| 摘要 |
PROBLEM TO BE SOLVED: To provide a memory control technology for rewriting only a required part at high speed even in a memory having a wide bus width. SOLUTION: The data of a background image are stored in a memory 10. As write data, the data of an upper layer image are propagated. A data value to permit write is written in an instruction register 12 in advance. Data are compared for each byte by a first comparator 22 or the like and when data to permit write come, the signal of an MSK1 or the like is negated. In the other case, the MSK1 or the like is asserted and rewrite is protected. COPYRIGHT: (C)2003,JPO
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