【正文】 8255 的 PC 口 輸出 至雙位數(shù)碼管） ； 車輛闖紅燈報警；綠燈時間可檢測車流量并可通過雙位數(shù)碼管顯示。 。 The traffic light circulation lightens, the countdown remains when for 5 seconds the yellow light twinkle police shows (traffic light signal through PA mouth output, demonstration time directly through 8255 PC mouth output to twoposition nixietube)。 The green light time may examine the traffic flow magnitude and may through the twoposition nixietube system usability strong, operation simple, expansion function. Keywords： monolithic integrated circuit traffic light runs a red light the examination traffic flow magnitude 目錄 III 目 錄 摘 要 ................................................................................................................................................................................................ I ABSTRACT ....................................................................................................................................................................................II 目 錄 ............................................................................................................................................................................................. III 第 1 章 緒論 .................................................................................................................................................................................... 1 第 2 章 總體規(guī)劃方案 .................................................................................................................................................................. 4 規(guī)劃設計方案 ...................................................................................................................................................................... 4 交通管理的方案論證 ........................................................................................................................................................ 4 第 3 章 系統(tǒng)的芯片簡介 ............................................................................................................................................................. 6 MSC51芯片簡介 ............................................................................................................................................................... 6 MCS51 單片機內部結構 ......................................................................................................................................... 6 MCS51 的引腳和功能概述 ..................................................................................................................................... 8 8255 芯片簡介 ................................................................................................................................................................... 9 8255A 的內部結構 .................................................................................................................................................... 9 8255 可編程并行接口芯片簡介 ............................................................................................................................ 11 第 4 章 系統(tǒng)硬件設計 ................................................................................................................................................................15 系統(tǒng)總框圖設計 ............................................................................................................................................................... 15 各個模塊電路設計 ........................................................................................................................................................... 16 鍵盤設置電路 ........................................................................................................................................................... 16 看門狗硬件電路 ....................................................................................................................................................... 19 顯示電路 .................................................................................................................................................................... 20 交 通燈的控制電路 .................................................................................................................................................. 21 第 5 章 系統(tǒng)的軟件設計 ...........................................................................................................................................................23 系統(tǒng)總程序設計 ............................................................................................................................................................... 23 每秒鐘的設定 .................................................................................................................................................................... 24 計數(shù)器初值計算 ........................................................................................................................................................ 24 計算公式 .................................................................................................................................................................... 24 １秒的方法 ................................................................................................................................................................ 25 相應程序代碼 ........................................................................................................................................................... 25 軟件延時 .................................................................................................................................................................... 26 顯示程序設計 .................................................................................................................................................................... 27 顯 示原理 .........................................................