arm9 mini2440按键驱动实例，可下载到开发板上测试,arm9 mini2440 key driver instance, can be downloaded to the development of on-board test

mini2440开发板上用的按键驱动程序，程序简短，很容易理解，适合新手下载阅读并加以移植-mini2440 development board with the key drivers, the program is short, it is easy to understand for novice download to read and transplantation