JP2002317687A - Microcomputer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide reduce the processing load of software in a microcomputer composed so as to periodically check a RAM storing the adaption data from other microcomputer. SOLUTION: When the adaption data are transmitted from a main microcomputer in the base processing (one transmission at starting), a sub-microcomputer stores them in a RAM and a backup RAM (S340). When the engine has made a one-stroke motion (S350: YES), a RAM diagnosing process (S360) is executed. That is, the frequency of RAM checks is synchronized with the rotation o the engine. At starting of the sub-microcomputer, first the initial processing is executed prior to the base processing, when the sub-microcomputer is restarted by any unexpected failure resetting during the foregoing run of operation, a failure reset history is sensed (S300: YES) in the initial processing after restarting, the adaption data are returned quickly from the backup RAM without requiring transmitting of the adaption data from other microcomputer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of storing control data received from another microcomputer in a RAM,
The present invention relates to a microcomputer configured to execute various control arithmetic processes based on the control data and to periodically check the contents stored in a RAM.

[0002]

2. Description of the Related Art Conventionally, for example, in an electronic control unit (hereinafter referred to as "ECU") mounted on an automobile,
A well-known microcomputer (hereinafter, simply referred to as a “microcomputer”) including a CPU, a RAM, a ROM, and the like is provided. There are various types of electronic control in a vehicle, for example, engine control, transmission control, skid control, various body controls, and the like.In each control, a microcomputer provided in accordance with the various controls executes processing. , The vehicle is controlled to an appropriate state.

By the way, for example, as engine control,
Generally, since a plurality of control processes such as fuel injection control, ignition timing control, knock control, etc. are performed, the entire processing amount is one C
In many cases, all the control related to engine control cannot be executed by one microcomputer (specifically, CPU) because the processing capacity of the PU is exceeded. Therefore, when such necessary control cannot be performed by only one microcomputer, as shown in FIG. 7, a plurality of microcomputers (two in FIG. 7)
The entire control is shared and executed.

FIG. 7 is an explanatory diagram showing a schematic configuration of a plurality of microcomputers provided in the engine control ECU. As shown in FIG. 7, in the engine control ECU 7, various engine controls are executed by the main microcomputer 1 and the sub microcomputer 70. It is configured to: The main microcomputer 1 executes main control for controlling the engine, such as fuel injection control and ignition timing control, among various engine controls, and performs various control programs and control adaptation data (hereinafter simply referred to as “adaptation data”). ) Is stored in the ROM 13, R
According to the program stored in the OM 13 and the ROM 13
CPU 11 for executing various control processes using the adaptation data stored in the RAM, RAM 12 for storing data processed during execution of various control processes by the CPU 11 and data temporarily generated in a calculation process, and data from outside I / O 14 for controlling input / output.

[0005] In addition to the above-mentioned control program and compatible data, the ROM 13 stores a CPU 7
The adaptation data used when the CPU 1 executes the control processing is also stored. The CPU 11 temporarily copies the adaptation data to the RAM 12 at the time of startup, and transmits it to the sub-microcomputer 70 via the I / O 14 therefrom. The adaptation data is fixed data that differs depending on the model (here, the vehicle type) in which the microcomputer is mounted. For example, in the knock control of the engine, it is used to determine whether knock has occurred based on a signal from a knock sensor. The judgment level and the like correspond to this.

On the other hand, the sub-microcomputer 70 is provided to execute other control (knock control or the like) that cannot be processed by the main microcomputer 1, and is stored in the ROM 73 in which various control programs are stored. CPU 71 that executes various control processes using the adaptation data transmitted from the main microcomputer 1 at the time of startup and stored in the RAM 72 via the I / O 74 in accordance with the executed program.
CPU 71, in addition to data processed during execution of various control processes by controller 71, data temporarily generated in an arithmetic process, and the like.
A RAM 72 for storing the above-mentioned conformity data (conformity data transmitted from the main microcomputer 1) necessary for executing various control processes according to the present invention, and an I / O 74 for controlling data input / output with the outside.

Thus, in the sub-microcomputer 70,
The reason that the adaptation data required for various controls is not stored in the ROM 73 in advance but is transmitted from the main microcomputer 1 at the time of startup is that the sub-microcomputer 70 is commonly used to some extent in other models other than the relevant model. This is because, by using a possible general-purpose microcomputer, the development cost can be reduced, and the number of part numbers can be reduced by using common components.

That is, in the ROM 73, only program data that can be used in common among a plurality of vehicle types is stored in advance, and when it is actually mounted on a specific vehicle,
By receiving the adaptation data necessary for controlling the vehicle from another microcomputer (main microcomputer 1), a general-purpose microcomputer can be used as the sub-microcomputer 70. Therefore, the ROM 1 of the main microcomputer 1
3 stores a program for transmitting the adaptation data to the sub-microcomputer 70 at the time of startup. On the other hand, the ROM 73 of the sub-microcomputer 70 stores the adaptation data transmitted from the main microcomputer 1 at the time of startup in the RAM. A program for storing is also stored.

In the configuration of the two microcomputers 1 and 70 illustrated in FIG. 7, ideally, once the adaptation data is transmitted from the main microcomputer 1 to the sub-microcomputer 70 at the time of startup, the adaptation data is stored in the RAM 72. Therefore, it is not necessary to transmit the adaptation data during the operation of the sub-microcomputer 70 thereafter, but actually, the stored contents of the RAM 72 may change (so-called data corruption) due to some factor such as external noise. .

Therefore, as one method for restoring the stored contents at an early stage even if data is garbled in the RAM 72, for example, as shown in FIG.
Is started, a method of continuously transmitting the adaptation data to the sub-microcomputer 70 at a constant transmission cycle ta is known. And
In the sub-microcomputer 70, every time the matching data is transmitted,
The contents of the RAM 72 are updated (overwritten).

As described above, by periodically refreshing the contents of the RAM 72, even if data is garbled in the RAM 72, the RAM 72 is re-transmitted by the compatible data.
Can be restored. However,
In such a continuous transmission method, the transmission cycle needs to be very short depending on the control target.
There is a problem in that the communication load between the devices 70 increases.
That is, for example, in engine rotation synchronous control such as knock control, CP per engine stroke (720 ° CA)
When U71 refers to (uses) the adaptation data once, the higher the engine speed, the more frequently the adaptation data is used.

In such a case, for example, at a low speed rotation in which the required time for one engine stroke is longer than the adaptation data transmission cycle ta, even if data is garbled in the RAM 72, the RAM 72 is refreshed within one engine stroke. It is possible to prevent the control based on the adaptation data from being performed. However, if the data is garbled during high-speed rotation and the engine rotates several times during the transmission cycle ta, for example, the time until refresh is performed. In the meantime, control based on erroneous matching data after data conversion is performed.

For this reason, the transmission cycle ta of the adaptation data may be set short in consideration of the high speed rotation so that the engine is refreshed at least once per engine stroke even at the high speed rotation. If you do, low speed ~
The adaptation data is always transmitted in a short cycle in the entire rotation range up to the high speed (that is, unnecessary adaptation data is transmitted more than necessary except during the high-speed rotation), and the communication load between the microcomputers 1 and 70 is increased. Steadily increases, and eventually it may become impossible to transmit the conforming data at a desired cycle.In addition, it may be susceptible to external noise or may be used for communication of data other than the conforming data. There is a possibility that it may have an effect.

Therefore, instead of the above method, for example, FIG.
As shown in (b), the conforming data transmission from the main microcomputer 1 is performed only once at the time of startup, and thereafter, the sub-microcomputer 70 periodically checks the storage content of the RAM 72, and only when there is an abnormality, to that effect (RAM There is also known a method of transmitting an abnormal signal (refer to a broken line arrow in FIG. 7) to the main microcomputer 1 to have the main microcomputer 1 retransmit the adaptation data.

[0015]

However, in the above-described method, the transmission of the adaptation data from the main microcomputer 1 is basically performed only once at the time of startup, and then the retransmission should be performed only when the RAM 72 is abnormal. Therefore, the communication load caused by the transmission of the conforming data is drastically reduced.
However, there is a problem that the processing load of the software (software) by the CPU 71 increases.

That is, even in the case of this method, FIG.
As in the case of the continuous transmission described in (a), the adaptation data is transmitted to the engine 1 by rotation synchronous control such as knock control.
In the case where the data is referred to once per stroke, the check cycle of the RAM 72 by the CPU 71 is set short in consideration of the high-speed rotation so that the control based on the incorrect adaptation data is not performed even at the high-speed rotation. There is a need.

In this case, an appropriate RAM check is performed at the time of high-speed rotation, but an unnecessary wasteful RAM check is performed at times other than the high-speed rotation. Since the amount of processing that can be processed by the CPU 71 is naturally limited, if the ratio of the RAM check processing to the total amount of processing that can be performed by the CPU 71 increases,
The amount of other control processing that can be executed by the CPU 71 is accordingly limited. Further, when the processing load of the software by the CPU 71 is steadily increased, the amount of heat generated by the CPU 71 increases, which causes a problem that the thermal runaway of the CPU 71 easily occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and stores conforming data received from another microcomputer in a RAM, executes various control arithmetic processing based on the conforming data, and stores the contents stored in the RAM. It is an object of the present invention to reduce the processing load of software in a microcomputer configured to periodically check.

[0019]

Means for Solving the Problems and Effects of the Invention A microcomputer according to the first aspect of the present invention, which has been made to solve the above-mentioned problems, comprises a microcomputer which is set in advance and stored in a storage medium. A control data storage program for receiving control data and storing the control data in a RAM, a function program for executing an arithmetic process for controlling a control target based on the control data stored in the RAM by executing the control data storage program, and a RAM The CPU executes various processes in accordance with various programs including at least a RAM diagnostic program for periodically executing a RAM diagnostic process for checking contents stored in the CPU.

In the microcomputer according to the present invention, the operating state detecting means detects the operating state of the control target, and based on the detection result, the diagnostic timing setting means executes the RAM diagnostic program implemented by executing the RAM diagnostic program. The execution timing of the processing is set so as to reduce the processing load on the CPU.

The operating state of the controlled object detected by the operating state detecting means includes not only the state of the object directly controlled by the execution of the control arithmetic processing based on the function program (for example, the rotational state of the engine in the engine control of the vehicle) but also the control state. It also includes the state of other elements required for controlling the target (eg, vehicle speed in vehicle suspension control and door lock control, or outside air temperature in an indoor air conditioning system).

That is, in the microcomputer of the present invention, the CPU
However, at the time of startup, after storing control data from another microcomputer in the RAM, various controls (control calculation processing) based on the function program are executed, and the content stored in the RAM is checked at a predetermined timing. The execution timing of the diagnosis process is set based on the operation state of the control target so that the processing load on the CPU is reduced (in other words, the RAM diagnosis process is not executed more than necessary).

Therefore, according to the microcomputer of the present invention, C
To prevent the PU from executing the RAM diagnostic processing more than necessary,
The execution timing of the AM diagnosis process is set, and the RAM can be checked at a minimum frequency according to the state of the control target. Therefore, the processing load of software by the CPU can be reduced.

If the contents of the RAM are determined to be abnormal by the execution of the RAM diagnosis processing, the contents of the RAM are returned to the normal state by, for example, receiving the same control data again from another microcomputer. Should be returned to Here, the types and application fields of various types of control processing using microcomputers are diverse, but in the case of vehicles in particular, the types of control objects and control contents, such as engine control, body control, and vehicle body control, are as described above. Cross over. For example, in engine control, not only control of fuel injection amount and ignition timing, but also multiple control such as knock control and idle speed control are executed in parallel to properly rotate the engine, so one microcomputer It is difficult to execute these multiple controls alone.

Therefore, in such a case, as described in the related art, various engine controls are performed by two or more microcomputers, and there is control data used when each microcomputer executes a control process. In many cases, only a specific microcomputer is provided, and other microcomputers are configured to have control data transmitted from the specific microcomputer at startup.

Therefore, the microcomputer according to the present invention is preferably mounted on a vehicle for executing various controls in the vehicle. By applying the microcomputer of the present invention to a vehicle, even in a vehicle having a large number of types and amounts of control, the RAM can be controlled according to the operation state of the control target.
Can be set, so that a larger amount of processing that can be performed by the microcomputer can be secured, and the vehicle can be more appropriately controlled.

In the second aspect of the present invention, R
The factors that determine the execution timing of the AM diagnosis process differ depending on the control target. For example, in a case where control data is used only once per engine stroke in a rotation synchronous control such as a knock control, if a RAM diagnosis process is executed at a fixed cycle regardless of the rotation state of the engine, a conventional technique is used. The problem as described in the section arises.

The control data (stored in the RAM) used for performing such rotation synchronization control is described in RA
When executing the M diagnosis process, as described in claim 3, the operating state detecting means detects the rotation state of the prime mover,
The diagnosis timing setting means may set the execution timing based on the detected rotation state of the prime mover so that the RAM diagnosis processing is executed in synchronization with the rotation of the prime mover. By doing so, the RAM diagnostic processing is always executed in synchronization with the rotation regardless of the rotation speed of the prime mover, so that the proportion of the processing amount occupied by the RAM diagnostic processing in the total processing capacity of the CPU is minimized. Can, CP
It becomes possible to reduce the processing load of software by U.

In a vehicle, in addition to the above-described rotation synchronization control, there are many so-called time synchronization controls that are executed at predetermined time intervals, for example. More specifically, an example of the time synchronization control is, for example, a vehicle anti-theft system. This is a system that issues an alarm or the like when a third party illegally operates the vehicle while the vehicle is stopped and the owner is away from the vehicle. When diagnosing control data stored and used in the RAM in such a system, when setting the diagnosis timing, not only does the rotation speed of the prime mover (engine) not particularly matter, but also the engine is rotating in the first place. Sometimes there is basically no need to run the system itself.

Therefore, in such a case, the operating state detecting means detects the rotational state of the prime mover, and the diagnostic timing setting means determines the rotational state of the prime mover based on the detection result by the operational state detecting means. The execution timing may be set so that the RAM diagnosis process is executed when the is not rotating. If you do this,
In a control such as the anti-theft system exemplified above, which is operated only when the prime mover is not rotating,
The RAM diagnosis processing is executed only when it is necessary (during the stop of the prime mover).
Since the AM diagnosis processing can be prevented from being executed, the processing load of the RAM diagnosis processing can be minimized as in the case of the third aspect, and the processing load of software by the CPU can be reduced. It becomes possible.

For example, there is control such as air-fuel ratio feedback control of a vehicle that is executed only when the engine speed is within a predetermined range. Control data (stored in RAM) used in such control
When performing the diagnostic processing, the diagnostic processing need only be performed when the diagnostic processing is within a predetermined rotation speed range.

Therefore, in such a case, the operating state detecting means detects the rotational state of the prime mover, and the diagnostic timing setting means determines the rotational state of the prime mover based on the detection result by the operational state detecting means. The execution timing may be set so that the RAM diagnosis processing is executed only when the rotation speed of the RAM is within a predetermined range. Even in this case, the RA is the same as in the third or fourth aspect.
The processing load of the M diagnosis processing can be minimized, and the processing load of software by the CPU can be reduced.

In addition, the control is executed only for a predetermined period after the engine is started (while the engine is cold), and is not executed thereafter (or the execution frequency is reduced), such as a fuel increase correction control at the time of engine start. Control data (stored in RAM)
In the case where the RAM diagnosis process is executed, the process may be executed only for a predetermined period after the engine is started, and thereafter, may not be executed or may be executed less frequently.

Therefore, in such a case, the operating state detecting means detects the rotational state of the prime mover, and the diagnostic timing setting means determines the rotational state of the prime mover based on the detection result by the operating state detecting means. When R is rotating
The AM diagnosis process may be performed, and the execution timing of the RAM diagnosis process may be set so that the execution interval of the RAM diagnosis process is different between the start of the prime mover and a predetermined time after the start of the prime mover. Even in this case, claims 3 to
As in the invention of any one of the fifth to fifth aspects, the processing load of the RAM diagnosis processing can be reduced to a necessary minimum, and the processing load of software by the CPU can be reduced.

By the way, as described above, when the contents stored in the RAM change, data may be garbled due to external noise or the like during normal operation of the microcomputer.
The CPU is reset for some reason (an abnormal reset other than a normal reset function such as a power-on reset or a manual reset generally provided in a microcomputer) in addition to such a factor that directly changes the storage content of the RAM. In some cases, the contents stored in the RAM may be erased. In a general microcomputer, when reset, R
This is because most of the contents of the AM are once cleared.

Even in the case of abnormal reset as described above,
As described above, it is of course possible to store the control data in the RAM again by having the control data retransmitted from another microcomputer. However, of course, the control data is stored in the RAM again after the abnormal reset. Until this time, a certain communication period is required, during which normal control cannot be performed. Therefore, at the time of abnormal reset,
It was desired to restore the contents of the RAM as soon as possible.

Therefore, the microcomputer according to claims 1 to 6
For example, as described in claim 7, a rewritable backup memory in which stored contents are retained by being constantly supplied with power by a battery is provided, and the control data storage program is configured such that the CPU is activated by another microcomputer at startup. The received control data is stored in the RAM and also stored in the backup memory, and the storage medium further stores the content of the RAM based on the content of the backup memory when the CPU is abnormally reset. It is preferable that an abnormal reset data restoration program for restoring is stored.

That is, the storage contents of the backup memory are always retained by the power supply from the battery regardless of the operation state of the microcomputer, and the storage contents of the backup memory are not erased even when the microcomputer is reset. Therefore, for example, if the data is corrupted due to external noise or the like, the data in the backup memory may be similarly corrupted, and the control data should be retransmitted from another microcomputer. Should be, but R
If the AM data is erased, the contents of the backup memory are not erased and the contents of the backup memory are normally retained, so there is no need to resend the data from another microcomputer. The control data can be stored again in the RAM based on the content.

Therefore, according to the microcomputer of the present invention, at the time of abnormal reset, the storage contents (control data) of the RAM are quickly restored based on the storage contents of the backup memory without waiting for retransmission from another microcomputer. Therefore, deterioration of controllability due to erasure of RAM data at the time of abnormal reset can be further reduced.

In this case, the control data may be stored in the backup memory in a state where the control data is stored as it is, but more preferably, for example, as described in claim 8. It is preferable to store data (bit inversion data) obtained by inverting each bit value of the control data stored in the RAM. In this case, the RAM diagnosis processing is performed by storing the control data stored in the RAM and the backup data in the backup memory. It is preferable to perform the comparison by comparing the obtained bit-reversed data.

If the control data is stored as it is in both the RAM and the backup memory and compared with each other, for example, all storage areas of both are cleared to 0 or 1 due to some influence of external noise or the like. Also,
When the two are compared, the same data is stored, so that the storage content of the RAM is erroneously determined to be normal.

However, if the backup memory stores bit-reversed data of the control data stored in the RAM in the backup memory, all the storage areas of both are cleared to 0 or 1. In this case, when the two are compared, they are all the same data, so that it can be determined that an abnormality has occurred.

Therefore, according to the microcomputer of the present invention, it is possible to judge that the clearing of the entire storage area is abnormal as compared with the case where exactly the same control data is stored in both the RAM and the backup memory. Therefore, the reliability of the RAM diagnosis processing can be further improved.

The diagnostic timing setting means for setting the execution timing of the RAM diagnostic processing, for example, fetches the detection result of the operating state detecting means, and based on the result,
It may be configured by hardware such as a logic circuit or the like that outputs a command to execute the RAM diagnosis processing at a predetermined timing to the CPU. As described above, the diagnostic timing setting program stored in the storage medium is
The diagnosis timing setting means may be realized by the execution of the PU.

That is, the storage medium stores a diagnosis timing setting program for setting the execution timing of the RAM diagnosis processing so as to reduce the processing load on the CPU based on the detection result of the operation state detecting means. , CP
When U executes this program, the diagnosis timing setting means of the present invention is realized. With this configuration, the diagnostic timing setting means can be replaced by the CPU as in the above example.
It is not necessary to add new hardware as in the case of configuration with hardware other than the above, and the configuration can be realized by adding software (diagnosis timing setting program), so that the configuration of the microcomputer can be further simplified.

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a plurality (two in the present embodiment) of microcomputers provided in an engine control ECU 10 mounted on a vehicle. Like the engine control ECU 7 (see FIG. 7) described in the section of the prior art, the engine control ECU 10 of the present embodiment also performs main control for controlling the engine such as fuel injection control and ignition timing control by the main microcomputer 1. And the sub-microcomputer 2 executes other control (rotational synchronization control such as knock control in the present embodiment) which cannot be processed only by the main microcomputer 1 among various engine controls. The engine is operated in an optimal state. Therefore, the same components as those in FIG. 7 are denoted by the same reference numerals, and description thereof will be omitted.

The sub-microcomputer 2 of the present embodiment
The storage content of the ROM 22 is partially different from that of the ROM 73 of FIG.
In addition to 72, a backup RAM 21 is separately provided. The engine control ECU 10 starts power supply from a battery (not shown) by turning on an ignition switch (hereinafter abbreviated as “IG switch”) normally provided in the vehicle, and performs the operation (that is, the main microcomputer 1 and the sub-microcomputer). Various controls by the microcomputer 2 and the like are started.

A signal (Ne signal) from the crank angle sensor 5 is input to each of the microcomputers 1 and 2, and in each of the microcomputers 1 and 2, the rotational speed of the engine and the crankshaft are determined based on the Ne signal. Is calculated. Further, in addition to the Ne signal, the microcomputers 1 and 2
Although not shown, various sensor / switch signals (for example, IG switch signal, oil pressure, air flow rate, oxygen concentration, etc.) necessary for engine control are also input via the I / Os 14 and 74 and output from the microcomputers 1 and 2. Various control outputs are
It is configured to output to various devices (not shown) (for example, an injector and an igniter) via / O14 and 74.

Similar to the contents stored in the ROM 73 shown in FIG. 7, the ROM 22 receives the adaptation data (corresponding to the control data of the present invention) transmitted from the main microcomputer 1 at the time of starting by turning on the IG switch. RAM 72
Data stored in the RAM 72, and after executing the suitable data storage program (that is, after storing the suitable data in the RAM 72), various types of control of an engine as a control object based on the suitable data stored in the RAM 72. A function program (knock control program) for executing arithmetic processing (knock control or the like) is stored.

The adaptation data storage program according to the present embodiment stores the adaptation data in the RAM 72 as described above and the adaptation data (2
The data (mirror value) obtained by inverting each bit value of the value data) is stored in the backup RAM 21. In the present embodiment, for example, a determination level serving as a reference for knock determination is transmitted from the main microcomputer 1 to the sub-microcomputer 2 as matching data. This determination level is data serving as a reference for determining whether or not knock has occurred in response to a signal from a knock sensor (not shown). In the knock control executed by the sub-microcomputer 2, once per engine stroke. used.

The ROM 22 of the present embodiment stores, in addition to the above programs, a RAM diagnostic program for executing a RAM diagnostic process for checking the contents stored in the RAM 72 and the execution timing of the RAM diagnostic program. A diagnostic timing setting program for setting based on the Ne signal is stored, and the storage content of the RAM 72 is checked at predetermined intervals by comparing with the content of the backup RAM 21 as described later.
If the contents of the RAM 72 are determined to be abnormal,
An M abnormal signal is transmitted to the main microcomputer 1.

In the main microcomputer 1, when the RAM abnormality signal is transmitted from the sub-microcomputer 2, the adaptation data is transmitted to the sub-microcomputer 2 again. That is, the adaptation data is transmitted once to the ROM 13 of the main microcomputer 1 at the time of startup, and thereafter, the RAM 13
A program (adaptation data transmission program) for executing an adaptation data transmission process for retransmitting the same adaptation data only when an abnormal signal is received is stored.

The backup RAM 21 (corresponding to the backup memory of the present invention) stores the mirror value of the adaptation data stored in the RAM 72 as described above, and compares the mirror value with the contents of the RAM 72 during the RAM diagnosis processing.
In addition to checking whether the contents of the AM 72 are normal or not, when the CPU 71 abnormally resets (erases the contents of the RAM 72) due to external noise or the like as described later, the data is written to the RAM 72 and the conforming data is stored in the RAM 72. It is for returning early, power is always supplied by the battery, regardless of the state of the IG switch,
As long as power is supplied from the battery, the stored contents are always retained.

An abnormal reset is an unexpected reset caused by some factor such as external noise, in addition to a normal reset such as a power-on reset or a manual reset generally provided in a microcomputer. In the case of such an abnormal reset, in the present embodiment, the history of the abnormal reset occurrence is left by setting the abnormal reset flag, and the abnormal reset flag is set at the time of restart after the abnormal reset. Is confirmed, and R is determined based on the mirror value stored in the backup RAM 21.
The compatible data is restored (written) to the AM 72. Therefore, the ROM 22 determines whether or not there is an abnormal reset flag at the time of startup, and if the flag is set, the abnormal reset for executing the process (initial process) for restoring the contents of the RAM 21 as described above. An hour data recovery program is also stored.

In this embodiment, the backup RAM 2
1 stores the mirror value of the RAM 72 because the RAM 72 and the backup RAM
This is so that even when an abnormality (except for an abnormal reset) occurs in which all the storage areas 21 are cleared to 1 or 0, the abnormality can be detected. That is, if the backup R
If the same data as that of the RAM 72 is stored in the AM 21, even if the data in the backup RAM 21 and the data in the RAM 72 are both cleared to 0 for some reason, they are compared and coincide with each other. Will not be determined. Therefore, if the mirror value is stored in the backup RAM 21, if the data of the backup RAM 21 and the data of the RAM 72 are all cleared to 0 as described above, the contents of the backup RAM 21 are not the mirror value of the RAM 72. Thus, the abnormality can be detected.

Next, the adaptive data transmission process executed by the CPU 11 of the main microcomputer 1 and the CPU
71, an initial process executed immediately after startup, and a matching data storage program, a diagnosis timing setting program, and an RA after execution of the initial process.
A process (base process) repeatedly executed according to the M diagnostic program will be described.

First, the CPU 11 of the main microcomputer 1
The adaptation data transmission process that starts executing immediately after the activation will be described with reference to FIG. FIG. 2 is a flowchart illustrating the adaptation data transmission process executed by the CPU 11. In the main microcomputer 1, the CPU 11 reads out the compatible data transmission program from the ROM 13 at startup,
The processing is executed according to this program.

When this process is started, first, in step (hereinafter abbreviated as "S") 210, the appropriate data used in various control processes in the sub-microcomputer 2 is fetched (copied) from the ROM 13 to the RAM 12, and then the process proceeds to S220. Then, the matching data fetched to the RAM 12 is transmitted to the sub-microcomputer 2.

After the transmission of the adaptation data, it is determined in S230 whether or not a RAM abnormal signal has been transmitted from the sub-microcomputer 2. Then, while the RAM abnormality signal is not transmitted (S
230: NO), that is, the RAM 72 in the sub-microcomputer 2
While the matching data stored in the memory is normal, the process of S230 is repeated. If the RAM abnormality signal is transmitted (S230: YES), the matching data transmitted in S220 is transmitted to the sub-microcomputer 2 again. (S240), S2
It returns to the process of 30.

Next, the initial processing executed by the CPU 71 of the sub-microcomputer 2 immediately after its activation will be described with reference to FIG.
Description will be made based on (a). FIG. 3A shows the CPU 71.
5 is a flowchart showing an initial process executed by the CPU. In the sub-microcomputer 2, at the time of startup, the CPU 71
An abnormal reset data recovery program for executing this initial process is read from M22, and the process is executed according to this program.

When this processing is started, first, in S300
It is determined whether or not an abnormal reset flag indicating that an abnormal reset has occurred is set (presence or absence of an abnormal reset history). If the abnormal reset flag has not been set (S300: NO), the initial process is terminated assuming that the normal startup by turning on the IG switch has been performed. On the other hand, when the abnormal reset flag is set (S300: YES)
Assuming that the CPU 71 has been reset abnormally for some reason during operation, the CPU 71 restores the adaptation data to the RAM 72 based on the mirror value stored in the backup RAM 21 (S310), and terminates the initial processing.

After the end of the initial processing, the base processing is continuously executed. Hereinafter, the base process executed by the CPU 71 will be described with reference to FIG. FIG.
3B is a flowchart illustrating a base process executed by the CPU 71. This base processing is performed by combining the above-described adaptation data storage program, diagnosis timing setting program, and RAM diagnosis program, and is executed at every crank angle 30 ° CA of the engine (not shown) based on the Ne signal. This is a so-called rotation synchronization process.

When the base processing is started, first, in S3
At 30, it is determined whether or not the adaptation data has been transmitted from the main microcomputer 1. Engine control ECU of the present embodiment
Reference numeral 10 denotes a state in which the main microcomputer 1 and the sub-microcomputer 2 are activated almost at the same time, and when the initial processing is completed in the sub-microcomputer 2 and the base processing is started after the activation, the conforming data is transmitted from the main microcomputer 1. Is set.

Therefore, in the first process in S330 at the time of activation, since the conforming data is transmitted from the main microcomputer 1 (S330: YES), the conforming data is stored in the RAM 72 and the mirror value of the conforming data is stored. It is stored in the backup RAM 21 (S34).
0), and then proceed to S350. On the other hand, when the base processing is executed for the second and subsequent times, the conforming data is not normally retransmitted unless the conforming data is retransmitted from the main microcomputer 1 (S240 in FIG. 2).
A negative determination is made.

In S350, the rotation state of the engine is determined based on the Ne signal, and it is determined whether the engine has operated one stroke (two rotations of the crankshaft: 720 ° CA).
At this time, if the engine has not yet been operated for one stroke (S350: NO), this base process is terminated as it is, but if one stroke of the engine is determined by the Ne signal (S350: YES), Proceed to S360 and RAM
Perform diagnostic processing.

This RAM diagnosis processing is performed by comparing the conforming data stored in the RAM 72 with the conforming data (mirror value) stored in the backup RAM 21 as described above. If it is determined that it is normal (S370: N
O), the base processing is terminated as it is,
2 is determined to be abnormal (S370: Y
ES), in S380, a RAM abnormality signal is transmitted to the main microcomputer 1, and the base processing ends. Subsequently, the base processing is continued at a crank angle of 30 ° CA
Execute every time. The RA transmitted from the sub-microcomputer 2
When the M abnormal signal is received by the main microcomputer 1, as described above, the conforming data is transmitted from the main microcomputer 1 to the sub-microcomputer 2 again in S230 to S240 of the conforming data transmitting process (FIG. 2) in the main microcomputer 1. You.

When the conforming data is retransmitted from the main microcomputer 1 in this way, in the base processing of the sub-microcomputer 2, an affirmative determination is made in S330, the retransmitted conforming data is stored in the RAM 72, and the mirror value is stored. It will be stored in the backup RAM 21 (S34).
0).

The processing of S330 to S340 is executed according to the appropriate data storage program.
The process of 350 is executed according to the diagnosis timing setting program, and the processes of S360 to S380 are executed according to the RAM diagnosis program.

As described in detail above, in the engine control ECU 10 of the present embodiment, the conformity data different for each vehicle type used when the CPU 71 of the sub-microcomputer 2 executes control (knock control or the like) is transmitted to the sub-microcomputer 2. It has the main microcomputer 1 transmit it at startup without having it, and stores the transmitted conformance data in the RAM 72 and its mirror value in the backup RAM 21. And R
The matching data stored in the AM 72 is checked by comparing it with the mirror value of the backup RAM 21, and the check timing is set to a timing synchronized with the engine rotation (in the present embodiment, once per engine stroke).

If the CPU 71 is abnormally reset during its operation and the data in the RAM 72 is erased, the conforming data is not resent from the main microcomputer 1 and the RAM 72 is reset based on the mirror value in the backup RAM 21. To return the conforming data.

Accordingly, the engine control ECU of the present embodiment
According to 10, the RAM is always synchronized with the engine rotation so that the CPU 71 does not execute the RAM diagnosis processing more than necessary.
Since the diagnostic processing is executed, the ratio of the processing amount occupied by the RAM diagnostic processing in the total processing capacity of the CPU 71 can be minimized, and the processing load of software by the CPU 71 can be reduced. This can be used for executing other control processes.

When the CPU 71 resets abnormally,
Since the adaptation data can be quickly returned to the RAM 72 based on the storage contents (mirror value) of the backup RAM without having the adaptation data retransmitted from the main microcomputer 1, the adaptation data in the RAM 72 is erased by an abnormal reset. It is possible to further reduce deterioration in controllability during the operation.

Further, the backup RAM 21 has RA
Since the mirror value of the adaptation data stored in M72 is stored, an abnormality can be detected even in clearing the entire storage area as compared with the case where exactly the same adaptation data is stored in both the RAM 72 and the backup RAM 21. Therefore, the reliability of the RAM diagnosis processing can be further improved.

In this embodiment, the crank angle sensor 5 corresponds to the operating state detecting means of the present invention, and the CPU 71 of the sub-microcomputer 2 corresponds to the diagnostic timing setting means of the present invention. Further, in the base processing of FIG.
The determination processing at 350 corresponds to the processing executed by the diagnosis timing setting means of the present invention.

The embodiments of the present invention are not limited to the above-described embodiments, and it goes without saying that various forms can be adopted as long as they fall within the technical scope of the present invention. For example, in the above embodiment, the case where the present invention is applied to the sub-microcomputer 2 that performs rotation synchronization control such as knock control has been described. However, the present invention is not limited to this, and may be applied to, for example, a vehicle anti-theft system. it can. In this case, as described above, since the system generally operates only when the rotation of the engine is stopped (during stop), the RAM diagnosis process is also performed only when the engine is stopped. You can do it

Hereinafter, it is assumed that the engine control ECU 10 in FIG. 1 is a body ECU, and among these, various control processes constituting the anti-theft system are executed by the sub-microcomputer 2, and the conformity data necessary for the control process is as follows. The base processing executed by the CPU 71 of the sub-microcomputer 2 will be described with reference to FIG. Also in this case, similarly to the above embodiment, the CPU 11 of the main microcomputer 1 transmits the adaptation data (see FIG. 2) at the time of startup, and the CPU 71 of the sub-microcomputer 2 first performs the initial processing (FIG. 3) at the time of startup.
(See (a)), and then execute the base processing of FIG.

Since the base processing in FIG. 4 is the same as the base processing in FIG. 2B except for S400, the same reference numerals (steps) are assigned to the same processing as in FIG. Is omitted. The base processing in FIG. 4 is time synchronization control that is not synchronized with the rotation of the engine, and is executed at a predetermined cycle (for example, every 50 msec. In the present embodiment).

When the base processing is started, when the adaptation data is transmitted from the main microcomputer 1 (S33)
0: YES), the relevant data is stored in the RAM 72 and the mirror value is stored in the backup RAM 21 (S340: YES), and the process proceeds to S400, where no suitable data is transmitted from the main microcomputer 1 (S33).
(0: NO) proceeds to S400 as it is.

In S400, it is determined whether or not the engine is rotating based on the Ne signal. If the engine is rotating (S400: YES), the base process is terminated as it is not necessary to perform a RAM check. If not (S400: NO), the processing after S360 (RAM diagnostic processing is executed, and if abnormal, RA
M abnormal signal is transmitted).

As described above, in the control processing executed only when the engine is stopped, the check (RAM diagnosis processing) of the conformity data (stored in the RAM 72) used for the control processing is also performed by stopping the engine. This is performed only when the CPU 7
1 can minimize the processing load of the RAM diagnosis processing.

Further, for example, the present invention can be applied to a microcomputer that performs control such as air-fuel ratio feedback control of a vehicle that is executed only when the engine speed is within a predetermined range. it can. In this case, the RAM diagnosis processing may be performed only when the engine is rotating within a predetermined rotation speed range in which the control is performed.

Hereinafter, in the engine control ECU 10 of FIG. 1, it is assumed that the sub-microcomputer 2 performs the air-fuel ratio feedback control, and that the adaptation data necessary for the control processing is transmitted from the main microcomputer 1. The base processing executed by the CPU 71 of the sub-microcomputer 2 will be described with reference to FIG. In this case, also in this case,
As in the above embodiment, the controls shown in FIGS. 2 and 3A are respectively performed. The base processing in FIG.
Except for this, the processing is the same as the base processing of FIG. 2B or FIG. 4, and therefore the same processing as that of FIG. 2B or FIG. still,
The base process of FIG. 5 is also the same time-synchronized control as that of FIG. 4, and is executed, for example, every 50 msec. After the engine is started.

That is, in the base processing shown in FIG. 5, when the conforming data is not transmitted from the main microcomputer 1 (S
330: NO) Alternatively, after the adaptation data is transmitted from the main microcomputer 1 and the adaptation data is stored in the RAM 72 and the backup RAM 21 (S340), the engine speed is within a predetermined range based on the Ne signal. It is determined whether or not (S500). If the rotation speed is not within the predetermined rotation speed range (S500: NO), the base process is terminated as it is because there is no need to check the RAM.
If it is within the predetermined rotation speed range (S500: YE
S), and execute the processing after S360.

As described above, in the control processing executed only when the engine speed is within a predetermined range, the adaptation data (stored in the RAM 72) used for the control processing.
Is checked only when the engine speed is within a predetermined range, so that C
The processing load of the RAM diagnosis processing by the PU 71 can be minimized.

Further, the present invention is also applied to a microcomputer which performs control such that the control is executed frequently for a predetermined period after the engine is started (while the engine is cold), and thereafter, the frequency of execution is reduced. Can be. In this case, the frequency of diagnosing the adaptation data stored in the RAM used for the control may be set to be large during a predetermined period after the engine is started, and may be set to be small thereafter.

Therefore, assuming that the sub-microcomputer 2 in the engine ECU 10 of FIG. 1 performs the above-described control, the base processing executed by the CPU 71 of the sub-microcomputer 2 in that case will be described with reference to FIG. I do. This processing itself is performed for a predetermined period (for example, 50 ms) after the engine is started.
ec.)).

Note that the base processing of FIG.
The same reference numerals are given to the same processes as the base process of (b), and the description thereof will be omitted. As shown in FIG. 6, S330,
In S600 after the processing of S340, it is determined whether or not a predetermined period has elapsed since the start of the engine. At this time, if the predetermined period has not elapsed (S600: NO), S3
After performing the processing of 60 or less, the base processing is temporarily terminated. That is, until the predetermined period elapses, the RAM diagnosis process is executed every time the base process is repeated.

On the other hand, if the predetermined period has elapsed (S60
0: YES), the counter is incremented in S610, and the flow proceeds to S620. This counter is set to 0 at the start of the base processing for the first time.
By the process of 0, the counter value is incremented to 1. In S620, it is determined whether or not the counter value is a predetermined value (N). If not, the counter value is not N (S62).
0: NO), the base process is temporarily terminated without performing the RAM diagnosis process. However, at this time, the value of the counter is kept as it is even after the base processing is completed.

When the base process is started again in this state, since a predetermined period has already elapsed after the engine is started, a positive determination is always made in S600 in the subsequent base process, and the counter is incremented each time.
When the counter value reaches N (S620: Y
ES), the counter is reset in S630, and S360
Perform the following processing. That is, after the elapse of the predetermined period, the RAM diagnosis process is executed every time the counter value becomes N (every 50 × N msec.).

As described above, with respect to the control having different execution frequencies before and after a predetermined period elapses after the engine is started, the check frequency of the matching data used for the control processing is set to be different before and after the predetermined period elapses. As in the above embodiment, the processing load of the RAM diagnosis processing by the CPU 71 can be minimized.

In the above embodiment, the present invention has been described assuming that the present invention is applied to a vehicle having a gasoline engine as a prime mover. However, the present invention is not limited to a gasoline engine, but may be a diesel engine or a CNG (natural gas) engine. The type of the prime mover is not particularly limited. For example, the present invention can be applied not only to a mounted vehicle but also to an electric vehicle driven by an electric motor.

In the above embodiment, the sub microcomputer 2
Is checked by comparing the data (mirror value) of the backup RAM 21 with the data (mirror value) of the backup RAM 21. For example, a check sum or parity is added to the conforming data and stored in the RAM 72, and these additional data are used. May be used to check for abnormalities in the adaptation data, and various methods can be used for the RAM check.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a schematic configuration of a plurality of microcomputers included in an engine control ECU according to an embodiment.

FIG. 2 is a flowchart illustrating a compatible data transmission process executed by a CPU of a main microcomputer.

FIG. 3 is a flowchart illustrating an initial process and a base process executed by a CPU of a sub-microcomputer.

FIG. 4 is a flowchart showing another embodiment of the base processing executed by the CPU of the sub-microcomputer.

FIG. 5 is a flowchart showing another embodiment of the base processing executed by the CPU of the sub-microcomputer.

FIG. 6 is a flowchart showing another embodiment of the base processing executed by the CPU of the sub-microcomputer.

FIG. 7 is an explanatory diagram illustrating a schematic configuration of a plurality of microcomputers included in a conventional engine control ECU.

FIG. 8 is an explanatory diagram illustrating a method of restoring normal data again when the RAM is corrupted.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main microcomputer, 2, 70 ... Sub microcomputer, 5 ... Crank angle sensor, 7, 10 ... Engine control ECU, 1
1,71 ... CPU, 12,72 ... RAM, 13,22,
73 ROM, 14, 74 I / O, 21 Backup RAM

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G06F 15/78 510 G06F 15/78 510K

Claims (9)

[Claims] 1. A CPU that executes various processes in accordance with a preset program, a RAM that stores control data used for the execution of various processes by the CPU, A control data storage program for receiving the control data and storing the control data in the RAM;
A function program for executing an arithmetic process for controlling a control target based on the control data stored in the M, and a RAM for checking contents stored in the RAM
A storage medium storing a RAM diagnostic program for periodically executing a diagnostic process; and an operating state detecting means for detecting an operating state of the controlled object; and Diagnostic timing setting means for setting an execution timing of the RAM diagnosis processing realized by execution based on a detection result of the operation state detecting means so as to reduce a processing load on the CPU. Microcomputer. 2. The microcomputer according to claim 1, wherein the microcomputer is mounted on a vehicle to execute various controls on the vehicle. 3. The operation state detection means detects a rotation state of the prime mover, and the diagnostic timing setting means executes the RAM diagnosis processing in synchronization with the rotation of the prime mover based on the rotation state. The microcomputer according to claim 2, wherein the execution timing is set as described above. 4. The operating state detecting means detects a rotating state of the prime mover, and the diagnostic timing setting means executes the RAM diagnosis processing based on the rotating state when the prime mover is not rotating. 3. The microcomputer according to claim 2, wherein the execution timing is set as described above. 5. The operation state detection means detects a rotation state of the prime mover, and the diagnostic timing setting means determines the RAM diagnosis processing based on the rotation state only when the rotation speed of the prime mover is within a predetermined range. 3. The microcomputer according to claim 2, wherein the execution timing is set so that the execution is performed. 6. The operating state detecting means detects a rotation state of the prime mover, and the diagnostic timing setting means executes the RAM diagnosis processing when the prime mover is rotating based on the rotational state, 3. The microcomputer according to claim 2, wherein the execution timing is set such that an execution interval of the RAM diagnosis processing is different before and after a predetermined time elapses after the start of the prime mover. 7. The microcomputer according to claim 1, further comprising: a rewritable backup memory that retains stored contents by being constantly supplied with power by a battery, and wherein the control data is stored. The program is configured so that the CPU stores the control data received from another microcomputer at the time of startup in the RAM and also in the backup memory. For restoring the storage content of the RAM based on the storage content of the backup memory upon abnormal reset of the CPU;
A microcomputer storing an abnormal reset data recovery program. 8. The backup memory, wherein the RA
M, bit inversion data of the control data stored in M is stored. The RAM diagnosis process is performed by comparing the control data stored in the RAM with the bit inversion data stored in the backup memory. The microcomputer according to claim 7, wherein the microcomputer is operated. 9. The diagnostic timing setting means according to claim 1, wherein:
9. The microcomputer according to claim 1, wherein the microcomputer is realized by executing a diagnostic timing setting program by a PU, and the diagnostic timing setting program is stored in the storage medium.