I cant get the hardware serial on pins D0/D1 to work with rs485, using my Uno and max485. I expect it is because of the USB interfaced with these pins. My MEGA works using Serial1,2 and 3 so I don't imagine the problem is due to the uart but more likely the USB device thingy.
My question is, would you expect the hardware serial on the Pro mini (pins D0/D1 - same as Uno) to work with rs485 where the Uno won't? Because the pro mini doesn't have a usb jack attached to it.