Patent ID: 7908416

Claim:
A data processing unit comprising: a bus; a plurality of bus masters connected to said bus, each of said plurality of bus masters issuing a bus use request including a bus use request purpose and size information indicative of the size of data to be read or written, said plurality of bus masters thereby issuing a plurality of bus use requests, a bus master in said plurality of bus masters being configured to vary the bus use request purpose and vary the size information in accordance with the varied bus use request purpose; and a bus arbitration unit operable to perform arbitration of the plurality of bus use requests issued from said plurality of bus masters and grant bus ownership to one of said bus masters, said bus arbitration unit comprising: a priority control unit operable to select one of said bus masters from among a single or a plurality of said bus masters issuing the bus use requests on the basis of priority ranking information provided for determining the priority levels of said plurality of bus masters; and a bus access control unit operable to grant bus ownership to said one of the bus masters as selected by said priority control unit for using said bus for one or more bus cycles corresponding to the size information as issued by said one of the bus masters as selected by said priority control unit, wherein said priority control unit is configured to make the selection of said one of the bus masters once for each series of the one or more bus cycles corresponding to the size information, wherein the priority ranking information is used to determine the priority levels of the bus use request purposes, said priority control unit selects one bus use request purpose on the basis of the priority ranking information from among the bus use request purposes in association with which one or more bus masters of said bus masters are issuing bus use requests, and said bus access control unit grants bus ownership to said bus master having the bus use request purpose selected by said priority control unit for one or more bus cycles corresponding to the size information issued by said bus master having the selected bus use request purpose.