JP2000035923A - Abnormality detecting method and abnormality detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the wrong decision of abnormality detection for a nonvolatile memory such as an EEPROM by detecting and storing write interruption to a storing means due to the drop of power supply voltage and prohibiting the abnormality detection of the storing means at the time of detecting the storage of the writing interruption. SOLUTION: When an ignition switch IGS is switched from an on state to an off state, prescribed data stored in a RAM 3 are stored in a 1st data area A of an EEPROM 6 and data of the same content are stored in a 2nd data area B. Only when a writing operation in two areas of the prescribed areas A and B is completed, a write completion flag '1' is written in a prescribed area of a standby RAM 5. Then, the non-completion of the writing operation due to power cutout, etc., (the data of the two areas of the areas A and B are not the same contents can be identified with a flag and erroneous decision produced by writing interruption due to power cutout or short break can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method and an apparatus for detecting an abnormality in a storage means.

[0002]

2. Description of the Related Art A microcomputer control device (electronic control device) used in a vehicle-mounted automatic control device includes:
When the power is turned off and the device is stopped, data representing the situation of the vehicle at that time, input data from the sensor, control data, etc. are stored in an EEPROM, which is a non-volatile memory, and the status at the time when the device is stopped Save and prepare for data use. If the storage of the EEPROM is inaccurate, it is inconvenient when the operation of the device is restarted. For example, a plurality of backup data disclosed in JP-A-8-95868 is stored, and then the same data is stored. An abnormality detection method for an EEPROM element has been proposed, such as a method of comparing a plurality of expected backup data to determine an abnormality. Next, a basic method of the conventional failure diagnosis will be described. First, as shown in the operation at the time of writing the EEPROM data in FIG. 4, when the power supply (ignition switch IGSW) is turned off, the microcomputer stores predetermined information at the present time stored in the RAM in the EEPROM data area A.
Then, the same information is written to the EEPROM data area B. Next, when the operation of the device from which the data stored in the EEPROM is read is restarted, the EEPROM shown in FIG.
As shown in the process at the time of reading the ROM data, when the electronic control device is started and the EEPROM data is read, the electronic control device reads the information stored in the data area A and the information stored in the data area B. Is checked to see if they are the same, and if it is determined that they are not matched, a signal is output indicating that the EEPROM element is abnormal.
The M element outputs a signal when it is normal.

[0003]

A microcomputer control device (electronic control device) used in an on-vehicle automatic control device performs a normal operation of the electronic control device in order to ensure the running and operation reliability. Must be confirmed at a predetermined timing, and a failure diagnosis of an item specific to the characteristics of the control device is performed. The electronic control unit is also capable of self-checking for failures during operation, and the abnormalities and failure status identified by the failure diagnosis are automatically
Or, it is usually displayed according to the operation of the user. When an abnormality is found, many of the failed devices are replaced and repaired at a service factory or the like. The failure diagnosis for judging the abnormality of the EEPROM element mounted on the electronic control unit is one of these failure diagnoses.
If it is determined that the OM element is abnormal, the mounted electronic control unit is replaced and repaired.

[0004] Some of the electronic control units in which the EEPROM element has been determined to be abnormal in the conventional failure diagnosis include an EEPROM.
This included a case where the OM element was repaired and replaced due to an erroneous determination of an abnormality. This is an EE that was replaced and repaired at a service factory, etc.
This is a problem that a PROM element defective product has been found as a result of a precision test, and unnecessary repair costs have been incurred due to erroneous detection. However, such an error in the determination of the abnormality is shown in FIG.
During writing to the EEPROM data areas A and B described above, the power supply of the electronic control unit is momentarily interrupted (voltage drops momentarily), and subsequent writing cannot be continued. Has become apparent.

An object of the present invention is to avoid erroneous determination of abnormality detection for a nonvolatile memory such as an EEPROM.

[0006]

In order to achieve the above object, control data according to the state of the vehicle equipment is stored in storage means such as a standby RAM and an EEPROM when the vehicle equipment enters a predetermined state. Comparing the stored data with the copied and stored second stored data, and detecting an abnormality in the storage means based on a match or mismatch between the two stored data.
In the EPROM abnormality detecting device, write interruption detecting means for detecting interruption of writing to the storage means due to a drop in power supply voltage, and interruption storage means for storing the interruption of writing in the standby RAM when the writing interruption detection means detects interruption. An abnormality detection prohibition unit for prohibiting the abnormality detection of the storage unit when the interruption storage of the interruption storage unit is detected.

[0007]

Next, an electronic control unit according to an embodiment of the present invention will be described. FIG. 1 is a configuration diagram illustrating a configuration of an electronic control device according to an embodiment of the present invention. An electronic control unit 1 for controlling a vehicle or an on-vehicle device includes a CPU 2 for executing arithmetic control, a RAM (Ra) which is a volatile memory used during arithmetic operation and functions only while operating power is supplied.
ROM (R), which is a non-volatile memory storing constants, programs, and the like.
a standby RAM 5 in which standby memory is held by a microcomputer (microcomputer) including a backup memory (connected battery), and storage means to be subjected to abnormality detection.
An EEPROM (Electric), which is a rewritable non-volatile memory capable of holding data without a backup power supply
cally Erasable and Program
mmable ROM) 6. Signals from the temperature, pressure, and other various sensors 7 and signals for control set by the user from the operation panel 8 for operating the in-vehicle equipment are input, and the electronic control unit 1 responds to these input signals. Then, control signals are output to various actuators 8 such as motors and control valves to control the vehicle or the on-vehicle equipment.

The electronic control unit 1 is connected to a battery BT of a vehicle, which is a power supply, and detects ON / OFF of an ignition switch IGSW according to the input voltage H (high) and L (low) of the connection S. In addition, a signal from the operation panel 8 is determined, a control signal is output from the connection C, the power switch PSW is turned on / off, and the operation power supply from the connection P is turned on / off. Since the predetermined data among the data indicating the state of the device under control is necessary when the operation of the electronic control device 1 is restarted or the like, the EEPROM 6 which is a nonvolatile memory at a predetermined control timing or before the operation of the electronic control device 1 is stopped. The data is written to the standby RAM 5 and saved (the same data is written to the EEPROM 6 and the standby RAM 5, respectively). When the ignition switch IGSW is detected to be off, the CPU 2 saves predetermined data of the electronic control unit 1 to the EEPROM 6 and the standby RAM 5, and outputs a control signal from the connection C after delaying a sufficient time necessary for the saving. Then, the power switch PSW is turned off. Further, even when the backup power is always input from the connection B and the operation power from the connection P is turned off, the standby RA as the standby memory is stored.
M5, power supply to the CPU 2 is maintained. When the battery BT of the vehicle is removed for replacement or the like, and the potential of the contact T is lost, the standby RAM which is a standby memory is stored.
The memory of 5 is lost.

Next, an EEPROM for detecting an abnormality in the storage means.
The processing performed by the electronic control unit 1 for OM abnormality detection will be described. FIG. 2 is a flowchart showing a process at the time of writing data to the EEPROM 6 performed by the electronic control unit 1 according to one embodiment of the present invention. This processing is performed when the ignition switch IGSW of the vehicle is turned on and the electronic control unit 1 is turned on.
Is repeatedly performed together with the other control processing. Step a1
Then, it is determined whether or not the ignition switch IGSW is off. If the ignition switch IGSW is off (switched from the on state to the off state), the process proceeds to step a2. If not, the process ends. In step a2, the EEPROM 6
The predetermined data stored in the RAM 3 is stored in the first data area A, and the process proceeds to step a3. Step a
3, in the second data area B of the EEPROM 6, RA
From M3, data (mirror data) having the same contents as stored in the first data area A is stored, and the process proceeds to step a4.
In step a4, the EEPROM 6 write completion flag "1" is stored in a predetermined area of the standby RAM 5, and the process ends.

In this manner, data indicating the same contents is written to two areas A and B of the EEPROM 6. Further, the write completion flag “1” is written to the predetermined area of the standby RAM 5 only when the write operation to the two areas A and B is completed. Therefore, the write operation is not completed (area A , B do not have the same contents) with a flag.

FIG. 3 is a flow chart showing a process at the time of reading data from the EEPROM 6 performed by the electronic control unit 1 according to one embodiment of the present invention. This processing is performed by the electronic control unit 1
At the start of the operation (when the ignition switch is turned on). In step b1, the data in the EEPROM 6 is read, and the process proceeds to step b2. In step b2, EE
PROM6 write completion flag "1" is set to standby RA
It is determined whether the flag is at M5, and if there is a completion flag "1", the process proceeds to step b3. Not to be. In step b3,
The data in the first data area A of the EEPROM 6 and the second data
It is determined whether the mirror data in the data area B is consistent (identical) and valid, and if not, the process proceeds to step b4, and if not, the process proceeds to step b5.
At step b4, the EEPROM 6 element is abnormal (failure)
Is generated, and this processing ends. Step b
In step 5, a signal indicating that the EEPROM 6 element is normal is generated, and the process ends. In this example, the validity is determined by adding the data and the mirror data and setting the value to “FF”.
(All bits are set to "1").

In this way, only when the EEPROM 6 write completion flag "1" is present in the standby RAM 5, (data indicating the same contents should have been normally written to the two predetermined areas A and B of the EEPROM 6). Therefore, the failure of the EEPROM 6 is diagnosed, and if the same write data exists in the two areas A and B, the EEPROM
The M6 element is normal, and if different write data exists in two areas A and B, the EEPROM 6 element is notified as abnormal. If the EEPROM 6 element is normal, the operation of the electronic control unit 1 is continuously performed. If the EEPROM 6 element is abnormal, a failure is notified and a failure diagnosis is performed. If the EEPROM 6 write completion flag "1" is not present in the standby RAM 5, the abnormality detection of the EEPROM 6 is prohibited.
Erroneous detection of a six-element abnormality can be avoided. If the backup power supply is turned off, the standby RA
Since the EEPROM 6 write completion flag "1" in M5 is initialized, no erroneous detection occurs in this case as well. Therefore, unnecessary replacement and repair based on the erroneous detection of the EEPROM 6 element abnormality can be avoided. Also, by setting a completion flag using a volatile memory supplied with power such as the standby RAM 5, it is possible to reliably detect a write interruption due to power interruption or instantaneous interruption. Further, the determination of the validity of the data is not limited to the mirror check. For example, another check method such as an upper / lower limit value check or a sum value check may be adopted.

[0013]

As described above in detail, according to the present invention, it is possible to avoid erroneous determination caused by interruption of writing due to power interruption or instantaneous interruption when detecting an abnormality in the storage means.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration of a control unit according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a process at the time of writing to an EEPROM.

FIG. 3 is a flowchart showing a process at the time of reading an EEPROM.

FIG. 4 is a flowchart showing a conventional EEPROM writing process.

FIG. 5 is a flowchart showing a conventional EEPROM reading process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electronic control device 2 ... CPU 3 ... RAM 4 ... ROM 5 ... Standby RAM 6 ... EEPROM BT ... Battery IGSW / ignition switch PSW / power switch

Claims (4)

[Claims] 1. Control data according to a state of a vehicle device,
When the vehicle device is in a predetermined state, it is written to the storage means and evacuated, and when the vehicle device returns from the predetermined state, the control data written in the storage means is read, and the validity of the control data is determined. An abnormality detection method for performing an abnormality detection process for detecting an abnormality in the storage unit based on the data stored in the storage unit when the writing of the control data is completed; If there is no data indicating completion of writing, a process for inhibiting the abnormality detection process is performed. 2. The abnormality detection processing is performed on a nonvolatile memory, and data indicating the completion of writing is stored in a volatile memory to which power is supplied regardless of a predetermined state of the vehicle device, 2. The abnormality detection method according to claim 1, wherein a process of prohibiting an abnormality detection process for the nonvolatile memory is performed based on the presence of data indicating write completion to be stored in the volatile memory. 3. A storage device for storing control data according to a state of a vehicle device, an evacuation device for writing the control data into the storage device and retreating when the vehicle device enters a predetermined state; When the device recovers from the predetermined state, the control data written in the storage device is read, and an abnormality detection device that detects an abnormality in the storage device based on the validity of the control data. When the writing of the control data by the evacuation unit is completed, a write completion setting unit that stores data indicating the completion of the writing of the control data in the storage unit, and when reading the control data written in the storage unit, If there is no data indicating the completion of the writing, a prohibition unit for prohibiting the abnormality detection processing in the abnormality detection unit is provided. An abnormality detection device characterized by the following. 4. The storage means comprises a nonvolatile memory and a volatile memory to which power is supplied irrespective of a predetermined state of the vehicle equipment. The write completion setting means stores the data indicating the write completion in the volatile memory, and the prohibition means is stored in the volatile memory. 4. The abnormality detection device according to claim 3, wherein an abnormality detection process for said nonvolatile memory is prohibited based on the presence of data indicating completion of writing to be performed.