I'm a newbie to the NanoPi M4 and haven't been able to find helpful material regarding my doubts
Any help would be appreciated

1. How do I configure the GPIO pins to function as a UART4 TX and RX pins?
2.  The level signals of UART4 are of 3V but the supply to the board is 5V. All standard buck converters are of 5V to 3.3V so how would I go about that?

 

 

I think you should search the internet for "NanoPi M4 uart", first result I found gives the pinout.

 

If you are not sure how to use UART, you should probably search internet about that, too...

 

Thank you for the reply

Can you suggest something for the 5 to 3V conversion? I have only been able to find conversion of 5 to 3.3V 

I don't think you are understanding how UART works, you need to study more.

 

Clue: According to http://wiki.friendlyarm.com/wiki/index.php/NanoPi_M4 (which was the very first link I found, as noted above) the UART pins are already 3V. Everything you need should be there.

 

What are you trying to do (I suspect it's your homework)?

Edited January 21, 20206 yr by TRS-80
add clue

Apart from that 3.3V levels work just fine, the board should actually be 3.3V probably only the label has been shortened.