| 摘要 |
PURPOSE:To decide the runaway of a CPU and to reset this CPU for restoration by detecting that the waveform of a cyclic pulse sent from the CPU is deviated from a prescribed form. CONSTITUTION:A CPU1 detects the runaway of a deadman's timer circuit and restores it, and a pulse signal showing the normalcy is transmitted through an output terminal OUT of the CPU1. The normalcy is decided from the pulse width. In a normal mode the level 'H' lasts for a period T1 and then the 'L' level lasts for a period T2. These two levels are repeated cyclically. The generation of a runaway is decided, when the fundamental rule of the waveform of said pulse signal is lost. Then a reset signal is inputted to a reset terminal of the CPU1. No resetting action is carried out with the level 'H' held in a normal mode. Then an active state is started to reset the CPU1 when a pulse of 'L' is inputted. |
