基于单片机出租车计价器设计.doc

目 录 摘要 3 Abstract 4 前言 5 1. 系统总体方案选定 7 1.1 出租车计价器系统构成及工作原理 7 1.2 计价器各组成部分的功能 7 1.2.1 里程检测单元 8 1.2.2 键盘控制及LED显示部分 8 1.2.3 单片机部分 8 2. 系统硬件设计 9 2.1 里程检测单元电路设计 9 2.2 按键控制及LED显示电路设计 11 2.2.1按键控制部分 11 2.2.2六位LED动态显示电路 12 2.2.3 LED的结构及工作原理 14 2.2.4三位一体LED的结构及工作原理 15 2.3 单片机部分的硬件设计 17 2.3.1单片机的特点 17 2.3.2 AT89S51的最小系统 17 2.3.3 AT89S51I/O端口 18 3. 系统软件设计 20 3.1主程序模块 20 3.2 89S51芯片内部RAM分配 20 3.3 按键程序设计 22 3.4中途等待中断服务程序 23 3.5里程计数服务程序 24 3.6 BCD译码子程序 25 3.7显示服务子程序 26 结论 27 总结与体会 29 致谢 30 参考文献 31 附录1源程序 32 附录2元件清单 41 附录3电路图 42 附录4英文翻译 43 摘要 随着电子技术的发展,出租车计价器技术也在不断进步和提高,国内出租车计价器已经经历了四个阶段的发展,从传统的全部由机械元器件组成的机械式,到半电子式即用电子线路代替部分机械元器件的出租车计价器,再从集成电路式到目前的单片机系统设计的出租车计价器。 本设计是以单片机AT89S51为核心以74LS04芯片、和LED数码管为外设的出租车计价器的微机系统设计，该系统满足集计程、计费等主要功能为一体的出租车计价器的实用要求。其里程计算是将A44E霍尔传感器安装在车轮上并将检测到的信号传输给单片机，通过测量转速来计算汽车的行关键词：单片机 霍尔传感器Along with the electronic technology development, mileage fare meter technology is also progressing and the enhancement, the domestic rental car mileage fare meter has already experienced four stage development, from the tradition completely the mechanical type which is composed by the mechanical primary device, namely replaces the part mechanical primary device to half electronic formula with the electronic circuit the rental car mileage fare meter, again from integrated circuit type to present monolithic integrated circuit system design rental car mileage fare meter. This design is take monolithic integrated circuit AT89S51 as a core, take 74LS04, A44E, LED numerical code tube and so on the chips as the peripheral rental car mileage fare meter microcomputer system design, this system satisfies the collection idea regulation, the cost, and so on many kinds of measurement function is a body rental car mileage fare meter practical request. Its mileage calculation is sensor installs A44E the Hall on the wheel and, will examine the signal and give the monolithic integrated circuit, will calculate the automobile based on the wheel trundle number of times the travel distance