单片微型计算机简称单片机，又称为微控制器，是将CPU、RAM、ROM、定时/计数器、I/O接口电路集成到一块电路芯片上构成的微型计算机。本次设计的系统由单片机系统、数码管显示系统、键盘、蜂鸣器等组成，通过按键来控制单片机实现数字时钟的时、分、秒显示，12、24制转换，设定时间、闹钟等不同功能，并通过P0口的输出在LED上显示。该设计具有结构简单、使用方便等特点。(As the single chip computer, also known as micro controller, CPU, RAM, is ROM, timer / counter, I/O interface circuit to form a micro computer circuit on a chip. This system is composed of single-chip microcomputer system, digital display system, keyboard, buzzer and other components, to control the MCU digital clock through the button, minutes and seconds display, 12, 24 for conversion, set time, alarm clock and other different functions, and through the P0 port output displayed on the LED. Has the characteristics of simple structure, convenient use and so on the design)