| 摘要 |
PURPOSE:To preclude the possibility of confusion in an effective data by designating a duplicated device based on a prescribed priority and selecting a data of the designated device to prevent the superimposition of the data. CONSTITUTION:State signals s0, s1 of networks NW0, NW1 are inputted to a priority circuit PR consisting of an inverter I1 and a gate G4, a designating signal (p) is outputted, and the signal (p) is fed to a selecting circuit SEL consisting of gates G5-G7. In switching the network NW0 to a spare system and the network NW1 to the active system, first the signal s1 is set to a logical value 1 and the signal s0 is set to ''0'' after a prescribed period, but the signal (p) is kept to ''0'' even if the signals s1, s0 are both ''1'', and set to ''1'' after the signal s0 is set to ''0''. Then, the gate G5 is brought into blocking state, the gate G6 is brought into a conductive state, only a data d1 of the network NW1 is used as an effective data (d) and outputted via the gates G6, G7. |
