| 摘要 |
In a serial interface system wherein a master unit (26, 27) selects one or more of slave units (26, 27) as a destination by an identification number assigned to each slave unit and transmits a data signal to the destination in synchronism with a clock signal, a control path is added to a serial interface. When one of the slave units acts as a source either in transmitting data to the master unit or in transferring data to one or more of other slave units selected as a destination, the source activates the control path to activate, in turn, the master unit. When activated, the master unit sends a clock signal to the interface to make the source transmit or transfer the data in synchronism with the clock signal. Alternatively, the control path is dispensed with. In this event, the master unit is activated either by a command signal produced by the master unit or by a like command signal set forth from a source to the interface in response to an interrogation from the master unit. Preferably, signals except for the clock signal are sent from the master unit or from the source with an identification code included in each frame of the signals to indicate each of the slave units by the identification number that is concerned with the signals. |
