| 摘要 |
PURPOSE:To use a buffer while packing its memory from its end by discriminating the necessity of a received frame and resetting the address generating circuit designating the address of the reception buffer to be restored in case of an undesired frame. CONSTITUTION:A sequence circuit 4 selects the 1st buffer 5 and the 2nd buffer 7 alternately for each reception frame and gives a signal to corresponding address generating circuits 6, 8. The address generating circuit gives an address to each buffer and stores a reception frame. A discrimination controller 9 reads a control information area written in a specific location of the reception frame from the buffer received just now and gives a reset signal to the corresponding address generator 6 or 8 when an unrequired frame is discriminated. The address generation circuit restores the address counter for write to a value before the unrequired frame is received to prepare the reception of the succeeding frame. Thus, only the required frame is stored continuously in the area at all times.
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