JP2001022571A - Electronic equipment and rewriting method for control program of the equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily rewrite a control program to a nonvolatile memory which is fixed on a printed board and cannot be detached from the board. SOLUTION: A control program is stored in a memory 3 fixed on a printed board 10, and a CPU 1 start its operation to execute the control program. When the memory 3 is rewritten, a mounting base board 14 is mounted on an extension connector 12 of the board 10. At the same time, an address conversion means 7 mounted on the board 10 detects a prescribed potential via the mounting of the board 14 and switches the start address of the CPU 1 to a storage means 15 of the board 14. Then the CPU 1 starts a transfer execution program of the means 15 and transfers the object program to the memory 3 to rewrite the contents of the memory 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in an electronic device which is started by executing a control program stored in a rewritable memory which can hold stored contents when power is not supplied, and is particularly stored in this memory. The present invention relates to a data rewriting device and method capable of easily rewriting a control program.

[0002]

2. Description of the Related Art An electronic apparatus equipped with a CPU reads a control program from a predetermined start address "0H" when power is turned on, and executes the control program. This control program includes a vector for the control operation of the CPU (for example, an address of a save destination when a register inside the CPU is used or a destination when a CPU error occurs), and shifts to another address after executing a series of processing. Thus, a predetermined program for operating the electronic device is started to be executed.

The above control program is generally rewritten for maintenance or the like, and is stored in a removable non-volatile memory (for example, EEPROM, flash ROM, FRAM, etc.). Here, the nonvolatile memory is used because it is necessary to retain the contents of the control program even when the power of the electronic device is turned off. Note that a configuration in which an SRAM or the like is backed up by a battery or the like as a nonvolatile memory can also be included.

[0004]

If the above-mentioned control program is stored in a non-volatile memory detachable from the board, the non-volatile memory can be replaced with a new one, and the device can be replaced by a new program. Can be activated. However, in recent years, with the miniaturization of the nonvolatile memory itself, surface mounting on a printed circuit board (SMT: Surface mounting)
t technology) has been increasingly used. In this SMT, after a control program is written in a nonvolatile memory, it is surface-mounted on a printed circuit board by soldering.
As described above, the nonvolatile memory fixed to the printed circuit board cannot physically be attached or detached, so that repair, version upgrade of the control program, and bug correction cannot be easily performed.

In response to this, JTAG (Joint Test Ac
The configuration of the nonvolatile memory fixed to the printed circuit board is rewritten in accordance with the communication protocol of the Communication Group), but rewriting by this method takes a long time to write to the non-volatile memory because of serial transfer. Further, a computer device is required for writing, which is troublesome.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a data rewriting apparatus and method which can easily rewrite a control program in a non-removable nonvolatile memory fixed to a printed circuit board. It is intended to be.

[0007]

According to a first aspect of the present invention, there is provided a data rewriting device for use in an electronic device having a rewritable memory, the method comprising the steps of: A processor for reading and starting data from the memory, and a rewritable internal storage means for storing a control program for an electronic device in an address space starting from the start address and holding the stored data even when power is not supplied And a medium on which an external storage means storing a transfer execution program for rewriting the control program and a transfer target program is detachable from the electronic device, and the medium is the electronic device. When the power of the device is turned on when the device is mounted on the device, the processor executes the transfer execution process. The start address of the ram so as to be regarded that it is the start address, and having an address conversion means for switching the correspondence between the two storage means and the start address.

[0008] According to a second aspect of the present invention, there may be provided a configuration having an extension connector which is connected to the bus of the processor and to which the medium is attached and detached.

According to a third aspect of the present invention, the medium is provided with a potential supply means for supplying a predetermined potential to the address conversion means when the medium is attached to the extension connector, and the address conversion means comprises The correspondence may be switched based on the supply of a predetermined potential from a potential supply unit.

According to a fourth aspect of the present invention, the transfer execution program writes the management number of the transfer target program to a predetermined address when the transfer of the transfer target program to the internal storage means ends normally. It may be.

[0011] The method according to the present invention comprises:
A control program for controlling an electronic device is a data rewriting method used for an electronic device having an internal storage unit that retains stored data even when power is not supplied. On the bus,
A medium mounted with an external storage means in which a transfer execution program and a transfer target program are stored is mounted, and when the device is powered on, the processor sets the start address of the transfer execution program based on the mounting of the medium. By switching the correspondence between the two storage means and the start address so as to be regarded as the start address, executing the transfer execution program and transferring the transfer target program to the internal storage medium, It is characterized in that the control program of the internal storage means is rewritten.

According to the above configuration, the control program stored in the memory 3 provided on the control board 10 can be rewritten by mounting the mounting board 14 on the extension connector 12. When detecting a predetermined potential by mounting the mounting board 14, the address conversion means 7 on the control board 10 switches the start address of the processor 1 to the storage means 15 on the mounting board 14 instead of the memory 3. The processor 1 starts up from the transfer execution program in the storage unit 15 and rewrites the data by causing the transfer target program to be transferred to the memory 3.

[0013]

FIG. 1 is a block diagram showing the entirety of an electronic apparatus to which a data rewriting device according to the present invention is applied.
This device can be applied to all devices controlled by a processor (hereinafter, referred to as a CPU) 1. For example, a computer game machine, a print controller interposed between a computer and an image forming apparatus, and the like can be given.

The CPU 1 is connected to each section via a bus 2. A rewritable memory (hereinafter referred to as a non-volatile memory for convenience) 3 that retains the stored contents even when power is not supplied stores a control program that is read first by the CPU 1 when the device is powered on. In this embodiment, the nonvolatile memory is a flash ROM
It is composed of

A memory 4 such as an SRAM is used for storing data and the like when the CPU 1 executes processing. The control circuit 5 adjusts the timing of data transmission and reception between the units. The decoder 6 decodes the address of the output of the CPU 1 and supplies it to each unit.

The address conversion circuit 7 selectively switches the read address of the CPU 1 when the power of the electronic device is turned on, to either the nonvolatile memory 3 or an external storage means 15 described later. Here, each part of the CPU 1 to the address conversion circuit 7 is mounted on a control board 10 inside the electronic device. The control board 10 is provided with an extension connector 12.
Is connected to the address conversion circuit 7 via the.

A mounting board 14 is detachably attached to the extension connector 12. The mounting substrate 14 is mounted from the outside of the electronic device. The mounting substrate 14 is configured to be inserted from the outside into an insertion slot portion opened in the housing of the electronic device, or the electronic device is opened by opening the housing of the electronic device. This is a configuration that is installed inside the device. By mounting the mounting board 14 on the extension connector 12, the mounting board 14
, And the connection is switched by the address conversion circuit 7.

The mounting board 14 is provided with storage means 15 such as a ROM. The storage unit 15 stores in advance a rewriting program for rewriting the contents of the nonvolatile memory 3 and a program to be transferred to the nonvolatile memory (a transfer target program).
The transfer target program is not limited to the program code, but may be data. The storage means 15 may be configured to be detachable from the mounting board 14, such as a memory card.

FIG. 2 is a block diagram showing the address conversion circuit 7. By mounting the mounting board 14 on the extension connector 12, the storage means 15 of the mounting board 14 stores the data bus 2a, the address bus 2b,
It is connected to a control bus (READ signal) 2c.

The address conversion circuit 7 is provided with a multiplexer 20, which switches the activation target when the power of the electronic device is turned on (when the CPU 1 is activated) to the nonvolatile memory 3 or the storage means 15. Can be

The CPU 1 outputs a CS signal (CS0, CS1)
To the input terminal 2 of the multiplexer 20 via the decoder 6
Input to 0a and 20b. The CS signal is for specifying a target to be activated, and the connection relationship with the output terminals 20c and 20d is switched depending on whether or not the mounting board 14 is mounted.

The mounting board 14 is supplied with power from the control board 10 via a power supply line 18 via the extension connector 12. Further, the ground terminal 19 for mounting detection is connected to the internal switch 21 (see FIG. 3) of the multiplexer 20 via the ground line 18b. The potential of the ground line 18b is at the ground level when the mounting board 14 is mounted on the control board 10, and is open when the mounting board 14 is not mounted. As shown in Table 1, the internal switch 21 has a circuit configuration that can switch the connection relationship depending on whether the mounting board 14 is mounted or not.

[0023]

[Table 1]

FIG. 3 is a diagram showing the switching operation inside the multiplexer 20. When not attached, the input terminal 20a,
Output terminals 20c and 20d are connected to 20b, respectively (FIG. 3A). At the time of mounting, the input terminals 20a, 20
Output terminals 20d and 20c are connected to b, respectively (FIG. 3 (b)).

FIG. 4 is an address map showing the use state of the nonvolatile memory 3 during normal operation of the electronic device. The non-volatile memory 3 is assigned the address CS0, and has a control program for operating the electronic device and a work area. In the storage means 15, CS
The address 1 is assigned, but in this case, the storage means 15 is not attached, and is in an unused state. CPU
1 starts processing with the start address of the address CS0 as a start address. Therefore, when the mounting board 14 is not mounted, the CPU 1 starts processing by reading the control program from the nonvolatile memory 3.

After the execution of the control program, the CPU 1 reads and executes an address at a predetermined address where a predetermined operation program (not shown) is described, so that the electronic device starts a normal operation.

FIG. 5 is an address map showing the use state of the nonvolatile memory 3 and the storage means 15 during the rewriting operation. The nonvolatile memory 3 is assigned an address CS1, and has a control program for operating the electronic device and a work area. The storage means 15 is assigned the address CS0, and stores a transfer execution program and a control program to be transferred. The transfer execution program includes a vector, an initial setting for executing a rewrite operation for the nonvolatile memory 3, and a program for actual work. As in the normal operation, the CPU 1 starts processing with the start address of the address CS0 as a start address. Therefore, when the mounting board 14 is mounted on the extension connector 12, the CPU 1 operates the storage unit 15 provided on the mounting board 14. The transfer execution program is executed using the work area of the nonvolatile memory 3.

Then, a process for transferring the transfer target program stored in a predetermined area of the storage means 15 to the non-volatile memory 3 from the address CS1 is executed by the transfer execution program. By transferring the transfer target program, the control program stored in the nonvolatile memory 3 is rewritten.

That is, as shown in the figure, the past control program described from the address CS1 is rewritten to a new transferred program to be transferred. The transfer target program can include a control program (so-called vector) starting from address 0H which is read first when the CPU 1 starts execution. If the transfer target program is composed of a part of the control program to be rewritten, only the corresponding part of the control program is rewritten by the execution of the transfer.

FIG. 6 shows the nonvolatile memory 3 having the above configuration.
9 is a flowchart showing the rewriting operation of FIG. When rewriting the control program of the nonvolatile memory 3, (S1-
YES), the mounting substrate 14 is used. The storage means 15 of the mounting board 14 previously stores a control program to be rewritten (a transfer target program) and a transfer execution program. Then, the mounting board 14 is mounted on the extension connector 12 of the control board 10 (S3).

On the other hand, when the control program is not rewritten (S1-NO), the mounting board 14 is connected to the extension connector 12
The control program is not rewritten unless it is attached to the control program. In this case, a normal operation (reading and execution of the control program in the nonvolatile memory 3) is performed (S2).

By mounting the mounting board 14 on the extension connector 12, the potential of the ground line 18b becomes the ground level. Next, when the power of the apparatus is turned on (S
4), the internal switch 21 of the multiplexer 20 is switched so that the input terminal 20a and the output terminal 20d are connected, and is activated from the storage means 15 at the address CS0 (S5).

Thus, after the device is initialized according to the transfer execution program stored in the storage means 15, the transfer execution process is started (S6). Then, the transfer execution program writes the contents of the transfer target program in the control program area of the nonvolatile memory 3 (S
7). Thereby, a new control program is transferred.

It is determined whether this data transfer has been completed normally (S9). If the processing ends normally (S9-Y
ES), the notifying means (for example, LED, buzzer, etc.) provided on the control board 10 is operated to notify the end of the transfer (S10), and the power of the apparatus is turned off to end (S11).

On the other hand, if there is an error in the data transfer (S9-NO), the number of errors is counted (S1).
2) If the error is within a predetermined number of times set in advance, S5
And transfer is executed again. If this error has reached a predetermined number of times (for example, two times), it is determined that the transfer cannot be executed (S14), and a notification prompting an inspection of the control board 10 or the mounting board 14 is activated by the notification means. Perform (S14).

At the end of the data transfer in S9, it can be determined whether or not the data transfer has been completed normally by referring to the management number corresponding to the transfer target program. That is, the transfer program executes a process of writing the management number to a predetermined address at the end of the transfer of the transfer target program. For example, this address is written in the address space of the nonvolatile memory 3.

Thereafter, by reading the written management number, the contents of the control program stored in the nonvolatile memory 3 can be determined. This management number is not written when transfer fails. Thus, it is possible to determine whether the control program stored in the non-volatile memory 3 is an old version or the latest version by simply reading the management number.

In the above embodiment, a flash ROM has been described as an example of a rewritable memory (non-volatile memory). However, the present invention is not limited to this, and an EEPROM, an FRAM, or the like can be similarly applied. Further, even when these memories are configured to be detachable, the same can be applied.

In the above embodiment, the mounting of the mounting board 14 to the control board 10 is performed by detecting the presence or absence of the ground potential. However, the present invention is not limited to this. A configuration may be adopted in which the potential is output and the control board 10 detects this. In addition, a configuration in which the setting SW on the control board 10 is manually operated and set, or detection of mounting of the mounting board 14 using a sensor may be considered.

[0040]

According to the data rewriting device of the present invention,
The control program stored in the memory can be rewritten by attaching storage means from the outside. At this time, the processor starts up from the transfer execution program stored in the storage means and transfers the transfer target program to the memory.
The control program including the vector can be rewritten. Thus, even if the memory is fixed on the control board by surface mounting or the like, the control program of the memory can be completely or partially rewritten. Rewriting can be applied not only to the control program but also to data. According to the second aspect, the data in the memory can be rewritten only by attaching the mounting board provided with the storage means to the expansion connector on the control board provided with the memory. According to the third aspect, simply by mounting the mounting board on the control board, a predetermined potential is supplied and the processor can be started from the storage means side, so that setting operation is unnecessary and easy. Rewriting can be performed. According to the fourth aspect, when the rewriting of the memory is completed normally, the management number is written, so that the rewriting state can be easily grasped. According to the data rewriting method of the present invention, the external storage means is connected to the processor before the power supply of the processor is turned on, and the start address read by the processor at the time of power supply is switched to the start address of the transfer execution program. The configuration is such that the control program of the memory can be rewritten by starting from the side, and the memory can be easily rewritten by a simple procedure.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an entire electronic device to which a data rewriting device of the present invention is applied.

FIG. 2 is a configuration diagram showing an address conversion circuit.

FIG. 3 is a diagram showing a switching operation inside a multiplexer.

FIG. 4 is an address map during normal operation of the electronic device.

FIG. 5 is an address map at the time of a rewriting operation of a nonvolatile memory.

FIG. 6 is a flowchart showing a rewriting operation of a nonvolatile memory.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... CPU, 2 ... bus, ... nonvolatile memory, 7 ... address conversion means, 10 ... control board, 12 ... expansion connector, 1
4 mounting board, 15 storage means, 20 multiplexer, 21 internal switch, 19 ground terminal.

Claims (5)

[Claims] 1. A processor which reads out data from a predetermined start address when power is turned on and starts, and a control program for an electronic device is stored in an address space starting from the start address. An electronic device having rewritable internal storage means for holding stored data, wherein the medium having an external storage means storing a transfer execution program for rewriting the control program and a transfer target program is the electronic device. When the power of the device is turned on while the medium is mounted on the electronic device, the processor regards the start address of the transfer execution program as the start address. The address conversion means for switching the correspondence between the two storage means and the start address. Electronic equipment characterized by the above. 2. The electronic apparatus according to claim 1, further comprising an expansion connector connected to a bus of said processor and to which said medium is attached and detached. 3. The medium is provided with a potential supply means for supplying a predetermined potential to the address conversion means when the medium is attached to the extension connector, and the address conversion means is provided with a predetermined potential from the potential supply means. 3. The electronic device according to claim 2, wherein the correspondence is switched based on supply. 4. The transfer execution program according to claim 1, wherein said transfer execution program writes a management number of said transfer target program to a predetermined address when transfer of said transfer target program to said internal storage means ends normally. Electronics. 5. A data rewriting method for use in an electronic device having an internal storage means for storing a control program for controlling the electronic device and holding the stored data even when power is not supplied, comprising: A medium mounted with an external storage means storing a transfer execution program and a transfer target program is mounted on a bus of a processor of an electronic device. When the device is powered on, the processor performs the transfer based on the mounted medium. The correspondence between the two storage means and the start address is switched so that the start address of the execution program is regarded as the start address, and the transfer execution program is executed to store the transfer target program in the internal storage. Controlling the electronic device by rewriting a control program in the internal storage means by transferring the control program to a medium. Program rewriting method.