| 摘要 |
When a first bus master device issues a bus request on a first request signal line, a centralized arbitration circuit in a system bus manage circuit issues a bus grant signal on a first grant signal line if the bus is available for use. This causes the first bus master device having gained the ownership of the bus to issue a read request to a first slave device. At this time a first signal line is designated. Even before the sending of the read data constituting a response to this read request to the first bus master device, a bus request from a second bus master device can be accepted if the data bus is unoccupied. Thus, the centralized arbitration circuit in the system bus manage circuit issues a grant signal on a second grant signal line. This causes the second bus master device having gained the ownership of the bus to designate a second end signal line, and to issue a read request to a second slave device. After that, the first end signal line is activated, and read data from the first slave device is sent to the first bus master device. On the other hand, the second end signal line is activated, and read data from the second slave device is sent to the second bus master device. |
