开发环境为Keil，基于89RC51单片机简单I/O口的应用，使用到定时器中断，独立键盘，是简单的时钟，具有暂停、校时、校分、整点闹铃的功能。-Development environment for the Keil, based 89RC51 simple microcontroller I/O port of the application, use the timer interrupt, separate keyboard, it is a simple clock, with paus