程序员：钱树勇 采用定时中断检测4*4按键；次程序只支持短按模式（若需要支持长按模式，请搜索我的另一程序源码：src-V0.1.1-2012-02-041701.rar）；具有松手检测功能。采用定时扫描模式，无死循环代码，所以更少占用Cpu资源（按键测试正常工作，不理解代码者可留言或至新浪博客：钱树勇留言）-Timer interrupt to detect the 4* 4 buttons　this program only recognizes the short mode　(need to identify long-press mode, clear search the src-V0.1.1-2012-02-041701.rar) has let go of detection. Timing scan mode, no infinite loop code, so the less occupied Cpu resources (key tests are normal)