Abstract: A portable computer having a primary and secondary displays is disclosed. The portable computer includes a step value storage device for storing a set of manipulation step values for simultaneously controlling the luminance of the primary and secondary displays. The portable computer also includes a first luminance table and a second luminance table. The first luminance table stores a set of first control step values that corresponds to a luminance value to be set to the primary display for each of the manipulation step values. The second luminance table stores a set of second control step values that corresponds to a luminance value to be set to the secondary display for each of the manipulation step values so that the luminance values set for the secondary display becomes substantially identical to the luminance values set for the primary display within a range of a predetermined number of consecutive manipulation step values.

Abstract: An identification information acquisition apparatus for acquiring identification information set in an external device includes a first acquisition portion for acquiring a first identification signal output from a first terminal of an external device, a second acquisition portion for acquiring a second identification signal output from the first terminal in a state where a first change signal that instructs to change a signal output from the first terminal has been output to a second terminal of the device, and an identification information determination portion for determining identification information on the basis of the first and second identification signals.

Abstract: To expand display data for a low-resolution matrix display apparatus to display data for a high-resolution matrix display apparatus without causing a reduction in the speed of processing and without requiring clocks of different frequencies. This is accomplished by providing intermediate value generating circuits for generating intermediate values of a plurality of adjacent display data according to an expansion ratio in a driver circuit of a matrix display apparatus and by also applying the outputs of the intermediate value generating circuits to the matrix display panel. Thus, the display data is expanded by the driver.