2812开发板上有扩展中断输入接口，其中可屏蔽中断源EXINT1—EXINT5，非屏蔽中断EXNMI1，EXNMI2，其中EXINT5输入端接有小按键，只要用户按下小按键，EXINT5引脚上就出现低电平。只要在软件进行相应设置，就可发生中断。-2812 has extended the development of on-board interrupt input interface, which may interrupt source shielding EXINT1-EXINT5, non