做一个扫描键盘和数码显示实验，把按键输入的键码在六位数码管上显示出来。

实验程序可分成三个模块：

①键输入模块：扫描键盘、读取一次键盘并将键值存入键值缓冲单元。

②显示模块：数码管显示键值。

③主程序：调用键输入模块和显示模块

-A keyboard and digital display scanning experiment, the key input in the key code on the six digital tube display. Experimental procedures can be divided into three modules: ① key input module: scan the keyboard, a keyboard and read the key into the key buffer unit. ② Display Module: digital tube display key. ③ the main program: call key input module and display module