This is a theoretical question. I would like to know what the lowest latency is which can be achieved when interfacing a microcontroller with USB interface. Consider a USB host (computer) sending one byte to a USB device (microcontroller) and waiting for it to respond the same byte. How much time would this at least take? Are there any experiments about that? Any information would help me.
When using serial communication (RS232) the minimum latency you can achieve is 1 ms (by using USB to serial converter). I am looking for a faster way to communicate with my microcontroller (in terms of latency).