| 摘要 |
An image display system includes a register for storing a display address of a fixed display area, a register for storing an address of a scroll area, a register for storing an address from which scrolling is to be started, etc. By properly setting the addresses stored in those registers in counters for counting a display address of a display RAM 131, it is possible to count the display address while freely skipping addresses and to scroll a part of a screen. Therefore, the number of accesses made from an MPU 11 to the display RAM 131 is much lessened and power consumption can be greatly reduced in comparison with the case of rewriting data in the display RAM 131 for scrolling. By preparing a memory that has a larger capacity than required for displaying a full screen image, when an interrupt or the like is applied to the MPU 11 during scrolling, the data in the course of the scrolling is avoided from appearing on the screen.
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