There is provided a display device including an input unit configured to connect an external device to a serial peripheral interface (SPI) through a plurality of connection lines, a switching unit configured to connect the input unit and a flash memory of a driving board to the SPI, a data register configured to output connection setting data for determining a connection state of the switching unit, and a timing controller configured to output a control signal for determining the connection setting data according to an input of a write enable line among the plurality of connection lines.