| 摘要 |
A value obtained by adding a back porch period following a vertical sync signal output from a CRT controller to the total number of horizontal display lines of a display resolution is set in a register (27). A counter (25) counts the value set in the register (27) in synchronism with a horizontal sync signal, and outputs a scanning start signal (SD) to a Y driver (31). With this operation, when a designated display resolution is lower than the physical resolution of an LCD, the scanning start signal is output before scanning of all the physical display lines of the LCD is completed. As a result, upper and lower non-display portions on the LCD display screen are simultaneously scanned. <IMAGE> |
