摘 要：随着电子技术的迅猛发展，单片机技术也有了长足的发展，目前单片机渗透到我们生活的各个领域，几乎很难找到哪个领域没有单片机的踪迹。现下车子不再仅仅是普通的运输、代步的工具，而是成为人们娱乐、休闲、锻炼的首选。车辆的速度里程表能够满足人们最基本的需求，让人们能清楚地知道当前的速度、里程等物理量，从而利用单片机设计了一个测速仪，基于单片机的测速仪设计。91043

本测速仪以AT89C51 单片机为核心，A44E 霍尔传感器测转数，实现对车辆里程/速度的测量统计，并能将车辆的里程数及速度用LED实时显示。本论文详细介绍了车辆的速度里程表的硬件电路和软件设计。硬件部分利用霍尔元件将车辆每转一圈的脉冲数传入单片机系统，然后单片机系统将信号经过处理送显示。软件部分用汇编语言进行编程，采用模块化设计思想。

本设计主要包括车轮脉冲采集，信号输入和数据采集等部分。主程序用C语言编写，完成各项功能与数据的处理。本测速仪的设计具有结构简单，成本低廉，显示清晰，稳定可靠等特点。

毕业论文关键词：里程/速度，时间，霍尔元件，单片机，LCD

Abstract: With the rapid development of electronic technology, development of the monolithic integrated circuit technology has come a long way, the current SCM permeates every aspect of our lives, it is hard to find out which no traces of single-chip microcomputer in the field。 Now the car is no longer just transport, travel tools, but to become first choice for entertainment and leisure, exercise。 Speed odometer of vehicles to meet the people's most basic needs, so that people can clearly know the current physical quantities such as speed, distance, thereby using the single-chip design a tachometer, speedometer design based on single-chip microcomputer。 

The speedometer to AT89C51 MCU core, A44E Hall sensor measuring speed, achieving measurement statistics on vehicle mileage/speed and the vehicle's mileage and speed LED display。 This paper details the speed of vehicle odometer hardware circuit and software design。 Hardware using Hall elements to vehicle number of pulses per turn around incoming MCU system and single-chip computer system to send the signal processing display。 Software used for assembly language programming, modular design。 

The design includes wheel pulses acquisition, signal and data acquisition, and so on。 Main program written in c language, complete functions and data processing。 The design of the gun has a simple structure, low cost, and displayed a clear, stable and reliable。

KEYWORDS: Mileage / speed,time, Hall element, MCU,LCD

目录

第1章 绪论 5

1。1 课题研究的目的和意义 5

1。2 课题的发展概况 5

1。3 研究的主要内容 6

第2章 系统总体方案设计 7

2。1 系统方案 7

2。2 单片机选择 7

2。3 时钟芯片选择 8

2。4测速传感器选择 8

2。5显示器选择 8

第3章 系统硬件设计 9

3。1 单片机外围电路设计 9

3。1。1 单片机介绍 9

3。1。2 单片机外围电路图 12

3。2 时钟模块设计