| 摘要 |
PURPOSE:To select automaticallty an oscillator for data reception in IMPL by counting pulses of a strobe pulse signal for a specific time, and selecting the specific oscillator on the basis of the counted value. CONSTITUTION:A selected disk device 2 sends out a pulse signal to the pulse signal line 21 of a bus. A control circuit 22 is signified in a controller 20 with a signal 13 indicating the start of IMPL and inputs a received pulse signal 21 to a counter 23 for a specific period, so that its pulses are counted. A control circuit 24 outputs a set and a reset signal for a flip-flop circuit 10 to signal lines 25 and 26 when the counter 23 counts up to specific values within the constant period. The output of the flip-flop circuit 10 is a selection signal for oscillators 5 and 6.
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