| 摘要 |
PURPOSE:To access other input/output device and a memory device by disconnecting a signal bus part before a direct memory access device operates and connecting the signal bus part and a central processor at the end of the operation. CONSTITUTION:When data needs to be transferred between the memory device 6 and an input/output device 7, a central controller 1 operates a signal bus disconnecting device 5 at the end of access to the devices 6 and 7 when accessing them or instantaneously when not to disconnect signal buses 2 and 13 and informing an access controller 8 of that. When the data transfer between the devices 6 and 7 is completed, the access controller 8 informs the central controller 1 of th completion. The central controller 1 which receives it finishes the operation of the signal bus disconnecting device 5 and connects the signal bus parts 2 and 13 again.
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