Automatic Speed Breaker

INTRODUCTION

The important consideration in the present field of Electrical and Electronics related

technologies are Automation, Power Consumption and cost effectiveness. Automation is

intended to reduce manpower, with the help of intelligent systems and Power Saving is

the main consideration forever, as the source of the power is getting diminished due to

various reasons.

The main goal of the project is to implement an automatic speed braker which can work

under a given time constraint. These constraints are influenced by the needs of the

immediate locality. This allows the task efficiently and effectively without the

intervention of human by making it automated.

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PROJECT DESCRIPTION

The Automatic Speed Braker System makes it possible to adjust the time of speed

breaker on road. We use this innovative idea in front of every school, which is on main

road. When school is to start then clock connected to the speed breaker automatically

transfers the speed breaker on the road for a time being. After half an hour speed breaker

is automatically reversed to the flat position. Semi circle portion of the speed breaker is

turned automatically as per the time set.

Time set option is changeable. We can set the time of opening and closing of the speed

breaker as per our choice. Changeable time is to be stored in the external memory up to

next change. This memory is non-volatile and retains its data for a long time. Time is

automatically adjusted by the RTC IC with a small battery backup to save the clock

setting. Speed breaker is designed by a half flat and half semi circle shaped long metallic

pipe.

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BASIC BLOCK DIAGRAM

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HARDWARE USED:

1. MICROCONTROLLER

2. LCD DISPLAY CIRCUIT

3. MEMORY INTERFACE

4. CURRENT SENSOR/TRANSFORMER

5. RELAY CIRCUIT

6. REAL TIME CLOCK

7. DC MOTOR

SOFTWARE USED:

1. ASSEMBLY LANGUAGE/ EMBEDDED C

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BASIC COMPONENTS AND THEIR FUNCTIONS

1. MICROCONTROLLER(AT89S52)

Architecture of 8051 family:-

The figure – 1 above shows the basic architecture of 8051 family of microcontroller.

Features

• Compatible with MCS-51™ Products

• 4K Bytes of In-System Reprogrammable Flash Memory

• Endurance: 1,000 Write/Erase Cycles

• Fully Static Operation: 0 Hz to 24 MHz

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• Three-Level Program Memory Lock

• 128 x 8-Bit Internal RAM

• 32 Programmable I/O Lines

• Two 16-Bit Timer/Counters

• Six Interrupt Sources

• Programmable Serial Channel

• Low Power Idle and Power Down Modes

DESCRIPTION

The AT89S52 is a low-power, high-performance CMOS 8-bit microcomputer with 4K

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 pinout. The on-chip

Flash allows the program memory to be reprogrammed in-system or by a conventional

nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a

monolithic chip, the Atmel AT89S52 is a powerful microcomputer which provides a

highly flexible and cost effective solution to many embedded control applications. The

AT89S52 provides the following standard features: 4K bytes of Flash, 128 bytes of

RAM, 32 I/O lines, two 16-bit timer/counters, five vector two-level interrupt architecture,

a full duplex serial port, and on-chip oscillator and clock circuitry.

In addition, the AT89S52 is designed with static logic for operation down to zero

frequency and supports two software selectable power saving modes. The Idle Mode

stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system

to continue functioning. The Power down Mode saves the RAM contents but freezes the

oscillator disabling all other chip functions until the next hardware reset.

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PIN DESCRIPTION

VCC Supply voltage.

GND Ground.

Port 0

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

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

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

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

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

outputs the code bytes during program verification.

External pull-ups are required during program verification.

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Port 1

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

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

by the internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are

externally being pulled low will source current (IIL) because of the internal pull-ups. Port

1 also receives the low-order address bytes during Flash programming and verification.

Port 2




externally being pulled low will source current (IIL) because of the internal pull-ups. Port

2 emits the high-order address byte during fetches from external program memory and

during accesses to external data memory that uses 16-bit addresses (MOVX @ DPTR). In

this application it uses strong internal pull-ups when emitting 1s. During accesses to

external data memory that uses 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




externally being pulled low will source current (IIL) because of the pull-ups. Port 3 also

serves the functions of various special features of the AT89C51 as listed below:

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

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RST

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

resets the device.

ALE/PROG

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

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

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

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

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

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

set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is

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

external execution mode.

PSEN

Program Store Enable is the read strobe to external program memory.

EA/VPP

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

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

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

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

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

require 12-volt VPP.

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XTAL1

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

XTAL2

Output from the inverting oscillator amplifier.

Oscillator Characteristics

XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier

which can be configured for use as an on-chip oscillator, as shown in Figure 1. Either a

quartz crystal or ceramic resonator may be used. To drive the device from an external

clock source, XTAL2 should be left unconnected while XTAL1 is driven as shown in

Figure 2.There are no requirements on the duty cycle of the external clock signal, since

the input to the internal clocking circuitry is through a divide-by-two flip-flop, but

minimum and maximum voltage high and low time specifications must be observed.

.

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2) LCD DISPLAY CIRCUIT

We have used 16x2 LCD display for displaying the value of measured distance. The

detail of the LCD is given in separate document.

LCD SECTION DETAILS

Frequently, an 8051 program must interact with the outside world using input and output

devices that communicate directly with a human being. One of the most common devices

attached to an 8051 is an LCD display. Some of the most common LCDs connected to

the 8051 are 16x2 and 20x2 displays. This means 16 characters per line by 2 lines and 20

characters per line by 2 lines, respectively.

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

majority of LCDs regardless of their manufacturer. The standard is referred to as

HD44780U, which refers to the controller chip which receives data from an external

source (in this case, the 8051) and communicates directly with the LCD.

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

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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.

INITIALIZING THE LCD

Before you may really use the LCD, you must initialize and configure it. This is

accomplished by sending a number of initialization instructions to the LCD.

The first instruction we send must tell the LCD whether we'll be communicating with it

with an 8-bit or 4-bit data bus. We also select a 5x8 dot character font. These two options

are selected by sending the command 38h to the LCD as a command. As you will recall

from the last section, we mentioned that the RS line must be low if we are sending a

command to the LCD. Thus, to send this 38h command to the LCD we must execute the

following 8051 instructions:

SETB EN

CLR RS

MOV DATA,#38h

CLR EN

LCALL WAIT_LCD

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CLEARING THE DISPLAY

When the LCD is first initialized, the screen should automatically be cleared by the

44780 controller. However, it's always a good idea to do things yourself so that you can

be completely sure that the display is the way you want it. Thus, it's not a bad idea to

clear the screen as the very first opreation after the LCD has been initialiezd.

An LCD command exists to accomplish this function. Not suprisingly, it is the command

01h. Since clearing the screen is a function we very likely will wish to call more than

once, it's a good idea to make it a subroutine:

CLEAR_LCD:

SETB EN

CLR RS

MOV DATA,#01h

CLR EN

LCALL WAIT_LCD

RET

WRITING TEXT TO THE LCD

Now we get to the real meat of what we're trying to do: All this effort is really so we can

display text on the LCD. Really, we're pretty much done.

Once again, writing text to the LCD is something we'll almost certainly want to do over

and over--so let's make it a subroutine.

WRITE_TEXT:

SETB EN

SETB RS

MOV DATA,A

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CLR EN

LCALL WAIT_LCD

RET

PINWISE DETAIL OF LCD

1. Vss GROUND

2. Vcc +5VOLT SUPPLY

3 Vee POWER SUPPLY TO CONTROL CONTRAST

4. RS RS = 0 TO SELECT COMMAND REGISTER

RS = 1 TO SELECT DATA REGISTER

5. R/W R/W = 0 FOR WRITE

R/W = 1 FOR READ

6 E ENABLE

7 DB0

8 DB1

9. DB2

10. DB3

11. DB4

12 DB5

13 DB6

14 DB7

15 16 FOR BACK LIGHT DISPLAY

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3) REAL TIME CLOCK

Introduction

In this project we show that how we control the distribution control system with real time

application. In this project we provide a smart solution for perfect distribution system. .

In this project we program the 4 different output for different time with real time clock.

Assume that we want to distribute the line 1 to from 6 of clock to 9 0 clock in Monday,

and from 6 o clock to 8 o clock on Tuesday. The we save this data in the memory. This

data is to be store in the memory for long time unless we change the data. In future it is

possible to program the 4 different output for particular day and particular time.

In this project we design a digital calendar with the help of the RTC. In this digital

calendar data is to be store in the RTC for a long l time with CMOS battery back up

circuit.

In this project we use one 89s51 controller to control all the function and relate with the

memory and RTC automatically and program the 4 different output .

First of all when supply is on then circuit is on and takes few second to intialize and

RTC and take a data from the RTC automatically.

Now on the LCD show the RTC CLOCK in first line and 4 CHANNEL TIMER in the

second line, after few second RTC provide a pulse to the controller and controller the day

on the first line with data with month and year.

TUE 11/03/2008

In the second line

CLOCK 13:35:01

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Time is display in the 24 hour system .this time is display , if you want to change the any

detail then with the Menu button and up –down key we change the detail of the digital

clock automatically.

With the help of the up-down key it is possible to change the detail of the clock. We

change the day , second time or whatever we want

Now with the help of CH switch we go the menu of on off time for four different

channel. Whatever want to enter a time then with the help of the up-down key we change

the time and save this data in the memory automatically. This memory is a non- voltaic

memory and save the data for a long time without battery.

Four output is connected to the load through relay driver circuit. In this relay driver

circuit we use four relay with 5 ampere socket. To control a relay we connect two

transistor circuit with NPN and pnp transistor. To control the relay.

General description

The PCF8563 is a CMOS real time clock/calendar optimized for low power consumption.

A programmable clock output, interrupt output and voltage-low detector are also

provided. All address and data are transferred serially via a two-line bidirectional I2C-

bus. Maximum bus speed is 400 kbit/s. The built-in word address register is incremented

automatically after each written or read data byte.

Features

1) Provides year, month, day, weekday, hours, minutes and seconds based on

32.768 kHz quartz crystal

2) Century flag

3) Clock operating voltage: 1.8 V to 5.5 V

4) Low backup current; typical 0.25 μA at VDD =and Tamb = 25 °C

5) 400 kHz two-wire I2C-bus interface (at VDD =

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6) Programmable clock output for peripheral devices (32.768 kHz, 1 024 Hz,

32 Hz and 1 Hz)

7) Alarm and timer functions

8) Integrated oscillator capacitor

9) Internal power-on reset

10) I2C-bus slave address: read A3h and write A2h

11) Open-drain interrupt pin

12) Electrostatic Discharge (ESD) protection exceeds 2 000 V Human Body Model

(HBM) per JESD22-A114, 200 V Machine Model (MM) per JESD22-A115 and 2

000 V Charged Device Model (CDM) per JESD22-C101

13) Latch-up testing is done to JEDEC standard JESD78 which exceeds 100 mA

Applications

1) Mobile telephones

2) Portable instruments

3) Electronic metering

4) Battery powered products

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OSCI 1 1 oscillator input

OSCO 2 2 oscillator output

n.c - 3 not connected

INT 3 4 interrupt output (open-drain; active LOW)

VSS 4 5 ground

SDA 5 6 serial data input and output

SCL 6 7 serial clock input

CLKOUT 7 8 clock output, open-drain

VDD 8 9 positive supply voltage

n.c - 10 not connected

Pin no 25 and 24 is connected to the non voltaic memory. Pin no 8 is connected to the positive

supply. Pin no 7 is connected to the ground.

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Here in this project we connect pin no 5 and 6 is to the controller directly. Pin no 1to 4 is

connected to the ground. Here we ground all the address of the ic. Pin no 8 is also connected to

the positive 5 volt supply. Pin no 7 is wp pin. Here pin no 7 is also grounded.

SERIAL CLOCK (SCL):

The SCL input is used to positive edge clock data into each

EEPROM device and negative edge clock data out of each device.

When we want to enter a data in the memory then we provide a low to high pulse and when we

get a data from the memory then we provide a high to low signal.

SERIAL DATA (SDA):

The SDA pin is bi-directional for serial data transfer. This pin is open-drain driven and may be

wire-ORed with any number of other open-drain or open collector devices.

DEVICE/PAGE ADDRESSES (A2, A1, A0):

The A2, A1 and A0 pins are device address inputs that are hard wired for the AT24C01A and the

AT24C02. As many as eight 1K/2K devices may be addressed on a single bus system (device

addressing is discussed in detail under the Device Addressing section). The AT24C04 uses the

A2 and A1 inputs for hard wire addressing and a total of four 4K devices may be addressed on a

single bus system. The A0 pin is a no connect. The AT24C08 only uses the A2 input for

hardwire addressing and a total of two 8K devices may be addressed on a single bus system. The

A0 and A1 pins are no connects.

WRITE PROTECT (WP): The AT24C01A/02/04/16 has a Write Protect pin that provides

hardware data protection. The Write Protect pin allows normal read/write operations when

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connected to ground (GND). When the Write Protect pin is connected to VCC, the write

protection feature is enabled and operates as shown in the following table.

Operation CLOCK and DATA TRANSITIONS:

The SDA pin is normally pulled high with an external device. Data on the SDA pin may change

only during SCL low time periods (refer to Data Validity timing diagram). Data changes during

SCL high periods will indicate a start or stop condition as defined below.

START CONDITION: A high-to-low transition of SDA with SCL high is a start condition

which must precede any other command (refer to Start and Stop Definition timing diagram).

STOP CONDITION: A low-to-high transition of SDA with SCL high is a stop condition. After

a read sequence, the stop command will place the EEPROM in a standby power mode (refer to

Start and Stop Definition timing diagram).

ACKNOWLEDGE: All addresses and data words are serially transmitted to and from the

EEPROM in 8-bit words. The EEPROM sends a zero to acknowledge that it has received each

word. This happens during the ninth clock cycle.

STANDBY MODE: The AT24C01A/02/04/08/16 features a low-power standby mode which is

enabled: (a) upon power-up and (b) after the receipt of the STOP bit and the completion of any

internal operations.

AT24C01A/02/04/08/16

Device Addressing The 1K, 2K, 4K, 8K and 16K EEPROM devices all require an 8-bit device

address word following a start condition to enable the chip for a read or write operation (refer to

Figure1 ) The device address word consists of a mandatory one, zero sequence for the first four

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most significant bits as shown. This is common to all the EEPROM devices. The next 3 bits are

the A2, A1 and A0 device address bits for the 1K/2K EEPROM. These 3 bits must compare to

their corresponding hard-wired input pins. The 4K EEPROM only uses the A2 and A1 device

address bits with the third bit being a memory page address bit. The two device address bits must

compare to their corresponding hard-wired input pins. The A0 pin is no connect. The 8K

EEPROM only uses the A2 device address bit with the next 2 bits being for memory page

addressing. The A2 bit must compare to its corresponding hard-wired input pin. The A1 and A0

pins are no connect. The 16K does not use any device address bits but instead the 3 bits are used

for memory page addressing. These page addressing bits on the 4K, 8K and 16K devices should

be considered the most significant bits of the data word address which follows.

The A0, A1 and A2 pins are not connect.

The eighth bit of the device address is the read/write operation select bit. A read operation is

initiated if this bit is high and a write operation is initiated if this bit is low.

Upon a compare of the device address, the EEPROM will output a zero. If a compare is not

made, the chip will return to a standby state

.

Write Operations BYTE WRITE: A write operation requires an 8-bit data word address

following the device address word and acknowledgment. Upon receipt of this address, the

EEPROM will again respond with a zero and then clock in the first 8-bit data word. Following

receipt of the 8-bit data word, the EEPROM will output a zero and the addressing device, such as

a microcontroller, must terminate the write sequence with a stop condition.

At this time the EEPROM enters an internally timed write cycle, WR, to the non volatile

memory. All inputs are disabled during this write cycle and the EEPROM will not respond until

the write is complete (refer to Figure 2).

PAGE WRITE: The 1K/2K EEPROM is capable of an 8-byte page write, and the 4K, 8K and

16K devices are capable of 16-byte page writes.

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A page write is initiated the same as a byte write, but the microcontroller does not send a stop

condition after the first data word is clocked in. Instead, after the EEPROM acknowledges

receipt of the first data word, the microcontroller can transmit up to seven (1K/2K) or fifteen

(4K, 8K, 16K) more data words. The EEPROM will respond with a zero after each data word

received. The microcontroller must terminate the page write sequence with a stop condition.

The data word address lower three (1K/2K) or four (4K, 8K, 16K) bits are internally incremented

following the receipt of each data word. The higher data word address bits are not incremented,

retaining the memory page row location. When the word address, internally generated, reaches

the page boundary, the following byte is placed at the beginning of the same page. If more than

eight (1K/2K) or sixteen (4K, 8K, 16K) data words are transmitted to the EEPROM, the data

word address will “roll over” and previous data will be overwritten.

ACKNOWLEDGE POLLING: Once the internally timed write cycle has started and the

EEPROM inputs are disabled, acknowledge polling can be initiated. This involves send-

AT24C01A/02/04/08/16

3256D–SEEPR–11/03

The read/write bit is representative of the operation desired. Only if the internal write cycle has

completed will the EEPROM respond with a zero allowing the read or write sequence to

continue.

Read Operations Read operations are initiated the same way as write operations with the

exception that the read/write select bit in the device address word is set to one. There are three

read operations: current address read, random address read and sequential read.

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CURRENT ADDRESS READ: The internal data word address counter maintains the last

address accessed during the last read or write operation, incremented by one. This address stays

valid between operations as long as the chip power is maintained. The address “roll over” during

read is from the last byte of the last memory page to the first byte of the first page. The address

“roll over” during write is from the last byte of the current page to the first byte of the same

page. Once the device address with the read/write select bit set to one is clocked in and

acknowledged by the EEPROM, the current address data word is serially clocked out. The

microcontroller does not respond with an input zero but does generate a following stop

condition.

RANDOM READ: A random read requires a “dummy” byte write sequence to load in the data

word address. Once the device address word and data word address are clocked in and

acknowledged by the EEPROM, the microcontroller must generate another start condition. The

microcontroller now initiates a current address read by sending a device address with the

read/write select bit high. The EEPROM acknowledges the device address and serially clocks out

the data word. The microcontroller does not respond with a zero but does generate a following

stop condition (refer to Figure 5).

SEQUENTIAL READ: Sequential reads are initiated by either a current address read or a

random address read. After the microcontroller receives a data word, it responds with an

acknowledgement. As long as the EEPROM receives an acknowledgement, it will continue to

increment the data word address and serially clock out sequential data words. When the memory

address limit is reached, the data word address will “roll over” and the sequential read will

continue. The sequential read operation is terminated when the microcontroller does not respond

with a zero but does generate a following stop condition (refer to Figure 6).

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10 AT24C01A/02/04/08/16

(* = DON’T CARE bit for 1K)

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4) RELAYS

In order to enable a circuit to be isolated from the system only under faulty conditions, protective

relays are used. In normal cases, it is open circuit relay. The relay is usually provided with 4

terminals, two of which are connected to relay winding and other two are connected to the circuit

to be controlled. It has following characteristics :

Sensitivity

Speed

Selectivity

TYPES OF RELAYS :

Electromagnetic Attraction Type : These relays are actuated by DC or AC quantities.

Electromagnetic Induction Type : It’s operation depends upon EMI phenomena.

Thermal Relays : It’s operation depends upon the heating effect of electric Current.

Distance Relays : It’s operation depends upon the ratio of voltage to current.

ELECTROMAGNETIC RELAY :

These relays are electromagnetically operated. The parts of these relays are an iron core & its

surrounding coil of wire. An iron yoke provides a low reluctance path for magnetic flux, the

yoke being shaped so that the magnetic circuit can be closed by a movable piece of iron called

the armature, and a set of contacts. The armature is hinged to the yoke and is held by a string in

such a way that there is an air gap in the magnetic circuit. Figure shows the principle of

operation of this relay. When an electric current flows in the coil, the armature is attracted to the

iron core. Electrical switching contacts are mounted on the armature. When the armature coil is

energized, these movable contacts break their connections with one set of fixed contacts and

close a connection to a previously open contact. When electric power is removed from the relay

coil, spring returns the armature to its original position.

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Standard voltages for D.C. relay are 6,12,24,48 & 110 volts and for A.C. relays are

6,12,24,48,120 & 240 volts.

Fig. Basic Diagram Showing the Operating Principle of a Relay

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5) MEMORY INTERFACE

AT24C02 is an electrically erasable and programmable ROM. It has a 2Kbits of memory size

arranged in 32 pages of 8 byte each. There are 256 (32 x 8) words each of one byte. The data is

transferred and received serially through serial data (SDA) pin.

The SCL is clock input and is used to synchronize EEPROM with microcontroller for various

operations. When data is to be read or write, first a start condition is created followed by device

address, byte address and the data itself. Finally a stop condition is provided. The start condition

occurs when SDA and SCL get high to low simultaneously. The stop condition is when SDA

remains low while SCL goes from high to low. The data is read or written between the start and

stop conditions on every transition of SCL from high to low. For more details on different

operations and addressing, refer interfacing 24C02 with 8051.

A total of eight EEPROMs can be connected through a bus. There are three address pins in

AT24C02 for selecting a particular chip. The device can be addressed serially by the software. It

makes use of an internal register of the EEPROM whose 4 MSB bits are 1010, the next three are

the EEPROM address bits and the LSB signifies whether data is to be read or written. This last

bit is 1 for write and 0 for read operation.

For example, if in an EEPROM all address bits are grounded, then for write operation a hex

value 0xA1 (1010 0001) will be sent. Here 000, in last bits, addresses the EEPROM and 1 in

LSB indicates a write operation. Similarly for read operation the device address to be sent is

0xA0 (1010 0000).

Next, the byte or page address is sent followed by the data byte. This data byte is to be written on

or read by the microcontroller.

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PIN DIAGRAM :

Pin No Function Name

1 Address input pins; Provide addresses when more than one EEPROM is interfaced to a single microcontroller;

Ground when only one EEPROM is used

AD0

2 AD1

3 AD2

4 Ground (0V) Ground

5 Bi-directional pin for serial data transfer Serial Data

6 Provides clock signals Serial Clock

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7 Ground allows normal read/write functions;

Vcc enables write protection

Write protect

8 Supply voltage; 5V (up to 5.5V) Vcc

EEPROM stands for electrically erasable programmable read only memory. It is a secondary

storage device that once written (programmed) can hold data even when the power is removed.

The EEPROM is a class of read only memory that can be electrically erased and reprogrammed.

AT24C02 is a two wire 2Kbits serial EEPROM by Atmel. The memory is organized in 256

words of single byte each arranged in 32 pages of 8 bytes each. The addressing of memory

locations requires eight bit addresses.

AT24C02 is two-wire serially programmable i.e., for programming, the data and control signals

are provided serially along with clock signals from the other wire. The read-write operations are

accomplished by sending a set of control signals including the address and/or data bits. The

control signals must be accompanied with proper clock signals.

The AT24C02 has hard wire addressing of 3 bit length. This facilitates interfacing of a

maximum of eight (23) 24C02 devices to a system thereby, incorporating a maximum 16Kbits

memory. Multiple 24C02 devices can be connected to a microcontroller/microprocessor based

system using I2C interface.

The project demonstrates interfacing of a single 24C02 IC with AT89C51 (8051)

microcontroller. The microcontroller is programmed to perform write operation of a single byte

and read the same. The byte written and read is displayed on a LCD display.

Of the two wire serial EEPROMs from ATMEL, 24C02 is one of them and comes in different

packages. No matter what the package type, following are the pins of 24C02 IC.

32

PIN DETAIL :

A0-A2: Pins 1-3 are the address pins. Since multiple 24C02 and other similar devices can be

connected to a system, they require addressing. These devices are hard wire addressed i.e. the

address pins are permanently grounded and/or connected to Vcc. It is notable that in other two-

wire serial EEPROMs from Atmel, all the address pins may not be used.

In this circuit all address pins are grounded, so the device will have an address 000.

WP: Pin7 is the Write Protect pin. When it is kept low (ground), normal read and write

operations are allowed. When it is given a high, 24C02 is protected from any write operation.

In the circuit WP pin has been grounded to allow write operation.

Vcc: A 5V DC supply is required to power the AT24C02. This is same as the power supply of

the microcontroller. So a separate supply to power 24C02 is not required.

GND: Pin4 is Ground pin (0V)

SDA: Pin5 is serial data pin. The data and control bits are read and write serially from this

bidirectional pin.

SCL: Pin6 is serial clock pin. A clock signal is required every time a bit is transferred to or from

the SDA pin. A positive edge clock, i.e., a low to high, transfers data to the EEPROM and a

negative edge trigger, i.e., a high to low, carries data from the EEPROM.

In the circuit SDA and SCL are connected to bits 0 and 1 of port P1, respectively.

The data pins of the LCD are connected to port 2 of the microcontroller. The RS, RW and enable

pins of the LCD are interfaced to bit 0, 1 and 6 of port P3, respectively.

As many 24C02 devices can be used in a system using a two wire serial (I2C) interface. The

controller needs to send a device address to select a particular 24C02 device. Also whether a read

or write operation is to be done must be specified. This is done by device addressing.

Since 24C02 devices understand 8 bit words the device addresses are also single byte long. The

first four MSBs are a fixed sequence of high and low (1010). The next three bits are the device

33

address bits which must match with the hard wire address of the 24C02 device. The LSB

specifies whether a write or read operation is to be done. If this bit is high (1), a read operation is

initiated; and if it is low (0), write is initiated.

Any read or write operation in 24C02 requires a sequence of interaction with the controller. This

involves the following steps:

1. To set Start condition to initiate any Read or Write operation.

2. To transfer a bit to/from EEPROM.

3. A superset of these is used to transfer a word to/ from EEPROM.

4. To monitor acknowledgements for the receipt or transfer of each word.

5. A superset of signals for transferring words perform Read or Write operations.

6. Setting the Stop condition to terminate the operation.

These steps are explained in more detail in following sections.

34

http://www.engineersgarage.com/microcontroller/8051projects/interface-serial-eeprom-24c02-AT89C51#Stop_condition

http://www.engineersgarage.com/microcontroller/8051projects/interface-serial-eeprom-24c02-AT89C51#Read_write_operation

http://www.engineersgarage.com/microcontroller/8051projects/interface-serial-eeprom-24c02-AT89C51#Acknowledgement

http://www.engineersgarage.com/microcontroller/8051projects/interface-serial-eeprom-24c02-AT89C51#EEPROM_bit_transfer

http://www.engineersgarage.com/microcontroller/8051projects/interface-serial-eeprom-24c02-AT89C51#EEPROM_word_transfer

Start condition:

Any read or write operation in EEPROM is initiated by Start condition. This occurs when there

is a high to low transition of SDA while SCL is high. (Refer the following diagram) This tells the

EEPROM that words from the controller are ready for it. SCL is set low at the end of start

condition. This is because any read or write operation first involves transfer of some words to

EEPROM. That requires a low to high transition of clock corresponding to each bit of the word.

Transfer a bit of a word to/from EEPROM:

First of all, it must be noted that transferring a bit to/from EEPROM is not the same as write/read

operation and so they should not be confused with each other. A read or write operation is the

whole process that takes place only after a start condition and before stop condition. Transfer of

bits to/from an EEPROM is a part of transferring 8 bit word(s) in between the start and stop

conditions because every byte is transferred serially bit by bit. SDA is normally pulled high by

the device it is interfaced with. When SCL is high the signal changes (H-L or L-H) at SDA are

35

considered as start or stop condition. A low to high transition at SCL transfers a bit to the

EEPROM, i.e., at a low to high transition of SCL, SDA pin of EEPROM behaves as input for

bits of word(s). If the data changes when the SCL is high, it will be misinterpreted as start or stop

condition. At high to low transition of SCL a bit is transferred from the EEPROM i.e.

the SDA pin behaves as output for bits of word(s) or acknowledgement at high to low transition

of the SCL. When SCL is low again the data change is valid, i.e., when bits of a word are to be

read or write, they are differentiated by the low of the SCL.

Transfer of a word to/from EEPROM :

By sending or receiving eight bits, a complete word is sent to or received by the EEPROM.

When sending a word, the acknowledgement from the EEPROM must be checked. There should

a clock (high to low transition from an initial low) between two words.

Monitoring acknowledgement bit:

When a word is sent to the EEPROM, it sends back a zero (0) to tell the controller that the word

has been received successfully by it. The controller reads this acknowledgement bit by sending a

high to low transition at SCL. Acknowledgement bit must be checked every time a word is sent

to the EEPROM.

Read/ Write operations:

A sequential transfer of words from/to the EEPROM constitutes the read/write. Thus any read or

write operation supported by the EEPROM can be accomplished by sending and/or receiving a

36

sequence of words to/from the EEPROM. There is a fixed set of words which need to be sent to

and/or received by the EEPROM corresponding to each read and write operation.

Stop condition:

A stop condition is provided to terminate a read or write operation. A low to high transition of

SDA when SCL is high sets the stop condition.

37

Memory Addressing in 24C02:

In 24C02, the 8 bit words are arranged in 32 pages of 8 bytes each. The word/page address

should be sent to the EEPROM to identify the location of memory to be read or written. The

word location is specified by three bits since the total number of available words/bytes is 8 (23).

Similarly, the page location is given by five bits since the total number of available pages is 32

(25). The lower three bits (D0-D2) of the word address identify the word location in a page,while

the higher five bytes (D3-D7) identify the page location.

Clocking:

When a sequence of words is transferred to EEPROM, a clock is needed to be sent by the

controller after transmission of each word. This is required so that the controller can receive its

acknowledgement. Clock is just a high transition followed by a low transition of SCL when the

initial clock signal is low.

38

Byte Write Operation:

The Byte Write operation programs a single byte of the EEPROM memory. It involves following

sequences of instructions to be sent to the EEPROM by the microcontroller:

1. Set start condition

2. Send device address byte (specify write operation)

3. Clock

4. Send word address

5. Clock

6. Send data byte

7. Clock

8. Set stop condition

9. Clock

39

Random read Operation:

The random read operation reads the data from a word address clocked in by the microcontroller.

Any random location can be read by this operation. This involves the following sequence of

instructions to be sent to/from the EEPROM by/to the controller.


2. Send device address byte (specify write operation)

3. Clock

4. Send word address

5. Clock


7. Send device address byte (specify read operation)

8. Clock

40

9. Read data byte

10. Clock

11. Stop condition

6) CURRENT SENSOR / TRANSFORMER

41

Current transformers can perform circuit control, measure current for power measurement and

control, and perform roles for safety protection and current limiting. They can also cause circuit

events to occur when the monitored current reaches a specified level. Current monitoring is

necessary at frequencies from the 50 Hz/60 Hz power line to the higher frequencies of switch

mode transformers that range into the hundreds of kilohertz.

The object with current transformers is to think in terms of current transformation rather than

voltage ratios. Current ratios are the inverse of voltage ratios. The thing to remember about

transformers is that Pout = (Pin — transformer power losses). With this in mind, let's assume we

had an ideal loss-less transformer in which Pout = Pin. Since power is voltage times current, this

product must be the same on the output as it is on the input. This implies that a 1:10 step-up

transformer with the voltage stepped up by a factor of 10 results in an output current reduced by

a factor of 10. This is what happens on a current transformer. If a transformer had a one-turn

primary and a ten-turn secondary, each amp in the primary results in 0.1A in the secondary, or a

10:1 current ratio. It's exactly the inverse of the voltage ratio — preserving volt times current

product.

Fig. 1 shows an ideal transformation ratio. In this analysis, the secondary dc resistance (RDCR)

doesn't become part of the calculation. When considering the secondary current, only the actual

current affects V. How well that current can be determined controls the accuracy of the

prediction of V. The secondary dc resistance is best analyzed by reflecting it to the primary by

RDCR/N2.

A burden resistor connected across the secondary produces an output voltage proportional to the

resistor value, based on the amount of current flowing through it. With our 1:10 turns ratio

42

transformer that produces a 10:1 current ratio, a burden resistor can be selected to produce the

voltage we want. If 1A on the primary produces 0.1A on the secondary, then by Ohm's law, 0.1

times the burden resistor will result in an output voltage per amp.

When choosing the burden resistor, the engineer can create any output voltage per amp, as long

as it doesn't saturate the core. Core saturation level is an important consideration when

specifying current transformers. The maximum volt-microsecond product specifies what the core

can handle without saturating. The burden resistor is one of the factors controlling the output

voltage. There's a limit to the amount of voltage that can be achieved at a given frequency. Since

frequency = 1/cycle period, if the frequency is too low (cycle period too long) so that voltage-

time product exceeds the core's flux capacity, saturation will occur. The flux that exists in a core

is proportional to the voltage times cycle period. Most specifications provide a maximum volt-

microsecond product that the current transformer can provide across the burden resistor.

Exceeding this voltage with too large a burden resistor will saturate the transformer and limit the

voltage.

What happens if the burden resistor is left off or opens during operation? The output voltage will

rise trying to develop current until it reaches the saturation voltage of the coil at that frequency.

At that point, the voltage will cease to rise and the transformer will add no additional impedance

to the driving current. Therefore, without a burden resistor, the output voltage of a current

transformer will be its saturation voltage at the operating frequency.

There are factors in the current transformer that affect efficiency. For complete accuracy, the

output current must be the input current divided by the turns ratio. Unfortunately, not all the

current is transferred. Some of the current isn't transformed to the secondary, but is instead

shunted by the inductance of the transformer and the core loss resistance. Generally, it's the

inductance of the transformer that contributes the majority of the current shunting that detracts

from the output current. This is why it's important to use a high-permeability core to achieve the

maximum inductance and minimize the inductance current. Accurate turns ratio must be

maintained to produce the expected secondary current and the expected accuracy. Fig. 2 shows

the current transformed is smaller than the input current by:

43

ITRANSFORMED=IINPUT-ICORE-jIMAG (1)

The burden resistor on the secondary is reflected to the primary by (1/N2), which provides a

resistance in series with the current on the primary. This usually has minimal effect and is

usually only important when you are concerned about the current that would exist when the

transformer isn't in the circuit, such as when it's used as a temporary measuring device.

Notice the four loss components in the circuit of Fig. 2. The resistance of the primary loop

(PRIDCR), the core loss resistance (RCORE), the secondary DCR (RDCR) is reduced by 1/N2, and the

secondary burden resistor RBURDEN is also reduced by a factor of N2. These are losses that affect

current source (I). The resistances have an indirect effect on the current transformer accuracy. It's

their effect on the circuit that they are monitoring that alters its current. The primary dc

resistance (PRIdcr) and the secondary DCR/N2 (RDCR/N2) don't detract from the Iinput that is read or

is affecting the accuracy of the actual current reading. Rather, they alter the current from what it

would be if the current transformer weren't in the circuit. With the exception of the burden

resistor, these loss resistors are the components that contribute to the loss in the transformer and

heating.

This wasted energy is usually small compared with the power in the circuit it's monitoring.

Usually, the design of the transformer and choice of the burden resistor will be within the

maximum energy loss the end user can allow. As battery-operated devices come into wider use

and power consumption contributes to the energy crisis — even this power may be of concern.

Under these circumstances, it may require special design attention to power consumption.

Current transformers are an efficient way to measure current. Since the burden resistor is

reflected to the primary by 1/N2, the resistance seen in the circuit being monitored can be very

44

small. This allows a larger voltage to be created on the output with minimal effect on the circuit

being measured. A simpler and lower-cost method to measure current is to use a sense resistor

connected in series with the current. However, this method can only be used when power

consumption is of secondary concern. With the more frequent use of battery-powered devices

and the prevailing need to reduce power consumption, the extra expense of a current transformer

can soon be recovered with use. Also, with high current or when a voltage of any magnitude is

required, a sense resistor would be impractical.

WORKING

45

First of all we use step down transformer to step down the voltage from 220 volt ac to 9 volt ac.

For this purpose we use step down transformer. Output of the transformer is converted into dc

with the help of the bridge rectifier diode. Here we use IN 4007 diode. Output of the rectifier is

pulsating dc. So to convert pulsating dc into smooth dc, we use 1000mfd capacitor filter. Output

of the capacitor is connected to the three pin regulator. Here in this project we use IC 7805

regulator. Output of the regulator is 5 volt dc. This dc is further connected to the microcontroller

pin no 40. Pin no 31 is also connected to the positive supply. Pin no 20 is connected to the

ground pin. Pin no 31 is a excess enable pin. If we use external memory for program code then

we connect pin no 31 to ground pin. Otherwise Pin no 31 is connected to the positive supply. Pin

no 9 is connected to the one capacitor and resistor circuit. This circuit is for the auto reset circuit

for the controller. When the power is on then pin no 9 is auto reset by this RC network circuit.

Pin no 18 and 19 is connected to the 12 Mhz crystal. With the help of this crystal, we provide a

constant frequency to the internal oscillator of the IC. If we use 12 Mhz crystal then it means

internal speed of the controller is approx 1 microsecond for one instruction cycle.

Pin no 12, 22 and 21 is connected to the real time clock. Here in this project we use serial RTC

for time base. Pin no 1 and 2 of the IC is connected to the 32 khz crystal oscillator to provide a

exact time delay. This RTC is serial time signal provider. For the real time clock we use 8563 IC.

8563 is a 8 pin IC. Pin no 8 connected to the positive supply. Pin no 4 is connected to the ground

pin. Pin no 1 and 2 is connected to the external crystal to provide a constant frequency for long

time. External battery from battery backup is connected to the pin no8 to provide a battery

backup for long time.

PROGRAM CODE

46

LCD_DATA equ P0

lcd_rs bit P2.7

lcd_rw bit P2.6

lcd_en bit P2.5

flag equ 20h

flag0 bit flag.0

flag1 bit flag.1

flag2 bit flag.2

flag3 bit flag.3

flag4 bit flag.4

flag5 bit flag.5

flag6 bit flag.6

flag7 bit flag.7

flagg equ 21h

flag8 bit flagg.0

flag9 bit flagg.1

flag10 bit flagg.2

flag11 bit flagg.3

flag12 bit flagg.4

flag13 bit flagg.5

flag14 bit flagg.6

flag15 bit flagg.7

flaggl equ 22h

flag16 bit flaggl.0

47

flag17 bit flaggl.1

flag18 bit flaggl.2

flag19 bit flaggl.3

flag20 bit flaggl.4

flag21 bit flaggl.5

flag22 bit flaggl.6

flag23 bit flaggl.7

flaggh equ 23h

flag24 bit flaggh.0

flag25 bit flaggh.1

flag26 bit flaggh.2

flag27 bit flaggh.3

flag28 bit flaggh.4

flag29 bit flaggh.5

flag30 bit flaggh.6

flag31 bit flaggh.7

ch0_on_seconds equ 25h

ch0_on_minutes equ 26h

ch0_on_hours equ 27h

ch0_off_seconds equ 28h

ch0_off_minutes equ 29h

ch0_off_hours equ 2ah

ch1_on_seconds equ 2bh

ch1_on_minutes equ 2ch

ch1_on_hours equ 2dh

48

ch1_off_seconds equ 2eh

ch1_off_minutes equ 2fh

ch1_off_hours equ 30h




ch2_off_seconds equ 34h

ch2_off_minutes equ 35h

ch2_off_hours equ 36h




ch3_off_seconds equ 3ah

ch3_off_minutes equ 3bh

ch3_off_hours equ 3ch

seconds equ 3dh

minutes equ 3eh

hours equ 3fh

days equ 40h

weekdays equ 41h

months equ 42h

years equ 43h

RTC_ADD equ 44h

RTC_ADD_DATA equ 45h

key0 bit p1.0

49

key1 bit p1.1

key2 bit p1.2

key3 bit p1.3

OUT0 bit p1.4

OUT1 bit p1.5

OUT2 bit p1.6

OUT3 bit p1.7

WRITE_C EQU 0a2h

READ_C EQU 0a3h

ACK_READ EQU 8ah

main:

lcall DELAY11

mov psw,#00h

mov sp,#070h

mov tmod,#00h

mov tcon,#00h

mov scon,#00h

mov ie,#81h

mov ip,#00h

mov tl1,#00h

50

mov th1,#00h

mov p0,#0ffh

mov p1,#0ffh

mov p2,#0ffh

mov p3,#0ffh

mov ch0_on_seconds,#00h

mov ch0_on_minutes,#00h

mov ch0_on_hours,#00h

mov ch0_off_seconds,#00h

mov ch0_off_minutes,#00h

mov ch0_off_hours,#00h















51





mov seconds,#00h

mov minutes,#00h

mov hours,#00h

mov days,#00h

mov weekdays,#00h

mov months,#00h

mov years,#00h

setb OUT0

setb OUT1

setb OUT2

setb OUT3

clr flag0

clr flag1

clr flag2

clr flag3

clr flag4

clr flag5

clr flag6

clr flag7

setb flag8

clr flag9

52

clr flag10

clr flag11

clr flag12

clr flag13

clr flag14

clr flag15

setb flag16

setb flag17

clr flag18

clr flag19

clr flag20

clr flag21

clr flag22

clr flag23

clr flag24

clr flag25

clr flag26

clr lcd_rs

clr lcd_rw

clr lcd_en

MOV RTC_ADD,#0DH

MOV RTC_ADD_DATA,#83h

lcall WRITBYTE

lcall INIT_LCD

lcall CLR_LCD

53

lcall data_read_eeprom

mov dptr,#MSG0

lcall LINE_1

mov dptr,#MSG1

lcall LINE_2

lcall DELAY11

lcall DELAY11

mov dptr,#MSG2

lcall LINE_1

mov dptr,#MSG3

lcall LINE_2

setb flag0

mov dptr,#MSG12

MOV RTC_ADD,#02H

lcall READBYTE

MOV seconds,RTC_ADD_DATA

MOV RTC_ADD,#03H

lcall READBYTE

MOV minutes,RTC_ADD_DATA

MOV RTC_ADD,#04H

lcall READBYTE

MOV a,RTC_ADD_DATA

ANL a,#3fh

MOV hours,a

54

MOV RTC_ADD,#05H

lcall READBYTE

MOV a,RTC_ADD_DATA

ANL a,#3fh

MOV days,a

MOV RTC_ADD,#06H

lcall READBYTE

MOV a,RTC_ADD_DATA

ANL a,#07h

MOV weekdays,a

MOV RTC_ADD,#07H

lcall READBYTE

MOV a,RTC_ADD_DATA

ANL a,#1fh

MOV months,a

MOV RTC_ADD,#08H

lcall READBYTE

MOV years,RTC_ADD_DATA

lcall OUTPUT_ON_OFF

ljmp WAIT

OUTPUT_ON_OFF:

mov a,seconds

cjne a,ch0_on_seconds,ch0_on_nxt

mov a,minutes

55

cjne a,ch0_on_minutes,ch0_on_nxt

mov a,hours

cjne a,ch0_on_hours,ch0_on_nxt

clr OUT0

ch0_on_nxt:

mov a,seconds

cjne a,ch0_off_seconds,ch0_off_nxt

mov a,minutes

cjne a,ch0_off_minutes,ch0_off_nxt

mov a,hours

cjne a,ch0_off_hours,ch0_off_nxt

setb OUT0

INIT_LCD:

mov LCD_DATA,#038h

lcall COMMAND_BYTE

lcall DELAY1

mov LCD_DATA,#038h

lcall COMMAND_BYTE

lcall DELAY1

mov LCD_DATA,#038h

lcall COMMAND_BYTE

lcall DELAY1

mov LCD_DATA,#038h

lcall COMMAND_BYTE

56

lcall DELAY1

mov LCD_DATA,#008h

lcall COMMAND_BYTE

lcall DELAY1

mov LCD_DATA,#00ch

lcall COMMAND_BYTE

lcall DELAY1

mov LCD_DATA,#006h

lcall COMMAND_BYTE

lcall DELAY1

ret

CLR_LCD:

mov LCD_DATA,#001h

lcall COMMAND_BYTE

lcall DELAY1

ret

WRITE_MSG:

mov a,#00h

movc a,@a+dptr

cjne a,#'$',WRITE_CONT

ret

WRITE_CONT:

mov LCD_DATA,a

lcall DATA_BYTE

inc dptr

57

ljmp WRITE_MSG

COMMAND_BYTE:

clr lcd_rs

lcall DELAY

ljmp CMD10

DATA_BYTE:

setb lcd_rs

lcall DELAY

CMD10:

clr lcd_rw

lcall DELAY

setb lcd_en

lcall DELAY

clr lcd_en

lcall DELAY

ret

DELAY:

mov r0,#10d

DEL:

djnz r0,DEL

ret

DELAY1:

mov r0,#0d

mov r1,#20d

DELAY10:

58

djnz r0,DELAY10

djnz r1,DELAY10

ret

DELAY41:

mov r0,#0d

mov r1,#15d

DLP410:

djnz r0,DLP410

djnz r1,DLP410

ret

DELAY11:

mov r0,#0d

mov r1,#0d

mov r2,#10d

DLP11:

djnz r0,DLP11

djnz r1,DLP11

djnz r2,DLP11

ret

data_read_eeprom:

mov 1bh,#0d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read

59

mov ch0_on_seconds,19h

mov 1bh,#1d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read

mov ch0_on_minutes,19h

mov 1bh,#2d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read

mov ch0_on_hours,19h

mov 1bh,#3d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read

mov ch0_off_seconds,19h

mov 1bh,#4d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read

mov ch0_off_minutes,19h

60

mov 1bh,#5d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read

mov ch0_off_hours,19h

mov 1bh,#6d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#7d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#8d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#9d

61

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#10d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#11d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#12d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#13d

mov r6, #00h

62

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#14d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#15d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#16d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#17d

mov r6, #00h

djnz r6,$

63

djnz r6,$

lcall read


mov 1bh,#18d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#19d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#20d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#21d

mov r6, #00h

djnz r6,$

djnz r6,$

64

lcall read


mov 1bh,#22d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


mov 1bh,#23d

mov r6, #00h

djnz r6,$

djnz r6,$

lcall read


ret

MSG0: db ' RTC CLOCK $'

MSG1: db ' 4 CHANEL TIMER $'

MSG2: db ' 00/00/2000 $'

MSG3: db 'CLOCK 00:00:00 $'

65

MSG4: db 'CH0ON 00:00:00 $'

MSG5: db 'CH0OFF 00:00:00 $'

MSG6: db 'CH1ON 00:00:00 $'

MSG7: db 'CH1OFF 00:00:00 $'

MSG8: db 'CH2ON 00:00:00 $'

MSG9: db 'CH2OFF 00:00:00 $'

MSG10: db 'CH3ON 00:00:00 $'

MSG11: db 'CH3OFF 00:00:00 $'

MSG12: db 'SUNMONTUEWEDTHUFRISAT$'

ADVANTAGES AND CONCLUSIONS

66

1. It is a very reliable circuit and also there s a complete elimination of

manpower.

2. It uses high technology, products, core devices are intelligent controllers and

the time control of the braker can be set in advance in long durations

depending upon the need of the locality.

3. It has a long life and its operation can be set for an year in advance.

4. It leads to the conservation of the natural resources particularly the fuel which

is consumed by vehicles.

5. Leads to more organized traffic on roads and hence considerably reduces

number of accidents.

67

FUTURE PROSPECTS

Solar powered brakers

Since our original system uses ac power supply which is generated from a renewable source of

energy, we can always replace it with a solar powered system as they are green form of energy.

Other applications

The system can also be coupled with sensors which provides instant information about any

natural calamities like land slides which can affect the traffic on roads. Now the brakers

installed a kilometer away from the affected area are switched on giving them prior information

about any detours ahead.

REFERENCES

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1) The 8051 Microcontroller and Embedded Systems using Assembly

and C, Muhammad Ali Mazidi, Janice Gillispie Mazidi, Rolin

D.McKinlay.

2) http://www.keil.com/dd/docs/datashts/atmel/at89s52_ds.pdf

(Microcontroller)

3) http://www.dfrobot.com/image/data/FIT0127/datasheet.pdf ( LCD)

4) http://www.google.co.in

5) http://www.wikipedia.org

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http://www.wikipedia.org/

http://www.google.co.in/

http://www.dfrobot.com/image/data/FIT0127/datasheet.pdf

http://www.keil.com/dd/docs/datashts/atmel/at89s52_ds.pdf

Automatic Speed Breaker

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Transcript of Automatic Speed Breaker