| 摘要 |
PURPOSE: A retry apparatus and method for maintaining a cache consistency in a hi-fi bus is provided to prevent a deadlock phenomenon of a system by simply checking a cache consistency maintaining operation at a pertinent address region to re-try an algorithm. CONSTITUTION: An RQ(Requester) module requests to a bus use, an arbitration is made. When the RQ module obtains a bus privilege, it drives an address of a region desired to be accessed on the bus. In case of reading, the RQ module waits for an acknowledge(ACK) signal from an RP(Responder) module. If a response to a received ACK signal is a cache signal or an LBUSY signal, the RQ module comes to a standby/sampling address acknowledge(ACK) unit and checks whether a cache-related operation at the corresponding address region has been completed. Upon checking, if the cache signal or the LBUSY signal has been released, the RQ module is transited to a request and acquisition state to request a bus use and acquire a bus privilege, and repeatedly performs a bus cycle. In case of writing, the RQ module drives an address and a data, and then waits for an ACK response. If a response result to a received ACK signal is a cache signal or an LBUSY signal, the RQ module performs a re-trying operation through the standby/sampling address ACK unit as in the case of reading.
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