44B0的测试程序。此程序为44B0的4*4键盘的应用程序，基于中断0触发，当按下其中一个键时，会把0-F的相应键值显示在8段LED上。-44B0 testing procedures. This procedure for the 44B0 4 * 4 keyboard applications, based on the interruption 0 trigger, which when pressed a button, will be 0-F to the corresponding keys shown in the last eight of the LED.