Here is an academic question regarding the differences between CAN bus and USB differential _signals_. I'm not interested in the protocol differences-- just the signaling.
CAN bus was created around 1983 and uses a differential signal alternating between V+/2 and V+ for CAN H, and V+/2 and CAN L for the other end. The recessive bit returns back to V+/2.
USB, which came later, OTOH, pulls the signal D+ low, and D- high and otherwise returns to the idle state of their respective D+/D- idle levels.
My question is about the differential signal design:
Is there an advantage to the CAN bus approach with the recessive bit at V++/2, or is the USB differential signal with its wider differential voltage better for noise immunity or other reasons?
Another way to phrase the question might be:
if CAN were to be redesigned today with the lessons learned from USB (signalling), would they have still chosen the same V+/2 idle signal that they chose to use?
Just curious, Warren