| 摘要 |
PROBLEM TO BE SOLVED: To provide a data input device in which a circuit simpler than the conventional one reads data stored in a memory even when a memory data managing means is eliminated and variable-length record data on a plurality of pages are received and written in a ring buffer memory. SOLUTION: In this data input device in which an image memory 10 is configured as a ring buffer, when data exceeds a memory maximum address, a memory address is returned to the first address to perform overwriting processing, and the oldest data acquired in the image memory 10 is first overwritten. In the data input device, when software reads the ring memory 10, information stored in the ring memory 10 such as the page size and the first address of the acquired data to refer to is stored in a dedicated FIFO memory, and if the ring memory 10 is ringed to cause page overwriting, hardware automatically reads a page status FIFO 7 to read the overwritten first page information and throw the first page information away. COPYRIGHT: (C)2006,JPO&NCIPI
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