摘要：单片机具有稳定可靠、 体积小、 价格低廉等特点，成为设计智能化仪器仪表的首选微控制器，因此本次设计我们采用了AT89C52芯片，此款单片机可以使用软件对其进行在线编程，其灵活性和可靠性都相对提高。本设计中的电子钟的核心是AT89S51单片机，其内部带有4KB在线可编程Flash存储器的单片机，无须外扩程序存储器，硬件电路主要由四部分构成：时钟电路，复位电路，键盘以及显示电路。系统时钟电路采用的晶振的频率为12MHz，定时计数个数为5000，定时器采用的是定时器0工作在方式1定时，用于实现时、分、秒的计时，定时时间为5ms。复位电路可使电子表恢复到初始状态。键盘可对电子表进行开启、停止，还能实现时、分、秒的显示及设定等操作。显示电路由一个共阳级6位一体LED数码管构成，它的段控端和位控端通过7447及9015PNP型号三极管与AT89C52单片机的I/O口相连，显示器可使电子表显示出时、分、秒。 本次设计完成了利用单片机内部定时器实现时、分、秒计时且在6个数码管上同时显示时、分、秒计时时间，并能通过按键对计时时间进行重新设置。-Abstract: microcontroller with a stable and reliable, small size, low price and so become the instrument of choice for the design of intelligent micro controller, so this design we use the AT89C52 chip, the microcontroller can use this section to its online software program, which Flexibility and reliability are relatively increased. The core of the design of the electronic clock is AT89S51 microcontroller, its internal memory with 4KB of Flash programmable microcontroller line, no external expansion program memory, the hardware circuit consists of four parts: a clock circuit, reset circuit, keyboard and display circuit. The frequency of the system clock oscillator circuit is used to 12MHz, timing counting the number is 5000, Timer 0 uses a timer to work in a regular way for the realization of the hours, minutes, seconds, chronograph, timer time is 5ms. Reset circuit can be restored to the original state of the electronic form. When the keyboard can be turned on spreadsheets, stop, but