JPH04125730A - Controller - Google Patents

Abstract

PURPOSE:To easily update a control program by providing a controller with a non-volatile memory and storing change information in this memory at the time of changing the control program of a microprocessor stored in a ROM in a device like a printer. CONSTITUTION:This controller consisting of a processing means (MPU) 1 and a ROM 2 is provided with non-volatile memories 3 and 4. When it is necessary to change the contents of the ROM 2 due to bugs, improvement, etc., of the program, the MPU 1 is controlled through a line by a center terminal to write information, which indicates th change of contents of the ROM 2, and information of the changed page in the memory 3. Further, the changing information of this page in the ROM 2 is written in the memory 4. The MPU 1 first reads the information, which indicates whether contents are changed or not, from the memory 3 in the case of reading out change information. When they are changed, the read of the memory 4 is permitted, and the read of teh designated page of the ROM 2 is inhibited, and the memory 4 is read.

Description

[Detailed Description of the Invention] [Summary] Regarding a control device that updates the control program of a processing means operated by a program such as a microprocessor to the latest program level and operates it, the read-only memory can be replaced at the device installation site. Program updates and/or
The purpose of the control device is to provide a control device that is capable of executing the program, and is controlled by a processing means that operates on a program. a first non-volatile memory that stores the presence or absence of change information for each divided area; and a second non-volatile memory that can store change information corresponding to a predetermined page of the read-only memory.
non-volatile memory, and when it becomes necessary to change the contents of the read-only memory, information indicating that there is change information is transferred to the first non-volatile memory and change information is transferred to the second non-volatile memory. are stored respectively, and when the processing means reads information from the read-only memory, if information indicating that there is change information is stored in the first non-volatile memory, the page with the change in the read-only memory is stored. The second non-volatile memory is read by replacing only the change information with the corresponding change information in the second non-volatile memory.

[Industrial Field of Application] The present invention relates to a control device that updates a control program of a processing means, such as a microprocessor, to the latest program level and operates the program.

In recent years, there has been a demand for high performance and high functionality of the devices constituting the system, and at the same time, there has been a demand for reductions in size, weight, and cost.

In printers and other devices that are required to be smaller and lighter, masks are used to downsize the entire device while storing the complex and large-capacity programs needed to achieve high functionality. Efforts are being made to adopt ROM.

However, if it becomes necessary to modify part of the control program due to user requests or program bugs,
It is necessary to create a mask ROM in which new necessary contents are written and replace it with the conventional ROM at the equipment installation site or the like.

Such countermeasures required a great deal of time and effort, and were accompanied by various difficulties.

[Conventional technology]

In conventional control devices, the ROM is mainly replaced at the location where the device is installed, consuming a huge amount of manpower and time. After that, the ROM creation period was shortened by adopting EFROM (erasable and programmable ROM), whose memory contents can be erased by irradiation with ultraviolet rays, for example, instead of mask ROM.
The work of replacing the ROM could not be omitted and still required a huge amount of manpower and time.

In recent years, a method has also been adopted in which a ROM and a RAM are installed in duplicate, so that a program is once loaded onto the RAM and modified data is modified on the RAM.

However, the RAM capacity in this case requires a storage capacity that can include the entire ROM, and the physical dimensions of the element also tend to increase, which is contrary to the demand for miniaturization.

In addition, methods have been adopted that use non-volatile memory and download from a higher-level device such as a terminal controller or a centrally installed host computer via a line, but it takes a considerable amount of time to transfer the entire program or stored data. It has the disadvantage of requiring time and RAM.
In the case of battery storage, the control program for download must be stored in a separate ROM, which ultimately requires dual installation of ROM and RAM, which goes against the demand for device miniaturization. It had become a thing.

In addition, in the method of updating the memory contents using EEPROM, which is a ROM whose memory contents are electrically erasable and programmable, an EEPROM with a sufficiently large capacity is used.
ROMs have the disadvantage of being difficult to obtain and expensive, and cannot be used as a fundamental solution. Therefore, in the conventional technology, it is difficult to obtain ROMs depending on the scale of the device, the system configuration, or the degree of demand for miniaturization and weight reduction. Depending on the situation, we may have to replace the ROM unavoidably, which requires manpower and time, or we may need to download it from a host device.
Dual memory system of ROM and RAM or EEPROM
Compromise measures were adopted, such as abandoning miniaturization in favor of

[Problem to be solved by the invention]

The present invention has been made in view of the above circumstances, and provides a control device that does not require replacing the ROM at the device installation site and can update/execute stored information while minimizing transfer time and number of transfers. The purpose is to provide

[Means to solve the problem]

FIG. 1 is an explanatory diagram of the principle of the present invention, and the entire apparatus is controlled by a processing means 1. In FIG.

Reference numeral 2 is a read-only memory (ROM) for storing programs, which is directly read by the processing means 1 and executes the stored program; 3 is a first non-volatile memory; , the area is divided into a plurality of pages (N pages), and information indicating the presence or absence of change information of the program or data contents stored in the ROM 2 and the storage area of the corresponding data is stored, and 4 is the specified page. This is a second nonvolatile memory that stores change information for a predetermined page (M pages) corresponding to .

These first and second nonvolatile memories 3 and 4 can be directly read/written by the processing means 1, and information can be written by downloading from a host device or by an external storage device, etc., and can be controlled. The device can be executed with the changed information (new program) replaced according to this information.

[Operation] In the present invention, when it becomes necessary to change the contents of the information stored in the read-only memory 2 shown in FIG. Necessary information is stored in the nonvolatile memory 3 and the second nonvolatile memory 4.

At this time, no electrical or physical changes are made to the read-only memory 2.

When the processing means 1 reads stored information, it first reads the read-only memory 2 depending on the contents of the first non-volatile memory 3.
It is determined whether or not it is necessary to change the contents of the information stored in the memory. If there is no change, reading of the second non-volatile memory 4 is prohibited and the contents of the read-only memory 2 remain unchanged. Read out.

On the other hand, if information indicating that the storage contents of the read-only memory 2 need to be changed is stored, reading of the corresponding page of the read-only memory 2 is prohibited, and at the same time,
The second page that stores the updated information for the corresponding page part
The non-volatile memory 4 is read. Therefore, only when the first non-volatile memory 3 has information instructing a change, the processing means 1 uses the change information stored in the second non-volatile memory 4 instead of the corresponding part of the information stored in the read-only memory 2. The information stored in the read-only memory 2 appears to be changed, and the program or information can be updated/executed without replacing the read-only memory 2 or changing the information.

〔Example〕

FIG. 2 shows a block diagram showing an embodiment of the control device of the present invention shown in FIG. Note that the same parts as in FIG. 1 are given the same reference numerals.

1 is a processing means, and a microprocessor (hereinafter referred to as rMPU) is usually used.

Reference numeral 2 denotes a read-only memory (hereinafter referred to as rROMJ), which stores programs or other data, and the entire storage area is divided into N pages.

In this case, N is determined depending on the device scale, control method, control content, etc.

The first non-volatile memory 3 stores N pieces of information corresponding to the number of pages of the ROM 2, and under normal conditions, the stored contents are retained even if the power is cut off.

The second non-volatile memory 4 has a storage area corresponding to M pages of the ROM 2. In this case, M is determined as appropriate depending on the contents of the program or data to be stored.

The circuit selection section 5 outputs selection signals for the first nonvolatile memory 3, the second nonvolatile memory 4, and the ROM 2 according to respective selection conditions.

The memory selection unit 6 specifies a specific page of the second non-volatile memory 4, and at the same time selects the MPU according to the information stored in the first non-volatile memory 3 in the case of an MPUI read request.
Control is performed so that I can read only either the ROM 2 or the second nonvolatile memory 4.

The operation of this embodiment is performed as follows. When the device is completed, the necessary programs or data are stored in the ROM 2, and the first nonvolatile memory 3 is in a state without change information.

Due to user requests, bugs or improvements to the program, R
When it is necessary to change the contents of OM2, the MPUI is controlled from the center terminal or the center control machine via a line not shown, and the changes are made to the corresponding page in ROM2 in the first non-volatile memory 3. Information to that effect and information on the changed area on the second volatile memory 4 are written. Further, change information for the corresponding page in the ROM 2 is written into the second nonvolatile memory 4.

In this way, the control device to which the change information has been written is the MP
When reading from the UI occurs, the operation shown in FIG. 3 is performed. That is, first, the memory selection unit 6 checks whether the information in the ROM 2 has been changed in accordance with the information stored in the first nonvolatile memory 3 (step 511). If it is determined that there is no change, reading from the second nonvolatile memory 4 is prohibited and a read enable signal is given to the circuit selection section 5. As a result, the designated page of ROM2 is read out (step 512).

On the other hand, if it is determined in step Sll that there is a change, reading from the second nonvolatile memory 4 is permitted, and a read prohibition signal is given to the circuit selection section 5. As a result, reading from the designated page of the ROM 2 is prohibited, while reading from the second nonvolatile memory (EEFROM) 4 is performed (step 513).

Next, the data read out in step S12 or S13, that is, the program, is executed (step 514). Next, it is determined whether the program has ended or not (step 515), and the series of processes described above are repeated until the program ends.

With such a configuration and operation, even if it becomes necessary to change the contents stored in the ROM 2, only the contents of the first and second non-volatile memories 3 and 4, which have small capacities, can be changed.
Programs can be updated/executed easily and inexpensively without creating or replacing the ROM2.

FIG. 4 explains the embodiment of the present invention in more detail, and shows an example of required numerical values in FIG. 2.

In this embodiment, the ROM 2 has a capacity of 64 bytes, but it can be selected as appropriate depending on the type or scale of the control device.

RO'M2 is divided into pages in units of 256 bytes,
It consists of a total of 256 pages. Therefore, the address is, for example, 80000 in hexadecimal as shown on the right.
~)100FF, )10100~HOIFF,
110200~HO2FF,...HFFOO~
It becomes HFFFF. Note that the above rH indicates that it is a hexadecimal number.

The first and second nonvolatile memories 3 and 4 include electrically erasable and programmable ROM, that is, EEPROM.
is adopted.

The first non-volatile memory 3 is selected here to have a capacity of 2 to 100 liters, which is sufficient to store information on the number of pages N=256 of the ROM 2.

This first non-volatile memory 3 is configured as a ROM in accordance with control from a host device (not shown) when there is change information.
Change the state of the page corresponding to the page requiring change in step 2. Therefore, the presence or absence of change information and specific information of the relevant page are written.

In response to such a change, the signal HOO indicating no change is outputted to a signal H01 indicating a changed state only for the corresponding page.

The example shown in FIG. 4 shows that page 3 of ROM2 has been changed, and the changed contents are on page 1 of EEFROM4.

The second non-volatile memory 4 has an area for one eight pages of 256-height units, which corresponds to the page of the ROM 2, and the capacity of the second non-volatile memory 4 is selected to be Hyde, but depending on the size of the program It is also optional to adopt a larger capacity or a smaller capacity depending on the control content. This second non-volatile memory 4 is for storing new information of pages of the ROM 2 that need to be changed. In this embodiment, update information of page 3 of the ROM 2 transferred from the host device is stored.

The operation of the configuration shown in FIG. 4 is as follows. Now, when the instruction fetch address is output from MPUI,
A first non-volatile memory, EEFR, in division units of page N.
OM3 outputs the corresponding data. Upon receiving this output, the memory selection section 6 checks the presence or absence of the changed data, and if the output is 1 (00), sends a permission signal to the circuit selection section 5 to select the ROM 2, and then sends a permission signal to the circuit selection section 5 to select the ROM 2. The output of the external memory EEFROM 4 is inhibited by an inverted signal. Therefore, the data of the ROM 2 is read into the MPUI as usual.

On the other hand, if the memory selection unit 6 receives the signal 1 (01) indicating that there is change data as shown in page 3 of the figure, the ROM
A prohibition signal is applied to the circuit selection unit 5 for specifying page 2, and a permission signal is applied to the EEFROM 4. As a result, in the case of page 3, the data specified by the lower addresses AO to A7 from page 1 of the second non-volatile memory 4, which is specified by the MPUI, is sent to the MPUI instead of reading the corresponding page of the ROM 2. Loaded. As a result, the MPU 1 executes the program as if the changed data were read from the ROM 2.

In the embodiment shown here, the ROM is divided into pages of 256 bytes, and the EEFR is used to store changed data.
Although the OM consists of 8 pages, it can be set somewhat arbitrarily depending on the device scale, control details, etc.

Furthermore, the data written to the EEFROM 3 is set to ``00'' with no data change, ``Hot'' with change, and a numerical value expressed in hexadecimal as the page designation, but any other data structure may be adopted.

Furthermore, the stored information can be a program alone or data that requires storability, and it is also possible to include both, depending on the page structure.

〔Effect of the invention〕

According to the present invention, a program can be easily updated by writing change information into an EEFROM from a host device such as a terminal controller or host computer, or from an external storage device. Therefore, ROM
The same effect as replacement can be obtained. EEFROM in this case
It suffices to have a small capacity, low price and small size, and can satisfy the demands for lower prices and smaller size. With such a configuration, it is possible to update the program of the control device by downloading it from the host device, and it is possible to obtain the effect that there is no need to create a change ROM or replace the ROM at the device installation site.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a diagram showing the principle configuration of a program update/executable control device according to the present invention. FIG. 2 is a program update/executable control device according to the present invention. FIG. 3 is a flowchart showing the operation of the main parts of the program update/executable control device according to the present invention; FIG. 4 is a program update/executable control according to the present invention. FIG. 3 is a more detailed block diagram of an embodiment of the device; In the figure, 1... Processing unit (MPU), 2... Read only memory (ROM), 3... First non-volatile memory (EEPROM), 4... Second non-volatile memory (EEPROM) ), 5...Circuit selection section, 6...Memory selection section. In the figure, the same symbols indicate the same or equivalent parts. Applicant Fujitsu Limited Agent

Claims (2)

[Claims] (1) In a control device controlled by a processing means (1) that operates on a program, there is a read-only memory (2) in which programs or data are stored, and each read-only memory (2) is divided into multiple pages. A first non-volatile memory (3) that stores the presence or absence of change information for an area; and a second non-volatile memory (4) that can store change information corresponding to a predetermined page of the read-only memory (2). ), and when it becomes necessary to change the contents of the read-only memory (2), information indicating that there is change information is transferred to the first non-volatile memory (3) and to the second non-volatile memory (3). (4) respectively store change information, and when the processing means (1) reads information from the read-only memory (2), information indicating that change information is stored in the first non-volatile memory (3). is stored, only the changed page of the read-only memory (2) is stored in the second non-volatile memory (4).
) is replaced with corresponding change information and read out. (2) In the control device according to claim (1), the first
The information stored in the second non-volatile memory (3) is composed of information indicating the presence or absence of change information and information specifying the page of the second non-volatile memory (3) in which the change information is stored. Characteristic control device.