Control Arduino through UART txd rxd

[jamos.tan@gmail.com]

I am not yet sure if this is possible, but I was wondering if I can remove the USB cable and go for a more solid connection between the pi and the arduino.
So, my question is, will the motor.ino and pypilot still work when connecting them both through txd / rxd pins? Or does it only work with USB.
I've tried it before, and have set the serial port accordingly in op, but it didn't work then. Tried looking for documentation and see that UART is mentioned, but usually I see that most people use the USB connection.

Looking for some confirmation of some working examples without USB.

Thanks in advance.