| 摘要 |
PURPOSE:To improve the stability and reliability of a device by executing a diagnostic action by means of a clock signal with a speed higher than a reference clock signal supplied to the device at the time of detecting the start of the diagnostic action. CONSTITUTION:When the start of the diagnostic action is detected by a diagnosis instruction FF 3 at the time of the action of the device, a changeover to a clock signal 101 for a diagnosis with a speed higher than a clock signal 102 for an ordinary action is executed with a selecting circuit 4 by diagnosis instructing signals 105 and 106 from the diagnosis instruction FF 3. By supplying the clock signal 101 for the diagnosis to each flip-flop circuit in the device, the diagnostic action can be surely executed by the high-speed clock signal. By executing the diagnostic action by the high-speed clock signal, the diagnostic action is executed under conditions stricter than the time of the ordinary action. Thus, the deterioration of an element or a margin lowering in the early stage of a trouble, etc., can be detected, and the stability and reliability of the device can be improved. |
