LED燈所在的GPIO管腳：GPIO1_A2

GPIOa_bc
d=b-'A'='A'-'A'=0
a=1, d=0, c=2

GPIO號=32a+8d+c
      =32×1+8×0+2
      =34

產生gpio34文件夾：echo 34 > /sys/class/gpio/export

GPIO管腳設置為輸入：echo in > /sys/class/gpio/gpio34/direction
讀取輸入的電平：cat /sys/class/gpio/gpio34/value

GPIO管腳設置為輸出：echo out > /sys/class/gpio/gpio34/direction
GPIO輸出高電平（燈亮）：echo 1 > /sys/class/gpio/gpio34/value
GPIO輸出低電平（燈滅）：echo 0 > /sys/class/gpio/gpio34/value