| 摘要 |
PURPOSE:To remove the occurrence of system-down owing to the abnormality of a clock signal source by switching a clock signal used for the execution of a data processing to a clock signal which a local clock signal source generates. CONSTITUTION:When a clock monitor means 5 detects the abnormality of the clock signal source 3 since the clock signal from the clock signal source 3 is not supplied for a prescribed period, it gives an instruction for selecting the clock signal which the local clock signal source 4 generates to a clock selection means 6. The clock section means 6 selects the clock signal which the local clock signal source 4 generates and gives it to a hardware mechanism by receiving the instruction. Thus, the means 6 processes the individual processor modules to asynchronously control a system bus 2 and to execute a data processing. Thus, the occurrence of system-down owing to the abnormality of the clock signal source can be removed. |
