A controller outputs display data in a j-bit unit through first to j-th data output terminals and command data for controlling a data line drive circuit through a (j+1)th data output terminal. The controller also outputs a command identification signal for identifying command data, to the data line drive circuit through a (j+2)th data output terminal. The data line drive circuit includes a latch which fetches command data specified according to the command identification signal, a decoder which decodes the fetched command data, and a control section which outputs a control signal corresponding to a decoding result by the decoder, and the data line drive circuit drives a plurality of data lines of a liquid-crystal panel, based on the input display data and the control signal.