Hello, i am trying to use the GPIOs 21 and 23 and when i look at this guide: https://tinker-board.asus.com/doc_er.html#started/ i dont find ttyS4 or any of the locations the guide provides.
I am using the latest version of the TinkerOS Android v1.0.6.
Where can i find ttyS0-4 or how to enable them.
Thanks.