It was working fine and well but I tried connecting it to a USB cable that only had power and ground cables in it the data cables were removed. this was to test another problem that isn't relevant to this. after this it won't show up on any port or in the device manager. I don't think it's even trying to communicate over USB now but I'm very unsure. it's an Uno wifi r2
plz help, I'm doing Mark Robers engineering course and need it to work for that.
Does the Uno WiFi Rev2 show any signs it is getting power? The power input from the USB connector goes through a polyfuse followed by an inductor, then has a zener diode to ground that should protect against overvoltage (although I have not found a reference to what the zener voltage is). A direct connection to a 9v battery may have either damaged the USB connector itself, the polyfuse, or the inductor.