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。(Single-chip microcomputers, also known as microcontrollers, are microcomputers that integrate CPU, RAM, ROM, timing/counter, I/O interface circuits into a circuit chip. The system is composed of single chip computer system, digital tube display system, keyboard, buzzer and so on. The digital clock can be displayed in time, minutes and seconds, 12-24 system conversion, setting time, alarm clock and other functions by controlling the single chip computer by keys, and displayed on the LED through the output of P0 port.)