Emlid Neutis has 60 GPIO pins. See the pinout section for more information. GPIO can be accessed through Linux’s sysfs interface. (/sys/class/gpio directory).

GPIO Sysfs Numbers

To obtain the correct number of the desired pin you have to calculate it from the pin name: (position of letter in alphabet - 1) * 32 + pin number

Also, you can use this formula in Python interpreter:

(ord(pin_letter) - ord("A")) * 32 + pin_number

In this example, we are controlling user LED connected to the pin PA10. According to the formula above, the correct pin number is (1 - 1) * 32 + 10 = 10.

Let there be light

1) To control a GPIO bit you should first to export the pin:

echo 10 > /sys/class/gpio/export

After that, you'll see a new directory gpio10 in /sys/class/gpio containing the files you need to control the pin.

2) Write "out" to /sys/class/gpio/gpio10/direction:

echo out > /sys/class/gpio/gpio10/direction

3) Set the value:

echo 1 > /sys/class/gpio/gpio10/value

4) To turn off the LED you need to write 0:

echo 0 > /sys/class/gpio/gpio10/value

When you are done, remove GPIO pin by just unexporting it:

echo 10 > /sys/class/gpio/unexport