JPH0495138A - Detection system for microprocessor processing abnormality - Google Patents

Abstract

PURPOSE:To detect the processing abnormality of a microprocessor due to the abnormality of a peripheral circuit by performing the access processing of a watchdog times after discriminating that the peripheral circuit is in the processable state. CONSTITUTION:An arbitrary peripheral circuit 31 which performs arbitrary processing and a watchdog timer 33 are provided, and this timer outputs an alarm to the external when it is not accessed by a microprocessor 32 for a certain determined time, and the access processing of the watchdog timer 33 is performed after it is judged that the peripheral circuit 31 is in the processable state. Consequently, the watchdog timer 33 is not accessed when the peripheral circuit 31 cannot perform the processing because of abnormality. Thus, the abnormality of the peripheral circuit 31 is detected also.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting abnormality in microprocessor processing, and particularly to a method for detecting abnormality in microprocessor processing using a watchdog timer.

[Conventional technology]

Conventional microprocessor processing abnormality detection method in a microprocessor system that has an arbitrary peripheral circuit that performs arbitrary processing and a watchdog timer that outputs an alarm to the outside if it is not accessed by the microprocessor for a predetermined period of time As shown in FIG. 2, the state of the peripheral circuit is detected (step 5ll),
Next, watchdog timer access processing (step 5)
12) After that, the state of the detected peripheral circuit is judged (Step 513). If the state is possible, the process is performed (Step 514); if the state is impossible, the state of the peripheral circuit is judged again. It was a method for determining the status.

[Problem to be solved by the invention]

With this conventional microprocessor processing abnormality detection method, it is possible to detect the stoppage of microprocessor processing, but even if an abnormality occurs in a peripheral circuit and processing is impossible, it continues to detect the state of the peripheral circuit. Since microprocessor processing continues, watchdog timer access is also executed, which has the disadvantage that microprocessor processing abnormalities due to abnormalities in peripheral circuits cannot be detected.

SUMMARY OF THE INVENTION An object of the present invention is to provide a microprocessor processing abnormality detection method that eliminates such drawbacks.

[Means for Solving the Problems] The present invention includes an arbitrary peripheral circuit that performs arbitrary processing and a watchdog timer that outputs an alarm to the outside if the microprocessor is not accessed for a predetermined period of time. A method for detecting a microprocessor processing abnormality in a microprocessor system is characterized in that a watchdog timer access process is performed after determining that a peripheral circuit is in a processable state.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 shows a microprocessor system to which the microprocessor processing abnormality detection method of the present invention is applied. This microprocessor system includes a microprocessor 32, a peripheral circuit 31, and a watchdog timer 33.

FIG. 1 is a flowchart showing a microprocessor processing abnormality detection method according to an embodiment of the present invention. After detecting the state of the peripheral circuit 31 (step SL), the detection result is judged (step S2), and if it is in a processable state, the watchdog timer 33 is accessed (step S3).
Then, any processing for the peripheral circuit 31 is executed (step 34), and if it is determined in step S2 that the peripheral circuit 31 is in an unprocessable state, the state of the peripheral circuit is detected again.

The measurement time of the watchdog timer 33 is set to the peripheral circuit 31.
If the watchdog timer 33 is set to a value longer than the time at which it is determined that processing is possible when the state of the peripheral circuit 31 is normal, the watchdog timer 33 will not be accessed if there is an abnormality in the peripheral circuit 31. Anomaly is detected.

(Effects of the Invention) As explained above, the present invention has the effect of being able to detect abnormalities in the peripheral circuits because access to the watchdog timer is not executed when the peripheral circuits are abnormal and cannot be processed. .

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a method for detecting a microprocessor processing abnormality according to an embodiment of the present invention. FIG. 2 is a diagram showing a method for detecting a microprocessor processing abnormality according to the prior art. FIG. 1 shows a microprocessor system to which the microprocessor processing abnormality detection method is applied. 31...Peripheral circuit 32...Microprocessor 33...Watchdog timer agent Patent attorney Yoshiaki Iwasa

Claims (1)

[Claims] (1) Detection of microprocessor processing abnormalities in a microprocessor system that has arbitrary peripheral circuits that perform arbitrary processing and a watchdog timer that outputs an alarm to the outside if the microprocessor is not accessed for a predetermined period of time. A microprocessor processing abnormality detection method, characterized in that a watchdog timer access process is performed after determining that a peripheral circuit is in a processable state.