KEY按键输入LED发光二极管显示实验。

　　1、I/O口实验，检测PE口上按键状态，然后在PB口上显示出来。

　　2、内部1 M晶振，程序采用单任务方式，软件延时。

　　3、进行此实验请插上LED短路块。

　　4、此实验让大家认识最基本的IO口输入与输出方法。-KEY key input LED light-emitting diode display experiment. 1, I/O port experiments, testing the key state of PE mouth, and then displayed on the PB mouth. 2, the internal 1 M oscillator, the program single-task mode, the software delay. 3, to conduct this experiment plug in the LED short block. 4, this experiment to make people understand the most basic IO port input and output method.