JP4076113B2 - Electronic control unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic control device, and more particularly to an electronic control device that can easily rewrite a control program.
[0002]
[Prior art]
In recent years, a storage medium for storing a program (firmware) for operating an electronic control device has been written in software from a ROM (one-time ROM, EPROM, etc.) that cannot be rewritten in software once the program has been written. It is shifting to a possible ROM (flash ROM, etc.).
This is in order to suppress the constraints associated with the increase in cost of having to replace the media hardware every time the firmware is upgraded, etc. It is also for the purpose of improving convenience such as being able to rewrite the firmware in software.
[0003]
As this rewriting method, a method using a communication means as disclosed in Japanese Patent Laid-Open No. 8-307480, a method by downloading from an external device such as an external ROM as disclosed in Japanese Patent Laid-Open No. 11-65835, etc. was there.
However, the method using the communication means is an absolute condition that the program to be rewritten does not operate, so rewriting according to this condition is not a little due to recent enlargement / multitasking of programs. With difficulty.
In addition, the method of downloading from an external device requires an external device and a worker who operates the device at the time of rewriting, so it is extremely difficult to upgrade the firmware of a large number of identical electronic control devices. Cost.
For this reason, an electronic control device that can upgrade the firmware without a special external device is desired.
[0004]
Also, it usually takes time to rewrite the ROM in which the firmware is stored. In the conventional technology, since it is assumed that only the entire firmware is upgraded, considerable time is required for the upgrade. Moreover, since other functions cannot be used at all while the firmware is being rewritten, there is a lack of convenience as a device.
For example, there may be a case where transmission cannot be performed on time, such as when it takes time to upgrade the firmware while waiting for FAX transmission.
In order to solve these problems, it is desired to realize an electronic control device that can shorten the version upgrade time and can perform work in consideration of the priority order between the version upgrade and the current work.
[0005]
[Problems to be solved by the invention]
As described above, since the program (firmware) for operating the conventional electronic control device is stored in a medium that cannot be rewritten by software once it is written, the firmware cannot be rewritten unless the medium is replaced. There was a face to sexually. In order to avoid this, a method using communication means or a method by downloading from an external device has been announced, but rewriting is not easy, takes time and costs, and during rewriting, other functions There were problems such as not being able to use.
The present invention solves this problem in a relatively simple manner, and rewrites stored firmware easily in software without the need for an external device. It is an object of the present invention to realize an electronic control device that can be realized without interrupting work in standby and that can partially rewrite firmware.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is an electronic control device that operates in accordance with control firmware stored in a first storage means ,
The electronic control device downloads new firmware input from an external host device as a firmware upgrade function , temporarily stores it in the second storage means, and the new firmware temporarily stored in the second storage means In the electronic control device for writing the new firmware by the firmware writing means for writing to the first storage means in which the conventional firmware existed,
This electronic control device comprises a program reset branching means for branching to a program reset vector for starting a program when the power is turned on by software,
The program reset branching unit accesses the firmware writing unit, terminates the program running on the multitasking OS of the electronic control unit, and continues to the multitasking OS until the writing of the new firmware is completed. And a function of branching to the multitask activation program in the first storage means after the completion of writing of the new firmware is included.
As a result, the firmware stored in the built-in storage means can be rewritten in software, and an electronic control device that can be easily executed without relying on an external device to upgrade the firmware is inexpensively realized. be able to.
In addition, since the new firmware that has been upgraded is downloaded from the outside in advance and temporarily stored therein, the firmware can be upgraded without the need for a special external device or an operating person.
Also, flash ROM rewriting work for multitasked programs can be performed immediately after the power is turned on and on a program that operates before migrating to multitasking. By doing so, there is no need to worry about the failure of firmware upgrade.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electronic control device according to the present invention will be described in detail with reference to the accompanying drawings.
[0008]
FIG. 1 is a block diagram of a minimum necessary configuration in an embodiment of an electronic control device of the present invention.
In FIG. 1, reference numeral 11 denotes a CPU for performing calculations for controlling each unit. Reference numeral 12 denotes a firmware unit, which stores a program for controlling the electronic device using the CPU unit 11. Specifically, it is formed of a flash ROM, which is a rewritable medium programmatically.
[0009]
Reference numeral 13 denotes a volatile memory unit that records firmware to be upgraded. Specifically, it is a large capacity DRAM or the like. Reference numeral 14 denotes a nonvolatile memory unit. Data that should not be erased even when the power is turned off is recorded. Specifically, it is an SRAM or the like backed up by a lithium battery.
[0010]
Reference numeral 15 denotes a download unit which controls physical connection with the outside and firmware download. Specifically, it is a device that can be connected to a telephone line such as PSTN or ISDN, or a LAN.
Reference numeral 16 denotes a display / operation unit. Display and input operations are performed. It is possible to instruct firmware version upgrades and the like.
In addition, a printer unit is connected to a printer device, a reading unit is connected to a scanner device, and a video board or HDD is connected to a PC.
[0011]
FIG. 2 shows an example of memory mapping in the embodiment of the present invention.
In FIG. 2, reference numeral 21 denotes a boot area. This is an area in which a program that operates first when the power is turned on is recorded. This program initializes the CPU, peripheral devices, and the like. A program for rewriting the firmware area 23 when the firmware is upgraded is also recorded in this area. If this program is destroyed, it can cause a fatal error, so this area is usually not rewritten. Therefore, there is a case where it is not on the flash ROM but on a medium such as EPROM that is not software rewritable.
[0012]
Reference numeral 22 denotes a program reset vector. This is the address at which the PC (program counter) is initialized when the power is turned on. The program always starts from this address when it is reset in electrical hardware.
Reference numeral 23 denotes a firmware area. An area in which a program for controlling the apparatus is recorded, and the normal program operates in this area. In preparation for upgrading the firmware, a rewritable medium such as a flash ROM is allocated.
[0013]
Reference numeral 24 denotes a volatile memory area which can be read and written by a program, but its value becomes undefined when the power is turned OFF / ON. Generally, a large amount of data to be processed at high speed is stored on a program.
Reference numeral 25 denotes a non-volatile memory area which can be read and written by a program and retains a value even when the power is turned OFF / ON. In general, it stores data registered by the user and device settings.
[0014]
FIG. 3 shows a flowchart of a program for firmware upgrade operation in the apparatus of the present invention.
This operation is performed when a user or a service person explicitly requests from the display / operation unit 16.
[0015]
In step 100, the “firmware version upgrade procedure” of this program is entered.
Next, in step 101, the upgraded firmware is read from the download unit 15. In step 102, the read firmware is recorded in the volatile memory unit 13. Volatile memory has a lower unit price than volatile memory compared to nonvolatile memory, and the memory incorporated in the device has a larger capacity if the price is the same. That is why.
If the data size of the firmware is sufficiently small, or if the nonvolatile memory installed in the apparatus is sufficiently large, the data may be read into the nonvolatile memory unit 14.
[0016]
Next, in step 103, the firmware rewrite information is written into the volatile memory unit 13 or the non-volatile memory unit 14. This firmware rewrite information records “how much size” firmware to be rewritten from “which address of the firmware part”.
Next, in step 104, it is checked whether there is any work currently in operation or waiting. If there are any, a loop is performed at this point, and no subsequent firmware upgrade is performed. Version upgrade will be performed after all work is completed.
Since the program so far is assumed to operate in multitasking, other program operations are not interrupted even if a loop is made in this part. If the program is a single task program, the “firmware version upgrade” program itself is in a standby state and operates another program.
[0017]
Next, in step 105, the program branches to the program reset vector. As a result, the program running on the multitasking OS is terminated.
Thereafter, the multitask OS does not operate until the version upgrade is completed, and the program does not operate on the firmware to be rewritten.
Further, since reset is not generated in an electric hardware manner, all data in the volatile memory unit is held as it is.
Next, in step 106, the firmware is copied from the volatile memory unit 13 to the firmware unit 12 in accordance with the rewrite information written in step 103.
[0018]
In step 107, the written firmware data is verified.
If the verification fails, the process proceeds to step 108, where it is determined that the version upgrade operation has not ended normally, and a serviceman call is performed. Here, writing and verifying is performed only once, but it is also possible to put in a control to repeat this several times.
If the verification is successful, the process proceeds to step 109, where it is determined that the version upgrade operation has been completed normally, and the process branches to the multitask OS activation program in the firmware unit 12. After that, the upgraded firmware will operate.
[0019]
As described above, according to the present invention, it is possible to upgrade the firmware without requiring a special external device or work. In addition, the upgrade can be performed without paying special attention to the work in progress or the standby work of the apparatus, and the failure of the upgrade is reduced.
[0020]
【The invention's effect】
As described above, according to the first aspect of the present invention, the electronic control device operates according to the control firmware stored in the first storage means, and the electronic control device has a firmware upgrade function. The new firmware input from the external host device is downloaded and temporarily stored in the second storage means. The new firmware temporarily stored in the second storage means is the existing firmware. the electronic control unit for writing the new firmware by the firmware writing means for writing in the first storage means is, the electronic control unit, the software to power-on of the program branches to program the reset vector to start operation comprising a program reset branching means, said The program reset branch means accesses to the firmware writing means and to end the program running on the multitask OS of the electronic control device, the multi-task OS to the new firmware writing is completed A function of branching to the multitask activation program in the first storage means after the completion of the writing of the new firmware without operation is included.
As a result, the upgraded new firmware is downloaded from the outside in advance and temporarily stored therein, so that the firmware can be upgraded without the need for a special external device or a human operator. Also, flash ROM rewriting work for multitasked programs can be performed immediately after the power is turned on and on a program that operates before migrating to multitasking. By doing so, there is no need to worry about the failure of firmware upgrade.
[0021]
According to a second aspect of the present invention, there is provided an upgrade information storage means for recording various information relating to firmware upgrades, and an upgrade information reading means for reading various information relating to upgrades stored in the upgrade information storage means. And firmware limiting means for limiting firmware to be upgraded in accordance with various types of information related to the upgrade read by the upgrade information reading means.
Thereby, a partial firmware upgrade is possible, the upgrade time is shortened, and the convenience for the user is improved. Also, the possibility of version upgrade failure due to unexpected power interruption during version upgrade is reduced.
[0022]
According to a third aspect of the present invention, a work detection means for detecting a work currently being executed and a work on standby for execution within the electronic control device, and a work being executed and standby for execution detected by the work detection means. And a version upgrade start control means for extending the start of the operation of the firmware version upgrade function until the end of the middle work.
As a result, it is possible to upgrade the firmware without interrupting the work currently being executed or the work waiting for execution, and the convenience in use of the apparatus is improved.
[0023]
According to a fourth aspect of the present invention, the first storage means is a flash ROM.
As a result, the software can be rewritten and the firmware can be protected even when the power is OFF or unexpectedly.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an electronic control device of the present invention.
FIG. 2 is a layout view showing an example of memory mapping in the present invention.
FIG. 3 is a flowchart of firmware upgrade operation in the apparatus of the present invention.
[Explanation of symbols]
11 CPU unit 12 Firmware unit 13 Volatile memory unit 14 Non-volatile memory unit 15 Download unit 16 Display / operation unit

Claims (4)

An electronic control device that operates in accordance with control firmware stored in a first storage means ,
The electronic control device downloads new firmware input from an external host device as a firmware upgrade function , temporarily stores it in the second storage means, and the new firmware temporarily stored in the second storage means In the electronic control device for writing the new firmware by the firmware writing means for writing to the first storage means in which the conventional firmware existed,
This electronic control device comprises a program reset branching means for branching to a program reset vector for starting a program when the power is turned on by software,
The program reset branching unit accesses the firmware writing unit, terminates the program running on the multitasking OS of the electronic control unit, and continues to the multitasking OS until the writing of the new firmware is completed. The electronic control device includes a function of branching to the multitask activation program in the first storage means after the completion of the writing of the new firmware without operating . Upgrade information storage means for recording various information related to the firmware upgrade;
Upgrade information reading means for reading various information related to the upgrade stored in the upgrade information storage means;
The electronic control device according to claim 1, further comprising: a firmware limiting unit that limits firmware to be upgraded according to various types of information related to the upgrade read by the upgrade information reading unit. Within the electronic control device, work detection means for detecting work currently being executed and work waiting for execution;
An upgrade start control means for extending the start of the operation of the firmware upgrade function until a time when the work being executed and the work waiting for execution detected by the work detection means are completed. The electronic control device according to claim 1 or 2.   4. The electronic control device according to claim 1, wherein the first storage means is a flash ROM.

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