Upload
sridevikumaresan
View
220
Download
0
Embed Size (px)
Citation preview
7/30/2019 PC based differential and over current protection
1/47
CHAPTER 1
INTRODUCTION
Embedded systems are computers which are part of special-purpose devices.
Due to the limited duties this systems can be highly optimized to the particular
needs. Traditionally most of this systems are used for control and process
measurement, as a side-effect of higher integration of integrated circuits more
complex applications can be solved by embedded systems. To be able to solve
these problems embedded systems are commonly equipped with various kinds of
peripherals. Early applications of embedded devices include the guidancecomputer of the Minuteman I missiles and the Apollo guidance computer. The
Minuteman I & II missiles are intercontinental ballistic nuclear warheads,
produced by Boeing in the 1960s. Due to the large quantities of ICs used in the
guidance system of Minuteman II missiles, prices for ICs fell from 1000$ each to
3$ each. This lead to wide adoption of embedded systems in consumer electronics
in the 1980s. Nowadays embedded systems can be found in devices from digital
watches to traffic-control systems. The broad ranges of applications with totally
different requirements lead to various implementation approaches
1.1HARDWARE PLATFORMS
Based on the metrics, introduced in the above section, processors for
embedded systems can be distinguished by the grade of customization they grant
and the performance they achieve.
Examples are:
Motorola ARM
Atmel AVR
Microchip PIC
1
7/30/2019 PC based differential and over current protection
2/47
Intel Pentium-(I/II/III/IV)-Series
AMD Athlon (or other)
VIA EDEN
1.2PROGRAMMING EMBEDDED SYSTEMS
Unlike personal computers, embedded systems usually arent programmed
on the platform the program is intended to run. This requires special tool chains
with cross-compilers and emulators to test the code before deploying it to the target
platform. Depending on the applications needs, there are different approaches to
implement the software. One possibility is to directly control the hardware out of
the program. This is the approach with the highest performance, but requires more
knowledge about the used architecture and peripherals than using an operating
system. On the other hand operating systems provide functionalities for
multiprocessing and allow the designer to develop mostly independent from the
underlying architecture.
2
7/30/2019 PC based differential and over current protection
3/47
1.3 BLOCK DIAGRAM
1.3.1RECEIVER:
3
MICROCONTROLLER89C51
PC
POWERSUPPLY
HT 648
DECODER
RF Rxer
GSM
7/30/2019 PC based differential and over current protection
4/47
1.3.2TRANSMITTER:
4
RFIDREADER
MICROCONTROLER89C51
RFID TAG
RFID TAG
RFID TAG
IRSENSOR
POWERSUPPLY
LCD
HT 640
ENCODER
RF Txer
7/30/2019 PC based differential and over current protection
5/47
CHAPTER 2
MICROCONTROLLER
2.1INTRODUCTION:
A microcontroller is a complete microprocessor system built on a single IC.
Microcontrollers were developed to meet a need for microprocessors to be put into
low cost products. Building a complete microprocessor system on a single chip
substantially reduces the cost of building simple products, which use the
microprocessor's power to implement their function, because the microprocessor is
a natural way to implement many products. This means the idea of using a
microprocessor for low cost products comes up often. But the typical 8-bit
5
7/30/2019 PC based differential and over current protection
6/47
microprocessor based system, such as one using a Z80 and 8085 is expensive. Both
8085 and Z80 system need some additional circuits to make a microprocessor
system. Each part carries costs of money. Even though a product design may
require only very simple system, the parts needed to make this system as a low cost
product.
6
7/30/2019 PC based differential and over current protection
7/47
2.2APPLICATIONS OF MICROCONTROLLERS
Microcontrollers are designed for use in sophisticated real time applications
such as
1. Industrial Control
2. Instrumentation and
3. Intelligent computer peripherals
They are used in industrial applications to control
Motor
Robotics
Discrete and continuous process control
In missile guidance and control
In medical instrumentation
Oscilloscopes
Telecommunication
Automobiles
For Scanning a keyboard
Driving an LCD
For Frequency measurement
CHAPTER 3
7
7/30/2019 PC based differential and over current protection
8/47
RADIO FREQUENCY
3.1 INTRODUCTION
The mode of communication for wireless technologies of all kinds,
including cordless phones, radar, ham radio, GPS, and radio and television
broadcasts. RF technology is so much a part of our lives we scarcely notice it for
its ubiquity. From baby monitors to cell phones, Bluetooth to remote control
toys, RF waves are all around us. RF waves are electromagnetic waves which
propagate at the speed of light, or 186,000 miles per second (300,000 km/s). The
frequencies of RF waves, however, are slower than those of visible light, making
RF waves invisible to the human eye.
The frequency of a wave is determined by its oscillations or cycles per
second. One cycle is one hertz (Hz); 1,000 cycles is 1 kilohertz (KHz); 1 million
cycles is 1 megahertz (MHz); and 1 billion cycles is 1 gigahertz (GHz). A station
on the AM dial at 980, for example, broadcasts using a signal that oscillates
980,000 times per second, or has a frequency of 980 KHz. A station a little further
down the dial at 710 broadcasts using a signal that oscillates 710,000 times a
second, or has a frequency of 710 KHz. With a slice of the RF pie licensed to each
broadcaster, the RF range can be neatly divided and utilized by multiple parties.
3.2RFID Reader
An RFID reader is a device that is used to interrogate an RFID tag. The
reader has an antenna that emits radio waves; the tag responds by sending back its
data.
8
http://www.wisegeek.com/what-is-gps.htmhttp://www.wisegeek.com/what-is-mhz.htmhttp://www.wisegeek.com/what-is-ghz.htmhttp://www.technovelgy.com/ct/Technology-Article.asp?ArtNum=50http://www.wisegeek.com/what-is-gps.htmhttp://www.wisegeek.com/what-is-mhz.htmhttp://www.wisegeek.com/what-is-ghz.htmhttp://www.technovelgy.com/ct/Technology-Article.asp?ArtNum=507/30/2019 PC based differential and over current protection
9/47
A number of factors can affect the distance at which a tag can be read (the
read range). The frequency used for identification, the antenna gain, the orientation
and polarization of the reader antenna and the transponder antenna, as well as the
placement of the tag on the object to be identified will all have an impact on the
RFID systems read range.
3.2.1Types:
9
7/30/2019 PC based differential and over current protection
10/47
There are three types of RFID tags: active RFID tags, passive RFID tags,
and semi-passive RFID tags. Active RFID tags are typically larger and more
expensive to produce, since they require a power source. Active RFID tags
broadcast their signal to the reader, and are typically more reliable and accurate
than passive RFID tags. Since active RFID tags have a stronger signal, they are
more adept for environments that make it hard to transmit other types of tags, such
as under water, or from farther away.
Passive RFID tags, on the other hand, do not have internal power supplies
and rely on the RFID reader to transmit data. A small electrical current is received
through radio waves by the RFID antenna, and power the CMOS just enough to
transmit a response. Passive RFID tags are more suited for warehousing
environments where there is not a lot of interference, and relatively short distances
(typically ranging anywhere from a few inches to a few yards). Since there is no
internal power supply, passive RFID tags are much smaller and cheaper to
produce.
3.3RF TRANSMITTER
10
7/30/2019 PC based differential and over current protection
11/47
3.3.1Features:
Modulate Mode: ASK
Circuit Shape: SAW
Date Rate: 8kbps
Supply Voltage: 3~ 12 V
Power Supply and All Input / Output Pins: -0.3 to +12.0 V
Non-Operating Case Temperature: -20 to +85
Soldering Temperature ( 10 Seconds ) : 230 ( 10 Seconds)
Frequency Range: 433.92 MHz
3.3.2Electrical Characteristics:
11
7/30/2019 PC based differential and over current protection
12/47
3.3.3Application Note:
3.4RF RECEIVER
12
7/30/2019 PC based differential and over current protection
13/47
3.4.1Features:
Frequency Range: 433.92 MHZ
Modulate Mode: ASK
Circuit Shape: LC
Date Rate: 4800 bps
Selectivity: -106 dB
Channel Spacing: 1MHZ
Supply Voltage: 5V
High Sensitivity Passive Design.
Simple To Apply with Low External Count.
13
7/30/2019 PC based differential and over current protection
14/47
3.4.2DC Characteristics
3.4.3Electrical Characteristics
3.4.4Application Note:
CHAPTER 4
14
7/30/2019 PC based differential and over current protection
15/47
4.1IR SENSOR
The IR sensor is a very simple device that works by reflecting infrared light
off of an object and detecting the reflecting with a photo-transistor that is tuned to
the same frequency of light. The LED is mounted next to the photo-transistor,
however, the emitted light from the LED does not directly shine into the photo-
transistor. Appropriate values for resistance are in series with both the LED to limit
current and the photo-transistor in order to show a voltage drop based on distance
to the object in front of the sensor. The effective range of the sensor is a few
centimeters. Object detection can be enhanced by placing a reflective surface
between the object and the sensor. When the object passes between the sensor and
reflective surface, a large drop will be observed in the output signal.
4.2Applications:
CCD Camera
Night Vision
Infrared Applied System
15
7/30/2019 PC based differential and over current protection
16/47
4.3Dimensions
IR-1WS-850
16
7/30/2019 PC based differential and over current protection
17/47
CHAPTER 5
5.1MAX 232:
The MAX232 is an integrated circuit that converts signals from an RS-232
serial port to signals suitable for use in TTL compatible digital logic circuits. The
MAX232 is a dual driver/receiver and typically converts the RX, TX, CTS andRTS signals.
The drivers provide RS-232 voltage level outputs (approx. 7.5 V) from a
single + 5 V supply via on-chip charge pumps and external capacitors. This makes
it useful for implementing RS-232 in devices that otherwise do not need any
voltages outside the 0 V to + 5 V range, as power supply design does not need to
be made more complicated just for driving the RS-232 in this case.
The receivers reduce RS-232 inputs (which may be as high as 25 V), to
standard 5 V TTL levels. These receivers have a typical threshold of 1.3 V, and a
typical hysteresis of 0.5 V.
The later MAX232A is backwards compatible with the original MAX232
but may operate at higher baud rates and can use smaller external capacitors 0.1
F in place of the 1.0 F capacitors used with the original device.
17
7/30/2019 PC based differential and over current protection
18/47
The newer MAX3232 is also backwards compatible, but operates at a
broader voltage range, from 3 to 5.5V.
5.2VOLTAGE LEVELS
It is helpful to understand what occurs to the voltage levels. When a
MAX232 IC receives a TTL level to convert, it changes a TTL Logic 0 to between
+3 and +15V, and changes TTL Logic 1 to between -3 to -15V, and vice versa for
converting from RS232 to TTL. This can be confusing when you realize that the
RS232 Data Transmission voltages at a certain logic state are opposite from the
RS232 Control Line voltages at the same logic state.
CHAPTER 6
18
7/30/2019 PC based differential and over current protection
19/47
6.1 GSM:
The Global System for Mobile communication (GSM) is a huge, rapidly
expanding and successful technology. Less than five years ago, there were a small
number of companies working on GSM. Each of these companies had a few GSM
experts who brought knowledge back from the European Telecommunications
Standards Institute committees designing the GSM specification. Currently, there
are hundreds of companies working on GSM and thousands of GSM experts.
In the US, bands have been allocated at approximately 2 GHz for a personal
communications system (PCS). Unlike Europe and the Far East, the PCS license
holders will not be forced to use any particular radio technology. The three main
system contenders are GSM, code-division multiple access and 15-136 time-
division multiple access (TDMA), all likely to have nationwide coverage. The
ready availability of GSM equipment and expertise has made GSM at 1.9 GHz
attractive for many operators. PCS1900 operators have banded together to form the
North American Interest Group and help advance the development of GSM. Theseven member companies include American Personal Communications (APC),
American Portable Telecom, Bell South Personal Communications, Intercel,
Omnipoint, Pacific Bell Mobile Services and Western Wireless Co. Many of the
large GSM manufacturers are also backing PCS1900, including Nokia, Ericsson,
19
7/30/2019 PC based differential and over current protection
20/47
Matra, AEG and Northern Telecom. The first commercial PCS system based on
PCS1900 was launched by APC under the Sprint Spectrum name on November 15,
1995. The majority of US PCS licenses will became operational over the next two
years.
A GSM network is composed of several functional entities, whose functions
and interfaces are defined.
The GSM network can be divided into three broad parts. The Mobile Station
is carried by the subscriber, the Base Station Subsystem controls the radio link
with the Mobile Station. The Network Subsystem, the main part of which is the
Mobile services Switching Center, performs the switching of calls between the
mobile and other fixed or mobile network users, as well as management of mobile
services, such as authentication. Not shown is the Operations and Maintenance
center, which oversees the proper operation and setup of the network. The Mobile
Station and the Base Station Subsystem communicate across the Um interface, also
known as the air interface or radio link. The Base Station Subsystem
communicates with the Mobile service Switching Center across the A interface.
6.2Mobile Station:
The mobile station (MS) consists of the physical equipment, such as the
radio transceiver, display and digital signal processors, and a smart card called the
Subscriber Identity Module (SIM). The SIM provides personal mobility, so that
the user can have access to all subscribed services irrespective of both the location
of the terminal and the use of a specific terminal. By inserting the SIM card into
another GSM cellular phone, the user is able to receive calls at that phone, make
calls from that phone, or receive other subscribed services.
20
7/30/2019 PC based differential and over current protection
21/47
The mobile equipment is uniquely identified by the International Mobile
Equipment Identity (IMEI). The SIM card contains the International Mobile
Subscriber Identity (IMSI), identifying the subscriber, a secret key for
authentication, and other user information. The IMEI and the IMSI are
independent, thereby providing personal mobility. The SIM card may be protected
against unauthorized use by a password or personal identity number.
6.3Base Station Subsystem:
The Base Station Subsystem is composed of two parts, the Base Transceiver
Station (BTS) and the Base Station Controller (BSC). These communicate across
the specified Abis interface, allowing (as in the rest of the system) operation
between components made by different suppliers.
The Base Transceiver Station houses the radio tranceivers that define a cell
and handles the radiolink protocols with the Mobile Station. In a large urban
area, there will potentially be a large number of BTSs deployed. The requirements
for a BTS are ruggedness, reliability, portability, and minimum cost.
The Base Station Controller manages the radio resources for one or more
BTSs. It handles radiochannel setup, frequency hopping, and handovers, as
described below. The BSC is the connection between the mobile and the Mobile
service Switching Center (MSC). The BSC also translates the 13 kbps voice
channel used over the radio link to the standard 64 kbps channel used by the Public
Switched Telephone Network or ISDN.
Network Subsystem
The central component of the Network Subsystem is the Mobile services
Switching Center (MSC). It acts like a normal switching node of the PSTN or
21
7/30/2019 PC based differential and over current protection
22/47
ISDN, and in addition provides all the functionality needed to handle a mobile
subscriber, such as registration, authentication, location updating, handovers, and
call routing to a roaming subscriber. These services are provided in conjuction
with several functional entities, which together form the Network Subsystem. The
MSC provides the connection to the public fixed network (PSTN or ISDN), and
signalling between functional entities uses the ITUT Signalling System
Number 7 (SS7), used in ISDN and widely used in current public networks.
The Home Location Register (HLR) and Visitor Location Register (VLR),
together with the MSC, provide the callrouting and (possibly international)
roaming capabilities of GSM. The HLR contains all the administrative
information of each subscriber registered in the corresponding GSM network,
along with the current location of the mobile. The current location of the mobile is
in the form of a Mobile Station Roaming Number (MSRN) which is a regular
ISDN number used to route a call to the MSC where the mobile is currently
located. There is logically one HLR per GSM network, although it may be
implemented as a distributed database.
The Visitor Location Register contains selected administrative information
from the HLR, necessary for call control and provision of the subscribed services,
for each mobile currently located in the geographical area controlled by the VLR.
Although each functional entity can be implemented as an independent unit, most
manufacturers of switching equipment implement one VLR together with one
MSC, so that the geographical area controlled by the MSC corresponds to that
controlled by the VLR, simplifying the signalling required. Note that the MSC
contains no information about particular mobile stations - this information is stored
in the location registers.
22
7/30/2019 PC based differential and over current protection
23/47
The other two registers are used for authentication and security purposes.
The Equipment Identity Register (EIR) is a database that contains a list of all valid
mobile equipment on the network, where each mobile station is identified by its
International Mobile Equipment Identity (IMEI). An IMEI is marked as invalid if
it has been reported stolen or is not type approved. The Authentication Center is a
protected database that stores a copy of the secret key stored in each subscriber's
SIM card, which is used for authentication and ciphering of the radio channel.
6.4SIM:
A SIM card or Subscriber Identity Module is a portable memory chip used in
some models of cellular telephones. The SIM card makes it easy to switch to a new
phone by simply sliding the SIM out of the old phone and into the new one. The
SIM holds personal identity information, cell phone number, phone book, text
messages and other data. It can be thought of as a mini hard disk that automatically
activates the phone into which it is inserted.
A SIM card can come in very handy. For example, let's say your phone runs
out of battery power at a friend's house. Assuming you both have SIM-based
phones, you can remove the SIM card from your phone and slide it into your
friend's phone to make your call. Your carrier processes the call as if it were made
from your phone, so it won't count against your friend's minutes.
If you upgrade your phone there's no hassle involved. The SIM card is all
you need. Just slide it into the new phone and you're good to go. You can even
keep multiple phones for different purposes. An inexpensive phone in the glove
compartment, for example, for emergency use, one phone for work and another for
home. Just slide your SIM card into whatever phone you wish to use.
23
7/30/2019 PC based differential and over current protection
24/47
High-end cell phones can be very attractive and somewhat pricey. If you
invest in an expensive phone you might want to keep it awhile. Using a SIM card,
it is even possible to switch carriers and continue to use the same phone. The new
carrier will simply issue you their own SIM card. The phone must be unlocked,
however, and operate on the new carrier's frequency or band.
A SIM card provides an even bigger advantage for international travelers --
simply take your phone with you and buy a local SIM card with minutes. For
example, a traveler from the U.S. staying in the U.K. can purchase a SIM card
across the pond. Now the phone can be used to call throughout England without
paying international roaming charges from the carrier back home.
6.5GSM MODEM:
A GSM modem is a specialized type of modem which accepts a SIM card,
and operates over a subscription to a mobile operator, just like a mobile phone.
From the mobile operator perspective, a GSM modem looks just like a mobile
phone.
A GSM modem can be a dedicated modem device with a serial, USB or
Bluetooth connection, or it may be a mobile phone that provides GSM modem
capabilities.
For the purpose of this document, the term GSM modem is used as a generic
term to refer to any modem that supports one or more of the protocols in the GSM
evolutionary family, including the 2.5G technologies GPRS and EDGE, as well as
the 3G technologies WCDMA, UMTS, HSDPA and HSUPA.
24
7/30/2019 PC based differential and over current protection
25/47
A GSM modem exposes an interface that allows applications such as
NowSMS to send and receive messages over the modem interface. The mobile
operator charges for this message sending and receiving as if it was performed
directly on a mobile phone. To perform these tasks, a GSM modem must support
an "extended AT command set" for sending/receiving SMS messages, as defined in
the ETSI GSM 07.05 and and 3GPP TS 27.005 specifications.
GSM modems can be a quick and efficient way to get started with SMS,
because a special subscription to an SMS service provider is not required. The
mobile operator charges for this message sending and receiving as if it was
performed directly on a mobile phone. In most parts of the world, GSM modems
are a cost effective solution for receiving SMS messages, because the sender is
paying for the message delivery.
Historically, we have recommended GSM modems from manufacturers such
as Multitech, Falcom, Siemens (now Cinterion), iTegno and Wavecom. While
these manufacturers make very good GSM modems, there are currently a lot of
GSM/3G USB stick modems available on the market, which are less expensive
(under $100), and in many cases significantly faster than older GSM modems.
Some recommended GSM/3G USB modems include the Option ICON 322,
Sierra Wireless Compass 885, SonyEricsson MD300, Novatel MC950D and
Huawei E160. Many other models from these manufacturers will also work well
with NowSMS.
We have posted some notes about experiences with specific modem models
at the following link: http://blog.nowsms.com/search/label/GSM%20modem.
A GSM modem could also be a standard GSM mobile phone with the
appropriate cable and software driver to connect to a serial port or USB port on
25
7/30/2019 PC based differential and over current protection
26/47
your computer. Any phone that supports the "extended AT command set" for
sending/receiving SMS messages, as defined in ETSI GSM 07.05 and/or 3GPP TS
27.005, can be supported by the Now SMS/MMS Gateway. Note that not all
mobile phones support this modem interface.
Due to some compatibility issues that can exist with mobile phones, using a
dedicated GSM modem is usually preferable to a GSM mobile phone. This is more
of an issue with MMS messaging, where if you wish to be able to receive inbound
MMS messages with the gateway, the modem interface on most GSM phones will
only allow you to send MMS messages. This is because the mobile phone
automatically processes received MMS message notifications without forwarding
them via the modem interface.
It should also be noted that not all phones support the modem interface for
sending and receiving SMS messages. In particular, most smart phones, including
Blackberries, iPhone, and Windows Mobile devices, do not support this modem
interface at all.Nokia phones that use the S60 (Series 60) interface, which is
Symbian based, only support sending SMS messages via the modem interface, and
do not support receiving SMS via the modem interface. Nokia phones using the
Series 40 3rd Generation or later interface have similar limitations and do not
support receiving SMS via the modem interface. This makes most Nokia phones
incompatible with the 2-way SMS functionality of NowSMS.
SonyEricsson phones generally have a good full GSM modem
implementation (except for the P and X series which use UIQ/Symbian or
Windows Mobile). They can be used for sending/receiving SMS messages and
sending MMS messages.
26
7/30/2019 PC based differential and over current protection
27/47
Motorola phones have a bug in their GSM modem implementation that
prevents them from being able to send binary SMS messages. They can
send/receive SMS text messages, and send MMS messages.
While using a phone as a modem may be a good way to get started with
NowSMS, the best solution is to use a dedicated GSM modem device, such as the
GSM/3G USB modems mentioned earlier on this page.
Additional notes about experiences with specific modem models can be found at
the following link: http://blog.nowsms.com/search/label/GSM%20modem
The Now SMS/MMS gateway can simultaneously support multiple modems,
provided that your computer hardware has the available communications port
resources.
6.6GSM MODULE WITH RS232:
GSM module GPRS module characteristics:
Full Type Approved Quad Band Embedded GSM Module (GSM
850/900 1800/1900) with AT command set and RS232 interface on
CMOS level.
This GSM wireless data module is the ready a solution for remote
wireless applications, machine to machine or user to machine and
remote data communications in all vertical market applications.
The GSM module offers the advantages as below
Ultra small size (22x22x3 mm), lightweight (3.2 g) and easy to
integrate
R&TTE type approval plus CE, GCF, FCC, PTCRB, IC
Full RS232 on CMOS level with flow control (RX, TX, CTS,
RTS, CTS, DTR, DSR, DCD, RI)
27
7/30/2019 PC based differential and over current protection
28/47
Embedded TCP/IP Stack UDP/IP Stack , Embedded FTP and
SMTP Client
High performance on low price
Smallest size designed for tiny applications
Tracking (people, animals, people), container tracking, PDA, POS
terminal, PCMCIA cards, AMR
Pin to Pin upgrade policy to save your developing investments
High level technical support to help you in the integration of your
solution
Exhaustive product documentation
Evaluation kit and reference design
6.7Product Features:
E-GSM 900/1800 MHz and GSM 1800/1900 with GSM Phase 2 / 2+
Output Power Class 4 (2W) at GSM 850/900 MHz and Class 1 (1W) at
GSM 1800/1900 MHz
Control via AT commands (ITU, GSM, GPRS and manufacturer
supplementary)
Supply Voltage range: 3.22 V - 4.2 V, nominal: 3.8 V
Power consumption: Idle mode:
7/30/2019 PC based differential and over current protection
29/47
Analogue audio for microphone, speaker and hands free set plus digital
voice interface
RS232 on CMOS 2,8 V (One RS232 (2,8V) with flow control (RX, TX,
CTS, RTS, CTS, DTR, DSR, DCD, RI), baud rate 300 - 115.200 bps,
autobauding 1200 - 57.600 bps
50 Ohm antenna connector
6.7.2Audio:
Telephony and emergency calls (Half Rate (HR), Full Rate (FR), Enhanced
Full Rate (EFR))
Echo cancellation and noise reduction
6.7.3SMS:
SMS Mobile Originated (MO), Mobile Terminated (MT) and Cell Broadcast
(CB - DRX)
6.7.4GPRS, data and Fax:
Circuit Switched Data (CSD) up to 14.4 kbps
Fax Group 3
Packed Data (GPRS class B, class 10) up to 115 kbps
6.7.5GSM Supplementary Services:
Call Barring and Call Forwarding
Advice of Charge
Call Waiting and Call Hold
Calling Line Identification Presentation (CLIP)
Calling Line Identification Restriction (CLIR)
Unstructured SS Mobile Originated Data (USSD)
Closed User Group
29
7/30/2019 PC based differential and over current protection
30/47
CHAPTER 7
ENCODING AND DECODING
In computers, encoding is the process of putting a sequence of characters
(letters, numbers, punctuation, and certain symbols) into a specialized format for
efficient transmission or storage. Decoding is the opposite process -- the
conversion of an encoded format back into the original sequence of characters.
Encoding and decoding are used in data communications, networking, and storage.
The term is especially applicable to radio (wireless) communications systems.
The code used by most computers for text files is known as ASCII
(American Standard Code for Information Interchange, pronounced ASK-ee).
ASCII can depict uppercase and lowercase alphabetic characters, numerals,
punctuation marks, andcommon symbols. Other commonly-used codes include
Unicode, BinHex, Uuencode, and MIME. In data communications, Manchester
encoding is a special form of encoding in which the binary digits (bits) represent
the transitions between high and low logic states. In radio communications,
numerous encoding and decoding methods exist, some of which are used only by
specialized groups of people (amateur radio operators, for example). The oldest
code of all, originally employed in the landline telegraph during the 19th century,
is the Morse code.
The terms encoding and decoding are often used in reference to the
processes ofanalog-to-digital conversion and digital-to-analog conversion. In this
sense, these terms can apply to any form of data, including text, images, audio,
video, multimedia, computer programs, or signals in sensors, telemetry, and
30
http://whatis.techtarget.com/definition/0,289893,sid9_gci211773,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci213380,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci211600,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci213250,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci211663,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci213268,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci212576,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci948465,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci948465,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci331058,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci1045112,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci213760,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci211773,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci213380,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci211600,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci213250,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci211663,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci213268,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci212576,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci948465,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci948465,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci331058,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci1045112,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci213760,00.html7/30/2019 PC based differential and over current protection
31/47
control systems. Encoding should not be confused with encryption, a process in
which data is deliberately altered so as to conceal its content.
PROGRAM 1:
#include
#include
sfr lcd=0xa0;
sbit rs=P3^2;
sbit rw=P3^3;
sbit en=P3^4;
sbit En1=P0^4;
sbit En2=P0^5;
sbit En3=P0^6;
sbit En4=P0^7;
sbit TE=P3^5;
sbit sw=P3^6;
sbit buzz=P3^7;
unsigned char *volt=" Student RFID ";
unsigned char *volt1=" Student A ";
unsigned char *volt2=" Student B ";
unsigned char *volt3=" Student C ";
unsigned char *volt4=" Student D ";
unsigned char *volt5=" Show Your Card ";
31
http://whatis.techtarget.com/definition/0,289893,sid9_gci212062,00.htmlhttp://whatis.techtarget.com/definition/0,289893,sid9_gci212062,00.html7/30/2019 PC based differential and over current protection
32/47
unsigned char card[11];
unsigned char a[9]="05356881";
unsigned char b[9]="05354915";
unsigned char c[9]="21460410";
unsigned char d[9]="05345786";
unsigned char m,n,o,p,q;
void delay(unsigned int w);
void lcd_cmd(unsigned char val);
void lcd_data1(unsigned char *val2);
void lcd_cmd(unsigned char val)
{
rs=0;
rw=0;
lcd=val;
en=1;
delay(10);
en=0;
}
32
7/30/2019 PC based differential and over current protection
33/47
void lcd_data1(unsigned char *val2)
{
for(;*val2;)
{
rs=1;
rw=0;
lcd=*val2++;
en=1;
delay(10);
en=0;
}
}
void delay(unsigned int w)
{
unsigned int i,j;
for(i=0;i
7/30/2019 PC based differential and over current protection
34/47
{
TE=1;
buzz=1;
lcd_cmd(0x38);
delay(1);
lcd_cmd(0x01);
delay(1);
lcd_cmd(0x0e);
delay(1);
lcd_cmd(0x06);
delay(1);
lcd_cmd(0x80);
lcd_data1(volt);
lcd_cmd(0xC0);
SCON=0x50;
TMOD=0x20;
TH1=0xFD;
TR1=1;
IE=0x85;
En1=1;
En2=1;
En3=1;
En4=1;
34
7/30/2019 PC based differential and over current protection
35/47
while(1)
{
while(sw!=1);
buzz=0;
lcd_cmd(0xC0);
lcd_data1(volt5);
delay(10);
for(m=0;m
7/30/2019 PC based differential and over current protection
36/47
delay(1);
buzz=1;
TE=0;
En1=0;
En2=0;
En3=0;
En4=1;
delay(500);
TE=1;
}
if(strncmp(b,card,8)==0)
{
lcd_cmd(0xC0);
lcd_data1(volt2);
delay(1);
buzz=1;
TE=0;
En1=0;
En2=0;
En3=1;
En4=0;
36
7/30/2019 PC based differential and over current protection
37/47
delay(500);
TE=1;
}
if(strncmp(c,card,8)==0)
{
lcd_cmd(0xC0);
lcd_data1(volt3);
delay(1);
buzz=1;
TE=0;
En1=0;
En2=1;
En3=0;
En4=0;
delay(500);
TE=1;
}
if(strncmp(d,card,8)==0)
{
37
7/30/2019 PC based differential and over current protection
38/47
lcd_cmd(0xC0);
lcd_data1(volt4);
delay(1);
buzz=1;
TE=0;
En1=1;
En2=0;
En3=0;
En4=0;
delay(500);
TE=1;
}
delay(50);
}
}
38
7/30/2019 PC based differential and over current protection
39/47
PROGRAM 2:
#include
#include
sfr lcd=0xa0;
sbit rs=P3^2;
sbit rw=P3^3;
sbit en=P3^4;
sbit Dc4=P0^4;
sbit Dc3=P0^5;
sbit Dc2=P0^6;
sbit Dc1=P0^7;
sbit VT=P3^5;
unsigned char *volt=" Student RFID ";
unsigned char *volt1=" Student A ";
unsigned char *volt2=" Student B ";
unsigned char *volt3=" Student C ";
unsigned char *volt4=" Student D ";
unsigned char *volt5=" Show Your Card ";
unsigned char card[11];
39
7/30/2019 PC based differential and over current protection
40/47
unsigned char a[9]="15314268";
unsigned char b[9]="15304459";
unsigned char c[9]="15310279";
unsigned char d[9]="15307733";
unsigned char m,n,o,p,q,str,TAG,java,z;
void delay(unsigned int w);
void lcd_cmd(unsigned char val);
void lcd_data1(unsigned char *val2);
void lcd_cmd(unsigned char val)
{
rs=0;
rw=0;
lcd=val;
en=1;
delay(10);
en=0;
}
void lcd_data1(unsigned char *val2)
{
for(;*val2;)
40
7/30/2019 PC based differential and over current protection
41/47
{
rs=1;
rw=0;
lcd=*val2++;
en=1;
delay(10);
en=0;
}
}
void delay(unsigned int w)
{
unsigned int i,j;
for(i=0;i
7/30/2019 PC based differential and over current protection
42/47
TI=0;
}
void main()
{
lcd_cmd(0x38);
delay(1);
lcd_cmd(0x01);
delay(1);
lcd_cmd(0x0e);
delay(1);
lcd_cmd(0x06);
delay(1);
lcd_cmd(0x80);
lcd_data1(volt);
lcd_cmd(0xC0);
SCON=0x50;
TMOD=0x20;
TH1=0xFD;
TR1=1;
while(1)
{
42
7/30/2019 PC based differential and over current protection
43/47
if(Dc1==0 && Dc2==0&& Dc3==0 && Dc4== 1 && VT==1)
{
lcd_cmd(0xC0);
lcd_data1(volt1);
for(z=0;a[z]!='\0';z++)
{
transmit_data(a[z]);
delay(1);
}
delay(1000);
}
if(Dc1==0 && Dc2==0 && Dc3==1 && Dc4== 0 &&
VT==1)
{
lcd_cmd(0xC0);
43
7/30/2019 PC based differential and over current protection
44/47
lcd_data1(volt2);
for(z=0;b[z]!='\0';z++)
{
transmit_data(b[z]);
delay(1);
}
delay(1000);
}
if(Dc1==0 && Dc2==1&& Dc3==0 && Dc4== 0 && VT==1)
{
lcd_cmd(0xC0);
lcd_data1(volt3);
for(z=0;c[z]!='\0';z++)
{
transmit_data(c[z]);
delay(1);
}
44
7/30/2019 PC based differential and over current protection
45/47
delay(1000);
}
if(Dc1==1 && Dc2==0 && Dc3==0 && Dc4== 0 &&
VT==1)
{
lcd_cmd(0xC0);
lcd_data1(volt4);
for(z=0;d[z]!='\0';z++)
{
transmit_data(d[z]);
delay(1);
}
delay(1000);
}
}
}
45
7/30/2019 PC based differential and over current protection
46/47
References:
[1] Qaiser, A.; Khan, S.A., Automation of Time and Attendance using RFID
Systems, International Conference on Emerging Technologies, ICET '06, 2006,
pp.60-63.
[2]Chung-Chih Lin; Ping-Yeh Lin; Po-Kuan Lu; Guan-Yu Hsieh; Wei-Lun Lee;
Ren-Guey Lee,A Healthcare Integration System for Disease Assessment and
Safety Monitoring of Dementia Patients, IEEE Transactions on Information
Technology in Biomedicine,Vol.12, No.5, 2008, pp.579-586.
[3] Ting, J.S.L.; Kwok, S.K.; Lee, W.B.; Tsang, A.H.C.; Cheung, B.C.F.,A
Dynamic RFIDBased Mobile Monitoring System in Animal Care Management
Over a Wireless Network, International Conference on Wireless
Communications, Networking and Mobile Computing, 2007,pp.2085-2088
[4]Sangyoon Chin, M.ASCE, Suwon Yoon, Cheolho Choi, and Changyon Cho ,
RFID+4D CAD for Progress Management of Structural Steel Works in High-Rise
Buildings, Journal Comp in Civil Engineering,Vol 22,No 2,2008 ,pp. 74-89
[5] Bizedge,RFID 2006-2010 Forecast and Analysis
byhttp://www.theedgedaily.com/cms/content.jsp ?
id=com.tms.cms.article.Article_d2cc4b9-
cb73c03a-29d65b00-cd5c3a50, 2006.
[6] Balachandran, G.K.; Barnett, R.E., A 110 nA Voltage Regulator System With
Dynamic Bandwidth Boosting for RFID Systems, IEEE Journal of Solid-State
Circuits, , Vol.41, No.9, 2006, pp.2019-2028.
46
7/30/2019 PC based differential and over current protection
47/47
[7] Savi Technologies, Savi Technologies: Active and Passive RFID and Selecting
the Right Active Frequency Q.E.D System. 2005.
[8] E. Ergen, B. Akinci, B. East & J. Kirby, Tracking Components and
Maintenance History within a Facility Utilizing Radio Frequency Identification
Technology. Journal of Computing in Civil Engineering, Vol.21, No.1, 2007,
pp.11-20.
[9] J.W. Satzinger & T.U. Orvik, The ObjectOriented Approach Concepts,
System
Development and Modeling with UML. 2nd. ed. Boston: Course Technology
Thomson Learning, 2001.
[10] D.M. Kroenke, Database Concepts, Prentice Hall, Upper Saddle River, New
Jersey, 2002.