本科毕业设计 题目： 基于单片机的超速报警器的设计
学 院: 专 业: 学 号: 学生姓名:
信息科学与工程学院
自动化 201004134143
樊迪 宋玉阶 二〇一四年六月
指导教师: 日 期:
武汉科技大学本科毕业设计
摘 要
随着汽车工业和高速公路建设的发展，每年由各种交通事故造成的人员伤亡数目惊人，造成了巨大的经济损失。据统计，造成各种交通事故的主要原因是车辆的超载和超速行驶，而后者随机性很大，纠章困难，并且由于中国公路条件复杂，不同等级的公路允许的最高速度不同，现有的限速装置难以适应这种情况。针对这种情形，开发具有智能超速报警功能的车载系统具有重要意义。
本文从驾驶员自身安全角度出发，设计了一种可设定阈值的汽车超速报警系统。该系统采用16位单片机MC9S12XS128为控制核心，可通过按键在液晶屏上设定报警阈值和显示汽车实际速度，利用8位A/D转换芯片和霍尔传感器采集车轮转速，通过IIC总线实现与单片机的双向通信，具有灯光闪烁报警和语音提示报警这两种预警机制，对可能的突发事件做到防患于未然。
根据目的和要求，本次设计利用万用板搭建了各个模块的硬件电路，并且通过编写代码实现了系统的具体功能，该系统能够长时间稳定的运行，达到了设计要求。
该系统结构简单，可靠性高，操作方便，可广泛应用于摩托车、汽车等各种机动车辆，为人们的安全出行提供有力保障。
关键词： 单片机； 液晶屏； IIC总线； 语音； 超速报警
I
武汉科技大学本科毕业设计
Abstract
With the development of auto industry and highway construction, each year the number of casualties caused by all kinds of traffic accidents is amazing, caused a great economic loss. According to statistics, the main causes of traffic accidents is the vehicle overloading and speeding, the latter is very random correcting formidably, and because of Chinese road condition is complex, the allowed highest speed of different grade highways are different, the current limiting device is difficult to adapt to the situation. Aiming at this situation, to develop the vehicle system with an intelligent speed alarm function is of great significance.
From drivers’ own security perspective, this paper designs a car speeding alarm system which can set the alarm threshold. The system adopts the 16-bit single chip computer MC9S12XS128 as the control core, by which can set alarm threshold through the button on the LCD panel and show the actual motor speed, using 8-bit A/D converter chip and holzer sensor to collect the wheel speed ,through the IIC bus to implement the two-way communication with single-chip microcomputer, with lights flashing alarm and voice alarm the two early warning mechanism, for possible emergencies do nip in the bud.
According to the purpose and requirements, the design uses universal board to set up hardware circuit of each module, and by writing code to realize the function of the system, the system can run stably for a long time ,which has reached the design requirements.
The system has the advantages of simple structure, high reliability, convenient operation, and can be widely applied to motorcycles, cars and other motor vehicles providing a strong guarantee for people’s safely traveling.
Key words: single-chip microcomputer; LCD panel; IIC bus; voice; over-speed
alarm
II
武汉科技大学本科毕业设计
目 录
1 绪论 .................................................................................................................................. - 1 -
1.1 概述 ........................................................................................................................ - 1 - 1.2 各章主要内容简介 ................................................................................................ - 1 - 2 系统总体方案设计 .......................................................................................................... - 2 -
2.1 系统设计需求分析 ................................................................................................ - 2 - 2.2 主控芯片的选择 .................................................................................................... - 2 - 2.3 超速报警器的工作原理 ........................................................................................ - 3 -
2.3.1 车轮转速检测原理 ...................................................................................... - 3 - 2.3.2 按键输入与液晶显示原理 .......................................................................... - 4 - 2.3.3 语音报警原理 .............................................................................................. - 5 - 2.4 系统整体框架 ........................................................................................................ - 5 -
2.4.1 系统运行流程简介 ...................................................................................... - 5 - 2.4.2 系统整体结构框图 ...................................................................................... - 6 -
3 系统硬件设计与实现 ...................................................................................................... - 7 -
3.1 整体电路设计框图 ................................................................................................ - 7 - 3.2 电源模块的设计 .................................................................................................... - 7 - 3.3 MC9S12XS128单片机最小系统设计 ................................................................. - 8 -
3.3.1 电源部分 ...................................................................................................... - 9 - 3.3.2 时钟部分 .................................................................................................... - 10 - 3.3.3 复位电路与BDM接口 ............................................................................. - 10 - 3.4 速度检测模块 ...................................................................................................... - 10 -
3.4.1 霍尔传感器 ................................................................................................ - 10 - 3.4.2 A/D转换器PCF8591T ............................................................................. - 11 - 3.5 人机交互模块 ...................................................................................................... - 13 -
3.5.1 按键部分 .................................................................................................... - 13 - 3.5.2 OLED显示部分 ........................................................................................ - 13 - 3.6 语音报警模块 ...................................................................................................... - 14 - 4 系统软件设计 ................................................................................................................ - 17 -
4.1 系统程序框架图 .................................................................................................. - 17 - 4.2 初始化程序设计 .................................................................................................. - 18 -
4.2.1 系统时钟模块 ............................................................................................ - 18 - 4.2.2 TIM定时模块 ............................................................................................ - 20 - 4.3 人机交互设计 ...................................................................................................... - 21 - 4.4 IIC总线读取A/D转换值 ................................................................................... - 22 - 4.5 语音芯片的驱动 .................................................................................................. - 23 - 5 系统开发平台与辅助调试工具 .................................................................................... - 25 -
5.1 系统硬件开发平台 .............................................................................................. - 25 - 5.2 系统软件开发平台及调试工具 .......................................................................... - 26 - 6 总结 ................................................................................................................................ - 28 - 参考文献 .............................................................................................................................. - 29 -
III
武汉科技大学本科毕业设计
致谢 ...................................................................................................................................... - 30 - 附录A .................................................................................................................................. - 31 -
IV