JP2000257502A - Electronic controller for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an electronic controller possible to write data into a nonvolatile memory storing a control program during a period of time when the control program for engine control, etc., is not executed. SOLUTION: The power supply from a battery 3 into a main power supply circuit 33 in a microcomputer 31 is continued through a main relay 2, even if an ignition(IG) switch 4 is turned off. Since the control by use of an engine control program in a flash ROM 31c is not executed while the IG switch is off, the flash ROM 31c itself can be switched from an operation mode to a write mode. Since the power supply in a route via the main relay 2 is maintained even if the IG switch is off, a flash write program can be operated by a RAM 31b, and flash write data can be written into the flash ROM 31c. During a predetermined period of time when the power supply is carried out, EEPROM write data in the RAM 31b and flash write data in the RAM 31b are written into EEPROM 35 and flash ROM 31c, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic control unit for a vehicle, which controls a predetermined control target mounted on the vehicle, and in particular, it is necessary to maintain its contents even when an ignition switch such as a diagnostic code is in an OFF state. The present invention relates to a technique for writing certain data to a nonvolatile memory.

[0002]

2. Description of the Related Art Conventionally, there has been known an electronic control unit (ECU) for controlling a predetermined control target such as an engine mounted on an automobile. For example, ECU for engine
If so, an abnormality related to engine emission and an abnormality of various sensors such as a water temperature sensor are diagnosed, and the diagnosis result is stored as a diagnostic code. Since it is necessary to keep the stored contents of the diagnostic code indicating the vehicle state even when the battery is removed, for example, an EEPROM, which is one of nonvolatile memories, is referred to as a microcomputer (hereinafter simply referred to as “microcomputer”). ) Is often provided outside.

In this configuration, the microcomputer monitors the state of the vehicle at regular intervals and writes it in the EEPROM as a diagnostic code. However, for example, due to an increase in the specifications of automobiles, the type of diagnostic code to be stored increases and the data amount increases. It is also conceivable that the storage capacity of the EEPROM becomes insufficient due to the increase. In this case, for example, a large capacity EEPRO
It can be dealt with by replacing with M or by adding an EEPROM, but replacement / additional work is required, and the cost is increased.

For example, in the case of an electronic control unit for a vehicle in which a flash memory is provided in a microcomputer and a control program is stored therein, the entire storage area of the flash memory is used for the control program. Is rarely performed, and an empty area is often generated.
Therefore, it is considered that the diagnostic code may be written in the empty area.

[0005]

However, a control program is stored in the flash memory, and during execution of engine control or the like using the control program, the flash memory itself operates in an "operation mode". , The data cannot be written. In order to write data to the flash memory, it is necessary to switch from the operation mode to the "write mode". As a result, data cannot be written during execution of engine control or the like.

Therefore, during a period in which a control program such as an engine control is not executed, data can be written to a nonvolatile memory storing the control program, thereby solving the above-mentioned problem. It is intended to provide a control device.

[0007]

According to the first aspect of the present invention, there is provided an electronic control apparatus for a vehicle, wherein the storage contents are electrically controlled in units of memory cell blocks. A rewritable read-only nonvolatile memory (hereinafter, also referred to as a “rewritable ROM”), and controls a predetermined control target mounted on the vehicle according to a control program stored in the rewritable ROM. . The predetermined control target is an engine or the like. In addition, the electronic control unit for a vehicle according to the present invention includes a state where power required for executing control according to the control program is supplied from a power supply device (so-called IG on state) and a state where power is not supplied (so-called IG off state). It has an ignition switch for switching. Then, the control according to the control program is executed by the power supplied from the power supply device by the ignition switch. For example, when controlling the engine, the engine control is performed only when the IG is on, and the engine control is not performed when the IG is off.

Here, in the electronic control apparatus for a vehicle according to the present invention, even when the power supply required for normal operation is not supplied by the ignition switch, the supply state control means switches the state. For a predetermined period from the point in time, the state in which the power required for the normal operation of the vehicle electronic control device is supplied from the power supply device is continued, and then the state is switched to the state in which the power required for the normal operation is not supplied. Then, during a predetermined period in which the power supply is maintained by the supply state control unit, the data writing unit performs the following processing. That is, rewritable ROM data obtained during a period in which power required for normal operation is supplied by the ignition switch and whose contents need to be maintained even when power required for normal operation is not supplied by the ignition switch. In this case, the control program is written in a predetermined block that is not stored.

[0009] As a problem of the prior art described above, during execution of engine control or the like using a control program stored in a rewritable ROM (flash memory in the above-described example), the rewritable ROM operates in an "operation mode". , The data cannot be written. However, in the electronic control apparatus for a vehicle according to the first aspect, the power supply is controlled by the supply state control means during a predetermined period after the power required for normal operation is not supplied by the ignition switch (IG off state). Is maintained. In the IG off state, control using the control program (engine control or the like) is not executed, so that the rewritable ROM can be switched from the operation mode to the “write mode”. Since the power supply is maintained by the supply state control means, the data writing means can write data in the rewritable ROM.

As described above, according to the electronic control apparatus for a vehicle according to the present invention, the control program is stored even during a period in which control based on the control program such as engine control is not executed. Data can be written to the rewritable ROM, and the above-described problem can be solved. That is, for example, on the assumption that the diagnostic code is written in the EEPROM, even if the type of diagnostic code to be stored increases due to an increase in the specification of the vehicle, the data amount increases, and the storage capacity of the EEPROM becomes insufficient. Rewritable ROM storing control program
Free space can be used. Therefore, for example, it is not necessary to replace with a large-capacity EEPROM or to add an EEPROM, so that replacement / additional work is not required, and cost does not increase.

Although the description of the effects here is based on the premise that the configuration in the prior art described above as a specific example, that is, the configuration in which an EEPROM is externally attached to the microcomputer, the EEPROM is indispensable in the present invention. That is not to say. For example, only the rewritable ROM in the microcomputer can be used as long as the diagnostic code to be stored has a data amount that can be entirely written by using an empty area of the rewritable ROM storing the control program. The effect in this respect is obtained.

By the way, after the so-called IG-off state, data is written by a data writing means into an empty area of a rewritable ROM (more precisely, a predetermined block in which a control program is not stored). Regarding "data whose contents need to be maintained", R is set during the period when the power required for normal operation is supplied by the ignition switch (while the IG is on).
It is preferable that the information be updated and stored in the AM. This is because the updated latest data can be finally written to the rewritable ROM.

The RAM may be a standby RAM constantly supplied with power by a power supply device. For example, in consideration of engine control and the like, when the control learning value is stored in the RAM, it is preferable to use the control learning value in the next control, so that the standby RAM is often used. Therefore, the standby RAM may be used (shared).

The data writing to the rewritable ROM is executed based on a predetermined writing program. Regarding where the write program is stored, for example, it is conceivable that the write program is stored in a rewritable ROM. In this case, a memory for program operation (usually a RAM) different from the non-volatile memory is provided for the operation of the write program, and the data writing means can rewrite data.
When writing to OM, the write program can be rewritten.
What is necessary is just to move from M to the memory for program operation and execute it.

Of course, it may be stored in a memory (ROM or the like) other than the rewritable ROM, but if it is stored in the rewritable ROM itself in which the control program is stored, another memory is unnecessary. Some advantages are obtained. As a rewritable ROM in which the control program is stored, a flash memory may be used. Of course, it may be an EEPROM.

When the flash memory is used as the rewritable ROM as described above, the data writing means stores the data content to be written as:
It is preferable to compare the corresponding data stored in the flash memory as the nonvolatile memory and update the data only when the content is different.

Similarly, when a flash memory is used as the rewritable ROM, the configuration described in claim 7 may be adopted. That is, separately from this flash memory, a power supply required for normal operation by an ignition switch is provided. And an EEPROM as a non-volatile memory for storing data whose contents need to be maintained even when the data is not supplied, and when the data writing means writes the data whose contents need to be maintained, According to the type, the data is distributed and written in the flash memory and the EEPROM.

In this case, for example, all data are EE
If the data can be written to the PROM, the data is written only to the EEPROM, and the number of codes to be stored increases and the data amount increases due to the increase in the specification of the vehicle, and the EEPROM is increased.
If the storage capacity of the OM becomes insufficient, it is conceivable to write data to the flash memory. Which data is stored in flash memory, EEPROM
Which of M is to be written may be set in advance for each data type.

In the case where data is written in a distributed manner according to the type of data, the data whose contents need to be maintained and whose data contents are unlikely to change frequently are low. , Write to flash memory and frequently change data content is EEPR
It is preferable to write in the OM. This is because, generally speaking, when the frequency of data rewriting is high, the EEPROM is more suitable than the flash memory in the number of times of data rewriting.

In the case where a flash memory is used as the rewritable ROM, the flash memory is stored in a microcomputer mainly constituted by a CPU, because the control program is stored therein. Is preferably deployed.

Of course, it is also possible to adopt a configuration in which the flash memory is externally attached to the microcomputer.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an engine ECU 30, a main relay 2, and peripheral devices as an embodiment of an electronic control unit for an automobile, which is mounted on an automobile (vehicle) and controls an internal combustion engine. is there.

The engine ECU 30 includes a main power supply circuit 3
3 is a battery 3 (corresponding to a power supply device) via both routes of the main relay 2 and the ignition switch 4
Is connected to The ON / OFF state of the main relay 40 is switched by a main relay control signal from the engine ECU 30. Therefore, when the ignition switch 4 is turned on or the main relay 2 is turned on, power from the battery 3 is supplied to the microcomputer 31 and the like via the main power supply circuit 33, so that the engine ECU 30 operates. . Further, with such a configuration, even if the ignition switch 4 is turned off, the engine ECU 30 can perform a normal operation as long as the main relay 2 is on. When the main relay 2 is turned off by the main relay control signal after the ignition switch 4 is turned off, the power supply from the main power supply circuit 33 is stopped, and the engine ECU 30 cannot operate normally.

Since the sub power supply circuit 34 is directly connected to the battery 3 without the intervention of the ignition switch 4, the microcomputer 31 is connected via the sub power supply circuit 34 even after the power supply via the main power supply circuit 33 is stopped. Is supplied with power. Therefore, the RAM 31 in the microcomputer 31
The data b is retained even after the ignition switch 4 is turned off. Therefore, this state is the above-mentioned state in which the engine ECU 30 cannot operate normally.

The battery 3 is configured to be charged by driving an engine (not shown).
Specifically, an alternator driven by an engine is provided, and the alternator generates electric power corresponding to the engine speed, and the generated electric power is supplied to the battery 3. The battery 3 is charged by the supplied power.

In the microcomputer 31, the CPU 31a
According to the control program stored in the shROM (flash memory) 31c, the input / output circuit 32 and the microcomputer 31
It outputs a signal for controlling the injector 47 and the igniter 48 so that the engine operates optimally based on the sensor signal input via the I / O 31d in the inside. In addition, a self-diagnosis of an abnormality related to the engine emission is performed to diagnose an operation of the engine, an abnormality of the sensors 41 to 46, and the like. And outputs the data of the diagnosis result in response to the request. The sensors 41 to 46 connected to the input / output circuit 32 are air-fuel ratio (A / F) sensors 4.
1. A rotation sensor 42 for detecting the number of revolutions of the engine, an air flow meter 43, a water temperature sensor 44, a throttle sensor 45, and a starter switch 46.

The RAM 31b in the microcomputer 31 has
The CPU 31a temporarily stores sensor data used for calculation processing, control data obtained by calculation, or various diagnostic data obtained by the above diagnosis. In addition, microcomputer 3
1 is connected to an EEPR0M35 externally.

Here, the FlashROM 31c and the EE
Each of the PROMs 35 is a read-only nonvolatile memory (rewritable ROM) capable of electrically erasing and writing stored contents while a predetermined rewrite voltage is supplied. The EEPROM 35 is capable of erasing and writing data in units of memory cells.
c is a configuration in which data can be erased and written in units of memory cell blocks.

The EEPROM 35 has the above-mentioned RAM 3
Data (for example, a feedback correction coefficient and a diagnostic code) that is to be stored even after the power supply or the battery is shut down among the data temporarily stored in 1b is written. And, in part of FlashROM31c,
Similar data is written.

Here, the FlashROM 31c and the RA
Further description will be given with reference to FIGS. 6 and 7 which are conceptual diagrams of the memory area of M31b. The FlashROM 31c is configured to be able to erase and write data for each block in memory cell blocks. In the present embodiment, the FlashROM 31c includes a plurality of blocks as shown in FIG. Here 6
It is assumed that each block is composed of two blocks, and block 1 of the blocks is a flash write program area,
5 is set as an engine control program area, and block 6 is set as a data area. The Flash writing program stored in the block 1 is a program for writing data in the data area of the block 6, and is specifically copied to the RAM 31b and operates on the RAM 31b.

The FlashROM 31c can take two modes, an "operation mode" and a "write mode". In the "operation mode", control using the engine control program stored in the blocks 2 to 5 is performed. Is performed. In this operation mode, writing to the data area cannot be performed, and data can be written only when the mode is switched to the “writing mode”. Switching from the “operation mode” to the “write mode” can be performed by inputting a Flash write signal (see FIG. 1) from the microcomputer 31 to the write mode terminal.

With such a memory configuration, when writing data, it is possible to erase or write data only in the data area without destroying (erasing) the data of the engine control program. . on the other hand,
The RAM area of the RAM 31b is divided into blocks according to the purpose of use, and in this embodiment, the RAM area is composed of a plurality of blocks as shown in FIG. Here, it is assumed that the data area is composed of six blocks, and block 1 of the data area is a data area for writing to the FlashROM 31c.
Block 2 is set as a data area for writing to the EEPROM 35, blocks 3 and 4 are set as storage areas for learning values, and blocks 5 and 6 are set as input data and output data areas.

Of these, the Flash data area (block 1) stores, for example, flight recorder data, vehicle-specific identification IDs, diagnostic codes, etc., whose data contents do not change frequently. In the EEPROM data area (block 2), for example, a feedback correction coefficient or a state storage data at the time of engine stall that the data content changes frequently is stored. On the other hand, the ignition switch 4 is provided in the input / output data area (blocks 5 and 6).
Is used as an area for storing data (for example, input data and output data of the sensors 41 to 46 and the like) whose contents may be destroyed in a state where is turned off, or a writing program (FIG. 6) in the above-described FlashROM 31c. ) Is used as an area for downloading.

The microcomputer 31 temporarily stores the various data fetched during execution of the engine control in the RAM 3.
1b, and periodically writes data to the EEPROM 35. After the ignition switch 4 is turned off, the data is written to the flash ROM 31c within a predetermined period in which power is supplied via the main relay 2.

Next, the processing executed by the microcomputer 31 of the engine ECU 30 will be described with reference to the flowcharts of FIGS. FIG. 2 is a flowchart showing a base routine executed immediately after the ignition switch 4 is turned on.
At 10, the main relay control signal is turned on.
And By doing so, the power is continuously supplied to the microcomputer 31 via the main relay 2 even after the ignition switch 4 is turned off. And
If the main relay control signal is turned off after the data writing to the FlashROM 31c described later is completed, the power supply can be stopped.

After turning on the control signal for the main relay in S10, the data written in the EEPROM 35 is copied to the RAM 31b in S20, and the data written in the Flash ROM 31c is copied to the RAM 31 in S30.
Copy to M31b. After such processing, the flow shifts to S40, where the engine control program (see FIG. 6) stored in blocks 2 to 5 in the FlashROM 31c is executed to perform various engine control processing.

The engine control process in S40 is as follows.
Based on various sensor signals and starter signals from the input / output circuit 32 and control data (for example, a feedback correction coefficient) stored in the EEPROM 35, an optimum fuel injection amount, ignition timing, and the like for the engine are calculated. , A signal for controlling the injector 47 and the igniter 48 is output.
Then, the engine can be operated by repeatedly executing the engine control process.

FIG. 3 is a flowchart showing a process related to abnormality detection executed at regular intervals. In the first step S110, it is checked whether the sensor values of the throttle sensor 45 and the water temperature sensor 44 (see FIG. 1) or the learning values are within a normal range. If the check result is abnormal (S12
0: YES), the code identifying the detected abnormal target is R
The data is stored in the corresponding area of the AM 31b (S130). The corresponding area is, as described with reference to FIG.
That is, data set to be written to the flash ROM 31c is stored in the block 1 area, and data set to be written to the EEPROM 35 is stored in the block 2 data area.

In step S110, a defective state of the injector 47 or a catalyst (not shown) may be determined. FIG. 4 shows EE executed at regular time intervals.
4 is a flowchart illustrating a process related to writing data to a PROM 35.

In the first step S210, the RAM 31
b in block b (see FIG. 7), ie, EEPROM
Data stored in a data area for storing data to be written to 35 (EEPROM write data)
Is compared with the data actually written in the EEPROM 35. Then, the EEPR in the RAM 31b
It is determined whether the OM writing data is the latest code, that is, whether the EEPROM writing data and the data in the EEPROM 35 are the same (S220).

If it is not the latest code (S220: N
O), the data is not written, but if it is the latest code (S220: YES), the EEPROM in the RAM 31b
Write the write data to the EEPROM 35 (S23
0). Thus, the latest code is always updated and stored in the EEPROM 35.

FIG. 5 is a flowchart showing a process related to writing data to the FlashROM 31c. This processing is executed when the ignition switch 4 is turned off. That is, since the main relay control signal is turned on in S10 of FIG. 2 described above, the power is continuously supplied to the microcomputer 31 via the main relay 2 even after the ignition switch 4 is turned off, whereby the processing is performed. Will be

In the first step S310, EEPRO
Write data to M35. This processing is actually the same as the processing described with reference to FIG.
The EPROM writing data is compared with the data written in the EEPROM 35, and if it is the latest code, the EEPROM writing data is written in the EEPROM 35.

At S320, the block 1 (see FIG. 7) in the RAM 31b, ie, the FlashROM 31
The data (Flash write data) stored in the data area for storing the data to be written to c is
The data is compared with the data actually written in the FlashROM 31c. And the Fla in the RAM 31b
It is determined whether or not the sh write data is the latest code, that is, whether the flash write data is the same as the data in the Flash ROM 31c (S33).
0).

If it is not the latest code (S330: N
O) If the code is the latest code (S330: YES), the process directly proceeds to S410 without writing data.
40, the write program stored in block 1 (see FIG. 6) in the FlashROM 31c is changed to R
It is downloaded to a predetermined area (blocks 5 and 6 shown in FIG. 7) of the AM 31b. Then, in S450, the program counter is set to the start address of the write program on the RAM 31b, and preparations are made to operate the RAM 31b.
Therefore, the following S360 to S400 are processes executed by the Flash writing program operating on the RAM 31b. Since the engine control program is stopped by turning off the ignition switch 4 which is a premise of this processing routine, such processing becomes possible.

In the first step S360 of the process executed by the flash writing program, the flash mode switching port is turned on. That is, switching from the “operation mode” to the “write mode” is performed by inputting the Flash write signal (see FIG. 1) to the write mode terminal.

Then, the data area of the block 6 (see FIG. 6) in the FlashROM 31c is erased (Erase).
After that (S370), the Flash area in the RAM 31b determined to be the latest code in S330 is stored in the data area.
h Write data is written (S380).

After the writing is completed, the contents of the written data and the contents of the flash writing data in the RAM 31b are verified (S390). This is a process for improving the reliability of the write data. Although not shown in detail in FIG. 5, if the verification results do not match, S3
80 is repeated, and if they match, the process proceeds to S400.

In S400, the flash mode switching port is turned off to return from the "write mode" to the "operation mode". After the processing (S360 to S400) executed by such a Flash writing program ends, in S410, the main relay control signal is turned off.
I do. As a result, power supply to the microcomputer 31 is stopped.

In this embodiment, the microcomputer 31 (particularly, the CPU 31a) and the main relay 2 correspond to the supply state control means. In the steps of the flowchart of FIG. The processing of S410 executed after the processing is performed corresponds to the processing as the supply state control unit. Further, the processing of S360 to S400 in FIG. 5 corresponds to the processing as data writing means.

According to the electronic control unit for a vehicle of the present embodiment as described above, the main power supply circuit 3 in the microcomputer 31 is supplied from the battery 3 through the ignition switch 4.
Even if the power supply to the power supply 3 is turned off, the main power supply circuit 33 in the microcomputer 31
Is supplied with power. Then, during a predetermined period during which the power is supplied, the EEPROM write data in the RAM 31b is written into the EEPROM 35 (S310),
Flash writing data Fla in the RAM 31b
Writing to the shROM 31c (S380).

As a problem of the prior art, FlashROM
During execution of the engine control and the like using the control program stored in the FlashRO 31c, the FlashRO
Since M31c is in the “operation mode”, data writing cannot be performed. However, in the case of this embodiment, data writing to the FlashROM 31c is performed with the IG turned off. That is, in the IG off state, the control using the engine control program in the FlashROM 31c is not executed.
The OM 31c itself can be switched from the operation mode to the write mode (S360). Since the power supply via the route via the main relay 2 is maintained even in the IG off state, the flash write data is stored in the flash ROM.
31c.

As described above, since data such as a diag code can be written in the FlashROM 31c, the problem in the prior art can be solved. In other words, on the premise that a diagnostic code or the like is written in the EEPROM 35, the number of types of diagnostic codes to be stored increases and the data amount increases due to an increase in the specification of the automobile, and the EEPROM becomes larger.
Even when the storage capacity of the ROM 35 is insufficient, the free area of the FlashROM 31c storing the control program can be used. Therefore, for example, it is not necessary to replace with a large-capacity EEPROM or to add an EEPROM, so that replacement / additional work is not required, and cost does not increase.

Although data writing to the FlashROM 31c is performed only after the IG is turned off, the data to be written is not changed even during execution of engine control.
It is updated and stored in the RAM 31b (see FIG. 3). Therefore, the updated latest data can be finally written to the FlashROM 31c.

Further, in the present embodiment, of the data whose contents need to be maintained even when the IG is off, F
For example, flight recorder data, a vehicle-specific identification ID, a diagnostic code, etc., whose data contents do not change frequently, are written in the flash ROM 31c.
In the PROM 38, for example, a feedback correction coefficient or a state storage data at the time of engine stall that the data content changes frequently is written. Generally speaking, if the frequency of data rewriting is high, the EEPROM
35 is the FlashROM3 in the number of data rewrites.
This is because it is more suitable than 1c.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and it goes without saying that various forms can be adopted. (1) In the above-described embodiment, the process of FIG. 5 is described without interruption in particular. However, for example, if a disconnection or the like occurs between the battery 3 and the main relay 2, the microcomputer 31 There is a possibility that the power supply to the power supply is stopped and the processing in FIG. The measures to be taken in this case will be briefly described.

In this case, the flowcharts of FIGS. 8 and 9 are executed in place of FIGS. 2 and 5 of the above embodiment. 8 and 9, the same processing numbers as those in FIGS. 2 and 5 are denoted by the same step numbers. The different parts will be described. Referring to FIG. 8, after S10, S15 for determining whether or not there is an end ID is added. If the determination in S15 is affirmative, the process proceeds to S20. The process is shifted to S17. After the process in S17, the process shifts to S40.

On the other hand, with respect to FIG. 9, only S405, which is a process of “writing an end ID to the EEPROM 35”, is added after S400. When a negative determination is made in S330, the same as in the case of FIG.
The process proceeds to S410 without passing through (405).

As described above, S40 after S400 in FIG.
5, the end ID is written in the EEPROM 35. Therefore, the state in which the end ID is written corresponds to S3
Writing data to EEPROM 35 in step 10 and S380
In this state, data writing to the FlashROM 31c has been completed. On the other hand, the state in which the end ID is not written means that the data is written to the EEPROM 35 in S310 and the FlashROM 31c in S380.
There is a possibility that at least one of the data writing to has not been completed.

Therefore, in the base routine of FIG. 8, it is determined whether or not the end ID exists (S15).
If there is an end ID (S15: YES), the data in the EEPROM 35 and the FlashROM 31c is copied to the RAM 31b as usual (S20, S30). However, if there is no end ID (S15: NO), the process proceeds to S17, where a data area for writing to the FlashROM 31c in the RAM 31b and a data area for writing to the EEPROM 35 (blocks 1 and 2; see FIG. 7)
Is set to an initial value.

In this way, it is possible to prevent the use of data that is not actually written normally. (2) In the above embodiment, as a general configuration, the flash ROM 31c is provided in the microcomputer 31 and the EEPROM 35 is externally attached to the microcomputer 31. However, for example, as shown in FIG. 10A, a FlashROM may be provided outside the microcomputer and the EEPROM may not be used, or as shown in FIG. 10B, the FlashROM and the EEPROM may be provided outside the microcomputer.
Can also be deployed together.

(3) Further, in the above embodiment, the engine ECU 30 for controlling the engine of the vehicle is taken as an example. However, the present invention is applied to a vehicle for controlling other controlled objects such as a brake, a transmission and a suspension. The same can be applied to the electronic control device in the same manner.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an engine ECU, a main relay, and peripheral devices as an embodiment of an electronic control unit for a vehicle.

FIG. 2 is a flowchart illustrating a base routine executed immediately after an ignition switch is turned on.

FIG. 3 is a flowchart illustrating a process related to abnormality detection performed at regular intervals.

FIG. 4 is a flowchart illustrating a process related to writing data to an EEPROM 35, which is executed at regular intervals.

FIG. 5 is a flowchart illustrating a process related to writing data to a FlashROM.

FIG. 6 is a conceptual diagram of a memory area of the FlashROM.

FIG. 7 is a conceptual diagram of a memory area of a RAM.

FIG. 8 is a flowchart illustrating a base routine executed immediately after an ignition switch is turned on in another embodiment.

FIG. 9 is a flowchart illustrating a process related to writing data to a FlashROM in another embodiment.

FIG. 10 shows a microcomputer and FlashROM or EEP.
It is explanatory drawing which shows another embodiment in the relationship with ROM.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 2 ... Main relay 3 ... Battery 4 ... Ignition switch 5 ... Communication line 30 ... Engine ECU 31 ... Microcomputer 31a ... CPU 31b ... RAM 31c ... FlashROM 31d ... I / O 32 ... Input / output circuit 33 ... Main power supply circuit 34 ... Sub power supply Circuit 35 EEPROM 41 A / F sensor 42 Rotation sensor 43 Air flow meter 44 Water temperature sensor 45 Throttle sensor 46 Starter switch 47 Injector 48 Igniter 49 DIAG tester

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G084 CA07 DA13 DA26 EB02 EB06 FA35 5B018 GA04 HA23 HA31 HA35 MA23 NA01 PA03 QA05 RA11

Claims (9)

[Claims] 1. A control system according to claim 1, further comprising: a read-only non-volatile memory capable of electrically rewriting the storage content in units of memory cells in blocks, wherein a predetermined control target mounted on the vehicle is controlled according to a control program stored in said non-volatile memory. And a switch for switching between a state in which power required for executing control according to the control program is supplied from a power supply device and a state in which power is not supplied, and the power supply by the switch. An electronic control unit for a vehicle configured to execute control according to the control program by a power supply supplied from a device, even when the power supply required for the normal operation is not supplied by the switch. For a predetermined period from the time of the switching, it is necessary for normal operation of the electronic control unit for the vehicle. Supply state control means for continuing the state in which power is supplied from the power supply device, and then switching to a state in which power required for normal operation is not supplied, and the power required for the normal operation by the switch. The data obtained during the power supply period, the data whose contents need to be maintained even when the power required for the normal operation is not supplied by the switch, the power supply is maintained by the supply state control means. An electronic control unit for a vehicle, comprising: data writing means for writing data in a predetermined block of the nonvolatile memory where the control program is not stored during a predetermined period. 2. The electronic control unit for a vehicle according to claim 1, wherein the data whose contents need to be maintained are updated in a RAM during a period in which power necessary for the normal operation is supplied by said switch. An electronic control unit for a vehicle, which is stored. 3. The electronic control unit for a vehicle according to claim 1, wherein the RAM is a standby RAM that is constantly supplied with power by the power supply unit. 4. The electronic control unit for a vehicle according to claim 1, wherein the nonvolatile memory stores a program for writing to the own memory, and a program for operating the program. A memory for program operation different from the non-volatile memory, wherein the data writing means is a memory which needs to maintain data even when power required for the normal operation is not supplied by the switch. When writing to the non-volatile memory, according to the write program that is moved from the non-volatile memory to the program operation memory and operates,
Executing the data writing, an electronic control unit for a vehicle. 5. The electronic control unit for a vehicle according to claim 1, wherein said nonvolatile memory is a flash memory rewritable in block units. . 6. The electronic control unit for a vehicle according to claim 5, wherein said data writing means compares data contents to be written with corresponding data contents stored in a flash memory as said nonvolatile memory. An electronic control unit for a vehicle, wherein data is updated only when the data is different. 7. The electronic control unit for a vehicle according to claim 5, wherein a power required for the normal operation is supplied by the switch separately from a flash memory which is a nonvolatile memory storing the control program. An EEPROM as a non-volatile memory for storing data whose contents need to be maintained even in a state where the data need not be maintained. According to the data type, the data is written in the flash memory and the EEPROM in a distributed manner, and the data is written to the EEPROM even during a period in which the power required for the normal operation is supplied by the switch. Characteristic electronic control unit for automobiles. 8. The electronic control unit for a vehicle according to claim 7, wherein said data writing means is a data whose contents need to be maintained and whose data is less likely to change frequently. An electronic control unit for a vehicle, wherein the data is written to the flash memory, and the data whose data content is likely to change frequently is written to the EEPROM. 9. The vehicle electronic control device according to claim 5, wherein said flash memory is provided in a microcomputer having a CPU as a center. For electronic control device.