| 摘要 |
PURPOSE:To decrease overrun errors and underrun errors caused in a logical device by allowing each logical device to acquire the right of use of bus with the highest priority periodically. CONSTITUTION:A signal line 7 provided with bus highest priority right for controlling the right of use of a bus highest priority control signal line 6 to each logical device on time-division basis is connected to each logical device in addition to the bus highest priority control signal line 6 acquiring the right of use of the bus 4 with highest priority. Thus, only one logical device permitted by a signal from the signal line 7 provided with bus highest right of use providing signal line can transfer a highest priority use request signal to the bus highest priority control signal line 6. In this case, the information on the line 7 is updated cyclicly in response to the number of logical devices connected to the bus 4. That is, each logical device uses the bus highest priority control signal line 6 on time-division basis by using the information on the the signal line 7 provided with bus highest priority right as a time slot. |
