JP2004005152A - Rewriting device for nonvolatile memory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically change over communication programs and to execute the rewriting when failing in the rewriting of an application program stored in a nonvolatile memory. <P>SOLUTION: A rewriting device stores the application program and a communication program (1) in a block B of a flash memory 4, stores a rewriting decision program and a communication program (2) in a block A of the flash memory 4, and rewrites decision data in the block B when the rewriting of the application program is completed. When the decision data is not rewritten in rewriting, the rewriting device decides that the rewriting fails, changes over to the communication program (2), and executes the rewriting. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a non-volatile memory in which data is electrically erased in block units, for example, a non-volatile memory rewriting device used for an engine control unit of a vehicle or the like.
[0002]
[Prior art]
Conventionally, as a rewriting device for a nonvolatile memory (flash memory) in which data is electrically erased in block units, there has been one disclosed in JP-A-2001-229014.
In this configuration, two communication programs for communicating with an external tool are stored in separate blocks of a flash memory, and a switch for selecting which of the two communication programs is used is provided.
[0003]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional device, when rewriting of the block storing the first communication program fails, it is possible to select the second communication program by a switch operation and to communicate with the external tool at the time of rewriting. However, the provision of the switch increases the number of parts, increases the number of steps by the switch operation, and lowers the efficiency.
[0004]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a rewriting device for a nonvolatile memory capable of accurately determining occurrence of a rewriting error and automatically switching communication programs. And
[0005]
[Means for Solving the Problems]
Therefore, according to the first aspect of the present invention, a plurality of communication programs for communicating with the external tool are stored in separate blocks, and the determination data for determining the rewriting error after the completion of the rewriting of the program is stored in a predetermined storage area. Before the rewriting of the program is started, the normal / abnormal judgment of the judgment data is performed, and a communication program used for communication with an external tool is selected based on the judgment result.
[0006]
According to the above configuration, when the rewriting of the program is completed, the data for determining the rewriting error is written to the predetermined storage area, and before the start of the rewriting, the judgment data is normal or abnormal. Is determined, and a communication program to be used for rewriting is selected.
Therefore, when rewriting is performed, the occurrence of an error in the previous rewriting (writing failure, rewriting to an incorrect program) is determined based on the determination data. The communication program can be automatically selected and rewritten.
[0007]
According to the second aspect of the present invention, as the plurality of communication programs, the first communication program stored in the same block as the application program to be rewritten and the second communication program stored in a block different from the first communication program Before the rewriting of the application program is started, the first communication program is used when the determination data is determined to be normal, and the second communication program is used when the determination data is determined to be abnormal. Communication with external tools is performed.
[0008]
According to the above configuration, when it is determined from the determination data that the rewriting of the application program has failed, the rewriting of the first communication program stored in the same block has also failed. Use it to communicate with external tools to enable rewriting.
Therefore, even if the rewriting of the application program fails and, at the same time, the first communication program becomes unusable, it is possible to automatically switch to the second communication program and rewrite the application program.
[0009]
In the invention according to claim 3, when the storage area of the determination data is set in the same block as the block in which the application program and the first communication program are stored, and the determination data is not written in the predetermined storage area, , It is configured to be determined to be abnormal.
According to the above configuration, after the judgment data is erased along with the rewriting, if the rewriting is not completed and the judgment data is not rewritten, it is determined that the rewriting is abnormal and the second communication program is used. Communication.
[0010]
Therefore, the rewriting failure is reliably determined based on the determination data. According to the fourth aspect of the present invention, the comparison data to be compared with the determination data is previously stored in a block in which the second communication program is stored, and the determination data stored in the application program after the rewriting of the application program is completed. Is written in a predetermined storage area, and a mismatch between the comparison data and the determination data is determined to be abnormal.
[0011]
According to the above configuration, the comparison data is stored in advance in a block different from the block in which the application program is stored, and the determination data stored in the application program is written upon completion of rewriting, and the written determination is performed. By comparing the data with the comparison data, it is determined whether the data has been rewritten to a desired application program registered in the nonvolatile memory in advance.
[0012]
Therefore, the correlation between the memory and the application program to be stored is set for each nonvolatile memory, and it is possible to reliably determine whether or not the rewritten application program is unauthorized.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a block diagram showing an overall configuration of a nonvolatile memory rewriting device according to the embodiment.
In FIG. 1, an engine control unit (hereinafter abbreviated as ECU) 1 is for controlling a fuel supply amount and an ignition timing in a vehicle engine. It is configured to include a flash memory (non-volatile memory) 4 that is erased in a permanent manner.
[0014]
The microcomputer 2 includes a CPU, a built-in RAM, a timer, an A / D converter, an SCI, and the like, and executes various programs stored in the RAM 3 and the flash memory 4.
The storage area of the flash memory 4 includes a block A and a block B.
[0015]
The block A stores a rewrite determination program for determining a rewrite error of the application program, and a communication program (2) (second communication program) for communicating with an external tool at the time of rewrite.
The rewriting determination program is a program having a function of determining whether or not determination data described later is normal when power is turned on.
[0016]
The rewriting determination program stores comparison data (reference data) to be compared with the determination data in advance.
The comparison data is set, for example, as information for identifying a vehicle type to which the ECU 1 corresponds.
The communication program (2) is a program having a function of initializing the communication system at the time of startup and a function of transferring a program stored in an external tool to the RAM 3 when a request for rewriting the flash memory 4 is made.
[0017]
On the other hand, the block B is a block where rewriting is performed, and stores a communication program (1) (first communication program) for communicating with an external tool at the time of rewriting, and an application program for engine control. , A storage area for the determination data is set.
Like the communication program (2), the communication program (1) has a function of initializing the communication system at startup and a function of transferring a program stored in an external tool to the RAM 3 when a request for rewriting the flash memory 4 is made. This is a program having
[0018]
The application program for engine control has a function of inputting detection signals from various sensors provided in a vehicle engine, performing arithmetic processing, and outputting control signals for a fuel injection valve, a spark plug (power transistor), and the like. It is a program equipped.
The storage area for the determination data is an area in which determination data used for determining a rewrite error is stored after the verification of the flash memory 4 is performed.
[0019]
The flash writing tool 5 as an external tool stores an erasing & writing program and a new engine control application program, and is connected to the ECU 1 via a communication line 6.
The rewriting process of the application program in the above configuration will be described with reference to the flowcharts of FIGS.
[0020]
When the flash writing tool 5 and the ECU 1 are connected via the communication line 6 and a power supply voltage is supplied to the ECU 1, the determination data stored in the determination data storage area is normal in step S100 of the flowchart of FIG. The determination as to whether the data is abnormal or not is performed by the function of the rewrite determination program.
The determination of normality / abnormality is determined as normal if the comparison data stored in the rewrite determination program in advance matches the determination data stored in the determination data storage area, and the two data do not match. The time and the case where no data is stored in the determination data storage area are determined to be abnormal.
[0021]
If it is determined that the determination data is normal, the process proceeds to step S110 to perform the processing of the communication program (1). If it is determined that the determination data is abnormal, the process proceeds to step S120 and the communication program (2) Is performed.
The flowchart of FIG. 3 shows the processing of the communication program (1). In step S200, communication between the ECU 1 and the flash writing tool 5 is established. In the next step S210, the flash writing tool 5 The stored erase & write program and new application program are transferred to the RAM 3.
[0022]
The flowchart of FIG. 4 shows the processing of the communication program (2). Like the processing of the communication program (1), first, in step S300, communication between the ECU 1 and the flash writing tool 5 is performed. In the next step S310, the erasing and writing program and the new application program stored in the flash writing tool 5 are transferred to the RAM 3.
[0023]
When the erase / write program and the new application program are transferred to the RAM 3 by the communication program (1) or the communication program (2), the process proceeds to step S130 in the flowchart of FIG. .
The flowchart of FIG. 5 shows the processing of the erase & write program. In step S400, the block B of the flash memory 4 is erased, and then the new application program is written in the storage area of the block B.
[0024]
Since the communication program (1) is erased together with the old application program by erasing the block B, the writing of the communication program (1) is performed simultaneously.
The writing of the communication program (1) may be performed by transferring the communication program (1) from the flash writing tool 5 to the RAM 3 together with the new application program.
[0025]
In step S410, verification is performed.
The verifying determines whether or not the program actually written in the flash memory 4 matches the program transmitted from the flash writing tool 5.
In step S420, it is determined from the verify determination whether the program contents match or a mismatch occurs due to the influence of noise or the like.
[0026]
Then, when it is determined that the program contents do not match, the process returns to step S400, and the erasing and writing operations are performed again.
If the program contents match, and it is determined that the rewriting of the program has been completed, the process proceeds to step S140 in the flowchart of FIG. 2, and the determination data is stored in the determination data storage area.
[0027]
The determination data is stored in advance in the new application program. For example, information on a vehicle type corresponding to the new application program is stored as determination data in the determination data storage area.
The rewriting process ends at the end of the storage of the determination data in step S140, but before the process in step S140 ends, the power supply is stopped or an error occurs in communication, so that the erasing process in step S130 is terminated. If the writing process is interrupted, the process does not proceed to step S140, so that the determination data is not written in the determination data storage area.
[0028]
If the judgment data is not written in the judgment data storage area, the judgment data is determined to be abnormal because there is no judgment data to be compared with the comparison data during the rewriting process.
If it is determined that the determination data is abnormal, a communication program (2) that is not erased / written is selected, and communication between the ECU 1 and the flash writing tool 5 is performed using the communication program (2). Will be established.
[0029]
Therefore, the communication program (2) is automatically selected in place of the communication program (1) that has failed to be rewritten and is unusable, and the application program can be rewritten using the communication program (2). The rewriting process can be performed efficiently.
Further, even when rewriting is completed, when an unauthorized (for example, for a different vehicle type) application program is rewritten, the determination data corresponding to the different vehicle type stored in the unauthorized application program is stored when the rewriting is completed. Is stored.
[0030]
Therefore, when it is determined that the determination data and the comparison data do not match, it is determined that the ECU 1 has been rewritten to an application program that is not an application program corresponding to a vehicle type to be supported.
Also in this case, since the communication program (2) is switched based on the abnormality determination of the determination data, the communication between the flash writing tool 5 and the ECU 1 is normally performed regardless of the contents of the rewritten communication program (1). By performing communication, rewriting to a correct application program can be performed.
[0031]
In the above embodiment, rewriting of the flash memory 4 provided in the ECU 1 has been described, but it is apparent that the present invention is not limited to the ECU 1.
Further, technical ideas other than the claims that can be grasped from the above embodiment will be described below together with their effects.
(A) The rewriting device for a nonvolatile memory according to any one of claims 1 to 4,
A rewriting device for a non-volatile memory, wherein a verify operation is performed after erasing and writing of the non-volatile memory, and the judgment data is written after a normal judgment is made by the verification.
[0032]
According to the above configuration, verification is performed to check whether or not the program has been correctly written. If there is a write error due to the influence of noise or the like, rewrite is performed, and finally there is no write error. After the determination is made, the determination data is written.
Therefore, it is possible to avoid writing of the determination data in a state where there is a writing error, and it is possible to correctly determine whether rewriting has failed based on the presence or absence of the determination data and to select a communication program.
(B) The rewriting device for a nonvolatile memory according to claim 4,
The nonvolatile memory is a nonvolatile memory provided in an engine control unit that controls an engine,
As the comparison data, while setting information indicating a vehicle type corresponding to the engine control unit,
A non-volatile memory rewriting device for writing data indicating a vehicle type corresponding to a rewritten application program as the determination data.
[0033]
According to the above configuration, when the data indicating the vehicle type corresponding to the new application program is written as the determination data when rewriting is completed, the vehicle type information indicated by the determination data is different from the vehicle type information indicated by the comparison data stored in advance. , It is determined that application programs corresponding to different vehicle types have been written.
[0034]
Therefore, it is possible to reliably determine that the application program adapted to the vehicle type is erroneously written in the engine control unit corresponding to the different vehicle type, and in this case, the communication program can be switched and rewritten.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a flash memory (nonvolatile memory) rewriting device according to an embodiment;
FIG. 2 is a flowchart showing a main routine of a flash memory rewriting process.
FIG. 3 is a flowchart showing processing of a communication program (1).
FIG. 4 is a flowchart showing processing of a communication program (2).
FIG. 5 is a flowchart showing processing of an erase & write program.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine control unit (ECU), 2 ... microcomputer, 3 ... RAM, 4 ... Flash memory (non-volatile memory), 5 ... Flash writing tool, 6 ... Communication line

Claims (4)

A non-volatile memory rewriting device in which data is electrically erased in block units,
While a plurality of communication programs for communicating with the external tool are stored in separate blocks, judgment data for judging a rewrite error is written in a predetermined storage area after the rewrite of the program is completed, and before the rewrite of the program is started, A non-volatile memory rewriting device for performing a normal / abnormal judgment on the judgment data and selecting a communication program to be used for communication with the external tool from the plurality of communication programs based on the judgment result. . As the plurality of communication programs, a first communication program stored in the same block as the application program to be rewritten, and a second communication program stored in a block different from the first communication program,
Before the rewriting of the application program is started, when it is determined that the determination data is normal, the communication with the external tool is performed using the first communication program, and the determination data is abnormal. 2. The non-volatile memory rewriting device according to claim 1, wherein when it is determined, communication with the external tool is performed using the second communication program. The predetermined storage area is set in the same block as the block where the application program and the first communication program are stored,
3. The non-volatile memory rewriting device according to claim 2, wherein before the rewriting of the program is started, when the judgment data is not written in the predetermined storage area, it is judged that there is an abnormality. Comparison data for comparison with the determination data is stored in advance in a block in which a second communication program is stored, and after the rewriting of the application program is completed, the determination data stored in the application program is stored in a predetermined storage area. 4. The non-volatile memory rewriting device according to claim 2, wherein the comparison data and the determination data are determined as abnormal if the comparison data does not match.

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