【正文】 f mechanical transmission, with LED display instead of a pointer display and then display the time and reduce the timing error, this table has the hours, minutes and seconds displays the time function, but also in progress and subproofreading, the flexibility of a good chip select. In this paper, MCU function digital clock timing the main contents of which AT89S51 is a core element at the same time the use of digital control dynamic display time, sub, second modern timing devices. Compared with the traditional mechanical watch, it has a traveltime accuracy, display and intuitive and so on. It is a time period of 24 hours, substantially fullscale as 23:59:59, another time with a school function, memory function after power outages, power restoration can be realized when the time synchronization and so on. The design by the MCU AT89S51 chip and LED digital tube as the core, supplemented by the necessary circuitry to form a single chip digital clock. Key words: shrapnel machine digital clock LED digital tube display button 電 子 時 鐘 的 設 計 與 制 作 目 錄 引言 …………. ………… . ………. ……… …. …………. … ……… .… …. …………. 1 1 AT89S51 芯片簡介： ............................................................................. 2 內(nèi)部結(jié)構(gòu) ...................................................................................... 2 . 中央處理器： ........................................................................................... 3 . 數(shù)據(jù)存儲器（ RAM）： .......................................................................... 3 89S51 的引腳說明： ................................................................... 4 . Pin9： RESET/Vpd 復位信號復用腳： ................................................. 5 . Pin30： ALE/PROG 引腳： ..................................................................... 5 . Pin31： EA/Vpp 引腳： ............................................................................ 6 2 驅(qū)動器 74LS245 簡介： .................................................................... 7 3 LED 數(shù)碼管簡介 ..................................................................................... 8 LED 數(shù)碼管顯示器結(jié)構(gòu)與原理 .................................................. 8 LED 顯示器接口及顯示方式 ...................................................... 8 . 數(shù)碼管使用條件： ................................................................................... 9 . 數(shù)碼管使用注意事項： ......................................................................... 10 4 相關硬件的其他元器件的簡介 ....................................................... 11 晶體振蕩器簡介 ........................................................................ 11 . 晶體振蕩器的應用： ............................................................................. 11 電子電容器的標識 .................................................................... 12 . 電容器標識的方法： ........................................................................... 12 . 常用電容的幾項特性： ....................................................................... 12 . 電容容量的標注及使用常識： ........................................................... 12 電阻的選用簡介 ........................................................................ 13 . 作用 : ...................................................................................................... 13 . 計算原則： ............................................................................................ 14 . 注意： .................................................................................................... 14 電 子 時 鐘 的 設 計 與 制 作 5 電路制作原理制作分析 .................................................................. 15 主程序執(zhí)行流程圖 .................................................................... 15 數(shù)碼管顯示模塊 ........................................................................ 19 定時器計數(shù)器 T0 中斷服務程序： ........................................... 19 按鍵 處理模塊： ........................................................................ 19 整個電路原理圖： .................................................................... 20 致謝 ……… ……… ……………………………… … ………………………… 20 參考文獻 … ……… … …………………… ……… …… ……… …………………… 21 附錄一、源程序代碼 …………………………… ……… .…… .