I don't use any uart port ttyS1, ttyS2, ttyS3 on ubuntu_lxde_desktop_OrangePipcplus_v0_9_1.img os on OrangePiPcPlus board.
I Used some software as minicom, gtkterm .. but don't anything happen on TDX, RTX pin.
when run command line folow
$ gpio readall
Help me please.