOV A,#02 ;RETURN HOME ACALL COMMAND

MOV A,#01 ;CLEAR DISPLAY SCREEN ACALL COMMAND MOV A,#0CH ;DISPLAY ON CURSOR OFF ACALL COMMAND MOV A,#80H ;MOVE CURSOR TO FIRST LINE SECOND COLOUMN ACALL COMMAND MOV DPTR,#TABLE1 ;DISPLAY ERP ACALL DISPLAY ACALL DELAY1 MOV R1,#00 MOV R0,#00 MOV R2,#00 MOV R3,#00 MOV R4,#00 MOV R5,#00 MOV A,#80H ;MOVE CURSOR TO FIRST LINE SECOND COLOUMN ACALL COMMAND MOV DPTR,#TABLE1 ;DISPLAY ERP ACALL DISPLAY MOV A,#0C0H ;MOVE CURSOR TO FIRST LINE SECOND COLOUMN ACALL COMMAND MOV DPTR,#TABLE7 ;DISPLAY ERP ACALL DISPLAYMAIN: jnb p1.0,act1jnb p1.1,act2jnb p1.2,act3jnb p1.3,act4jnb p1.4,act5 ; CHECK ATTENDENCEjnb p1.5,act6jnb p1.6,act7jnb p1.7,act8JNB P3.0,STARTJB P3.1,MAINacall READING41 SJMP MAIN

act1:INC R0INC R4 cpl p2.0ACALL BUZZEACALL READING5 SJMP MAINact2:INC R1 INC R4 ACALL BUZZEcpl p2.1ACALL READING5SJMP MAINact3:INC R2INC R4 ACALL BUZZEcpl p2.2ACALL READING5SJMP MAINact4:INC R3 INC R4ACALL BUZZEcpl p2.6 ACALL READING5

SJMP MAINact5: ACALL READING1SJMP MAINact6: ACALL READING2SJMP MAINact7:ACALL READING3SJMP MAINact8:ACALL READING4

SJMP MAIN READING5: ACALL LCDCLRMOV A,#0C0H ;MOVE CURSOR TO FIRST LINE SECOND COLOUMN ACALL COMMAND MOV DPTR,#TABLE6 ;DISPLAY ERP ACALL DISPLAYSJMP MAINREADING1: ACALL LCDCLR MOV A,#0C0H ACALL COMMAND MOV DPTR,#TABLE2 ACALL DISPLAYMOV A,#0CAH ACALL COMMAND MOV A,R0 ACALL HTDACALL OUT1 AJMP MAIN READING2: ACALL LCDCLR MOV A,#0C0H ACALL COMMAND MOV DPTR,#TABLE3 ACALL DISPLAYMOV A,#0CAH ACALL COMMAND MOV A,R1 ACALL HTDACALL OUT1AJMP MAIN READING3: ACALL LCDCLR MOV A,#0C0H ACALL COMMAND

MOV DPTR,#TABLE4 ACALL DISPLAYMOV A,#0CAH ACALL COMMAND MOV A,R2

ACALL HTDACALL OUT1 AJMP MAIN READING4: ACALL LCDCLR MOV A,#0C0H ACALL COMMAND MOV DPTR,#TABLE5 ACALL DISPLAYMOV A,#0CAH ACALL COMMAND MOV A,R3

ACALL HTDACALL OUT1 AJMP MAIN READING41: ACALL LCDCLR MOV A,#0C0H ACALL COMMAND MOV DPTR,#TABLE8 ACALL DISPLAYMOV A,#0CAH ACALL COMMAND MOV A,R4

ACALL HTDACALL OUT1 AJMP MAIN BUZZE: clr buzz acall delay1

ACALL delay1 ACALL delay1 ACALL delay1 SETB BUZZ RETHTD: ;CONVERT HEX(BINARY) TO ASCII MOV B,#10 DIV AB MOV C1,B MOV B,#10 DIV AB MOV C2,B MOV C3,A RET OUT1: MOV A,C3 ORL A,#30H ACALL WRITE MOV A,C2 ORL A,#30H ACALL WRITE MOV A,C1 ORL A,#30H ACALL WRITE RET LCDCLR: MOV A,#01H ;CLEAR DISPLAY SCREEN ACALL COMMAND RET ; DISPLAY DATA ON LCD DISPLAY: CLR A MOVC A,@A+DPTR JZ NEXT ACALL WRITE INC DPTR JMP DISPLAY NEXT: RET WRITE:

ACALL CHKBUSY MOV LCD,A SETB RS CLR RW SETB Eacall delay1 CLR E RET COMMAND: ACALL CHKBUSY MOV LCD,A CLR RS CLR RW SETB E acall delay1 CLR E RET delay1: MOV R6,#255 AGAIN1: MOV R7,#255BACK1: DJNZ R7,BACK1 DJNZ R6,AGAIN1 RET TABLE1: DB 'ATTENDANCE SYSTEM',0 TABLE7: DB 'MARK THE ATTENDANCE ',0 TABLE2: DB 'CAND NO.1',0 TABLE3: DB 'CAND NO.2',0 TABLE4: DB 'CAND NO.3',0TABLE5: DB 'CAND NO.4',0TABLE6: DB 'ATTENDANCE MARKED',0TABLE8: DB 'TOTAL ATTENDANCE',0

Statement of problem:

1. EEprom not working- when I was testing project voter rfid did not saved in eeprom. . I tested no. of time my program.

Reason- problem in eeprom connection with Microcontroller.

2. RFid controller not giving output port0 and input to attendance ic at port1Reason- Port 0 is open collector port. So it need pull up resistor. So I used 10k+5% -1/4 watt resistor.

Structure-

First of all bring RFid tag close to RFid reader

RFID reader will display on LCD. When card in contact it will show card no and will show valid/invalid

Mcu will give low pulse at pin p0.0 when card 1 detected

P0.0 is connected to p1.0 of mcu2. It will show attendance marked

Every time system will ask for rfid tag to mark attendance

Final Result:

Finally project is working. We marked the attendance with different card to different candidates. Hardware is working properly.

Scope of Future Study-

Benefit of this project is that a electronics RFID +GSM Attendance system could be provided to each candidate. It can be used for the safety & security purpose.

Problems

RFID reader rarely available in the market.

BIBILIOGRAPHY

1. HAND BOOK OF ELECTRONICS A.K. MAINI.

2.HAND BOOK OF ELECTRONICS GUPTA & KUMAR.

3.LET US C YASHWANT KANITKAR.

4.SHYAM SERIES TATA MC GRILL.

5.DIGITAL SYSTEMS PRINCIPLES AND APPLICATION RONALD LTOCCI.

(Sixth addition)

6.ELECTRONICS FOR YOU (MARCH 1998).

7.DIGITAL DESIGN MORIS MANO.

(Second addition)

8.RELAYS AND ITS APPLICATION SHARMA, MC.

(Bpb-publishers)

9.MODERN ALL ABOUT MOTHERBOARD LOTHIA, M.

(Bpb-publishers)

10.POWER SUPPLY FOR ALL OCCASION SHARMA, MC.

(Bpb-publishers)

11.CMOS DATA BOOK (74SERIES) ECA.

(Bpb-publishers)

12.PRACTICAL VALUE AND TRANSISTOR DATA POPE.

(Bpb-publishers)

13.PRACTICAL TRANSFORMER DESIGN HAND BOOK LABON. E.

(Bpb-publishers)

14 MODERN IC MANAHAR LOTIA.

(DATA AND SUBSTITUTIONAL MANUAL)