| 摘要 |
PURPOSE:To execute data transfer under priority conditions of the whole system by providing a transfer request deciding means and a priority comparing means, etc., and adding the priority conditions depending on fixed hardware and conditions depending on a fluid software. CONSTITUTION:A titled device is provided with an exclusive OR circuit 7 being a means for deciding whether a transfer request has been executed at the same time or not, and a comparing circuit 8 for comparing a priority degree, etc. First of all, an initial value of a data transfer request is set to counter circuits 1, 3 and 5, respectively, so that that of a large priority degree becomes a large number. Subsequently, in case the transfer request is not generated at the same time, a transfer request generating means which has generated a request is received through the circuit 7, the circuit 8, etc., and a value of the corresponding counter circuit is brought to count-down. Also, in case the transfer request has been generated simultaneously, it is received in accordance with the priority order, and also a value of the corresponding counter circuit is brought to count- down, and a value of other counter circuit is brought to count-up. In this way, data transfer can be executed under the priority conditions of the whole system. |
