Can connect Arduino Mega ATMEGA2560 to Dragon Board 410c via UART

I seen that dragon board UART supports 1.8V only.
I want to connect Arduino Mega ATmega2560 via UART.

Is there any way of connecting them?

You will need some kind of voltage level shifters.

Historically I would have recommended the Audio Mezz board for this but I think it is getting very hard to find stock. However you should be able to adopt a stand alone level shifter board.

UART signals are uni-directional but bi-directional level shifters are much easier to find. Bi-directional shifters can work but they may be a little “fussy” (some won’t work with I2C, others won’t work with long cables because the edge detector gets confused by reflections within the cable). Sparkfun do a couple that will probably work. If you got that route and postage is more then the shifter boards then considering buying both the MOSFET and IC based designs. That way you can see which one works best for your system.

Why don’t you just plug the ATMEGA into one of the Dragonboard USB ports?