Electronic device and method of controlling interface thereof

In an electronic device having a USB controller capable of transferring data in a High-Speed mode for transferring data at a first transfer rate and in a Full-Speed mode for transferring data at a rate lower than the first transfer rate, whether the connection mode is the High-Speed mode or the Full-Speed mode is acquired when a USB cable is connected. The first or second configuration conforming to the acquired mode is selected, the USB controller is controlled based upon the selected first or second configuration, and processing for transferring data to a connected external device is executed. This makes it possible to execute data transfer processing that is suited to the connection mode.