说明：  本次设计中以单片机的发展过程和发展方向为背景，介绍了单片机的输入输出的工作原理和操作方法，中断的工作原理和操作方法。4511的工作原理和操作方法，LED的内部结构。电路设计及调试过程。 本次做的数字钟是以单片机（AT89C51）为核心，结合相关的元器件（共阴极LED数码显示器、BCD-锁存/7段译码/驱动器CC4511等），再配以相应的软件，达到制作简易数字钟的目的，其硬件部分难点在于元器件的选择、布局及焊接。
(The design of a single-chip development process and the development direction for the background, introduced the single-chip input and output of the working principle and method of operation, interruption of the working principle and method of operation. 4511 the working principle and method of operation, LED s internal structure. Circuit design and debugging process. To do this is based on single-chip digital clock (AT89C51) as the core, combined with related components (common cathode LED digital display, BCD-latch/7 segment decoder/driver CC4511, etc.), together with the corresponding software to create simple digital clock The purpose of the hardware part of the difficulties lies in the choice of components, layout and welding.)