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目 录 引言 一、设计思路············································································································ 1 http://www.paper51.com 二、明确设计系统的功能·························································································· 1 http://www.paper51.com 2.1 要实现的功能要求··························································································· 1 copyright paper51.com 2.2 拟定数字系统的方案······················································································· 1 http://www.paper51.com 三、触发器的选定····································································································· 2 paper51.com 3.1R-S触发器·········································································································· 2 内容来自www.paper51.com 3.2触发器逻辑功能转换·························································································· 2 paper51.com 四、系统工作原理····································································································· 3 http://www.paper51.com 4.1“四人智力抢答器”应实现两点基本逻辑功能···················································· 2 内容来自www.paper51.com 4.2工作时的逻辑状态分析······················································································· 2 内容来自论文无忧网 www.paper51.com 五、连接调试············································································································ 5 copyright paper51.com 六、总结··················································································································· 5 内容来自www.paper51.com 参考文献··················································································································· 6 paper51.com 致谢·························································································································· 7 内容来自论文无忧网 www.paper51.com
引言 copyright paper51.com
在知识竞赛中，特别是做抢答题时，在抢答过程中，为了知道哪一组或哪一位选手先答题，必须要有一个系统来完成这个任务。如果在抢答中，只靠人的视觉是很难判断出哪组先答题。利用单片机来设计抢答器，使以上问题得以解决，即使两组的抢答时间相差几微秒，也可分辨出哪组优先答题。本文主要介绍了抢答器的工作原理及设计，以及它的实际用途。 copyright paper51.com
一、设计思路 copyright paper51.com 1、抢答器同时由4个人或4个组同时进行，分别有4个开关K1～K4。 http://www.paper51.com
2、设置一个清除开关S（即开关K5），该开关由主持人控制。 http://www.paper51.com 3、抢答器锁存与显示功能。即选手按动按钮，锁存相应的编号，并且相对应的小灯泡能够亮，同时发出扬声器的蜂鸣声报警。 copyright paper51.com 4、当一轮抢答之后，定时器停止、禁止二次抢答。如果再次抢答必须由主持人再次操作"清除"和"开始"状态开关。 内容来自论文无忧网 www.paper51.com
二、明确设计系统的功能要求 paper51.com
2.1要实现的功能要求 内容来自www.paper51.com 当主持人宣布开始时，一旦任何参赛者最先按下按钮，则此参赛者对应的指示灯亮起，而其余三个参赛按钮不起作用，信号也不再被输出，直到主持人宣布下一轮开始为止。并且要求有声音提示。 paper51.com
抢答器主体电路：抢答器的主体电路，主要是由每个抢答组都具有的独立的抢答电路组成。它要求本组抢答电路的输出信号，能关闭其他再抢答的可能性。 内容来自www.paper51.com 灯光指示电路：当有一个抢答组已抢答时，则该组的抢答灯光指示电路应燃亮，使与会者一目了然地知道本组已经抢答。 内容来自www.paper51.com 显示器仅显示首先抢答者对应指示灯，同时音响电路发出蜂鸣声，而滞后者无显示，无蜂鸣声。这两点功能要求都具有组合逻辑电路和时序逻辑电路的特性。即要输入触发信号，又要输出寄存信号，还要识别控制信号。 内容来自www.paper51.com 2.2 拟定数字系统的总体方案 http://www.paper51.com
1、清零功能—在常见的触发器中，RS触发器的主要功能是置位(置，“1”)与复位(置“0”或清"0" ), D触发器和JK触发器都带有清除端CLR，它们的功能比较灵活，可实现RS触发器的功能，也可以相互转换，因此选用D触发器或1K触发器都可以满足此功能。 paper51.com
2、显示功能—可使用四只小灯泡，分别接四个触发器的输出端显示电平的高低，同时将四个输出端与音频信号一起加至控制门电路，即保证在四个拾出端均为低电平时可将控制门锁住，使音频信号不能传输至音响放大电路，而只要一个进出端为高电平时控制门打下，使音频信号加至音响放大电路产生蜂呜声。 http://www.paper51.com 3、抢答键控功能—根据其逻辑功能的要求必须将组合逻辑电路和时序逻辑电路相结合，对四个按钮状态在抢答前由一个控制门进行取值采样，将时钟脉冲加至触发器CP端，只要有一个按扭动作，即只要改变一个触发器输入端的状态。则相对应的输出端产生翻转后，瞬间使控制门锁定翻转后的输出状态，此时控制门将时钟脉冲锁住。 内容来自论文无忧网 www.paper51.com |