目录
摘 要.....................................................................................................................................................................................2
引 言.....................................................................................................................................................................................3
一、交通信号灯的设计目的以及要求..............................................................................................................................4
二.交通信号灯基本原理及设计方法.................................................................................................................................5
三、主控制器......................................................................................................................................................................7
3.1 74LS90 引脚排列图与逻辑图...................................................................................................................................7
3.2 74LS90 的功能表及引脚功能...................................................................................................................................8
四、计数器..........................................................................................................................................................................9
4.1 计数器的作用............................................................................................................................................................9
4.2 计数器的工作情况....................................................................................................................................................9
4.3 控制信号灯的译码电路的真值表..........................................................................................................................10
4.4 置数电路..................................................................................................................................................................11
4.5 状态译码电路..........................................................................................................................................................13
五.译码显示电路...............................................................................................................................................................14
5.1 共阳极 LED 七段数码管.........................................................................................................................................14
5.2 74LS247 译码器.......................................................................................................................................................16
六.555 振荡器构成的秒脉冲电路....................................................................................................................................18
6.1 555 定时器的引脚...................................................................................................................................................18
6.2 555 定时器构成的多谐振荡器...............................................................................................................................20
6.3 555 定时器工作原理...............................................................................................................................................21
七、交通灯信号灯控制总体框图....................................................................................................................................23
八.组装和调试过程...........................................................................................................................................................23
总 结...................................................................................................................................................................................25
参 考 文 献.........................................................................................................................................................................26