| 摘要 |
PROBLEM TO BE SOLVED: To prevent an inputted low-priority cell from being retained without being outputted. SOLUTION: A high-priority cell storage part 61 stores high priority set cells and outputs a high storage notice signal 62 reporting the storage of such cells. A low-priority cell storage part 67 stores low priority set cells and outputs a low storage notice signal 65 reporting the storage of such cells. An output selecting part 64 with timer outputs a high output permit signal permitting output at the time of receiving only the high storage notice signal 63 and outputs a low output permit signal 66 permitting output at the time of receiving only the low storage notice signal 65. Besides, when the low storage notice signal 65 is received while the high output permit signal 63 is outputted, the timer is set and after the lapse of prescribed time, the output of the high output permit signal 63 is stopped. Then, the low output permit signal 66 is outputted and the prescribed number of low-priority cells are outputted. Therefore, the low-priority cell can be prevented from being retained without being outputted.
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