| 摘要 |
PURPOSE:To automatically realize the clear operation of a memory in a short time by applying read modified write synchronously with a signal representing a display cycle. CONSTITUTION:When a display area of a picture memory 5 is cleared and ''0'' is written to a port X of a register j8a of a mode control means 10 from an MPU, a signal Diso representing th display cycle from a graphic processor 1 is active and write enable signal WE is active by and AND gate 8b. Moreover, simultaneously a data bus to a memory Din is selected to a specific pattern selector position (position of driver 9) from a processor 1 (side of driver 3b). Thus, areas of the memory Din are all made zero. Thus, the display area of the memory 5 is cleared. |
