However, even though I was referring to the Legato site and programming it, I kept failing.
The final goal is to use Serial Communicating by using RS-232 as a GPIO pin, but before that, simple LED control and switch control with a pin would be a great help.
I would appreciate it if you could give me directions to the place where such a source exists.
I used the sysfs command, but I don’t know what api can be used to produce the desired output on the digital pin through which function call can be used.