A DETECTOR OF AN OSCILLATION STOPPING AND AN APPARATUS FOR EXECUTING A TREATMENT AFTER THE DETECTION OF AN OSCILLATION STOPPING

摘要

When stopping the external clock oscillation, the oscillation stop that also without increasing the CPU load of the microcomputer, detects the oscillation stop of the external clock, or export signal to reset the microcomputer and converted into the internal clock of the microcomputer It provides a detection apparatus.; In one embodiment, each rising or falling edge of an external clock generates a one-shot pulse, and monitors the voltage of the charge-discharge circuit for charging and discharging each time the one-shot pulse as a Schmidt circuit. The voltage of the charge-discharge circuit exceeds a predetermined voltage sends out the reset signal of the microcomputer.; In another embodiment, an internal clock oscillator circuit comprising a ring oscillator or the like, the voltage of the charge-discharge circuit exceeds a predetermined voltage, activate the internal clock oscillator circuit, the internal clock to the system clock of the microcomputer from the external clock, switches.; In another embodiment, the charge-discharge circuit exceeds a predetermined voltage, by sending an interrupt signal to the microcomputer CPU, makes the process after the oscillation stop of the clock signal.; In other embodiments, monitoring the runaway of the microcomputer in the watchdog timer, it is determined that the congestion in that the oscillation stop of the clock microcomputer, and the processing after the oscillation stop of the clock signal, depending on the cause of the accident.