说明：  基于单片机的定时和控制装置在许多行业有着广泛的应用，而数字钟是其中最基本，也是最具有代表性的一个例子。在基于单片机系统的数字钟电路中，除了基于单片机系统和外围电路外，还需要外部的控制和显示装置。在本例中，输入装置是按键开关，由于控制数字钟的运行模式，显示装置是段式的LCD。
(Based on single-chip timing and control devices in many industries have a wide range of applications, while the digital clock is one of the most basic and most representative example. Single-chip microcomputer system based on the digital clock circuit, in addition to single-chip microcomputer-based system and the peripheral circuits, but also the need for external control and display devices. In this example, the input device is a key switch, digital clock as a result of the operation control mode, display device is a piece of the LCD.)