Bus coupling information processing system for multiple access to system bus

Abstract From the Canadian patent

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 …