A display device interface circuit comprises a primary skew circuit for skewing a video signal for a predetermined period converted to a serial signal; a secondary skew circuit for skewing a blank signal which determines the flyback time for a predetermined period; and a logic circuit for adding signal outputs of the secondary skew circuit to the head and tail of the video signal skewed by the primary skew circuit for a predetermined period.
A flat display driver in a drive circuit for driving a flat display including a memory storing data to be displayed on a display panel of a line scan type having a two-dimensional structure constituted with N rows by M columns, an address generator for generating a read address of the memory and a line clock signal, a data output terminal for supplying the display panel with data read from the memory, and a line clock signal output terminal for supplying the line clock signal from the address generator to the display panel. The memory is loaded at least with display data constituted with K rows by M columns (K<N) and the driver further includes a margin scan detect device in which respective margin lines ((N-KO/2) in upper and lower portions of the display panel are set in advance for receiving and for counting the line clock from the address generator, thereby detecting a margin detect signal when the count in equal to a value corresponding to the margin line and a margin display output device operative in response to an input of the margin detect signal from the margin detect device for outputting a margin display signal to the display panel.
