了解键盘结构，学习扫描法和行反转法判断按键的方法。了解用8个I/O设计更多的按键的方法。学会运用C语言编写键盘模块，并能体现SCI模块的功能。 -Understanding of the keyboard structure, learning method and line reversal scan to determine the method keys. Learn to use 8 I/O design more of the key methods. Learn to use t