PURPOSE: To prevent a whole system from being practically stopped due to a fault unit by providing a bus arbiter with a protocol monitoring circuit, and at the time of detecting a protocol error in a bus using right generating request, informing the error to a unit generating the request.
CONSTITUTION: The protocol monitoring circuit 8 always monitors the protocol of arbitration in co-operation with a bus using right control circuit 3, and at the time of detecting an exception, informs the generation of the exception to a bus monitoring circuit 10 and the control circuit 3. The circuit 10 receiving the information informs the generation of the exception from the circuit 8 to an exception generating unit 100-1. When the abnormal request is continuously generated even when the exception generation information is received, the circuit 8 decides the generation of a fault in the unit 100-1, informs the decided result to the circuit 3 so that the bus using right is not given until the recovery of the defective unit 100-1 is confirmed. Consequently, the whole system can be prevented from being practically stopped due to the fault unit.
| JPH05197671 | MASTER SLAVE COMMUNICATION METHOD |
| JP3057934 | [Title of Invention] Shared Bus Mediation Mechanism |
| JPS61109164 | BUS CONTROL |
TAKAHASHI HAJIME
KABEMOTO AKIRA
