Hi, I'm planning to make ATmega4808 based Arduino compatible.
The circuit currently being designed is as follows:

Writing pins are integrated into CN1.
I am new to designing UPDI circuits and I believe the best design is to have independent UPDI terminals, how would you guys rate this design?

Thanks,

 

Keeping the program/debug terminals separate from the rest of the circuitry will make you life a little bit easier, so if you the pins to spare, it is a good way to go.

 

Looks OK to me.

 

I decided to coexist with the traditional USB-Serial and the new UPDI interface.
UPDI pin uses with VCC and GND, so the final layout looked like this.

Thank you very much!