使用说明：

1、该头文件还处在更新中，已经可以从PS2键盘中提取所需的键盘扫描码，并能单独存储最后一次的通码和断码。

2、该头文件提供一个Scan_Key_Board_PS2()函数，该函数将PS2键盘的输出模拟成普通的 n*m 键盘扫描的输出模式，即当有键按下时，通过该函数将获得对应的键盘扫描码，当没有键按下时，将获得一个KEY_NULL的返回。

3、该头文件需要的硬件支持为：

一个下降沿触发的外中断，并将.h中的宏KEY_BOARD_PS2_INSERT_INT_ISR_CODE粘贴到中断处理程序中。该外中断接PS2的CLK线。

一个普通端口，接PS2的Data线。

4、将PROC_Key_Board_PS2_Scan()放到定时器的毫秒中断处理程序中，或者放到主程序的超级循环中（但必须保证该程序在超级循环中具有一定的实时性）。 -Instructions for use:

1, the header file is still in the update, it will be necessary to extract from the PS2 keyboard, the keyboard scan codes, and can separately store the last time the pass code and break code.

2, the header file provides a Scan_Key_Board_PS2 () function, which will simulate the output of the keyboard into the PS2 ordinary n* m keyboard scan output mode, that is, when there are key pressed by the function will receive the corresponding keyboard scan codes , when no key is pressed, it will get a KEY_NULL return.

3, the header files required hardware support for:

　 A falling edge triggered external interrupt, and will. H in the macro KEY_BOARD_PS2_INSERT_INT_ISR_CODE paste it into the interrupt handler. The external interrupt PS2 then the CLK line.

　 A common port, then the Data-line PS2.

4, the PROC_Key_Board_PS2_Scan () into the millisecond timer interrupt handler, or into the main program of the super-cycle (but must ensure that the program in the sup