Has anyone else found that a USB-serial adaptor connecting the Nano’s serial console to a host computer can stop working when the Nano is reset or power-cycled?
I have a USB-serial adaptor connecting the Nano’s serial console on J50 to a USB hub that’s built in to my monitor. If I power-cycle the Nano, or reset it using the reset button pins on J50, it stops working; it is still recognised by the host computer but no further characters are transferred and neither the transmit nor receive LEDs on the adaptor flashes. The Nano seems not affected and reboots normally. To get the adaptor to work again I have to unplug and reconnect it to the Nano - i.e. on the serial side, not the USB side.
My guess is that perhaps the Nano doesn’t like that a voltage is present on this input while its own power supply is absent. I am concerned that this could be damaging the board; is there any protection on those inputs?
Has anyone seen anything similar?