Design Of Handset Radio Frequency Reader

RFID (Radio Frequency Identification) is one of the identification technologies which can realize intercommunication by using wirelesss channel. With its unique advantages of contactless operation, rapid and multi-targets recognitions, it is widely used in many fields.This thesis is part of the project named as "Design of RF Reader" which is cooperated with Shanghai Belling CO., LTD. The task is to design a handset reader which support the RF protocols of both Tag-it and I·CODE1, and has the ability of second development.To realize the functions of "One Reader Two Protocols", anticollision algorithm and second development are the difficulties and innovations of the whole design.The hardware consists of power supply, main controller, RF transceiver, keyboard & LCD, serial communication interface, data memory and the auxiliary circuits. ATmega64 is selected as the main controller and RI-R6C-001A as the special RF transceiver chip. By using the register mode and the direct mode of the RF transceiver chip, it realizes the operation to Tag-it and I'CODEl respectively. Serial flash with SPI interface is used to avoid losing data and meet the demand of large storage. The real-time clock can be used to record the happening time of the operations which makes the background process very convenient. The soft-off circuit can reduce the power dissipation in a way.In the software design, it follows the principle of modularization and structured programming, uses C and inline assembly as the programme languages. The software consists of three parts: main program, RF card R/W program and peripheral equipment driver. The Boot Loader section can download the character library and refresh the code in Application section. The program in Application section completes all the users' functions. During the debugging the RF card R/W program, logic analyzer is used to help adjusting the time intervals in the communication of Reader and RF card. According the characteristic of serial flash, a fast and efficient data storage format is designed which can increase the device's lifetime moderately.This RF terminal unit has the advantages of high reliability, low consumed power, micromation and modularization. It can deal with the data in both online and offline states and the operation distance can up to 50mm. Abundant software interfaces make it very convient for the second development.