基于单片机at89c51的数字抢答器设计.doc

基于单片机AT89C51的数字抢答器设计

摘    要：抢答器作为一种电子产品已广泛应用于各种智力和知识竞赛场合。一个八路数字抢答器的设计需要考虑到可更改回答及抢答时间功能，利用AT89C51单片机及外围接口实现的抢答系统，利用单片机的定时器/计数器定时和记数的原理，将软硬件有机地结合起来，使得系统能够正确地进行计时，同时使数码管能够正确地显示时间。用开关做键盘输出，扬声器发声提示。同时系统能够实现在抢答中只有开始后抢答才有效，如果在开始抢答前抢答为无效；抢答限定时间和回答问题的时间可在1-99s设定，可以显示是哪位选手有效抢答和无效抢答，正确按键后有音乐提示，抢答时间和回答问题时间倒记时显示，满时后系统计时自动复位及主控强制复位，按键锁定，在有效状态下，按键无效非法。
基于单片机AT89C51的数字抢答器设计， 首先完成总体方案的论证制定，绘制控制台的总体框图，然后分析系统的工作原理，在此基础上设计出各部分单元电路原理图，分析其工作原理，进一步完成对系统电路的设计。在对系统工作原理充分研究的基础上，选择合适的元件型号和参数，再用protel绘图软件画出电路原理图。

关键词：AT89C51； LED数码管； 抢答器； 计时器

Eight-way first answer device based on AT89C51
Abstract: Responder as an electronic products have been widely used in intelligence and knowledge competitions occasions. An eight-way digital answering device designed to take into account to answer and answer in time to change the function, using AT89C51 microcontroller and external interface of the answer system, using single chip timer / counter the principle of timing and counting, will organically combine hardware and software , allows the system to correctly time, while the digital control to correctly display the time. Switching to do with the keyboard output, speaker voice prompts. At the same time the system can be achieved only after the beginning of the Responder Responder only effective if started before the Responder Responder to be invalid; answer in a limited time and the time to answer questions can be set in 1-99s, which players can display is effective and ineffective Responder Responder , the correct button prompt after the music, answer in time and answer the questions of time countdown display, the system time after the expiration of the master force automatic reset and reset, the keys are locked in an effective state, the button is not illegal.
AT89C51 microcontroller based digital answering device design, the first complete demonstration of the overall program development, rendering the overall block diagram of the console, and then analyze the working principle, based on the design of this unit of each part of the circuit schematic, and its working principle, further complete the system circuit design. The system works in full on the basis, select the appropriate component models and parameters, and then draw protel schematic drawing software. 
Key words: AT89C51; LED digital tubes; the first answer device; Time

目    录
1. 概    述 1
1.1 课题的相关背景 1
1.2 选题的目的和意义 1
1.3 课题研究的内容 1
1.4 课题的优点及组成 1
2. 方案论证 2
3. 抢答器的系统概述 3
3.1 国内外的研究现状 3
3.2 抢答器的简介 3
3.3 系统需求分析 4
3.4 抢答器运行的流程图 4
3.5 抢答器的工作过程 6
3.6 AT89C51的功能及简介 6
3.7 AT89C51特殊功能寄存器 9
4. 硬件设计模块 10
4.1 硬件电路的设计 10
4.2 稳压电源电路设计 11
4.3 时钟频率电路的设计 12
4.4 复位电路的设计 12
4.5 显示电路的设计 13
4.6 键盘扫描电路的设计 14
4.7 发声电路的设计 16
4.8 系统复位 16
5. 软件设计模块 19
5.1 主程序系统结构图 19
5.2 软件任务分析 19
5.3 程序流程图 20
5.4 Proteus软件仿真系列组图 21
6. 结束语 23
参考文献 24
致    谢 25