出租汽车计价器的设计.doc

出租汽车计价器的设计 Design of taximeter 出租汽车计价器的设计 [摘要] 出租汽车计价器是一种出租汽车专用的计量仪器，国家将其列为实行强制检定的工作计量器具。计价器的检定分为本机检定和使用误差检定两个部分，目前有多种进行出租汽车计价器本机检定的标准检定装置，可以实现计价器本机的计程检定，计时检定，切换速度检定等主要的检定项目。但是这些标准检定装置每次只能对单台计价器进行检定，在检定过程中，需要人工记录计价器的检定数据，并人工计算出检定项目的各项误差，此外，计价器检定记录也是由操作人员在检定结束后进行录入，这种方法不仅工作效率低、操作复杂，而且极易出现错误。 本设计采用了单片机进行设计，相对来说功能强大，用较少的硬件和适当的软件相互配合可以很容易的实现设计要求，且灵活性强，可以通过软件编程来完成更多的附加功能。针对计费模式的切换，通过软件编程就可以轻而举的实现。避免了机械开关带来的不稳定因素。Design of taximeter [Abstract] The taximeter is a kind of special measure built in a taxi. Under state policy, It is listed in those measures that are forcing to be detected. The detecting of a taxi meter consists of the local taximeter detecting and the use error detecting. Presently there are several kinds of measures used for the local taximeters detecting. They can detect the taximeters cyclometer, the calculagraph and the speeds change, but they only can detect a single taximeter once. In addition, the data of the taximeters detecting should be recorded by hand, and the error item of the detecting was still achieved by hand. Besides, the record of taximeters detecting is registered computer after detecting the taximeter by people. So, the method of detect taximeter is not only inefficient and complicated, but also easily to make a mistake. The design uses a single-chip design, relatively powerful, with less hardware and appropriate software can easily cooperate with each other to achieve the design requirements, and flexibility, through software programming to accomplish more additional functionality. Billing model for the switch, through the software programming and can easily give the realization of. Brought about by the mechanical switch to avoid the instability. [Keywords] taximeter microprocessor control unit Brown-out circuit 目 录 第一章 绪　论 1 1.1 选题背景 1 1.2 选题意义 1 第二章 计价器硬件设计 2 2.1 系统的硬件构成及功能 2 2.2 AT89S51单片机及其引脚说明 2 2.3 单片机串行通信 6 2.3.1 串行通信自身优点 6 2.3.2 输出接口电路扩展 6 2.3.3 输入接口电路扩展 7 2.3.4 其他软硬件准备工作 7 2.3.5 数据采集电路的设计 7 2.4 AT24C02结构图及其引脚功能 8 2.5