It is already a USB device. It implements the Serial interface.
You're probably looking for the Mass-Storage interface. That won't work with a Mega. It makes no sense. It's like asking a car to implement the "drive on train tracks" interface.
It is already a USB device. It implements the Serial interface.
You're probably looking for the Mass-Storage interface. That won't work with a Mega. It makes no sense. It's like asking a car to implement the "drive on train tracks" interface.