Uart pin in 40 pins header is pin15 and pin16
openg uart node via device tree overlays.
Make sure UART is in the overlays list (default is enable).
overlays=uart4 pwm_ao_a pwm_f i2c0
note: VIM1/VIM2 is uar4,VIM3/VIM3L is uart3
Connect you board’s uart and you PC via ttytoUSB tool.
The baud rate is set to
115200, here is Ubuntu as an example:
sudo minicom -b 115200 -D /dev/ttyUSBx
Open the terminal on the board and set the serial port baud rate.
sudo stty -F /dev/ttySx 115200
Print info via
echo khadas | sudo tee /dev/ttySx
You will receive
khadas in you PC