As per USB 2.0 protocol, when a USB device (e.g. a keyboard, a thumb drive or a web camera) is conneted to the Native USB port, the Native USB port IS the USB Host. As a USB Host, the DUE will PROVIDE up to 500 mA to power the USB device, except if this one is a self powered USB device, after the enumeration process (only 100 mA are provided during the enumeration process).