| 摘要 |
PURPOSE:To prevent the runaway of a microprocessor, by disconnecting the microprocessor from a bus line when the noise is likely to occur in a controller using the microprocessor. CONSTITUTION:A microprocessor 10 executes a program in a memory 14 and outputs a driving signal from an I/O port 18 at a required timing. A signal generator 22 receives this driving signal to supply a hold signal having a pulse width of a prescribed time to a microprocessor 10. The microprocessor 10 stops the operation in accordance with this hold signal and is disconnected from a bus line 12 to become in the hole state. A light source device 20 supplies a high voltage spark to a xenon lamp by this driving signal. Since the microprocessor is in the hold state for a prescribed time from the driving start, the runaway of the microprocessor 10 is prevented even if the noise is put on the bus line 12. |
