| 摘要 |
PROBLEM TO BE SOLVED: To provide a bus arbiter for arbitrating a bus acquirement request form a plurality of bus masters so that definite promise is given to the data transfer efficiency of the first bus master. SOLUTION: The scanner 3 of a device equivalent to the first bus master scans an original at constant speed and sequentially transfers the prescribed quantity of picture data to a memory 2 on a system bus in a raster system. A system control part 4 performs communication with a scanner 3 and with IEEE1394 (5) being a communication system device and transfers each command on an operation state and statuses. When the bus acquirement request from the first bus master, which is generated by the occurrence of a specified event in a device to which the bus arbiter is applied, exists, the occurrence of the event is detected and it is outputted as an event generation signal. The event generation signal is received, and frequency for giving bus use right is restricted much more than a regular case where the specified event is not generated with respect to the bus acquirement request from the bus master except for the first bus mater.
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