基于单片机的交通信号灯控制系统设计完整版

1、目录中文摘要·················································

2、··················································

3、··1. 引言···············································&

4、#183;·················································&

5、#183;······12. 设计任务及思路·········································&#

6、183;··············································13. 单片机··&

7、#183;·················································&

8、#183;················································33.1 单片

9、机简介·················································

10、83;···········································33.2 单片机基本结构 ····&#

11、183;·················································&#

12、183;······························3 3.3 单片机硬件特性 ·················

13、··················································

14、··················34. 芯片的选择······························

15、83;·················································

16、83;·············44.1 74LS373以及74LS07芯片简介································

17、83;··································44.2 8255芯片·············

18、3;·················································

19、3;·······························54.2.1 8255可编程并行接口芯片简介···············

20、················································54.2.2 8255可

21、编程并行接口芯片方式控制字格式说明·········································54.3 晶闸管·····

22、;··················································

23、;············································75. 交通灯控制原理分析及方案论证···

24、;··················································

25、;············86. 系统硬件设计····································&

26、#183;·················································&

27、#183;····96.1 总体设计···········································

28、3;·················································

29、3;··96.2 单片机最小系统·············································

30、3;········································96.2.1 振荡电路········

31、;··················································

32、;···································96.2.2 复位电路·············

33、··················································

34、····························106.3 显示及其驱动模块···················

35、3;·················································

36、3;···········116.3.1 键盘与状态显示功能····································

37、;·······································116.3.2 倒计时计数功能········&#

38、183;·················································&#

39、183;······················117. 系统软件设计·························

40、83;·················································

41、83;·············127.1 延时程序设计··································

42、83;·················································

43、83;···127.1.1 计数器硬件延时············································

44、·····································127.1.2 软件延时···········

45、··················································

46、······························137.2 时间及信号灯的显示·················

47、83;·················································

48、83;··········147.2.1 8031并行口的扩展····································

49、83;········································142设计任务及思路设计一个能够控制十二盏交通信号灯的模拟系统。通过交通信号灯控制系统的设计。3系统工作受开关控制

50、，起动开关 ON 则系统工作；起动开关 OFF 则系统停止工作。控制对象如下：东西方向红灯两个 , 南北方向红灯两个，东西方向黄灯两个 , 南北方向黄灯两个，东西方向绿灯两个 , 南北方向绿灯两个，图1 交通信号示意十字路口东西方向和南北方向各装有直行（包括右拐弯）控制红、黄、绿交通信号灯（如图1所示）。还有倒计时显示器，显示器用于显示相应方向直行控制当前点亮信号灯还要持续的时间（即剩余时间）。系统中有两个按钮启动和停止，启动按钮按下后信号灯系统开始工作，并周而复始地循环；停止按钮按下，所有信号灯都熄灭。信号灯的控制规律如表1所示。即系统启动后，东西方向先绿灯亮25s，然后绿灯闪烁3s，最后黄

51、灯亮2s，与此同时南北方向红灯亮30s。南北方向红灯亮30s后转为先绿灯亮25s，然后绿灯闪烁3s，最后黄灯亮2s，东西向红灯亮30s。由此周而复始地循环。要求采用单片机实现交通灯的控制规律。表1 信号灯控制规律东西方向信号绿灯亮绿灯闪烁黄灯亮红灯亮时间25s3s2s30s南北方向信号红灯亮绿灯亮绿灯闪烁黄灯亮时间30s25s3s2s设计电路中使用到的主要元器件，单片机芯片、8255芯片和晶闸管。十字路口分四条道，每条道有三个红绿灯，共十二个。每个红绿灯由一块8031芯片单独控制，我们只设计一个红绿灯的燃亮情况，同理根据燃亮顺序设计其它红绿灯。然后再组合起来，达到设计要求。3单片机3.1单片机

52、简介单片机是一种集成电路芯片，简称为单片微型计算机。是采用超大规模集成电路技术把具有数据处理能力的中央处理器CPU，随机存储器RAM，只读存储器ROM，多种I0口和中断系统，定时器，计时器等功能，集成在一块硅片上构成的一个小而完善的计算机系统。3.2单片机基本结构单片机由运算器，控制器，存储器，输入输出设备组成。3.3单片机硬件特性（1）单片机集成度很高，单片机包括CPU、4KB容量的ROM(8031无)、128B容量的RAM、2个16定时计时器、4个8位并行口、全双工串口行口。（2）单片机系统结构简单，使用方便，实现了模块化。（3）单片机可靠性能好，可工作很长时间。（4）处理功能强，速度快4

53、芯片的选择4.1 74LS373以及74LS07简介74LS373 是一种带三态门的8D锁存器，其管脚示意图2如下所示：图2 74LS373管脚示意图其中：1D-8D为8个输入端。1Q-8Q为8个输出端。LE为数据打入端：当LE为“1”时，锁存器输出状态同输入状态；当LE由“1”变“0”时，数据打入锁存器OE为输出允许端；当OE=0时，三态门打开；当OE=1时，三态门关闭，输出高阻。六驱动器(OC高压输出) 74LS07       Vcc  6A  6Y  5A  5Y&#

54、160; 4A  4          14  13  12  11  10   9   8Y = A    ）                  &

55、#160;                 1   2   3   4   5   6   7         7805实现正电压输出，负电压截止。4.2 8255芯片4.2.1 8255可编程并行接口芯片简介8255可编程并行接口芯片有三个输入输出

56、端口，即A口、B口和C口，对应于引脚PA7PA0、PB7PB0和PC7PC0。其内部还有一个控制寄存器，即控制口。通常A口、B口作为输入输出的数据端口。C口作为控制或状态信息的端口，它在方式字的控制下，可以分成4位的端口，每个端口包含一个4位锁存器。它们分别与端口AB配合使用，可以用作控制信号输出或作为状态信号输入。8255的内部组成框图如图3所示：图3 8255内部组成框图4.2.2 8255可编程并行接口芯片方式控制字格式说明8255有两种控制命令字：一个是方式选择控制字；另一个是C口按位置位复位控制字。其中C口按位置位复位控制字方式使用较为繁难，说明也较冗长，故在此不作叙述。方式控制字格

57、式说明如图4所示：图4 8255方式控制字方式0：基本输入输出方式。适用于三个端口中的任何一个。每一个端口都可以用作输入或输出。输出可被锁存，输入不能锁存。方式0适合于两种情况：一种是无条件传送，另一种是查询方式传送。方式1：选通输入输出方式。这时A口或B口的8位外设线用作输入或输出，C口的4条线中三条用作数据传输的联络信号和中断请求信号。方式2 ：双向选通输入/输出方式。只有A口具备双向选通输入/输出方式，8位外设线用作输入或输出。5交通灯控制原理分析与方案论证本设计以单片机为核心，以LED数码管作为倒计时指示，根据设计的要求我们考虑了各功能模块的几种设计方案，以求最佳方案，实现实时显示系统

58、各种状态，系统还增设了根据交通拥挤情况可分别设置主干道和次干道的通行时间，以提高效率，缓减交通拥挤。系统总体设计框图如图8所示：单片机最小系统倒计时交通灯键盘与状态显示图8 系统总体设计1电源提供方案为使模块稳定工作，须有可靠电源。本次设计考虑了两种电源方案：方案一：采用独立的稳压电源。此方案的优点是稳定可靠，且有各种成熟电路可供选用；缺点是各模块都采用独立电源，会使系统复杂，且可能影响电路电平。方案二：采用单片机控制模块提供电源。该方案的优点是系统简明扼要，节约成本；缺点是输出功率不高。综上所述，选择第二种方案。2显示界面方案该系统要求完成倒计时功能。基于上述原因，本次设计考虑了两种方案：方

59、案一：完全采用点阵式LED显示。这种方案功能强大，可方便的显示各种英文字符，汉字，图形等，但实现复杂，且须完成大量的软件工作。方案二：完全采用数码管显示。这种方案优点是实现简单，可以完成倒计时功能。缺点是功能较少，只能显示有限的符号和数码字符。根据本设计的要求，方案二已经满足了要求，所以本次设计采用方案二以实现系统的显示功能。图10 键盘电路6.3.2 倒计时计数功能本系统使用数码管完成倒计时显示功能。以南北方向为例，数码管显示的数值从绿灯的设置时间最大值往下减，每秒钟减1，一直减到1。然后又从红灯的设置时间最大值往下减，一直减到1。接下来又显示绿灯时间，如此循环。系统共有4个两位的LED数码管，分别放置在模拟交通灯控制板上的四个路口。各个方向的数码管个位（把数码管第二位定义为个位，第一位定义为十位）用一根信号线控制，十位用另一根信号线控制。这里采用动态显示。LED数码管如图11所示：图11 LED数码管7系统软件设计7.1延时程序设计延时方法可以有两种一种是利用MCS-51内部定