摘要:随着人们生活水平的不断提高，家用电器逐渐普及，市场对于智能控制系统的需求也越来越大的情况下。数字时钟的出现打破了人们对时钟的传统概念，它不仅可以通过数字直观地显示日历时间，用音乐及语音等声音报时；还可以定时发出各种声、光、电信号，以启动各种设备实现实时控制、时间顺序控制等。如作息时间自动打铃、家电设备自动定时启动和关闭、生产过程顺序控制等等，用途很广。所有这些都是以时钟数字化为基础的，因此，研究数字时钟及扩大其应用，有着非常现实的意义。

　　　本设计的数字自动打铃系统采用了DS1302作为时钟电路，时钟电路的主要任务是产生实时时钟信号，一方面送到数字显示器进行显示，另一个方面提供自动打铃电路的存储器地址信号。存储器用单片机AT89S52来读取、存储、写入时钟信号控制其时间电路的显示以及响铃电路的正常运作即发出“嘀-嘀”的打铃声设计到时自动打铃器。

　　　电源采用一个直流稳压电源。直流稳压电源一般由电源变压器,整流滤波电路及稳压电路所组成.

　　　但是日历时钟时常跑快跑慢的现象普遍存在，经过日积月累，就会产生较大的误差。为了解决这一问题，我们设计了能够自动校准和自动打铃的可编程时钟控制器。它能很好的帮助我们完成对操控方面的时序和时间的控制，能够让我们来掌握运筹时间而不是让时间来催促逼迫我们。

关键词：数字时钟；可编程控制器；时钟控制器

Abstract:People in the continuous improvement of living standards household electrical appliances gradually universal, intelligent control system for the market demand is increasing. The emergence of digital clock on the clock to break the people's traditional concept, It's not only through digital visual display calendar time, with sound, music and Chinese speech sounds, such as timekeeping; can also give a variety of sound, light, signals, To start to achieve real-time control of equipment, time sequence control. Such as auto-play and rest time bell, Home Appliances automatic timing hoist, the order of the production process control, etc., use a very wide. All of these are digital watches and clocks, as the basis and, therefore, on digital clocks and expand its applications, a very practical significance.

　　　   The design of the digital automatic rang the bell system USES a DS1302 as the clock circuit, clocking circuit is the main task of the produce real time clock signal, on the one hand, to the digital display said, another aspect of the bell ring circuit provides automatic memory address signals. And the memory use monolithic integrated circuit AT89S52 to read, storage, write the clock signal control of its time circuit of the display, and rang the bell of the circuit is a normal operation \"di-du\" play the bell ringing the bell schedules design automatic device. 

　　　   Power to adopt a DC power supply. DC power supply from the general power transformer, rectifier filter circuits and components by the regulator circuit 

　　　   However, the calendar clock ran sprints often slow the widespread phenomenon, after accumulated, it will have a greater error. In order to solve this problem, we can design the automatic calibration and broadcast the whole point of programmable clock controller. It's good to help us complete control of the timing and duration of control, so that we can master planning to allow time to time rather than forcing us to press.

Key words: digital clock;  PLC;  clock controlle