JP3489524B2 - Non-volatile memory rewriting device for vehicle - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a nonvolatile memory rewriting for a vehicle , which has a non-volatile memory storing a communication program for communicating with an external tool and rewrites the communication program. It relates to the device.

[0002]

2. Description of the Related Art As shown in FIG. 5, an electronic control unit (ECU) 11 functioning as a flash rewriting device includes a flash memory 12, a RAM 13, and a microcomputer 14. A storage area of the flash memory 12 is divided into two blocks A and B, and the stored data is erased for each block when rewriting. This flash memory 12
In block A, a boot program for initializing the system at the time of startup and a communication program for communicating with the external tool 15 are stored in block A.
Stores application programs for executing various controls.

At the time of rewriting the storage program of the flash memory 12, the communication program stored in the flash memory 12 is executed in response to the write request from the external tool 15, and the flash write program from the external tool 15 is transferred to the RAM 13. . Then, by executing this writing program, the storage block (A or B) to be rewritten is erased, and then a new program from the external tool 15 is written to the storage block.

[0004]

By the way, when rewriting the application program, the old application program stored in the block B is erased, and the new application program is written in the block B. In the middle of this writing, even if rewriting fails due to power cutoff or noise,
Since the communication program of block A is not erased,
The application program can be rewritten again.

However, when the communication program is rewritten, the old program (boot program + communication program) stored in the block A is erased.
If the rewriting fails, the normal program does not exist in the block A. Therefore, the ECU 11
Cannot communicate with the external tool 15 and cannot rewrite the flash memory 12.

The present invention has been made in view of the above problems, and an object thereof is a vehicle capable of communicating with an external tool even if rewriting of a communication program fails. A non-volatile memory rewriting device is provided.

[0007]

According to the invention described in claim 1, in a nonvolatile memory having a storage area divided into a plurality of blocks, a plurality of communication programs for communicating with an external tool are provided in different blocks. Is stored. The plurality of communications
Programs include communication programs with different communication methods
It is composed of. Then, any one of the plurality of communication programs is selected by the program selecting means, and the communication program is executed to communicate with the external tool. As a result, the communication programs other than the communication program selected by the program selecting means are rewritten.

When rewriting the stored data in the nonvolatile memory, new data is written after the stored data is erased in block units. Therefore, when the rewriting is interrupted due to the power interruption or the like, the communication program stored in the rewriting target block is erased. In other words, when the communication program is rewritten, if the communication program itself executed at that time is rewritten, communication with an external tool cannot be performed due to rewriting failure. On the other hand, in the present invention, a communication program different from the communication program executed to communicate with the external tool is rewritten. In this case, even if the rewriting of the communication program fails, the communication program executed at the time of rewriting is not erased. Therefore, in the subsequent re-communication, the communication program in the non-volatile memory that has not been erased can be used to communicate with the external tool, and the communication program can be rewritten again.
That is, even if the rewriting of the communication program fails, the inconvenience that the rewriting cannot be normally performed does not occur. Also, depending on the external tool used
A non-volatile memo is created by a communication program of an effective communication method.
Rewriting is performed.

According to the second aspect of the present invention, the initial program executed for initializing at the time of startup is stored in a block different from the block in which the communication program is stored. In this case, since it is not necessary to rewrite the initial program together with the communication program, even if the rewriting of the communication program fails, the initial setting at startup can be performed.

According to the third aspect of the present invention, when the communication program is rewritten, the operator operates the switch means so that any one of the plurality of communication programs communicates with the external tool. Set as a valid program. Then, the state of the switch means is monitored by the program selecting means, and the effective communication program is selected. In this case, the operator can select a communication program for communicating with the external tool. Further, even if the communication program rewriting fails, if the state of the switch means is maintained, the same communication program is validated, and the rewriting of the communication program whose rewriting has failed due to the execution of the same communication program is performed again. it can.

According to the fourth aspect of the invention, the latest communication program is determined from among the plurality of communication programs, and the latest communication program is selected as the communication program for communicating with the external tool. That is, the latest communication program is the communication program last rewritten in the nonvolatile memory, and the other communication programs are rewritten using the latest communication program. In this case, the latest communication program of the plurality of communication programs is selected as an effective communication program each time communication with the external tool is performed, which is preferable in practice.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The present embodiment is embodied in an electronic control unit (ECU) applied to a vehicle control system.

FIG. 1 shows an ECU 1 according to this embodiment.
The schematic configuration of is shown. In FIG. 1, the ECU 1 includes a flash memory 2, a RAM 3, and a microcomputer 4.

The memory area of the flash memory 2 is divided into four blocks A, B, C, and D, and at the time of rewriting, erasing and writing of stored data are performed in block units. In the flash memory 2, a block A stores a boot program and a determination program, a block B stores a first communication program, a block C stores a second communication program, and a block D stores an application program. There is. The boot program is
The determination program is a program for initializing the system at startup, and the determination program is a program for determining which of the first communication program and the second communication program is to be executed. The first communication program and the second communication program are programs for communicating with the outside, and the application program is a program for executing various controls necessary for driving the vehicle. In the present embodiment, the boot program and the determination program stored in block A correspond to the initial program.

The RAM 3 is a memory for temporarily storing predetermined data. In the present embodiment, this RAM 3 is used.
In addition, the program data transferred from the flash writing tool 5 is temporarily stored.

The microcomputer 4 is a well-known CPU and built-in RA.
An M, a timer, an A / D converter, an SCI, and the like are provided, and are configured to execute various programs stored in the flash memory 2, the RAM 3, and the like.

Further, the input terminal P1 of the microcomputer 4 is connected to the switch SW1, and the switch SW1 is connected to Vc.
By switching to the (high potential) side or the ground (low potential) side, the input terminal P1 becomes the Hi or Lo level. Then, the microcomputer 4 selects which of the first communication program and the second communication program stored in the flash memory 2 to execute, depending on the state of the input terminal P1. In particular,
The switch SW1 is operated by the operator and the input terminal P1
Goes to the Hi level, the first communication program is selected, and conversely, when the input terminal P1 goes to the Lo level, the second communication program is selected.

The input terminal P2 of the microcomputer 4 is grounded via the resistor R1 and is also connected to the flash writing tool 5. In this case, the input terminal P2
Is switched to the Hi or Lo level by the signal output from the flash writing tool 5. Then, the microcomputer 4 determines whether or not there is a write request of the flash memory 2 according to the state of the input terminal P2, and selects whether to execute the communication program or the application program. Specifically, when a worker or the like operates the flash writing tool 5 and the output signal thereof causes the input terminal P2 to reach the Hi level, it is determined that there is a writing request and the communication program is executed. On the other hand, when the input terminal P2 becomes Lo level, it is determined that there is no write request, and the application program is executed.

The ECU 1 and the flash writing tool 5 are connected by a communication line 6,
Communication is performed between the ECU 1 and the flash writing tool 5 via the communication line 6. By this communication,
The flash writing program and the new communication program are transmitted from the flash writing tool 5 to the ECU 1.
At this time, the flash writing program and the new communication program are transferred to the RAM 3, and the flash writing program transferred to the RAM 3 is executed by the microcomputer 4, whereby the new communication program is written from the RAM 3 to the flash memory 2.

In the ECU 1 in the present embodiment, when the switch SW1 is connected to the Vc side and the microcomputer 4 executes the first communication program, the second communication program is rewritten. On the other hand, when the switch SW1 is connected to the ground side and the second communication program is executed by the microcomputer 4, the first communication program is rewritten.

In this embodiment, the flash writing tool 5 corresponds to an external tool, and the switch SW1 corresponds to a switch means. Of the various processes executed by the microcomputer 4, the process of rewriting the communication program stored in the flash memory 2 will be described with reference to FIGS. 2 and 3. When rewriting the communication program, the operator first sequentially performs the following operations (a) to (c). (A) The switch SW1 is operated to select the communication program to be rewritten, and the input terminal P1 is set to the Hi or Lo level. (B) The flash writing tool 5 is connected to the ECU 1, and the flash writing tool 5 is operated to set the input terminal P2 to the Hi level. (C) The power switch is turned on to supply the power voltage to the ECU 1.

After the operation (c), the determination program is executed by the microcomputer 4 and the processing shown in FIG. 2 is performed.
Specifically, the microcomputer 4 detects the state (potential level) of the input terminal P1 in step 100 of FIG. 2, and determines in step 110 whether or not the potential level is the Hi level. Then, when a positive determination is made in step 110, the microcomputer 4 jumps to the first communication program stored in the block B of the flash memory 2 and executes the first communication process shown in FIG. On the other hand, step 1
When a negative determination is made in 10, the microcomputer 4 jumps to the second communication program stored in the block C of the flash memory 2 and executes the second communication processing shown in FIG.

In step 200 of FIG. 3, the microcomputer 4 detects the state (potential level) of the input terminal P2, and in the following step 210, it determines whether or not the potential level is Hi level. Then, if an affirmative determination is made in step 210, it is determined that there is a write request from the flash writing tool 5, and the rewriting processing from step 220 onward is executed. On the other hand, when a negative determination is made in step 210, the microcomputer 4 determines that there is no write request, and jumps to the application program without executing the rewriting process.

At step 220, the microcomputer 4 transfers the flash writing program and the new communication program received from the flash writing tool 5 to the RAM 3. After that, in step 230, the microcomputer 4 sets the RAM
3 jumps to the flash writing program transferred to step 3, and executes the flash writing program. By executing this program, the microcomputer 4 executes step 2
The storage area of the block C is erased at 40, and in the following step 250, the new communication program once stored in the RAM 3 is written as a second communication program into the storage area of the block C, and then this processing is terminated.

Further, in step 300 of FIG. 4, the microcomputer 4 detects the state (potential level) of the input terminal P2, and in the following step 310, it is determined whether or not the potential level is Hi level. Then, when the determination in step 310 is affirmative, the microcomputer 4 determines that there is a write request from the flash writing tool 5, and executes the rewriting process from step 320 onward. On the other hand, when a negative determination is made in step 310, the microcomputer 4 determines that there is no write request, and jumps to the application program without executing the rewriting process.

At step 320, the microcomputer 4 transfers the flash writing program and the new communication program received from the flash writing tool 5 to the RAM 3. After that, in step 330, the microcomputer 4 sets the RAM
3 jumps to the flash writing program transferred to step 3, and executes the flash writing program. By executing this program, the microcomputer 4 executes step 3
At 40, the storage area of the block B is erased, and at step 350, the new communication program once stored in the RAM 3 is written as the first communication program in the storage area of the block B, and then this processing is terminated.

As described above, when the switch SW1 is switched to the Vc side, the first communication program is selected,
By executing the program, the second communication program stored in the block C different from the first communication program is rewritten. On the other hand, switch SW
When 1 is switched to the ground side, the second communication program is selected and executed, thereby rewriting the first communication program stored in the block B different from the second communication program. Is carried out.

Further, during the rewriting of the communication program, if the rewriting fails due to the influence of power interruption or noise, the flash writing tool 5 warns that the rewriting has failed. In this case, the state of the switch SW1 is held and the operations (b) and (c) are performed again, so that the same communication program is rewritten.

Specifically, when the switch SW1 is connected to the ground side and the rewriting of the first communication program fails, the first communication program is erased at the time of rewriting, so that the flash memory 2 is stored. Although not present, the second communication program executed at that time is stored in the flash memory 2 as it is. Therefore, the switch S
The above operations (b) and (c) are performed again with W1 connected to the ground side. As a result, FIG. 2 and FIG.
Is performed, and the first communication program is rewritten. On the other hand, when the switch SW1 is connected to the Vc side, the above operations (b) and (c) are performed again with the switch SW1 being connected to the Vc side. As a result, the processes of FIGS. 2 and 3 described above are performed, and the second communication program is rewritten.

When a communication program that does not operate normally is written in the flash memory 2 by mistake, it is determined by the operator that the communication program does not operate normally when the switch SW1 is switched to execute the communication program. To be done. In this case, the operator returns the switch state to the original state, the communication program which operates normally is selected again, and the rewritten communication program is rewritten.

When the application program is rewritten, the flash writing tool 5 transfers the flash writing program and the new application program to the RAM 3. Then, by executing the flash writing program, the new application program transferred to the RAM 3 is written in the storage block D of the flash memory 2.

Further, in the ECU 1 of the present embodiment,
By storing two programs having different communication protocols in the flash memory 2 as the first and second communication programs, the flash memory 2 is rewritten by two types of communication methods. Specifically, for example, the first compatible with two types of flash writing tools 5 having different communication interfaces (RS232C, USB, etc.)
And the second communication program is stored in the flash memory 2. In this case, the operator rewrites the flash memory 2 by selecting the effective communication program by switching the switch SW1 according to the flash writing tool 5 used at the time of rewriting.

In the present embodiment, the process of FIG. 2 corresponds to the program selecting means, and steps 220 to 2 of FIG.
50 and the processing of steps 320 to 350 in FIG. 4 correspond to the program rewriting means.

According to this embodiment described in detail above, the following effects can be obtained. (1) Two communication programs for communicating with the outside are stored in separate blocks B and C of the flash memory 2,
A communication program different from the communication program executed to communicate with the flash writing tool is rewritten. In this case, even if the rewriting of the communication program fails, the communication program executed at the time of rewriting is not erased. Therefore, in the subsequent re-communication, the communication program that has not been erased can be used to communicate with the flash writing tool, and the communication program can be rewritten again. Therefore, even if the rewriting of the communication program fails, the inconvenience that the rewriting cannot be performed does not occur.

(2) In the flash memory 12 in the conventional device 11 of FIG. 5, the boot program and the communication program are stored in the same block A. To rewrite the communication program, the boot program and the communication program are booted together. The program had to be rewritten. On the other hand, in the present embodiment, the initial program (boot program + judgment program) and the first and second communication programs are stored in separate blocks A, B, and C, respectively. Therefore, the first communication program or the second communication program can be rewritten without rewriting the initial program. Since the boot program is a program for initializing the system, if the rewriting fails, the system malfunctions, but it is not necessary to rewrite the boot program together with the communication program as in the past. Therefore, there is no inconvenience that the system malfunctions due to the failure to rewrite the communication program.

(3) The operator can select the communication program executed by the microcomputer 4 and the communication program to be rewritten by switching the switch SW1.

The present invention can be embodied in the following modes other than the above. In the above-described embodiment, the configuration is such that the operator selects the communication program, but the microcomputer itself may select the communication program. Specifically, the microcomputer 4 executes the first communication program and rewrites the second communication program in response to the write request from the flash writing tool 5.
When the rewriting is completed, the microcomputer 4
Select the second communication program as a valid communication program. After that, the microcomputer 4 executes the second communication program in response to the write request from the flash writing tool 5, and rewrites the first communication program.
When the rewriting is completed, the microcomputer 4
Select the first communication program as a valid communication program. According to this structure, the latest communication program last rewritten in the flash memory 2 is used to rewrite a different communication program. In other words, the latest communication program is selected as an effective communication program every time when communicating with the flash writing tool 5, which is practically preferable. Further, at this time, the instruction by the operator is unnecessary.

In the above-described embodiment, the potential level of the input terminal P1 is switched by the switch SW1. However, like the input terminal P2, the input terminal P1 is grounded via a resistor to output from the flash writing tool 5. The potential level may be switched by a signal. In this case, the flash writing tool 5 corresponds to the switch means, and the operator operates the tool 5 to switch the potential level of the input terminal P1, and based on this, the first communication program and the second communication program. Either of the communication programs is effective.

In the above embodiment, the flash memory 2
Although two communication programs having different communication protocols are stored in, the present invention is not limited to this. That is, the same communication program may be written in the blocks B and C of the flash memory 2 so that one communication program is always used and the other communication program is used as a spare. In this case, when rewriting the communication program, the first
The second communication program is rewritten to the latest one using the communication program of the above, and the switch SW1 is switched, and the first communication program is also changed to the same latest communication program by using the second communication program. Rewrite.

Further, in the above embodiment, the two communication programs of the first communication program and the second communication program are stored in the blocks B and C, but three or more communication programs are stored in the flash memory. It may be stored in two separate blocks.

In the above embodiment, the flash memory is embodied as the non-volatile memory, but the present invention is not limited to this. For example, the non-volatile memory is an EEPROM.
May be embodied in. The point is that the non-volatile memory only needs to erase each block when rewriting the stored data.

[0042]

[Brief description of drawings]

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

FIG. 2 is a flowchart illustrating a flash memory writing process.

FIG. 3 is a flowchart for explaining a first communication process.

FIG. 4 is a flowchart for explaining a second communication process.

FIG. 5 is a configuration diagram showing an outline of a conventional flash memory rewriting device.

[Explanation of symbols]

1 ... ECU as flash memory rewriting device, 2
... Flash memory as nonvolatile memory, 4 ... Microcomputer, 5 ... Flash writing tool as external tool, SW1 ... Switch as switch means.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G06F 9/06

Claims (4)

(57) [Claims] 1. A storage area is divided into a plurality of blocks, and a plurality of communication programs for communicating with an external tool are provided.
A non-volatile memory that will be stored in separate blocks in a plurality of blocks, among the plurality of communication program stored in the nonvolatile memory, a program selecting means for selecting a communication program for performing the communication with an external tool, the program The communication program selected by the selecting means, and a program rewriting means for rewriting a communication program different from the communication program , wherein the plurality of communication programs are communication programs having different communication methods.
A vehicle characterized by including a program
Use non-volatile memory rewriting apparatus. 2. The vehicle non-volatile memory rewriting device according to claim 1, wherein the non-volatile memory stores an initial program executed to perform initial setting at startup, and the communication program. A non-volatile memory rewriting device for a vehicle, which is stored in a block different from the block. 3. The vehicle non-volatile memory rewriting device according to claim 1, wherein the rewriting of the communication program is operated by an operator,
Of the plurality of communication programs, a switch means for setting a communication program for communicating with an external tool is provided, and the program selection means monitors a state of the switch means and selects a communication program based on the state. A non-volatile memory rewriting device for a vehicle, comprising: 4. The non-volatile memory rewriting device for a vehicle according to claim 1, wherein the program selection means determines the latest communication program among the plurality of communication programs and communicates it with an external tool. A non-volatile memory rewriting device for a vehicle, which is selected as a communication program for carrying out.