Patent ID: 8838862

Claim:
A data transfer device that controls data transfer performed through a bus capable of separately processing a request and a response, the data transfer device comprising: a plurality of access control units that produce a data transfer process according to the request; and an arbitration unit that performs arbitration between the requests issued by the plurality of access control units so as to determine a request to be accepted among those requests, the arbitration including repeatedly alternating between an arbitration prohibited period and an arbitration enabled period, the arbitration unit configured to accept a new request irrespective of (i) a number of outstanding requests whose corresponding responses have yet to be received and (ii) whether the arbitration unit is operating within the arbitration prohibited period, if a requesting one of the plurality of access control units is exempt from arbitration restrictions, wherein the arbitration prohibited period is a period in which only the request issued by a high priority access control unit among the plurality of access control units is accepted and the requests issued by low priority access control units, whose priority is lower than the high priority access control unit, are prohibited, and the arbitration enabled period is a period in which the requests issued by the plurality of access control units are accepted.