CLOCK SYSTEM SWITCHING METHOD AND DEVICE THEREFOR

摘要

PURPOSE:To provide a clock system switching method/device for an intra-device clock distribution system that has a redundant constitution where the circuits of the precedent and next stages are duplicated in regard of a system that switches the clock systems. CONSTITUTION:In a clock distribution system having a redundant constitution where the circuits of the precedent and next stages are duplicated, the clock outputs of different systems 0 and 1 are selected out of two clock outputs of a circuit 1 of the system 0 of the precedent stage and two output clocks of a circuit 2 of the system 1 of the next stage and then combined together. Then a circuit 3 of the system 0 and a circuit 4 of the system 1 of the next stage select and generate the clock outputs of both systems 0 and 1 based on the combination of clock outputs. At the same time, both circuits 3 and 4 select the clock outputs based on the input cut-off monitoring results of both systems 0 and 1 acquired by the circuits 3 and 4 by a predetermined table 5.