说明：  ?程序启动后，D1处于熄灯，LED1处于黑屏状态；单击K1，可使D1亮灯状态反转一次；单击K2可使LED1显示值加1，并按十六进制数显示，达到F后从1开始。
(After the program starts, D1 is off, LED1 is in a black state; click K1, D1 can be turned on once; click K2 to increase LED1's display value, and displayed in hexadecimal, reaching F. Start with 1.)