JP2017214912A - Vehicular electronic control device and timer diagnostic method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular electronic control device including a microcomputer having a plurality of timers, which device is enabled to diagnose the presence of abnormality on each of the timers while an input terminal capable of being assigned for control is suppressed to decrease at a timer diagnostic time.SOLUTION: A microcomputer of an electronic control device for a vehicle causes a first timer to measure the period of a reference pulse signal SP inputted from the outside, and acquires the measurement times of second and third timers by a fixed period treatment, when the measured period is within a predetermined range. An interruption period of a fixed period treatment and a time period determined from the measurement times of second and third timers are compared to diagnose the presence of the abnormalities of the second and third timers.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a vehicle electronic control device and a timer diagnosis method, and more particularly, to a technique for detecting the presence or absence of an abnormality in a timer in a vehicle electronic control device including a plurality of timers.

  In Patent Document 1, a pulse signal generation source for generating a pulse signal having a predetermined period is provided in a monitoring circuit outside the microcomputer, and the period of the pulse signal is measured on the microcomputer side, and the measured period is out of the predetermined range. A failure detection device for an electronic control system for a vehicle that diagnoses an abnormality in a timer function when the timer is activated is disclosed.

JP 2002-089336 A

By the way, in a vehicle electronic control device including a microcomputer having a plurality of timers having a function of measuring the period of a pulse signal input from the outside, the period of a reference pulse signal input from the outside is measured by each of the plurality of timers. It is possible to detect whether each timer is normal or not by detecting whether or not the cycle measurement value matches the set cycle of the reference pulse signal.
However, in order to allow each timer to measure the period of the reference pulse signal, it is necessary to assign a plurality of input terminals of the microcomputer to input the reference pulse signal. The number of input terminals that can be reduced is reduced, and the control function of the vehicle may be impaired.

  The present invention has been made in view of the above problems, and in a vehicle electronic control device including a microcomputer having a plurality of timers, the number of input terminals (hardware resources) that can be allocated for control is reduced during timer diagnosis. An object of the present invention is to provide a vehicle electronic control device and a timer diagnosis method capable of diagnosing the presence or absence of an abnormality for each of a plurality of timers while suppressing the above.

  Therefore, an electronic control device for a vehicle according to the present invention is an electronic control device for a vehicle including a microcomputer having a plurality of timers, and the microcomputer determines a cycle of a reference pulse signal input from the outside. Diagnosis of measuring the presence of an abnormality in the other timer by monitoring the time measured by the other timer in the periodic processing when the period measurement value is within a predetermined range. Means.

  Further, the timer diagnosis method for a vehicle electronic control device according to the present invention is a microcomputer including a plurality of timers constituting the vehicle electronic control device, wherein a cycle of a reference pulse signal input from the outside is determined by the plurality of timers. A step of measuring using a part of them, a step of detecting whether or not a period measurement value of the reference pulse signal is within a predetermined range, and a period measurement value of the reference pulse signal being within a predetermined range In addition, there are a step of monitoring the measurement time by another timer in the periodic processing, and a step of detecting the presence or absence of abnormality of the other timer based on the measurement time.

  According to the above invention, the timer for measuring the period of the reference pulse signal input from the outside to the microcomputer is a part of the plurality of timers, and the remaining timers are not abnormal without measuring the period of the reference pulse signal. Therefore, it is possible to suppress a decrease in the number of input terminals that can be assigned for control accompanying timer diagnosis.

1 is a configuration block diagram of a vehicle electronic control device according to an embodiment of the present invention. It is a block diagram of the hardware timer in the embodiment of the present invention. It is a flowchart which shows the outline | summary of the timer diagnosis process in embodiment of this invention. It is a flowchart which shows the diagnostic process of the 1st timer in embodiment of this invention. It is a flowchart which shows the diagnostic process of the 2nd timer in embodiment of this invention. It is a figure which shows the correlation with the time period TI and the timer interruption period in embodiment of this invention. It is a figure which shows the correlation with the time period TI at the time of timer abnormality generation in the embodiment of this invention, and a timer interruption period. It is a flowchart which shows the diagnostic process of the 2nd timer in embodiment of this invention.

Embodiments of the present invention will be described below.
FIG. 1 is a block diagram showing an aspect of a vehicle electronic control device according to the present invention.
The vehicle electronic control device 100 in FIG. 1 is a device that inputs signals from various sensors and outputs an operation amount to a control target such as an engine mounted on the vehicle.

The vehicle electronic control device 100 includes a microcomputer (main microcomputer) 200 and a monitoring circuit 300.
The microcomputer 200 includes a CPU, a RAM, a ROM, an interface, and the like, and further includes a plurality of hardware timers used for measuring the period of a pulse signal input to the input terminals 213A-213C from external devices such as various sensors. 210A-210C is built in.

  The timer 210A-210C has a circuit configuration as shown in FIG. 2 as one aspect thereof, and adjusts the count cycle of the timer counter 211 and the timer counter 211 that count the number of inputs of the internal or external reference clock. A frequency divider 212 that divides the clock signal, an edge detection circuit 214 that detects an edge (rising edge and / or falling edge) of an external pulse signal input to the input terminals 213A to 213C of the microcomputer 200, A capture register 215 that captures the value of the timer counter 211 in response to an edge input is included.

A monitoring circuit (watchdog timer) 300 that is an external circuit of the microcomputer 200 is configured by a microcomputer (sub-microcomputer) or an IC having a monitoring function of the microcomputer 200.
The monitoring circuit 300 receives the program run signal P-RUN generated and output by the microcomputer 200 through software processing, checks whether the program run signal P-RUN is normal, and executes the program run signal P-RUN. A function of outputting a reset signal to the microcomputer 200 when an abnormality occurs.

The monitoring circuit 300 includes a pulse signal generation source 310 that generates a reference pulse signal SP having a predetermined period, and outputs the reference pulse signal SP generated by the pulse signal generation source 310 to the microcomputer 200.
The reference pulse signal SP is used for diagnosis of a timer function in the microcomputer 200, and the microcomputer 200 has a function (diagnostic means 220) for detecting whether or not the timer 210A-210C is abnormal as software.

Hereinafter, the timer function diagnosis process by the microcomputer 200 (diagnostic means 220) will be described in detail.
The flowchart of FIG. 3 is a diagram schematically showing the procedure of timer function diagnosis processing by the microcomputer 200 (diagnostic means 220).

In step S500, the microcomputer 200 performs a function diagnosis of the first timer 210A (main timer), that is, a process of determining whether the first timer 210A is normal or abnormal.
In the function diagnosis of the first timer 210A, the microcomputer 200 causes the edge detection circuit of the first timer 210A to input the reference pulse signal SP via the input terminal 213A and captures information on the edge detection time of the reference pulse signal SP. Store in a register.

  Then, the microcomputer 200 takes in the information of the edge detection time of the reference pulse signal SP stored in the capture register of the first timer 210A by fixed cycle processing (timer interrupt processing) started by an interval timer (not shown). Thus, the period of the reference pulse signal SP is calculated, and the period measurement value by the first timer 210A is compared with a predetermined range (normal range).

Next, the microcomputer 200 proceeds to step S600, and determines whether or not the period measurement value of the reference pulse signal SP by the first timer 210A is within a predetermined range and the normal state of the first timer 210A is detected.
When the microcomputer 200 detects that the first timer 210A is in the normal state, the microcomputer 200 proceeds to step S700, monitors the time measured by the second timer 210B and the third timer 210C in the periodic processing, and then performs the second timer. The presence or absence of abnormality of 210B and the 3rd timer 210C is detected.

  That is, in the function diagnosis of the first timer 210A, the microcomputer 200 causes the first timer 210A to measure the period of the reference pulse signal SP, but the other timers 210B and 210C measure the period of the reference pulse signal SP. (The reference pulse signal SP is not input) and the execution cycle of the fixed cycle processing is guaranteed, and the correlation between the execution cycle of the fixed cycle processing and the measurement times by the other timers 210B and 210C Based on this, the presence or absence of abnormality in the second timer 210B and the third timer 210C is detected.

That the period measurement value of the reference pulse signal SP by the first timer 210A indicates a normal value means that each component circuit (the timer counter 211, the frequency divider 212, etc.) of the first timer 210A is normal and the reference clock is In addition, the execution cycle of the fixed cycle processing is guaranteed by monitoring the program run signal P-RUN by the monitoring circuit 300, and the execution cycle of the fixed cycle processing matches the set cycle. Can be considered as being.
Therefore, when the time measured by the second timer 210B and the third timer 210C for each execution cycle of the fixed cycle processing does not change corresponding to the execution cycle of the fixed cycle processing, the reference clock is normal, but the second timer An abnormality has occurred in any of the circuits constituting 210B and the third timer 210C.

On the other hand, when the period measurement value of the reference pulse signal SP using the first timer 210A is outside the predetermined range and the abnormal state of the first timer 210A is detected, the microcomputer 200 proceeds to step S800, and the first timer 210A Execute the process at the time of abnormality when an abnormality is detected.
As the abnormal time process, the microcomputer 200 stores and holds the abnormal state of the first timer 210A by setting a flag indicating the abnormal state of the first timer 210A, while the functions of the second timer 210B and the third timer 210C. Diagnosis can be made.

Specifically, in the diagnosis of the second timer 210B and the third timer 210C, the microcomputer 200 inputs the reference pulse signal SP to the second timer 210B to perform the period measurement of the reference pulse signal SP. Diagnose the timer 210B and monitor the measurement time of the third timer 210C by the periodic processing when the period measurement value by the second timer 210B is within a predetermined range (when the second timer 210B and the clock are normal). Then, the presence or absence of abnormality of the third timer 210C is detected.
The diagnostic process for monitoring the measurement times of the second timer 210B and the third timer 210C and detecting the presence / absence of abnormality in the periodic process will be described in detail later.

On the other hand, if the microcomputer 200 detects an abnormality based on the period measurement value for the second timer 210B following the first timer 210A, the microcomputer 200 may be in an abnormal state of the clock, and therefore the control operation (control output) is stopped. Fail-safe operation such as can be performed.
In addition, as an abnormal process when the period measurement value by the first timer 210A is abnormal, the microcomputer 200 performs the control operation (control output) without performing diagnosis of the second timer 210B and the third timer 210C. Fail-safe operations such as stopping, outputting a fail-safe signal to the controlled object, and turning off the power relay to be controlled can be performed.

  Further, when the microcomputer 200 detects an abnormality in the second timer 210B and / or the third timer 210C when the first timer 210A and the clock are normal, the microcomputer 200 uses the timers 210B and 210C that have detected the abnormality. Can be prohibited and control using a normal timer can be continued.

Here, the diagnosis process of the first timer 210A by the microcomputer 200 in step S500 will be described in detail.
When the microcomputer 200 performs the function diagnosis of the first timer 210A, the microcomputer 200A inputs the reference pulse signal SP to the first timer 210A. Thus, the first timer 210A stores the value of the timer counter 211 (edge detection time) in the capture register 215 when the edge of the reference pulse signal SP is input, and then clears the timer counter 211.

On the other hand, the microcomputer 200 executes diagnosis of the first timer 210A by the periodic processing (timer interrupt processing) shown in the flowchart of FIG. Note that the periodic processing shown in the flowchart of FIG. 4 is started at regular time intervals by an interval timer (not shown).
In step S531, the microcomputer 200 acquires the value (edge detection time) of the timer counter 211 stored in the capture register 215 of the first timer 210A.

  Here, since the timer counter 211 is cleared when the edge of the reference pulse signal SP is input, the value of the timer counter 211 immediately before the clear represents the time from the previous edge input to the current edge input. Become. In other words, the value of the timer counter 211 stored in the capture register 215 of the first timer 210A corresponds to the period measurement value TSP of the reference pulse signal SP.

Next, the microcomputer 200 proceeds to step S532, and determines whether or not the period measurement value TSP measured using the first timer 210A is within a predetermined range.
The predetermined range is a range including a known cycle of the reference pulse signal SP, and a lower limit value TMIN (minimum cycle measurement value) and an upper limit value that define an allowable range of measurement variation due to a frequency division setting or the like. This is a range between TMAX (maximum cycle measurement value).

That is, the predetermined range is a range including the period measurement value TSP of the reference pulse signal SP when the first timer 210A and the reference clock are in a normal state, and the first timer 210A and / or the reference clock is abnormal. This is a range in which the period measurement value TSP of the reference pulse signal SP deviates when an error of a predetermined value or more occurs in the period measurement value TSP.
In step S532, the microcomputer 200 determines whether TMIN ≦ TSP ≦ TMAX is satisfied.

  When TMIN ≦ TSP ≦ TMAX is established, the first timer 210A has correctly measured the cycle of the reference pulse signal SP, so the microcomputer 200 proceeds to step S533 and the abnormal state of the first timer 210A is reached. The abnormality detection counter CT for counting the number of detections is reset to zero, and in the next step S534, the normal state of the first timer 210A is determined.

On the other hand, if TMIN> TSP or TSP> TMAX is established, the first timer 210A has not been able to correctly measure the cycle of the reference pulse signal SP, so the microcomputer 200 proceeds to step S535 and proceeds to step S535. The value of CT is incremented, and in the next step S536, it is determined whether or not the value of the abnormality detection counter CT is equal to or greater than a threshold value.
When the value of the abnormality detection counter CT is less than the threshold value, the microcomputer 200 proceeds to step S534 and maintains the normal determination of the first timer 210A.

On the other hand, when the value of the abnormality detection counter CT is equal to or greater than the threshold, the microcomputer 200 considers that the abnormality of the period measurement value TSP has occurred due to the abnormality of the first timer 210A and / or the reference clock, Proceeding to step S537, the abnormal state of first timer 210A is determined.
Here, if the threshold value ≧ 2, the microcomputer 200 determines the abnormality of the first timer 210A when detecting the abnormality of the periodic measurement value TSP continuously for a plurality of times, and temporarily causes noise or the like. It is possible to suppress erroneous detection of an abnormal abnormality of the periodic measurement value TSP as an abnormality of the first timer 210A.

However, with the threshold value = 1, the microcomputer 200 can immediately determine the abnormality of the first timer 210A when detecting the abnormality of the period measurement value TSP.
The start of the periodic processing shown in the flowchart of FIG. 4 is guaranteed by monitoring the program run signal P-RUN by the monitoring circuit 300.

  When the timer counter 211 of the first timer 210A is a free-run counter, the microcomputer 200 stores the capture register 215 of the first timer 210A in interrupt processing (external interrupt processing) based on edge detection of the reference pulse signal SP. The stored value of the timer counter 211 is acquired, and the period of the reference pulse signal SP is calculated as a difference between the value of the timer counter 211 acquired in the previous interrupt process and the value of the timer counter 211 acquired in the current interrupt process. A measurement value can be obtained, and the period measurement value can be compared with a predetermined range to diagnose the presence or absence of abnormality in the first timer 210A.

Next, the abnormality diagnosis procedure of the second timer 210B in step S700 of the flowchart of FIG. 4 will be described according to the flowchart of FIG.
The routine shown in the flowchart of FIG. 5 is a periodic processing (timer interrupt processing) that is started at regular time intervals by an interval timer.

In step S711, the microcomputer 200 sets the value CL2N (measurement time by the second timer 210B) of the timer counter 211 of the second timer 210B read at the previous execution of this routine to the previous value CL2O, and next step S712. Then, the value (time measured by the second timer 210B) of the timer counter 211 of the second timer 210B at the time of the current interrupt activation is read and set to the current value CL2N.
The microcomputer 200 can read the value of the timer counter 211 in the interrupt processing program by software processing, and stores the value of the timer counter 211 in a register based on, for example, an interrupt request pulse for periodic processing. be able to.

In the next step S713, the microcomputer 200 obtains the difference between the current value CL2N and the previous value CL2O and sets it to the time period TI2.
Here, the routine shown in the flowchart of FIG. 5 is fixed cycle processing, and the reference clock is normal and the execution cycle of the fixed cycle processing is guaranteed by monitoring the program run signal P-RUN by the monitoring circuit 300. The accuracy of the startup cycle of the routine shown in the flowchart of FIG. That is, the routine shown in the flowchart of FIG. 5 can be regarded as being accurately interrupted at set time intervals.

Therefore, if the second timer 210B is normal, the time period TI2 measured using the second timer 210B becomes a value corresponding to the set value of the interrupt period of this routine (see FIG. 6), and the second timer 210B When the time period TI2 measured using is deviated more than an allowable error from the value corresponding to the interrupt period setting value of this routine, some abnormality occurs in the second timer 210B, and a timing error occurs. Will be.
Therefore, in the next step S714, the microcomputer 200 determines whether or not the time period TI2 measured using the second timer 210B is within a predetermined range (second predetermined range).

The predetermined range in step S714 includes a value corresponding to the set value of the interrupt cycle of this routine, and includes a lower limit value TI2MIN (minimum time cycle) and an upper limit value TI2MAX that define an allowable range of measurement variation due to frequency division settings and the like. (Maximum time period).
In step S714, the microcomputer 200 determines whether TI2MIN ≦ TI2 ≦ TI2MAX is satisfied. In other words, in step S714, the microcomputer 200 determines whether or not the difference between the time period TI2 and the set value of the interrupt period of this routine is equal to or less than an allowable value.

  Here, if TI2MIN ≦ TI2 ≦ TI2MAX is satisfied, the second timer 210B has correctly measured the interrupt cycle (start cycle) of the routine shown in the flowchart of FIG. 5, and therefore the microcomputer 200 proceeds to step S715. Then, the abnormality detection counter CT2 for counting the number of times of detection of the abnormal state of the second timer 210B is reset to zero, and in the next step S716, the normal state of the second timer 210B is determined.

  On the other hand, if TI2MIN> TI2 or TI2> TI2MAX is satisfied, the second timer 210B has erroneously measured the interrupt cycle (start cycle) of the routine shown in the flowchart of FIG. Proceeding to S717, the value of the abnormality detection counter CT2 is incremented, and in the next step S718, it is determined whether or not the value of the abnormality detection counter CT2 is greater than or equal to a threshold value (threshold value ≧ 1).

When the value of the abnormality detection counter CT2 is less than the threshold value, the microcomputer 200 proceeds to step S716 and maintains the normal determination of the second timer 210B.
On the other hand, when the value of the abnormality detection counter CT2 becomes equal to or greater than the threshold value, the microcomputer 200 proceeds to step S719 and determines the abnormal state of the second timer 210B.

The abnormality of the second timer 210B includes an abnormality of the clock cycle after frequency division by the frequency divider 212, stop of the counter operation of the timer counter 211, and the like.
As shown in FIG. 7, the time period TI2 becomes longer than the interrupt period when the divided clock period becomes shorter than the set period, and the time period TI2 becomes longer when the divided clock period becomes longer than the set period. If the counter operation is stopped and the counter operation is stopped, the time period TI2 ≠ 0, and in any case, the microcomputer 200 determines the abnormality of the second timer 210B.

Next, the procedure for abnormality diagnosis of the third timer 210C in step S700 of the flowchart of FIG. 3 will be described with reference to the flowchart of FIG.
The routine shown in the flowchart of FIG. 8 is a fixed-cycle process (timer interrupt process) that is activated at regular time intervals by an interval timer, and is similar to the procedure for abnormality diagnosis of the second timer 210B shown in the flowchart of FIG. Then, abnormality diagnosis of the third timer 210C is performed.

In step S751, the microcomputer 200 sets the value CL3N (measurement time by the third timer 210C) of the timer counter 211 of the third timer 210C read at the previous execution of this routine to the previous value CL3O, and the next step S752 Then, the value (time measured by the third timer 210C) of the timer counter 211 of the third timer 210C at the time of the current interrupt activation is read and set to the current value CL3N.
In the next step S753, the microcomputer 200 sets the difference between the current value CL3N and the previous value CL3O in the time period TI3.

  Here, the routine shown in the flowchart of FIG. 8 is fixed cycle processing, and since the clock is normal and the execution cycle of the fixed cycle processing is guaranteed by monitoring the program run signal P-RUN by the monitoring circuit 300, FIG. The accuracy of the startup cycle of the routine shown in the flowchart is guaranteed. That is, the routine shown in the flowchart of FIG. 8 can be regarded as being accurately interrupted at set time intervals.

  Therefore, if the third timer 210C is normal, the time period TI3 measured using the third timer 210C becomes a value corresponding to the set value of the interrupt period of this routine, and is measured using the third timer 210C. If the time period TI3 deviates more than the allowable error from the value corresponding to the interrupt period setting value of this routine, it means that some abnormality has occurred in the third timer 210C and a time measurement error has occurred. Become.

Therefore, in the next step S754, the microcomputer 200 determines whether or not the time period TI3 measured using the third timer 210C is within a predetermined range.
The predetermined range in step S754 includes a value corresponding to the set value of the interrupt cycle of this routine, and includes a lower limit value TI3MIN (minimum time cycle) and an upper limit value TI3MAX that define an allowable range of measurement variation due to frequency division settings and the like. (Maximum time period).

In step S754, the microcomputer 200 determines whether TI3MIN ≦ TI3 ≦ TI3MAX is satisfied. In other words, in step S754, the microcomputer 200 determines whether or not the difference between the time period TI3 and the interrupt period setting value of this routine is equal to or less than an allowable value.
Here, when TI3MIN ≦ TI3 ≦ TI3MAX is satisfied, the third timer 210C has correctly measured the interrupt cycle (start cycle) of the routine shown in the flowchart of FIG. 8, and therefore the microcomputer 200 proceeds to step S755. Then, the abnormality detection counter CT3 for counting the number of times of detection of the abnormal state of the third timer 210C is reset to zero, and in the next step S756, the normal state of the third timer 210C is determined.

  On the other hand, if TI3MIN> TI3 or TI3> TI3MAX is established, the third timer 210C erroneously measures the interrupt cycle (start cycle) of the routine shown in the flowchart of FIG. Proceeding to S757, the value of the abnormality detection counter CT3 is incremented, and in the next step S758, it is determined whether or not the value of the abnormality detection counter CT3 is greater than or equal to a threshold value (threshold ≧ 1).

When the value of the abnormality detection counter CT3 is less than the threshold value, the microcomputer 200 proceeds to step S756 and maintains the normal determination of the third timer 210C.
On the other hand, when the value of the abnormality detection counter CT3 becomes equal to or greater than the threshold value, the microcomputer 200 proceeds to step S759 and determines the abnormal state of the third timer 210C.

  In the diagnosis of the first timer 210A to the third timer 210C described above, the reference pulse signal SP is input and the period measurement is limited to the first timer 210A, and the other second timer 210B and the third timer 210C are measured. The period measurement of the reference pulse signal SP is not performed, and the period measurement of the pulse signal from the sensor can be performed by the second timer 210B and the third timer 210C even during diagnosis.

For this reason, it can suppress that the input terminal which can be allocated for control during diagnosis of timer 210A-210C can be suppressed, and the controllability fall during diagnosis can be suppressed.
In addition, since the diagnostic processing of each timer 210A-210C is performed by fixed cycle processing (timer interrupt), it is possible to suppress an increase in processing load on the microcomputer 200 due to external interrupt processing accompanying the diagnostic processing.

Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. is there.
For example, in the above embodiment, there are three timers to be diagnosed, but it is clear that the number of timers is not limited to three.

In addition, when the number of timers to be diagnosed is n (n ≧ 3) or more, the number of timers to be diagnosed by performing the period measurement of the reference pulse signal SP can be set to 2 or more and less than n.
Further, when the number of timers to be diagnosed by performing the period measurement of the reference pulse signal SP is two or more, the number of timers that have detected an abnormality based on the period measurement of the reference pulse signal SP becomes plural. When there is a timer that detects an abnormality based on the period measurement of the reference pulse signal SP and a timer that detects a normality, it monitors the measurement time in the periodic process and cancels the abnormality diagnosis of other timers. It can be set as the structure which monitors the measurement time and performs abnormality diagnosis of the other timer.

Here, the technical idea that can be understood from the above-described embodiment will be described below.
The vehicle electronic control device, as one aspect thereof, is a vehicle electronic control device including a microcomputer having a plurality of timers, and the microcomputer determines the period of the reference pulse signal input from the outside of the plurality of timers. Diagnostic means for measuring by using a part of them and monitoring the time measured by the other timer in the periodic processing to detect the presence / absence of the other timer when the periodic measurement value is within a predetermined range Is provided.

In a preferred aspect of the vehicle electronic control device, the diagnostic means obtains a measurement time by the other timer in the periodic processing, obtains a time interval of the periodic processing from the acquired measurement time, and the time interval is the first time interval. The normal state of the other timer is detected when it is within a predetermined range of 2, and the abnormal state of the other timer is detected when the time interval is outside the second predetermined range.
In another preferred aspect, the plurality of timers are hardware timers including an edge detection circuit that detects an edge of a pulse signal input to the input terminal of the microcomputer from the outside.

  In addition, a timer diagnosis method for a vehicle electronic control device includes: a microcomputer including a plurality of timers constituting the vehicle electronic control device, wherein a period of a reference pulse signal input from the outside is a part of the plurality of timers. A step of measuring using a step, a step of detecting whether or not a period measurement value of the reference pulse signal is within a predetermined range, and a period when the period measurement value of the reference pulse signal is within a predetermined range. Monitoring the time measured by another timer in the process, and detecting whether or not the other timer is abnormal based on the time measured.

In a preferred aspect of the timer diagnosis method, the step of monitoring the measurement time includes a step of acquiring a measurement time by the other timer in a fixed cycle process, and a step of obtaining a time interval of the fixed cycle process for the acquired measurement time And including.
In another preferred aspect, the step of detecting the presence or absence of an abnormality of the other timer includes the step of comparing the time interval with a second predetermined range, and when the time interval is within the second predetermined range. Detecting a normal state of the other timer, and detecting an abnormal state of the other timer when the time interval is outside the second predetermined range.

  DESCRIPTION OF SYMBOLS 100 ... Electronic control apparatus for vehicles, 200 ... Microcomputer, 210A ... 1st timer, 210B ... 2nd timer, 210C ... 3rd timer, 211 ... Timer counter, 212 ... Frequency divider, 220 ... Diagnosis means, 300 ... Monitoring Circuit 310 ... Pulse signal generation source

Claims (6)

An electronic control device for a vehicle including a microcomputer having a plurality of timers,
The microcomputer measures the period of the reference pulse signal input from the outside using a part of the plurality of timers, and when the period measurement value is within a predetermined range, the other timer is used in the periodic process. An electronic control device for a vehicle, comprising diagnostic means for monitoring the measurement time by detecting whether or not the other timer is abnormal.   The diagnostic means acquires a measurement time by the other timer in the periodic processing, obtains a time interval of the periodic processing from the acquired measurement time, and when the time interval is within a second predetermined range, The vehicle electronic control device according to claim 1, wherein a normal state of the timer is detected, and an abnormal state of the other timer is detected when the time interval is outside the second predetermined range.   3. The vehicle electronic control device according to claim 1, wherein the plurality of timers are hardware timers including an edge detection circuit that detects an edge of a pulse signal input from the outside to an input terminal of the microcomputer. In a microcomputer provided with a plurality of timers constituting an electronic control device for a vehicle,
Measuring a period of a reference pulse signal input from the outside using a part of the plurality of timers;
Detecting whether the period measurement value of the reference pulse signal is within a predetermined range;
When the period measurement value of the reference pulse signal is within a predetermined range, monitoring the measurement time by another timer in a periodic process;
Detecting the presence or absence of an abnormality of the other timer based on the measurement time;
Including a timer diagnostic method. The step of monitoring the measurement time includes:
Obtaining a measurement time by the other timer in a periodic process;
Obtaining a time interval of the periodic processing for the acquired measurement time;
The timer diagnosis method according to claim 4, comprising: Detecting the presence or absence of an abnormality of the other timer,
Comparing the time interval with a second predetermined range;
Detecting a normal state of the other timer when the time interval is within the second predetermined range;
Detecting an abnormal state of the other timer when the time interval is outside the second predetermined range;
The timer diagnosis method according to claim 5, comprising: