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ABSTRACT
In Today’s Electronic communication take important role. Using
Today’s Communication technology the data transmission and reception from one
Place to another is easy and fast.
In our project we have two sections, one is transmitter another one
Receiver, in transmitting section we have AT89C52 Microcontroller, PC and
LCD. In receiver section we have another AT89C52Microcontroller and LCD
At the time when data will transfer from the transmitter a predefined code will be
Added with every eight bit data and when this data receive by the receiver this code
Will be decode by the receiver and generate the exact data that will be displayed
On LCD. In this project Wireless Encoding and decoding are using one of the techniques
Called cipher text technique. Encryption is any procedure to convert plaintext into
Cipher text. Decryption is any procedure to convert cipher text into plaintext.
Hardware components:
• AT 89C52 Micro controllers
• LCD
• RF Module.
• MAX 232
• DB-9 Connector.
Software tools:
• Kiel vision.
Advantages:
• The data secure is more while transferring data
• Used in data communication.
Applications:
This system can be used for Military application for security.
It can be used in Air craft applications.
BLOCK DIAGRAM
TRANSMITTER RECEIVER
2. MICROCONTROLLER
2.1 A Brief History of 8051
In 1981, Intel Corporation introduced an 8 bit microcontroller called 8051. This microcontroller had 128 bytes of RAM, 4K bytes of chip ROM, two timers, one serial port, and four ports all on a single chip. At the time it was also referred as “A SYSTEM ON A CHIP”
The 8051 is an 8-bit processor meaning that the CPU can work only on 8 bits data at a time. Data larger than 8 bits has to be broken into 8 bits pieces to be processed by the CPU. The 8051 has a total of four I\O ports each 8 bit wide.
There are many versions of 8051 with different speeds and amount of on-chip ROM and they are all compatible with the original 8051. This means that if you write a program for one it will run on any of them.
The 8051 is an original member of the 8051 family. There are two other members in the 8051 family of microcontrollers. They are 8052 and 8031. All the three microcontrollers will have the same internal architecture, but they differ in the following aspects.
 8031 has 128 bytes of RAM, two timers and 6 interrupts.
 89C51 has 4KB ROM, 128 bytes of RAM, two timers and 6 interrupts.
 89C52 has 8KB ROM, 128 bytes of RAM, three timers and 8 interrupts.
Of the three microcontrollers, 89C51 is the most preferable. Microcontroller supports both serial and parallel communication.
In the concerned project 89C52 microcontroller is used. Here microcontroller used is AT89C52, which is manufactured by ATMEL laboratories.
2.2 Description of 89C52 Microcontroller
The AT89C52 provides the following standard features: 8Kbytes of Flash, 256 bytes of RAM, 32 I/O lines, three 16-bit timer/counters, six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89C52 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.
By combining a versatile 8-bit CPU with Flash on a monolithic chip, the AT89C52 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications.