Abstract: A semiconductor device includes a plurality of first pads; a plurality of ports for performing a serial data communication with external devices through the first pads; a plurality of banks for performing a parallel data communication with the plurality of ports; a plurality of global data buses for supporting the parallel data communication between the plurality of ports and the plurality of banks; and a test mode controller for performing a core test with various data transfer modes by converting the serial data communication into the parallel data communication during a core test mode.