Based On The Legic Water Controller's Design

The RPID technique is a non-contact automatic identification technology, it has used wireless and radio frequency mode to transmit data between RFID card and RFID reader. The non-contact IC card is focused on by our society because of its many use of one card,without environmental impact and higher security. The non-contact IC card abroad apply in bus system,finance system,access control system and so on..With the development of smart card technique, the need for flexible and security of the card is growing. Compared with other products, LEGIC provides users the ability to fully protect of data during the entire communication path. The high security of LEGIC is built upon its unique Master-Token System. The authorization concept is well proven and unique in the industry by LEGIC and the users can add a new data segment to the existing application.This thesis has introduced a design of non-contact reader for water control system. The reader uses SM05-S security module which is produced by LEGIC company, and the thesis has introduced the design principle from both hardware and software aspect.In the basis of researching LEGIC technique specifically, The key points of the thesis is the SM05-S security module which is the reader used. The thesis has introduced the module and the interface between MCU and the module. The reader has EEPROM of large capacity and clock circuit, so the reader can work offline for a long time. The hardware of the reader also includes LED display circuit,keyboard circuit,power circuit,reset and watchdog circuit. The reader uses RS485 communication and takes measures to the RS485 circuit in order to improve the reliability of communication. Then the thesis discusses the sources of interference and the methods of how to decrease the interference.The communication mode between card and reader is half-duplex. The thesis has discussed the software program of the reader, including the communication protocol between card and reader,the order flow of the card,the main program of MCU and the charging method of the water control reader. At last discusses the methods that how to decrease the software interference.