JP2018067176A - Electronic control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten transmission time of a writing program.SOLUTION: An electronic control unit (ECU) 100 initializes, before loading and executing a writing program into a RAM 130, at least the area of the RAM 130 into which the writing program is loaded. On the other hand, a writing unit 300 which transmits a writing program dividedly to the ECU 100 omits, when data of the writing program to be transmitted to the ECU 100 has been set with an initial value, the transmission of the data, thus, resulting in reducing the data amount of the writing program to be transmitted from the writing unit 300 to the ECU 100, and shortening the transmission time of the writing program.SELECTED DRAWING: Figure 9

Description

  The present invention relates to an electronic control device mounted on an automobile or the like.

  An electronic control device mounted on an automobile or the like has a nonvolatile memory that can electrically erase and write data, and stores a control program and control data (hereinafter abbreviated as “control program”). The When there is a problem in the control program, the control program in which the problem is corrected is transferred from the external device to the electronic control device, and the electronic control device writes the control program in the nonvolatile memory. Since the program for writing the control program to the nonvolatile memory is temporarily used for dealing with problems, it is not a good idea to store it in the nonvolatile memory. Therefore, as described in JP-A-10-111863 (Patent Document 1), a writing program is transferred from an external device to the electronic control device, and the electronic control device expands the writing program in a volatile memory. A technique for reducing the amount of use of the nonvolatile memory by executing the technique has been proposed.

JP-A-10-111863

  The writing program is transferred from the external device to the electronic control device by dividing the writing program into “data sets” which are data transfer units and sequentially transferring the data. In order to shorten the transfer time of the writing program, when all the data bodies of the data set are set to the initial value (for example, 0xFF), the data set does not contribute to the control, so that the transfer may be skipped. It is done. However, since the initial value of the volatile memory of the electronic control unit is indefinite, transfer of a data set in which all of the data body is set to the initial value cannot be skipped.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electronic control device that can skip the transfer of a data set in which all of the data body is set to the initial value, and can shorten the transfer time of the writing program. .

  For this reason, the electronic control unit has a means for expanding and executing an arbitrary program acquired by communication in the volatile memory, and at least an area of the volatile memory for expanding the program before expanding the program in the volatile memory. Means for initializing.

  According to the present invention, the transfer time of the writing program can be shortened.

It is a block diagram which shows an example of a data writing system. It is a block diagram which shows an example of an electronic controller and a writing device. It is a figure which shows the detail of a communication buffer area. It is a flowchart which shows an example of the procedure which writes an application program in the non-volatile memory of an electronic controller. It is a figure which shows the outline | summary of a program write process. It is a figure which shows the detail of the communication buffer area | region after communication environment change. It is a flowchart which shows an example of the program writing process which a writing device performs. It is a flowchart which shows an example of the writing program expansion | deployment process which an electronic controller performs. It is explanatory drawing of the procedure which expand | deploys and executes a writing program in the volatile memory of an electronic controller. It is explanatory drawing of the problem of a prior art. It is explanatory drawing of the method of solving the problem of a prior art. It is a flowchart which shows an example of the application transfer process which a writing device performs. It is a flowchart which shows an example of the program write process which an electronic controller performs. It is a flowchart which shows an example of the program write process which an electronic controller performs. It is a flowchart which shows an example of the program write process which an electronic controller performs. It is a flowchart which shows an example of the data copy process which an electronic control apparatus performs.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an example of a data writing system that writes a control program in a non-volatile memory of an electronic control unit (ECU).

  The ECU 100 is detachably connected to a writing device 300 operated by an operator via a network cable 200 such as CAN (Controller Area Network), serial communication, or FlexRay (registered trademark).

  The ECU 100 is an electronic device that controls various devices mounted on the automobile, for example, a fuel injection valve, an automatic transmission, an electric brake system, an ABS (Antilock Brake System), a variable valve timing mechanism, and the like. Specifically, as shown in FIG. 2, the ECU 100 includes a microcomputer 110, a ROM (Read Only Memory) 120 as an example of a nonvolatile memory, a RAM (Random Access Memory) 130 as an example of a volatile memory, and a communication. A circuit 140 is provided. Here, as the ROM 120, a flash ROM that can be rewritten to arbitrary data by electrically erasing and writing data can be used.

  The microcomputer 110 includes a CPU (Central Processing Unit), a cache memory, and the like, and executes various programs stored in the ROM 120 and the RAM 130. The ROM 120 stores at least a RAM expansion program for expanding an arbitrary program transmitted from the writing device 300 into the RAM 130 and a RAM initialization program for initializing a predetermined area of the RAM 130. Note that the RAM initialization program may be incorporated in the RAM expansion program. The RAM 130 has a first buffer area 132 and a second buffer area 134 that are used when arbitrary data is written to the ROM 120. The communication circuit 140 has a communication buffer area 142 that is used when communicating with other devices including the writing device 300.

  The writing device 300 is constituted by, for example, a personal computer, and includes a storage 310 such as a hard disk drive or SSD (Solid State Drive), a communication circuit 320, a monitor 330 and a keyboard 340 functioning as a man-machine interface. The storage 310 stores a writing program and an application program that are transferred to the ECU 100. The communication circuit 320 has a communication buffer area 322 that is used when communicating with the ECU 100. Therefore, the operator who operates the writing device 300 can interactively specify the writing program and the application program to be transferred to the ECU 100 by operating the monitor 330 and the keyboard 340.

  Here, details of the communication buffer area 142 of the ECU 100 and the communication buffer area 322 of the writing apparatus 300 used when the ECU 100 and the writing apparatus 300 communicate with each other will be described.

  In the communication buffer area 142 of the ECU 100, as shown in FIG. 3, for example, there are a plurality of communication buffers of a certain size such as a mailbox in CAN. When ECU 100 communicates with each device, ECU 100 uses a communication buffer allocated in advance for communication with a communication partner device among communication buffers in communication buffer area 142. Each communication buffer is divided into a transmission buffer TX used for data transmission and a reception buffer RX used for data reception.

  On the other hand, the communication buffer area 322 of the writing device 300 has a plurality of communication buffers of a certain size. The size of the communication buffer in the communication buffer area 322 is the same as the size of the communication buffer in the communication buffer area 142 in the ECU 100.

  In FIG. 3, the communication buffer area 142 of the ECU 100 includes two communication buffers (transmissions) as communication buffers used by the ECU 100 to communicate with the writing device 300 (hereinafter abbreviated as “communication buffer for rewriting device”). 1 buffer TX and 1 reception buffer RX) are allocated. Further, other communication buffers in the communication buffer area 142 are allocated for communication with devices other than the writing device 300.

  Therefore, communication is performed between the ECU 100 and the writing device 300 so that the size of the communication buffer is 8 bytes and the ECU 100 returns a response to the writing device 300 every time one piece of data is received. When performing, since one reception buffer RX is used for reception of one data, it is necessary to communicate 16 times before the ECU 100 acquires 64-byte data. That is, the writing device 300 transfers 64 bytes of data in units of 8 bytes, and the ECU 100 returns a response to the writing device 300 in response to receiving 8 bytes, so the number of communications is 16.

FIG. 4 shows an example of a procedure for writing an application program in the ROM 120 of the ECU 100 using the data writing system.
In step 1 (abbreviated as “S1” in the figure, the same applies hereinafter), the operator connects the ECU 100 to the writing device 300. When ECU 100 is connected to writing device 300, power is turned on, communication with writing device 300 is enabled, and reception of data transferred from writing device 300 is awaited.

  In step 2, the operator interacts with the writing device 300 and designates an application program (for example, an engine control program) to be written in the ROM 120 of the ECU 100. When an application program is designated, writing device 300 transfers the application program to ECU 100. The ECU 100 writes the application program in the ROM 120 while receiving the application program transferred from the writing device 300. Hereinafter, the processing of step 2 is referred to as “program writing processing”.

  In step 3, the worker removes the ECU 100 from the writing device 300. When the ECU 100 is removed from the writing device 300, the power is cut off, and various data stored in the RAM 130 are lost.

FIG. 5 shows an outline of the program writing process.
In step 11, when a writing program and an application program are designated by the operator, the writing device 300 transmits a message for starting the transfer of the writing program (for example, the writing program 2) to the ECU 100, and then executes the writing program. Forward.

  Here, the writing program designated by the operator is stored in the writing program database 312 constructed in the storage 310. The writing program is transferred to the ECU 100 and executes initialization processing such as a change of the communication environment (a method of using a communication buffer, a communication speed, an encryption method, etc.) on the ECU 100 and responds to a request from the writing device 300. Thus, a data reception process and a process of writing the data in at least a part of the ROM 120 are executed.

  The application program designated by the worker is stored in the application program database 314 constructed in the storage 310. Each application program is, for example, a program for controlling the engine of an automobile to be controlled by the ECU 100.

  In step 12, when the ECU 100 receives a message for starting the transfer of the writing program from the writing device 300, the ECU 100 starts the RAM initialization program stored in the ROM 120 and initializes at least the area of the RAM 130 in which the writing program is developed. . Further, when initialization of the RAM 130 is completed, the ECU 100 activates a RAM expansion program stored in the ROM 120. Here, the RAM expansion program performs processing for expanding the writing program received by the ECU 100 into the RAM 130. Therefore, the ECU 100 develops the received writing program in the RAM 130 by the RAM developing program while receiving the writing program.

In step 13, when the development of the writing program is completed, the ECU 100 activates the writing program developed in the RAM 130 by the RAM development program.
In step 14, the ECU 100 changes the communication environment between the ECU 100 and the writing device 300 to a communication environment corresponding to the writing program by the writing program, and requests the writing device 300 to transmit the application program. Send a message.

  In step 15, when the writing device 300 receives a message requesting transmission of an application program, the writing device 300 starts transferring an application program (for example, application program 1) designated by the operator to the ECU 100.

  In step 16, the ECU 100 writes the received application program in the ROM 120 by the writing program while receiving the application program from the writing device 300.

  Note that after the writing of the application program is completed, the ECU 100 is removed from the writing device 300 and the power is turned off. Next, when the power of the ECU 100 is turned on, the communication environment of the ECU 100 returns to the initial state. Further, when any abnormality (for example, communication with the writing device 300 is interrupted) occurs during the program writing process, the ECU 100 resets itself and the communication environment returns to the initial state.

  Accordingly, by appropriately selecting the writing program, it is possible to operate the writing program suitable for the communication environment and the writing conditions of the application program in the program writing process. For this reason, for example, by operating a writing program having a higher communication speed, high-speed communication can be performed, and the program writing process can be speeded up. Further, since the writing program is transferred to the ECU 100 when the program writing process is executed, it is not necessary to store the writing program in the ROM 120, and the usage amount of the ROM 120 can be reduced. Furthermore, a new function can be added to the program writing process by changing the writing program.

  Note that even when other devices are connected to the ECU 100 in addition to the writing device 300, the ECU 100 executes the program writing process if the communication with the other device is interrupted and only the writing device 300 is communicated. can do. As an example of executing the program writing process in a situation where another device is connected to the ECU 100 in addition to the writing device 300, for example, writing the application program in a state in which the ECU 100 is assembled in a vehicle. It is done. In this case, in order to prevent communication path competition, the ECU 100 needs to use a communication environment used when communicating with the writing device 300 as a communication environment common to other devices (for example, a common communication speed). For this reason, the operator designates a writing program that establishes a common communication environment with other devices, and performs the program writing process.

Next, a method of using the communication buffer area 142 used when the ECU 100 receives an application program transferred from the writing device 300 will be described.
When writing an application program in the ROM 120, the ECU 100 does not communicate with any device other than the writing device 300. Therefore, the ECU 100 preliminarily allocates a communication buffer (hereinafter referred to as “communication buffer for other devices”). "Is abbreviated as") is not used. For this reason, the writing program can be changed to use another device communication buffer for communication between the ECU 100 and the writing device 300 in addition to the writing device communication buffer.

FIG. 6 shows details of the communication buffer area 142 after the change.
When communicating with the writing device 300, the ECU 100 uses two communication buffers as the writing device communication buffer and seven communication buffers among the other device communication buffers. In this case, the nine communication buffers used by the ECU 100 have one transmission buffer TX and eight reception buffers RX. On the other hand, the communication buffer in the communication buffer area 322 in the writing device 300 has eight transmission buffers TX and one reception buffer RX.

  For example, the size of one communication buffer is 8 bytes, and the ECU 100 and the writing device 300 are synchronized so that the ECU 100 returns a response to the writing device 300 every time one piece of data is received. When communication is performed, eight reception buffers RX can be used to receive one data. Therefore, until the ECU 100 acquires 64 bytes of data from the writing device 300, nine communications are required as compared with the prior art. It will be. That is, the writing device 300 divides and transfers 64-byte data as one data every 8 bytes, and the ECU 100 returns a response to the writing device 300 every time eight 8-byte data are received. For this reason, the number of communications is nine.

  Note that the writing program sets the number of communication buffers used by the ECU 100 for communication with the writing device 300 to the size of data transmission / reception, an integral multiple of the size of data transmission / reception, the size of writing to the ROM 120 once, It may be an integer multiple of a single write size.

  As described above, since communication can be performed using the communication buffer for other devices in addition to the communication buffer for the writing device, the number of times of communication is reduced and the time required for data transfer is reduced in communication such as synchronization. This shortens the data transfer speed. Further, since another apparatus communication buffer is used, the writing apparatus 300 can continuously transfer data without worrying about overwriting of the communication buffer.

  If there is an unused communication buffer that is not assigned to any device in the communication buffer area 142, the writing program uses the unused communication buffer for communication between the ECU 100 and the writing device 300. It can also be changed as follows.

  FIG. 7 shows an example of a program writing process executed by the writing device 300 when an operator connects the ECU 100 to the writing device 300 and designates a writing program and an application program.

  In step 31, the writing device 300 transmits to the ECU 100 a transfer start message indicating that transfer of the writing program is started. Here, the transfer start message can be stored in a header of a packet transmitted and received between the ECU 100 and the writing device 300, for example.

  In step 32, the writing device 300 sequentially divides the writing program designated by the operator into sizes that can be received by the ECU 100 in one communication, and stores them in the data body (payload) of the packet, for example. Further, the writing device 300 stores an address (relative address or absolute address) indicating a writing position of the writing program, for example, in the header of the packet. The address indicating the writing position of the writing program can also be stored in the data body of the packet.

  In step 33, the writing device 300 refers to the data body of the packet created in step 32, and determines whether or not all of the data stored therein has an initial value (for example, 0xFF). If the writing device 300 determines that all of the data is the initial value (Yes), the writing device 300 advances the process to step 35 in order to skip the transfer of the packet. On the other hand, if the writing device 300 determines that all of the data is not the initial value, in other words, that the data is part of realizing the function of the writing program (No), the processing proceeds to step 34.

In step 34, the writing device 300 transfers the packet created in step 32 to the ECU 100. Thereafter, the writing device 300 advances the process to Step 35.
In step 35, it is determined whether or not the writing device 300 has received a data request message requesting data from the ECU 100. Here, whether or not it is a data request message can be determined by referring to the header of the packet, for example. If the writing device 300 determines that the data request message has been received (Yes), the writing device 300 proceeds to step 36. On the other hand, if it is determined that the data request message has not been received (No), the writing device 300 waits until the data request message is received.

  In step 36, it is determined whether the writing device 300 has completed the transfer of the writing program designated by the operator. If the writing device 300 determines that the transfer of the writing program has been completed (Yes), the processing proceeds to step 37. On the other hand, if the writing device 300 determines that the transfer of the writing program is not completed (No), the writing device 300 returns the process to step 32.

  In step 37, the writing device 300 transmits to the ECU 100 a transfer completion message indicating that the transfer of the writing program has been completed. Here, the transfer completion message can be stored in the header of the packet, for example.

  In step 38, the writing device 300 determines whether or not any message (packet) has been received from the ECU 100. If the writing device 300 determines that the message has been received (Yes), the writing device 300 proceeds to step 39. On the other hand, if the writing device 300 determines that a message has not been received (No), the writing device 300 waits until a message is received.

  In step 39, the writing device 300 determines whether or not the message received from the ECU 100 is a transfer normal message indicating that the writing program has been transferred normally. Here, whether or not it is a normal transfer message can be determined by referring to the header of the packet, for example. If the writing device 300 determines that the message is a normal transfer message (Yes), the writing device 300 proceeds to step 40. On the other hand, if the writing device 300 determines that the message is not a transfer normal message, that is, a transfer error message indicating that the writing program has not been transferred normally (No), the writing device 300 advances the process to step 41.

  In step 40, the writing device 300 executes a subroutine-type application transfer process in which the application program designated by the operator is transferred to the ECU 100 while being divided. The application transfer process is not limited to the subroutine format, and may be developed at the position of step 40.

  In step 41, since the writing program has not been transferred normally, the writing device 300 performs settings for resending the writing program from the beginning, for example, setting the pointer indicating the position of the writing program to the beginning. Thereafter, the writing device 300 returns the process to step 32.

  In this way, the writing device 300 sequentially divides the writing program into sizes that can be received by the ECU 100 in one communication, when the writing program and the application program are designated by the operator. Store in the data body of the packet. Then, if all of the data body of the packet is set to the initial value, the writing device 300 skips the transfer of the packet, thereby reducing the transfer amount of the packet transferred from the writing device 300 to the ECU 100, The transfer time of the writing program can be shortened. The writing device 300 executes a process of transferring the application program if the writing program can be normally transferred by a message from the ECU 100. On the other hand, if the writing program cannot be transferred normally, the writing device 300 executes the writing program. resend.

  FIG. 8 shows an example of a writing program development process executed by the microcomputer 110 of the ECU 100 when the ECU 100 receives the writing program transfer start message. Here, the microcomputer 110 of the ECU 100 executes a write program expansion process according to the RAM expansion program and the RAM initialization program stored in the ROM 120.

  In step 51, the microcomputer 110 of the ECU 100 initializes at least an area for developing the writing program in the storage area of the RAM 130 with an initial value. When the RAM 130 is initialized, the first buffer area 132 and the second buffer area 134 may be initialized together.

  In step 52, the microcomputer 110 of the ECU 100 determines whether a packet has been received from the writing device 300. If the microcomputer 110 of the ECU 100 determines that the packet has been received (Yes), the process proceeds to step 53. On the other hand, if the microcomputer 110 of the ECU 100 determines that the packet has not been received (No), the microcomputer 110 waits until the packet is received.

  In step 53, the microcomputer 110 of the ECU 100 refers to, for example, the header of the packet to determine whether or not the packet from the writing device 300 is a write program transfer completion message. If the microcomputer 110 of the ECU 100 determines that the message is a transfer completion message of the writing program (Yes), the process proceeds to step 54. On the other hand, if the microcomputer 110 of the ECU 100 determines that it is not a write program transfer completion message, that is, the data of the write program has been transferred (No), the process proceeds to step 57.

  In step 54, the microcomputer 110 of the ECU 100 refers to, for example, a checksum stored in the header of the packet, and determines whether or not the writing program transferred from the writing device 300 has been transferred normally. If the microcomputer 110 of the ECU 100 determines that the writing program has been transferred normally (Yes), the microcomputer 110 advances the process to step 55. On the other hand, if the microcomputer 110 of the ECU 100 determines that the writing program has not been transferred normally (No), the microcomputer 110 advances the process to step 59.

In step 55, the microcomputer 110 of the ECU 100 transmits a transfer normal message to the writing device 300. Here, the transfer normal message can be stored in the header of a packet transmitted from the ECU 100 to the writing device 300, for example.
In step 56, the microcomputer 110 of the ECU 100 starts the writing program developed in the RAM 130.

  In step 57, since the data of the writing program is stored in the packet received from the writing device 300, the microcomputer 110 of the ECU 100 expands the data body of the packet in the RAM 130. At this time, the microcomputer 110 of the ECU 100 develops from the address stored in the header of the packet because the writing program transferred from the writing device 300 may not be continuous.

  In step 58, the microcomputer 110 of the ECU 100 transmits a data request message to the writing device 300 in order to request the next data. Here, the data request message can be stored in the header of a packet transmitted from the ECU 100 to the writing device 300, for example. Thereafter, the microcomputer 110 of the ECU 100 returns the process to step 52.

  In step 59, since the writing program is not normally transferred from the writing device 300, the microcomputer 110 of the ECU 100 transmits a transfer abnormality message to the writing device 300. Here, the transfer abnormality message can be stored in a header of a packet transmitted from the ECU 100 to the writing device 300, for example. Thereafter, the microcomputer 110 of the ECU 100 returns the process to step 51.

  In this way, the ECU 100 initializes at least an area for developing the writing program in the storage area of the RAM 130 when the writing program transfer start message is received from the writing device 300. When the initialization of the RAM 130 is completed, the ECU 100 expands the data of the writing program sequentially transferred from the writing device 300 to the RAM 130 and starts it. At this time, the ECU 100 refers to the header of the packet and develops the data of the writing program from the address stored therein.

  That is, as shown in FIG. 9, the ECU 100 initializes the RAM 130 with the RAM development program and RAM initialization program stored in the ROM 120 and then develops the write program sequentially transferred from the writing device 300 onto the RAM 130. . Then, ECU 100 activates a writing program and writes writing data sequentially transferred from writing device 300 to ROM 120.

  In the prior art, as shown in FIG. 10, when the initial value of the RAM 130 in the ECU 100 is indefinite, if the transfer of the packet in which the entire data body is set to the initial value is skipped, the corresponding RAM 130 The area may remain undefined and the writing program may behave unexpectedly. However, in this embodiment, a predetermined area of the RAM 130 is initialized as shown in FIG. 11 before the writing program is expanded in the RAM 130, so that the transfer of packets in which the entire data body is set to the initial value is transferred. Even if is skipped, the area of the RAM 130 corresponding to this is the initial value. Therefore, it is possible to skip the transfer of packets in which all of the data body is set to the initial value, and the transfer time of the writing program can be shortened. In short, the writing program is data that is divided for each predetermined size and is acquired sequentially without being entirely set to the initial value, so only the data that contributes to the writing of the application program is transferred and written. Program transfer time can be shortened.

FIG. 12 shows an example of application transfer processing executed by the writing device 300.
In step 61, the writing device 300 determines whether or not any message is received from the ECU 100. If the writing device 300 determines that the message has been received (Yes), the writing device 300 advances the process to step 62. On the other hand, if it is determined that the message has not been received (No), the writing device 300 waits until the message is received (No).

  In step 62, for example, the writing device 300 refers to the header of the packet to determine whether the message received from the ECU 100 is a transmission request message indicating a transmission request for divided data. If the writing device 300 determines that the message is not a transmission request message (Yes), the writing device 300 advances the process to step 63. On the other hand, if the writing device 300 determines that the message is a transmission request message (No), the writing device 300 advances the process to step 67.

  In step 63, for example, the writing device 300 refers to the header of the packet to determine whether the message received from the ECU 100 is a retransmission request message indicating a retransmission request for divided data. If the writing device 300 determines that the message is not a retransmission request message (Yes), the writing device 300 advances the process to step 64. On the other hand, if the writing device 300 determines that the message is a retransmission request message (No), the writing device 300 advances the process to Step 69 (No).

  In step 64, the writing device 300 refers to, for example, the header of the packet to determine whether the message received from the ECU 100 is a normal writing message indicating that the divided data has been normally written in the ROM 120. . If the writing device 300 determines that the message is a normal writing message (Yes), the processing proceeds to step 65. On the other hand, if the writing device 300 determines that it is a writing abnormality message indicating that the divided data has not been written normally (No), the processing proceeds to step 70.

  In step 65, the writing device 300 determines whether or not the transfer of the application program designated by the operator has been completed. If the writing device 300 determines that the transfer of the application program has been completed (Yes), the writing device 300 advances the process to step 66. On the other hand, if the writing device 300 determines that the transfer of the application program is not completed (No), the writing device 300 returns the process to Step 61 (No).

  In step 66, since the transfer of the application program is completed, the writing device 300 transmits a transfer completion message indicating that the transfer of the application program is completed to the ECU 100.

  In step 67, since the message from the ECU 100 is a divided data transmission request message, the writing device 300 creates divided data obtained by dividing the application program designated by the operator into a predetermined size. Specifically, the writing device 300 sequentially divides the application program into a predetermined size and stores it in the data body of the packet. Here, the predetermined size may be the total size of a plurality of communication buffers (reception buffers RX) used in a communication environment that is changed by a writing program transferred to the ECU 100. Further, the writing device 300 stores an address (relative address or absolute address) indicating a writing position of the application program, for example, in a packet header. The address indicating the writing position of the application program can be stored in the data body of the packet.

  In step 68, the writing device 300 transfers the divided data created in step 67 to the ECU 100. At this time, the writing device 300 stores the divided data separately for each size of the transmission buffer TX in the communication buffer area 322. For example, when there are 8 transmission buffers TX in the communication buffer area 322 with 64 bytes of divided data and 8 bytes per piece, the writing device 300 divides the divided data into 8 pieces of data every 8 bytes and transmits Store in buffer TX. The data stored in the transmission buffer TX is transferred to the ECU 100 by the communication circuit 320. Thereafter, the writing device 300 returns the process to step 61.

  In step 69, since the message from ECU 100 is a divided data retransmission request message, writing device 300 retransmits the divided data to ECU 100. Here, since the writing device 300 has already created the divided data in step 67, the writing device 300 may retransmit the created divided data without creating new divided data. Thereafter, the writing device 300 returns the process to step 61.

  In step 70, since the message from the ECU 100 is a write error message, the writing device 300 performs settings for resending the application program from the top, for example, setting the application program pointer back to the top. Thereafter, the writing device 300 returns the process to step 61.

  In this way, in response to the divided data transmission request message from ECU 100, writing device 300 transfers to ECU 100 the divided data obtained by sequentially dividing the application program for each predetermined size. In response to the divided data retransmission request message from ECU 100, writing device 300 retransmits the created divided data. Furthermore, in response to the write abnormality message from ECU 100, writing device 300 retransfers the application program from the beginning.

  13 to 15 show an example of a program writing process executed by the microcomputer 110 of the ECU 100 when the writing program is activated.

  In step 71, the microcomputer 110 of the ECU 100 changes the communication environment for the ECU 100 to communicate with the writing device 300. When ECU 100 can communicate with devices other than writing device 300, microcomputer 110 of ECU 100 does not have to change the communication environment.

  In step 72, the microcomputer 110 of the ECU 100 sets the first buffer area 132 of the RAM 130 as a copy area for copying the divided data received from the writing device 300.

In step 73, the microcomputer 110 of the ECU 100 starts a writing subprogram for writing the divided data received from the writing device 300 into the ROM 120.
In step 74, the microcomputer 110 of the ECU 100 assigns 1 to a counter variable n that indicates what part of the divided data of the application program written in the ROM 120 is being processed.

In step 75, the microcomputer 110 of the ECU 100 transmits a divided data transmission request message to the writing device 300 in order to acquire the first divided data.
In step 76, the microcomputer 110 of the ECU 100 determines whether or not a copy completion message indicating that the divided data received from the writing device 300 has been copied to the copy area has been notified from the writing subprogram. If the microcomputer 110 of the ECU 100 determines that the copy completion message has been notified (Yes), the microcomputer 110 advances the process to step 77. On the other hand, if the microcomputer 110 of the ECU 100 determines that the copy completion message is not notified (No), the microcomputer 110 waits until the copy completion message is notified.

  In step 77, the microcomputer 110 of the ECU 100 refers to the initial divided data stored in the copy area, and uses the checksum included in the divided data, for example, so that the divided data is normally displayed. It is determined whether or not reception is possible. If the microcomputer 110 of the ECU 100 determines that the first divided data has been successfully received (Yes), the process proceeds to step 78. On the other hand, if microcomputer 110 of ECU 100 determines that the first divided data cannot be received normally (No), the process proceeds to step 84.

  In step 78, the microcomputer 110 of the ECU 100 sets the first buffer area 132 of the RAM 130 as an area for writing used when writing the divided data received from the writing device 300, and the second buffer of the RAM 130. The area 134 is set as a copy area for copying the divided data received from the writing device 300.

  In step 79, the microcomputer 110 of the ECU 100 transmits a divided data transmission request message to the writing device 300 in order to acquire the second divided data. The microcomputer 110 of the ECU 100 may transmit a message indicating that the previous divided data has been normally received to the writing device 300 together with the divided data transmission request message.

  In step 80, the microcomputer 110 of the ECU 100 writes the data body of the nth divided data stored in the write area in the ROM 120 in accordance with the write address stored in the header of the divided data.

  In step 81, the microcomputer 110 of the ECU 100 compares the divided data stored in the writing area with the divided data written in the ROM 120, for example, so that the nth divided data is normally written in the ROM 120. It is determined whether or not. If the microcomputer 110 of the ECU 100 determines that the divided data has been written normally (Yes), the microcomputer 110 advances the process to step 82. On the other hand, if the microcomputer 110 of the ECU 100 determines that the divided data has not been written normally (No), the process proceeds to step 85.

  In step 82, the microcomputer 110 of the ECU 100 determines whether or not a copy completion message indicating that the divided data received from the writing device 300 has been copied to the copy area has been notified from the writing subprogram. If the microcomputer 110 of the ECU 100 determines that the copy completion message has been notified (Yes), the process proceeds to step 83. On the other hand, if the microcomputer 110 of the ECU 100 determines that the copy completion message is not notified (No), the microcomputer 110 waits until the copy completion message is notified.

  In step 83, the microcomputer 110 of the ECU 100 determines whether or not the data stored in the copy area is an application program transfer completion message. If the microcomputer 110 of the ECU 100 determines that the message is a transfer completion message (Yes), the process ends. On the other hand, if microcomputer 110 of ECU 100 determines that the message is not a transfer completion message (No), the process proceeds to step 88.

  In step 84, since the first divided data could not be normally received, the microcomputer 110 of the ECU 100 transmits a divided data retransmission request message to the writing device 300 in order to obtain the first divided data again. Note that the microcomputer 110 of the ECU 100 may transmit a message indicating that the divided data could not be normally received to the writing device 300 together with the divided data retransmission request message. Thereafter, the microcomputer 100 of the ECU 100 returns the process to step 76.

  In step 85, since the n-th divided data has not been normally written in the ROM 120, the microcomputer 110 of the ECU 100 transmits a writing abnormality message indicating that the divided data has not been normally written to the writing device 300. .

In step 86, the microcomputer 110 of the ECU 100 erases the area of the ROM 120 to which the divided data is to be written.
In step 87, the microcomputer 110 of the ECU 100 sets the first buffer area 132 of the RAM 130 as a copy area for copying the divided data received from the writing device 300. Thereafter, the microcomputer 110 of the ECU 100 returns the process to step 74 in order to execute the writing of the application program from the beginning.

  In step 88, since the transfer of the application program has not been completed, the microcomputer 110 of the ECU 100 has successfully received the (n + 1) th divided data copied to the copy area using, for example, a checksum. Determine whether or not. If the microcomputer 110 of the ECU 100 determines that the divided data has been successfully received (Yes), the microcomputer 110 advances the process to step 89. On the other hand, if it is determined that the divided data cannot be received normally (No), the process proceeds to step 92. Note that whether or not the (n + 1) th divided data can be normally received may be determined immediately after receiving the divided data.

  In step 89, the microcomputer 110 of the ECU 100 sets the buffer area set for copying as the writing area, and sets the buffer area set for writing as the copying area.

  In step 90, the microcomputer 110 of the ECU 100 transmits a divided data transmission request message to the writing device 300 in order to acquire the (n + 2) th divided data. The microcomputer 110 of the ECU 100 transmits a message indicating that the nth divided data has been written to the ROM 120 and a message indicating that the (n + 1) th divided data has been received to the writing device 300 together with the divided data transmission request message. You may make it do.

  In step 91, the microcomputer 110 of the ECU 100 adds 1 to the counter variable n, that is, increments the counter variable n. Thereafter, the microcomputer 110 of the ECU 100 returns the process to step 80.

  In step 92, since the (n + 1) th divided data could not be received normally, the microcomputer 110 of the ECU 100 sends a retransmission request message of the (n + 1) th divided data to the writing device 300 in order to acquire the (n + 1) th divided data again. Send. Thereafter, the microcomputer 110 of the ECU 100 returns the process to step 82. The microcomputer 110 of the ECU 100 may transmit a message indicating that the (n + 1) th divided data could not be normally received to the writing device 300 together with the divided data retransmission request message.

  FIG. 16 shows an example of a data copy process executed by the microcomputer 110 of the ECU 100 according to the writing subprogram when the ECU 100 receives the divided data from the writing device 300.

  In step 101, the microcomputer 110 of the ECU 100 copies the divided data received from the writing device 300 from the reception buffer RX of the communication buffer area 142 in the communication circuit 140 to the copy area.

  In step 102, the microcomputer 110 of the ECU 100 notifies the writing program of a divided data copy completion message. The microcomputer 110 of the ECU 100 may set the copy area to an area corresponding to the reception buffer RX of the communication buffer area 142, and receive the divided data using the copy area. . This eliminates the need to copy the divided data from the reception buffer RX in the communication buffer area 142 to the copy area.

  Also, if there is a difference between the processing time from the divided data transmission request to the completion of copying and the processing time from writing the divided data to the ROM 120 and verifying, when the processing with the longer time is completed, The divided data reception process and the process of writing the divided data into the ROM 120 may be started.

  In this way, the divided data received from the writing device 300 is copied to the reception buffer RX of the ECU 100, and two buffer areas for writing to the ROM 120 are prepared. While one of the two buffer areas is used for the process of writing to the ROM 120, the other buffer area is used for the process of copying the divided data received by the ECU 100. Thereby, in ECU100, the process which writes division data in ROM120 using one buffer area, and the process which receives division data, and copies division data to the other buffer area can be performed in parallel. For this reason, the time required for the program writing process can be shortened.

  In order to realize these processes, the process executed by the ECU 100 may be changed. Therefore, the time required for the program writing process can be shortened without significantly changing the writing device 300.

  Although the present embodiment is an example of the ECU 100 mounted on the automobile, it can be applied to other electronic control devices mounted with a nonvolatile memory instead of the ECU 100. Further, a plurality of ECUs 100 may be connected to one writing device 300, and one writing device 300 may transfer data to each ECU 100 in a time division manner.

Here, the technical idea that can be understood from the above-described embodiment will be described below.
(1) The electronic control unit expands and executes an arbitrary program acquired by communication in a volatile memory, and expands at least the program before expanding the program in the volatile memory. Means for initializing an area of the memory.

(2) The means for initializing the area of the volatile memory is realized by a program stored in advance in the nonvolatile memory.
(3) The program rewrites at least a part of data in the nonvolatile memory in response to a request from the outside.

(4) The program is data divided for each predetermined size, and is sequentially acquired in a state where the whole is not set to an initial value, and the program is expanded in a volatile memory and executed. The data body is expanded at the address of the volatile memory included in the divided data.

(5) The program is acquired by communication from a writing device that is detachably connected to the electronic control device.
(6) The electronic control device is turned on when connected to the writing device, and turned off when it is removed from the writing device.

(7) When the entire data body of the divided data is set to an initial value, the writing device skips the transfer.
(8) The electronic control device and the writing device communicate via a packet.

100 ECU (electronic control unit)
120 ROM (nonvolatile memory)
130 RAM (volatile memory)

Claims (4)

Means for developing and executing an arbitrary program acquired by communication in a volatile memory;
Means for initializing at least an area of the volatile memory in which the program is expanded before the program is expanded in the volatile memory;
An electronic control device comprising: The means for initializing the area of the volatile memory is realized by a program stored in advance in the nonvolatile memory.
The electronic control device according to claim 1. The program rewrites at least part of data in the nonvolatile memory in response to an external request.
The electronic control device according to claim 1 or 2, characterized by the above. The program is data divided for each predetermined size, and is sequentially acquired in a state where the whole is not set to an initial value,
The means for expanding and executing the program in a volatile memory expands the data body at an address of the volatile memory included in the divided data.
The electronic control device according to any one of claims 1 to 3, wherein