| 摘要 |
A DMA circuit include a read address register for storing a read address; a write address register for storing a write address; an OR register for storing data; a logic operation selection register for storing information indicating whether to write the read data without change or to carry out the OR operation; and a data calculation circuit for carrying out control either of writing the read data from the read address to the write address without change, or of writing the resultant data of the OR operation between the read data and the data stored in the OR register to the write address, in response to the information stored in the logic operation selection register. The DMA circuit can improve the controllability of the entire system.
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