Out of the box connecting the RVR to a Raspberry Pi requires connecting both the USB cable (for power) and the UART pins to the Pi’s GPIO for communication. Communication over USB is possible, however, since the RVR is able to communicate with Arduino Unos with just the USB cable.
What hardware would I need to power and communicate with a Raspberry Pi with just a USB cable?
AFAICT Arduino Unos use custom firmware on an ATmega8U2 for converting the usual 2 wire TXD, RXD <> USB’s D+, D- (No idea what protocol is used on the USB side. Is there some standard?). Is there a standalone board that provides this functionality? Or will any FTDI/CP210x/PL2303 board work? Maybe Adafruit’s PiUART https://www.adafruit.com/product/3589 ?
For context, I have a Picon Zero “HAT” (https://4tronix.co.uk/blog/?p=1224) that doesn’t expose the Pi’s UART pins so I’m looking for alternatives. Currently I’m stacking it on top of a Perma-proto HAT to get access to those pins, but it would be nice not to have to plug in two cables at all.
Super-long term it would be neat to create my own PCB based on the Picon Zero (without the motor driver stuff) that includes this ability (single USB for power & UART).