add settings

Signed-off-by: Andrea Corna <andrea.corna.ac.91@gmail.com>
completed set port connection

Signed-off-by: Andrea Corna <andrea.corna.ac.91@gmail.com>
add write function

Signed-off-by: Andrea Corna <andrea.corna.ac.91@gmail.com>
write function go well

Signed-off-by: Andrea Corna <andrea.corna.ac.91@gmail.com>
close connection ok

Signed-off-by: Andrea Corna <andrea.corna.ac.91@gmail.com>