JPH11175331A - Rom rewritting method for lan system for vehicle, and on-vehicle controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform data communication at an appropriate communication speed and to shorten the rewrite time of ROM data. SOLUTION: On-vehicle ECUs 10, 20, 30 and 40 are communicably connected to each other with a communication bus 50. For instance, an erasable and rewritable flash E<2> PROM 14 is provided in the memory part 11 of the ECU 10, and a ROM data rewrite device 60 as an external device is connected to the communication bus 50. In such a LAN system for a vehicle, test signals are transmitted and received at the different communication speeds between the ECU 10 and the ROM data rewrite device 60 and one communication speed is selected from the different communication speeds based on the transmitted and received results of the test signals. The ECU 10 receives data for rewrite from the ROM rewrite device 60 at the selected communication speed and rewrites the contents of the flash E<2> PROM 14 by the received data for the rewrite.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rewriting ROM data of an on-vehicle control device in a vehicle LAN (local area network) system, and a method of rewriting the ROM data.

[0002]

2. Description of the Related Art A vehicle that performs electronic control is provided with a vehicle-mounted control device mainly composed of a microcomputer.
The control device performs various controls based on program data in the ROM. Under such circumstances, an erasable and writable ROM such as a flash memory is employed so that it can be dealt with by changing the ROM data when an engine specification is changed or a trouble occurs in the market, and the ROM data is rewritten by an external rewriting device. Such a technique has been proposed (Japanese Patent Laid-Open No. 6-259982, etc.).

In recent years, with the construction of a vehicle LAN system, a plurality of vehicle-mounted control devices have been connected to be able to communicate with each other via a communication bus. Therefore, it has been considered to connect the in-vehicle control device and the ROM data rewriting device using the communication bus of the vehicle LAN system, and rewrite the ROM data by the rewriting device according to an external request. In this case, a dedicated harness or connector for connecting the ROM data rewriting device to a specific in-vehicle control device is not required, and the cost can be reduced. Incidentally, the connection between the in-vehicle control device and the ROM data rewriting device (external tool) may be achieved by connecting the external tool to a port on the communication bus, for example, in the same way as connecting the diagnostic checker when diagnosing a vehicle abnormality.

[0004]

However, in the above-mentioned prior art, the communication speed (baud rate) of data communicated via the communication bus depends on the length of the communication bus (harness) of the LAN system and the vehicle connected to each other. It is uniquely set according to the number of control devices. The communication speed is generally set to a value of a minimum condition so as to be compatible with all vehicles and various specifications. That is, the communication speed is set based on the slowest speed. Therefore, when the ROM data is rewritten using the LAN system, there is a problem that the data communication speed is generally slow and the rewriting takes time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problem, and has as its object to perform data communication at an appropriate communication speed and to reduce the time for rewriting ROM data. In LAN system for LAN
An object of the present invention is to provide an OM rewriting method and an in-vehicle control device.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a plurality of in-vehicle control devices having a rewritable ROM are connected to be able to transmit and receive via a communication bus. ROM applied to vehicle LAN system
A method for rewriting ROM data in the in-vehicle control device via the communication bus by a data rewriting device, wherein the ROM data rewriting device and the in-vehicle control device to be rewritten have different data rates at different communication speeds. Transmission / reception is performed, and thereafter, one of the different communication speeds is selected based on the result of the data transmission / reception, and the rewriting data is transmitted from the ROM data rewriting device to the in-vehicle control device at the selected communication speed. It is characterized by doing.

[0007] In short, if the specifications of the engine or the option settings are different, the number of on-board controllers differs for each vehicle, and the circuit configuration of each on-board controller differs even in the same vehicle. Therefore, the optimum value of the communication speed differs depending on which vehicle and which control device rewrites the ROM data. On the other hand, according to the above configuration, an appropriate value of the communication speed is selected between the ROM data rewriting device and the vehicle-mounted control device to be rewritten each time before the rewriting of the ROM data is started. Therefore, for example, when communication is possible at a speed higher than the preset communication speed, or when communication is possible at a speed higher than the communication speed (slowest communication speed) of the reference vehicle-mounted control device, The speed can be increased. As a result, data communication can be performed at an appropriate communication speed, and the ROM data rewriting time can be reduced.

According to the second aspect of the present invention, when selecting the communication speed, the communication speed is gradually increased each time.
The transmission / reception of the test signal is performed, and when the transmission / reception of the test signal becomes impossible, the communication speed is determined. In this case, the communication speed may be determined from the communication result immediately before transmission and reception of the test signal is disabled. According to the second and third aspects of the present invention, data communication can be performed at a speed at which communication can be reliably performed.

On the other hand, according to the invention described in claim 4, a vehicle-mounted control device applied to a vehicle LAN system in which a plurality of vehicle-mounted control devices provided with a rewritable ROM are communicably connected via a communication bus. Transmitting and receiving means for transmitting and receiving test signals at different communication speeds to and from the ROM data rewriting device connected via the communication bus; Communication speed selection means for selecting one communication speed from the above, and rewriting means for receiving rewriting data from the ROM data rewriting device at the selected communication speed and rewriting the contents of the ROM with the received rewriting data. And characterized in that:

According to the above configuration, the on-vehicle control device includes:
(1) transmitting and receiving test signals at different communication speeds with the ROM data rewriting device; (2) selecting one communication speed from the different communication speeds based on the test signal transmission and reception results; 3) RO at the selected communication speed
Rewriting data is received from the M data rewriting device, and the contents of the ROM are rewritten with the received rewriting data.

In such a case, the communication can be performed at a speed higher than a predetermined communication speed, or the communication can be performed at a speed higher than a reference vehicle-mounted control device, as in the first aspect of the invention. In such cases, the speed can be increased. As a result, data communication can be performed at an appropriate communication speed, and the ROM data rewriting time can be reduced.

According to the present invention, when the program size of the ROM to be rewritten is small,
A series of processing for selecting the communication speed is stopped. In other words, if the program size (processing capacity) is small, the communication of the rewrite data does not take a long time, and the calculation load is reduced by stopping the calculation process related to the change of the communication speed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The present embodiment is applied to a vehicle LAN system in which a plurality of electronic control units (hereinafter, referred to as ECUs) are connected by a communication bus, and an external device (ROM) is used by using the communication bus of the LAN system. Data rewriting device) rewrites ROM data. Particularly, the system according to the present embodiment is characterized in that the communication speed is appropriately set variably when rewriting the ROM data. The details will be described below.

As shown in FIG. 1, a vehicle LAN system according to the present embodiment includes a plurality of types of in-vehicle ECUs 10 and 2.
0, 30, and 40. Specifically, an engine control ECU 10 for controlling engine fuel injection and the like; a brake control ECU 20 for preventing the wheels from being locked during a brake operation of the vehicle; a wheel idle during the acceleration of the vehicle; A traction control ECU 30 for preventing the vehicle; a constant speed traveling control ECU 4 for causing the vehicle to travel at a constant speed.
0, etc.

The above-described ECUs 10, 20, 30, and 40 are connected by a communication bus 50, and mutually transmit and receive data. Among these ECUs 10 to 40, there are ECUs that are not actually mounted due to the specifications of the vehicle type or the option setting (in FIG. 1, the constant speed traveling control ECU 40 is indicated by a virtual line as an option setting).

Each of the ECUs 10 to 40 is constituted mainly by a well-known microcomputer and has almost the same configuration. The main part of the engine control ECU 10 will be described as an example. That is, the engine control ECU 10 has a memory unit 11, which includes: a mask ROM 12 for storing a ROM data rewriting program and the like, which will be described later; and an E ^ 2 PROM for storing, for example, a vehicle-specific password.
13. Flash E ^ 2PR for storing engine control procedures, etc.
An OM 14; and a RAM 15 for temporarily storing operation data.

The communication bus 50 has R
A ROM data rewriting device (hereinafter, simply referred to as a rewriting device) 60 for rewriting OM data is connectable. The rewriting device 60 is an external device having a microcomputer (not shown), and includes a display screen 61 for displaying an operation menu, an error message, etc.
An operation switch (keyboard) 62 for instructing 10 to 40 ROM data rewriting is provided.

In the LAN system having the above configuration, the EC
The data of each of the flash memories E2 to PROM U10 to U40 are appropriately rewritten in response to a rewrite request from the outside. Here, the rewriting operation will be described by taking the flash E2 PROM 14 of the engine control ECU 10 as an example.

As an outline, the rewriting device 60 is connected to the LAN
When connected to the connection port of the system, a process (FIG. 2) of outputting a rewrite request to the ECU 10 to be rewritten is executed. On the other hand, at the time of the initial operation accompanying the ON operation of the ignition key, the ECU 10
Is performed (FIG. 5).

The detailed operation of the rewriting device 60 will be described with reference to FIGS. When the routine of FIG. 2 starts, the rewriting device 60 first determines in step 110 whether or not there is a rewriting request. Specifically, each of the ECUs 10 to 4
It is determined whether or not the operation switch 62 of the rewriting device 60 has been operated by an operator to rewrite the ROM data in 0. If there is no rewrite request, the rewriting device 60 ends this routine as it is.

If there is a rewrite request, the rewrite device 60 proceeds to step 120 and outputs a signal indicating the rewrite request to the ECU to be rewritten (here, the engine control ECU 10) via the communication bus 50. Then, the rewriting device 6
0 proceeds to step 200, and in accordance with FIGS.
Execute the transfer process of the ROM data.

FIGS. 3 and 4 are flowcharts showing a process of outputting ROM data for rewriting to the ECU 10 to be rewritten. The rewriting device 60 first transmits, for example, a personal identification code unique to the vehicle to the ECU 10 in step 201 of FIG. In the subsequent step 202, the rewriting device 60
Determines whether the ECU 10 has received a response of the rewrite permission to the rewrite request signal in step 120 of FIG. If there is no response of the rewriting permission, the rewriting device 6
If it is 0, the process proceeds to step 203, and it is determined whether or not a predetermined time has elapsed in that state. If there is no response of rewriting permission within a predetermined time (YES in step 203), the rewriting device 60
Displays an error message on the display screen 61 in step 204, and then returns to the original routine of FIG.

When there is a response of the rewriting permission, the rewriting device 60
Performs a process for determining the transmission speed of the ROM data in steps 205 to 210. Specifically, the rewriting device 60
In step 205, the communication speed is gradually changed to the increasing side, and in a succeeding step 206, a test signal is output to the ECU 10 to be rewritten at the communication speed in step 205. In this case, at the beginning of the communication, LA
The slowest speed that can reliably communicate with any ECU in the N system is set (for example, 9.6 kbp).
s).

Then, on condition that there is a response to the test signal (YES in step 207), the rewriting device 60 returns to step 205, and again executes steps 205,
Step 206 is performed. In this case, the test signal is transmitted / received to / from the ECU 10 at each communication speed while gradually increasing the communication speed, for example, twice, three times, four times,... However, the width of changing the communication speed may be finer or wider than the above.)

When there is no response from the ECU 10, the rewriting device 60 proceeds to step 208, and determines whether or not a predetermined time has elapsed in that state. When a predetermined time elapses without a response from the ECU 10 (step 20).
8 is YES), the rewriting device 60 determines that communication is impossible at a higher communication speed, and determines the communication speed in step 209. At the time of this determination, the communication speed is set to the speed one time before (the speed lower than the speed at which there is no response). Then, the rewriting device 60 transmits the communication speed determined in step 210 to the ECU 10.

Thereafter, the rewriting device 60 transmits the rewriting ROM data to the ECU 10 in steps 211 to 215 of FIG.
Send to Specifically, the rewriting device 60 performs step 2
It is determined in step 11 whether there is a data transmission request from the ECU 10. If there is a transmission request, the rewrite data is transmitted in step 214. The data transmission in step 214 is continued until the transmission of all data is completed, that is, until the determination in step 215 is affirmative. Then, when all the rewriting data has been transmitted, the rewriting device 60 returns to the original routine of FIG.

If there is no transmission request in step 211, the rewriting device 60 proceeds to step 212 and determines whether a predetermined time has elapsed in that state. If a predetermined time has elapsed without a transmission request from the ECU 10 (YES in step 212), the rewriting device 60 proceeds to step 213.
After an error message is displayed on the display screen 61, the routine returns to the original routine of FIG.

Next, the detailed operation of the ECU 10 will be described with reference to FIG.
This will be described with reference to FIGS. When Figure 5 starts, EC
U10 first determines in step 310 whether or not a rewrite request signal has been transmitted from the rewrite device 60. If a rewrite request signal from rewriting device 60 has not been received, E
The CU 10 ends this routine as it is.

When a rewrite request is received (step 310)
Is YES), the ECU 10 sets the flash E ^ 2PROM1
4 is copied to the RAM 15, or the program execution mode is switched to the program mode on the RAM 15, that is, the operation mode based on the program stored in the RAM 15. Thereafter, the ECU 10 proceeds to step 400 and executes the rewriting program according to FIGS.

FIGS. 6 and 7 show a flash E ^ 2 PROM 14.
9 is a flowchart showing a process for writing a rewriting program into a program. The ECU 10 determines in step 401 of FIG.
It is determined whether or not the security code transmitted from the rewriting device 60 has been received, and if the security code has been received (step 4).
(YES at 01), at step 403, it is determined whether or not the received password coincides with a password stored in advance in the E ^ 2 PROM 13 of the ECU 10. If the passwords match, the ECU 10 transmits a rewrite permission signal to the rewriting device 60 in step 404.

If the password is not received in step 401, the ECU 10 proceeds to step 402,
It is determined whether a predetermined time has elapsed in that state. If the predetermined time has elapsed without receiving the password, or if the passwords do not match, the ECU 10 returns to the original routine of FIG.

After transmitting the rewrite permission signal, the ECU 10
In steps 405 to 410, the communication speed is determined.
That is, a test signal is transmitted from the rewriting device 60 to the ECU 10 while gradually increasing the communication speed. At this time, in step 405, the communication speed is changed based on the signal from the rewriting device 60, and in the following step 406, it is determined whether or not the test signal from the rewriting device 60 has been successfully received. When the test signal can be received normally, the ECU 10
Transmits a response signal to the rewriting device 60 in step 407, and thereafter returns to step 405.

When the test signal cannot be received, the ECU
10 proceeds to step 408, at which point the rewriting device 60
It is determined whether or not the communication speed transmitted from is received. If the communication speed from the rewriting device 60 has been received, E
The CU 10 determines that the transmission of the ROM data starts at the communication speed, and determines the communication speed in the next step 409.

If the communication speed has not been received, the ECU 1
If it is 0, the process proceeds to step 410, in which it is determined whether or not a predetermined time has elapsed. When the predetermined time has elapsed without receiving the communication speed, the ECU 10 returns to the original routine of FIG.

When the communication speed is determined, the ECU 10 proceeds to FIG.
To the step 411 of the flash E ^ 2 PROM 14
Of the predetermined area is erased. After that, the ECU 10
At step 412, a transmission request signal is transmitted to the rewriting device 60. Further, the ECU 10 receives the rewrite data from the rewriting device 60 in step 413, and in step 414, stores the received rewrite data in the flash E ^ 2 PROM 14.
Is written in a predetermined area.

The ECU 10 repeatedly executes the processing of steps 412 to 414 until the rewriting of all data is completed (until step 415 becomes YES). When the rewriting of all data is completed, the ECU 10 proceeds to step 4
16 to change the program execution mode to flash E ^ 2PROM
14, the program mode, ie flash E ^ 2P
After switching to the operation mode of the program stored in the ROM 14, the process returns to the original routine of FIG.

In this embodiment, steps 405 to 407 in FIG. 6 correspond to the transmitting / receiving means described in the claims.
Steps 408 and 409 correspond to the communication speed selecting means, and steps 411 to 415 in FIG. 7 correspond to the rewriting means. Steps 320 and 330 in FIG. 5 correspond to first operation switching means, and step 416 in FIG. 7 corresponds to second operation switching means.

According to this embodiment described in detail above, the following effects can be obtained. In the present embodiment, the rewriting device 6
0 and the ECU 10 perform transmission and reception of test signals at different communication speeds, select one of the different communication speeds based on the transmission and reception results of the test signal, and further select the communication speed at the selected communication speed. The rewriting data is received from the rewriting device 60, and the contents of the flash E ^ 2 PROM 14 are rewritten with the received rewriting data.

In short, if the specifications and options of the engine are different, the number of on-vehicle ECUs differs for each vehicle, and the circuit configuration of each on-vehicle ECU differs even in the same vehicle. According to the above configuration, for example, a case where communication is possible at a speed higher than a preset communication speed, or a case where communication is possible at a speed higher than a communication speed (slowest communication speed) of a reference vehicle-mounted ECU In such cases, the speed can be increased. As a result, data communication can be performed at an appropriate communication speed, and the ROM data rewriting time can be reduced.

In selecting a communication speed, a test signal is transmitted and received each time while gradually increasing the communication speed, and when the transmission and reception of the test signal become impossible, the communication speed is determined. At this time, the communication speed is determined from the result of the communication just before the transmission and reception of the test signal was disabled. In such a case, data communication can be performed at a speed at which communication can be reliably performed.

The embodiment of the present invention can be realized in the following modes other than the above. As an initial value when changing the communication speed, for example, a value corresponding to the number of ECUs on the LAN system is set. Specifically, E on the LAN system
The larger the number of CUs, the smaller the initial value of the communication speed and the same EC
As U decreases, the initial value of the communication speed increases.

When the communication speed is changed by the rewriting device 60 (steps 205 to 207 in FIG. 3), in the above embodiment, the communication speed is doubled, tripled, quadrupled,.
In this manner, the communication speed is gradually increased, and when the response to the test signal has ceased, the speed one time before is used as the communication speed at that time, but this is changed to set the communication speed more finely. If the communication speed is doubled → tripled → quadrupled from the initial value, for example, if communication becomes impossible due to “initial value × four times”,
The communication is performed again with "initial value x 3.5 times". If communication is still impossible, the communication speed is determined as "initial value x 3 times". If communication is possible, the communication speed is set to "initial value x 3.5". Times "
To be determined.

In the above embodiment, the rewritable ROM
Flash E ^ 2 PROM was used as the
It may be changed to PROM. When the program size of the ROM to be rewritten is small, a series of communication speed selection processing (the processing of the rewriting device 60 shown in FIGS.
In addition, the processing of FIGS. In other words, if the program size (processing capacity) is small, the communication of the rewrite data does not take a long time, and the calculation load is reduced by stopping the calculation process related to the change of the communication speed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an outline of a vehicular LAN system according to an embodiment of the invention.

FIG. 2 is a flowchart showing a process of transmitting a rewrite request by the ROM data rewriting device.

FIG. 3 is a flowchart showing processing of ROM data transfer.

FIG. 4 is a flowchart showing a process of ROM data transfer following FIG. 3;

FIG. 5 is a flowchart showing a data rewriting process by the ECU.

FIG. 6 is a flowchart showing a rewriting program.

FIG. 7 is a flowchart showing a rewriting program following FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Engine control ECU, 11 ... Memory part, 14 ... Flash E ^ 2PROM, 15 ... RAM, 20 ... Brake control ECU, 30 ... Traction control ECU, 40 ... Constant speed running control ECU, 50 ... Communication bus, 60 ... ROM Data rewriting device.

Claims (5)

[Claims] 1. A vehicle LAN system in which a plurality of in-vehicle control devices having a rewritable ROM are communicably connected via a communication bus. ROM in the control unit
A method for rewriting data, comprising: transmitting and receiving data at a different communication speed between the ROM data rewriting device and the on-board controller to be rewritten; A method for rewriting ROM in a vehicle LAN system, wherein one of the communication speeds is selected from the following, and rewriting data is transmitted from the ROM data rewriting device to the on-vehicle control device at the selected communication speed. 2. The method according to claim 1, further comprising: transmitting and receiving a test signal each time while gradually increasing the communication speed.
2. The method of rewriting ROM in a vehicle LAN system according to claim 1, wherein the communication speed is determined when the transmission and reception of the test signal become impossible. 3. The transmission / reception of the test signal is disabled.
3. The method according to claim 2, wherein the communication speed is determined from a result of the previous communication. 4. An in-vehicle control device applied to a vehicular LAN system in which a plurality of in-vehicle control devices provided with a rewritable ROM are communicably connected via a communication bus. Transmitting / receiving means for transmitting / receiving a test signal at different communication speeds to / from a connected ROM data rewriting device; and communication for selecting one communication speed from among the different communication speeds based on a result of transmission / reception of the test signal. A vehicle, comprising: speed selecting means; and rewriting means for receiving rewriting data from the ROM data rewriting device at the selected communication speed, and rewriting the contents of the ROM with the received rewriting data. Control device. 5. The in-vehicle control device according to claim 4, wherein when the program size of the ROM to be rewritten is small, the series of processing for selecting the communication speed is stopped.