| 摘要 |
PURPOSE:To execute subchannel (SCH) efficiently, by deciding the SCH being in use, holding the address of the decided SCH being in use, and executing the scanning only for the held SCH. CONSTITUTION:An FF15 is set by a scanning start signal, and a counter (CT) circuit 18 starts forward and stepwise. A selecting circuit 22 selects an output of the circuit 18, and outputs SCH scanning addresses (AD) SCN1-SCN4. When the circuit 18 starts forward and stepwise, SCHs are scanned in order, and each SCH sends a response signal to an AND circuit 10 when an AD assigned to itself coincides with the SCH scanning address, and its operation can be executed. Each SCH returns no response signal when its operation cannot be executed or the SCH is unused. An output of the circuit 10 makes a CT circuit 17 start forward and stepwise, and write-in the outputs of the circuits 17, 18 to a memory circuit 21 as AD and input data, respectively. When scanning has been executed up to the final AD, the circuit 18 resets the FF15, and the circuit 22 selects the circuit 21 and performs output. Accordingly, the AD to which a response signal is not returned is not scanned after the second time. |
