Metro AFC system design of RF card reader (1)

Introduction

Abroad in the early 1990s began Metro AFC system in full operation, and has its own professional manufacturers, such as the United States CUBIC Corporation, France and Australia ERG CGA Corporation.

Domestic first-use Metro AFC equipment is in 1999 Shanghai Metro, line, because at that time the domestic AFC equipment is still in prototype development phase, the introduction of the United States CUBIC Corporation's AFC equipment.

In recent years, China's largest urban rail traffic booming, AFC system in use, purchase, ticket, charges, fees, statistics of the whole process of automation, effective control of Metro's passenger traffic; but as direct contact with passengers, the relationship between the image of the reader, subway ticket and other devices, even more important [1].

At present, the RF card reader system mainly uses ARM7 processor to the controller, and the position machine communication typically use RS232 or RS422 cable communication method, limiting the AFC system of automation and networking process, at the same time as your business expands, the existing system of data storage capacity has been unable to meet the increasing requirements of transaction data. In response to the above questions, design an ARM9-based and MF RC531 high-performance reader, to further improve ticket card's efficiency, save time and out of the station for passengers, increase ticket card read-write data accuracy, and to provide a basis for the full nationalization of the reader.

Figure 1 Metro AFC System

1 reader functionality analysis

Metro AFC system from the central computer system, site, computer systems, terminals and ticket 4 parts.

Terminal equipment including a/inbound ticket gates, automatic ticket machines, station ticketing system, automatic recharge machines and other equipment, as shown in Figure 1.

Terminal device is directly provide passengers with fare, passengers through the RF card you can buy ticket, access gates, for ticket card recharge, while establishing RF card and terminal equipment of the bridge is the RF card reader.

RF card reader as and RF card communicating core, its performance and data handling capabilities directly affects the entire Metro AFC system of quality of work. Figure 2 overall chart for the reader.

Figure 2 overall structure chart reader

Currently reader mainly uses RS232 or RS422 cable communication method and field terminal device communication, interface transfer rate of a single, limited, but also with remote monitoring host for wireless communication, restricted the reader's network.

This design increases the USB transmission interface, improving data transfer efficiency, and convenience. At the same time increases the GPRS communication modes, to be able to host remote monitoring, and maintaining communication to monitor host send device status information. With this many interfaces work together, you can ensure that readers of reliability and security.

2 hardware circuit design

RF card reader hardware structure as shown in Figure 3, mainly by master CPU, Flash/SDRAM memory devices, RF transceiver modules, SAM card certification circuit, communication circuits and display alarm circuits, etc.

Master CPU with Atmel AT91SAM9260 company, based on the frequency of ARM926EJS reaches 180 MHz, significantly increase the processing speed of the reader. Peripheral expansion capacity of 256 MB NAND Flash to store data and 2 MB NOR Flash storage capacity, the implementation of the code data and code separation. On the one hand to improve data storage capacity, and on the other hand, increases the efficiency of the implementation of the code.

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