目 录
1 绪论 ..............................................................................................................................................1
1.1 研究背景 ...................................................................................................................................1
1.2 单片机的概述 ...........................................................................................................................1
1.3 单片机的应用 ...........................................................................................................................2
1.4 单片机的发展史 .......................................................................................................................2
2 系统硬件设计 ..............................................................................................................................3
2.1 系统原理 ...................................................................................................................................3
2.2 AT89C51 的介绍......................................................................................................................4
2.3 AT89C51 的引脚说明..............................................................................................................5
2.4 时钟电路 ...................................................................................................................................7
2.5 复位电路 ...................................................................................................................................7
2.6 单片机的最小系统构成 ...........................................................................................................8
2.7 7405 TTL 集电极开路六反相器 ............................................................................................8
2.8 指示电路 ...................................................................................................................................8
2.9 LED 数码显示器 ......................................................................................................................9
3 系统软件设计 ............................................................................................................................11
3.1 系统整体程序流程图 .............................................................................................................11
3.2 设置定时，显示初始化 .........................................................................................................11
3.3 处理状态、倒计时显示 .........................................................................................................13
3.4 路口红绿灯状态子程序 .........................................................................................................14
3.5 LED 显示子程序 ....................................................................................................................14
4 系统仿真 ....................................................................................................................................16
4.1 仿真平台介绍 .........................................................................................................................16
