The Design Of Intelligent Gas MeterGas meter is a gas flow meter; they are included in the national directory of strong compulsory seizure test measuring instruments. Gas metering system has been developing constantly. From unenlightened mechanical to intelligent nowadays, made peoples lives has been facilitated. In the past for a long period of time, we use most of all mechanical in the international, with the continuous advancement of electron technology, electron-type gas meter have also emerged in other country, but there is still a lot of non-convenience. Currently mechanical gas meter give a great deal of inconvenience to management and users, that is, issue of meter reading. We take original backward artificial way to look-up table charges generally. This charging method has several major disadvantages: occupy a great deal of manpower; Many drawbacks of artificially; inefficient and created a great waste of human, material, time to manage department. Therefore, research and development a new type of gas meter charging system is necessary. Abroad, intelligent gas metering system is also developing, and they have automatic billing, as well as alarm function, to protect the benefits of the Gas Company and the users. In China, Gas Meter remains at a fairly low level, most of the products just to play a role of switching, and the development of intelligent table also stagnated at a very low level, although there are a lot of manufacturers to product the intelligent gas meter. However, very few sophisticated products; they improve the products on the basis of foreign technology according to the actual situation, mostly the use of IC card technology. and manufacturers can not be simultaneously large quantities of products.In the view the actual situation, we reference to already exist product, according to the idea of it, and to design the intelligent gas meter. the system of the intelligent have application of advanced IC card billing functions, use of the remote communications, to connect the computer with all user terminals under control by Single chip, and have the best anti-cheating function, prevent users from stealing gas. To make the gas as a commodity after first use, the Gas Company can be to accelerate cash flow, eliminate the arrears of the phenomenon of gas charges happened. It completely overcomes the mechanical disadvantage of the gas meter, reduce the artificial factors; improve work efficiency; saving the managers time. At the same time, the metering system also takes a number of ways to enhance its practicality in using, such as transparency of user data, users can view intuitive their own usage amount, as well as the balance of the card. In order to improve the reliability of the system, the system also set up a brown-out protection, while the metering system also considering can be add gas alarm function, that is, when the gas leak happened, the system will provide users with alarm functions, to provide users with the use of safety sexual.Because of the smart electron card prepaid gas systems is build up of computer-intelligent electronic card writer and sales database software. It have set up users, user change, relocation, marketing, writing cards, statistics, search for, buy those statistics should be imprisoned, fined report functions etc. The smart cards electron gas distribution system can realize the modernization of the gas sales management, and user consumption because of the amount of data such as pre-purchase through intelligent electronic card to transmit automatically recorded, compared with the previous manual entry not only reduces costs but also ensured data accurate and reliable.Following, introduce of the overall design program.First, the controller: The design is based on the implementation of single-chip microcomputer control system, single-chip microcomputer used AT89S51/52, it manufacture by ATMEL company of the United, it is the single chip of states low-voltage, high-performance COMS 8-bit. Chip containing 8k bytes of repeatedly rewritable read-only program memory (PEROM) and 256k bytes of random data memory (RAM), the device used ATMEL Corporation high-density, nonvolatile memory technology. Convenient control and easy power, easy to program, while the prices were relatively cheap on market, and there is associated circuits, components are also abundant on the market, but also conducive to the promotion of the system. The chip also have four 8-bit parallel I/O port P0-P3,each port can be used as input,can also be used for output; There are two 16-bit timer/counter internal, each regular browser / counter can be set to count the way to count on the outside, also can be configured the way from time to time and from time to time in accordance with the results of counting or the achievement of the computer control; it have five interrupt sources with two interrupt Interrupt Priority Control system; and a full-duplex UART serial I/O port for the realizati