摘要 |
In a data processing unit, apparatus permits more than one central processing unit and associated control interface unit to transfer data to an input/output multiplexer. Thus, more than one central processing unit can have access to a peripheral subsystem. Apparatus is provided which causes the input/output multiplexer to receive sets of data signal groups from the control interface units in sequential order. A signal-free period null signal period is provided by the control unit interface between each set of data signal groups (e.g., each data signal group set includes a single processor sequence). The signal-free period allows the input/output multiplexer to accept waiting data signals from the next sequential control interface unit. Once begun, the transfer of the entire set of data signal groups will proceed without interruption. |