| 摘要 |
PURPOSE:To more securely detect a program fault accompanied by the infinite loop of a program and the like in an electronic exchange loading such a CPU system. CONSTITUTION:In a program fault detection system which has the CPU system having plural interruption levels and which periodically resets a watch dog timer 104 using one of the interruption levels, a mechanism which counts time when a system comes to a wait state by using a lowest-order interruption level as the interruption level that periodically resets the watch dog timer 104 or without depending on interruption and which is periodically started at every prescribed counting is provided, and the watch dog timer 104 is reset by the mechanism concerned. |
