VIM Pinout map show that there is only one UART (pin 15 16).But if i need two,is there any other solutions？
Yep, because some IO are duplicating, for both VIM, you can also use PIN22/23 as UART:
Check Schematic for further details.
Yes, I see PIN22/23 are duplicating,but how can i configure them as serial port mode?
It’s common Linux method to config the GPIO mode, you can reading the related source code and refer the Datasheet on Khadas Docc for further details.
I think you can try to resolve by yourself first, if with further problem, you can just paste with the detail question, and we will try to figure out the solution.
Thanks & Enjoy!