While using the pins in the alternate function, the GPIO read/write access to that pin is not
accessible and must be avoided.
AT#GPIO?
Read command reports, for any GPIO pin, a row showing the current parameters values. Row one
shows GPIO pin one, row two shows GPIO pin two, and so on.
#GPIO: <dir>,<stat><CR><LF>
#GPIO: <dir>,<stat><CR><LF>
...
If GPIO was previously set to <mode>= 3 or 4, the format of the returned message is:
#GPIO:<dir>,<stat>,<mode><CR><LF>
#GPIO:<dir>,<stat>,<mode><CR><LF>
...