该程序用于开关量的输入，并显示在与D口相连的LED上，S1~S8分别控制Q1~Q8，开关量采用SPI方式通过74HC165输入，在调试程序时必须把8位的拔码开关拔向相应的位置，即把8个LED接到PORTD口上

-The program used to switch the amount of input, and display associated with the LED on port D, S1 ~ S8 are controlled Q1 ~ Q8, switching capacity 74HC165 input by using SPI mode, the debugger must pull out of the 8-bit code switch pulling to the appropriate position, that is eight LED port on the receiving PORTD