| 摘要 |
PROBLEM TO BE SOLVED: To obtain the right to use common resources at the time of arbitration by providing a means which holds a priority request information and updating the priority request information with a request signal and use right information showing whether or not the use right is obtained. SOLUTION: When there are two or more use requests, the value of A[3] is set to 0. When there are three or more use requests, the value of A[2] is set to 0 and the value of A[3] is set to 1 indicating a priority request. Those set values are held in a shift register of a priority request information hold circuit 12 and updated each time an arbitration request signal OS is generated. Through the update of those values, its signal line OA after obtaining the use right once stops generating priority request information (bit 1) at an arbitration frequency corresponding to the number of simultaneously generated use request signals. Consequently, even when the priority is given up, the right to use common resources can be obtained at the time of arbitration.
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