JPH09305395A - Electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To modify data in a flash memory while mounting the memory on a printed board, etc., as it is. SOLUTION: This equipment is equipped with a data rewritable nonvolatile memory 3 which has a 1st area wherein a rewriting program rewriting program data and function setting data are stored and a 2nd area where the program data and function setting data are transferred and stored and a personal computer 10 which sends modified data of the program data and function setting data. Once the personal computer 10 is connected, a CPU 2 is actuated to execute the rewriting program in the 1st area; and the program data and function setting data in the flash memory 1 are transferred to the 2nd area, and the flash memory 1 is erased and also rewritten according to the modified data from the personal computer 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device capable of rewriting program data, function setting data, etc. in a flash memory that can be electrically written and erased.

[0002]

2. Description of the Related Art A memory such as a ROM is suitable for holding data such as a program since it can hold stored data even when the power is turned off. However, when a change in a program or the like occurs, it is impossible to electrically erase the program and write new data. Therefore, the ROM needs to be replaced with a ROM in which data is newly written. . For this reason, in recent years, flash memories are frequently used in various electronic devices. This flash memory is ROM
Similar to the above, it is a non-volatile memory that can retain data even when power is not supplied. It is suitable for storing various data. Further, unlike a ROM, a flash memory is a memory in which data can be electrically erased and rewritten, and can be rewritten with new data when program data or function setting data is changed.

[0003]

However, even in such a flash memory, when changing program data or the like, the data is normally rewritten by removing it from the printed circuit board mounted through a socket or the like.
In recent years, many flash memories are surface mount type,
Since the flash memory of this type is directly soldered to the printed circuit board, it is difficult to change the program data and the like. Therefore, an object of the present invention is to make it possible to rewrite data in a flash memory without removing the flash memory from a printed circuit board or the like.

[0004]

In order to solve such a problem, the present invention provides a first area for storing a rewriting program for rewriting data and a second area for storing and transferring data. A rewritable volatile memory (SRAM) and an external device for transmitting the changed data of the data, and the control means is activated under a predetermined condition to cause the CPU to execute the rewriting program of the first area. Transfer the data of the non-volatile memory (for example, flash memory) to the second area by executing it, erase the non-volatile memory after the transfer is completed, and rewrite the non-volatile memory based on the changed data from the external device. It is the one. The external device is the first SRAM.
Has the above rewriting program stored in the area
Moreover, the transfer program for receiving the rewriting program from the external device and transferring it to the first area is stored in the non-volatile memory.

The rewriting program and a transfer program for transferring the rewriting program to the first area of the SRAM are stored in a non-volatile memory. Also, the nonvolatile memory is configured in units of a plurality of blocks to enable partial rewriting of data. Further, a display unit, a check unit for checking whether data rewriting of the nonvolatile memory is correct or not, and a unit for displaying an error on the display unit when a check result of the check unit indicates an error are provided. Further, a restart means is provided for returning the processing of the CPU to the program execution processing of the nonvolatile memory after the data rewriting of the nonvolatile memory is completed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a main configuration of an electronic device according to the present invention. In the figure, reference numeral 1 is a flash memory which is a nonvolatile memory in which data such as program data and function setting data of the present electronic device is stored and which can be electrically written and erased. Instead of the flash memory 1, an SRAM which is a volatile memory may be backed up by a battery or the like and used as a non-volatile memory. Further, 2 is a CPU that executes a program in the flash memory 1 to perform a predetermined functional operation, 3 is a volatile memory that temporarily stores these data when the data in the flash memory 1 is changed, 4 Receives the address output from the CPU 2 and the flash memory 1 and SR
It is an address decoder that selects either one of AM3.

Reference numeral 5 is a start key for starting the rewriting of program data and the like, and 6 is a watchdog for operating a reset circuit described later to output a reset signal when the periodic output from the port P3 of the CPU 2 is lost. A circuit, 7 is a reset circuit for applying a reset signal to the reset terminal of the CPU 2 for resetting by a power-on signal or an output from the watchdog circuit 6, and 8 is a display means.

In FIG. 1, reference numeral 10 is a personal computer for transmitting program change data and the like to the CPU 2 of the electronic apparatus, AB is an address bus, and DB is a data bus. Here, RS-232 is provided between the personal computer 10 and the CPU 2.
Connected by the C signal line 9, the CPU 2 receives the rewriting data by the RS-232C signal sent from the personal computer 10 through the port P2. When the check result of the received rewrite data is NG, the retransmitted data is transmitted from the port P2 by the RS-232C signal.

In the electronic device constructed as described above, when the data stored in the flash memory 1 is changed, the personal computer 10 is connected to the CPU 2 and the start key 5 is pressed. Then, the CPU 2 detects this and executes a transfer program to be described later in the flash memory 1 to transfer the rewriting program in the flash memory 1 to the SRAM 3 and, after the transfer is completed, to the SRAM.
The rewriting program of No. 3 is executed.

In this way, the CPU 2 thereafter rewrites the data in the flash memory 1 by executing the rewriting program transferred to the SRAM 3. That is, C
When the PU 2 receives the rewrite data from the personal computer 10, the CPU 2 transfers the data of the sector corresponding to the rewrite data in the flash memory 1 to the SRAM 3,
A data editing process is performed on the SRAM 3 to rewrite the corresponding portion with the received data. When the data editing is completed, the data in the corresponding sector of the flash memory 1 is erased,
A process of writing the edit data of AM3 to the corresponding sector is performed. At the time of erasing and data rewriting of the flash memory 1, data rewriting and the like are performed while checking the busy signal output from the BUSY terminal of the flash memory 1.

By executing the rewriting program transferred to the SRAM 3 in this way, the data in the flash memory 1 is rewritten, and when the rewriting is completed, the CPU
2 returns to the normal processing for executing the program of the flash memory 1. In this way, the CPU 2 rewrites the data of the flash memory 1 by executing the rewriting program of the SRAM 3, so that the data can be rewritten without removing the flash memory 1 from the printed circuit board or the like on which the flash memory 1 is mounted. Also during this period CP
The program execution operation of U2 is not stopped, so that the data in the flash memory 1 can be rewritten quickly.

FIG. 2 shows a flash memory 1 and an SRAM.
It is a figure which shows the structure of 3. The flash memory 1 is divided into each sector as shown in FIG. 1A, the sector “0” stores the function setting data of the electronic device, and the sectors “1” to “n−1” are stored. Stores program data. Further, in the sector “n”, the initial program PG1 for performing initial processing at power-on and the first rewriting program PG for rewriting data.
2 is stored and this sector is called a protected area (non-rewritable area).

The first rewriting program PG2 stored in the protected area is a rewriting start program PG3 that detects the depression of the start key 5 and shifts to rewriting processing.
A first transfer program PG4 for transferring a program stored in a protected area in the flash memory 1 to the SRAM 3, a processing transfer program PG5 for transferring the CPU 2 to the processing of the program in the SRAM 3, and rewriting data from the personal computer 10. And a second program for transferring the data of another sector of the flash memory 1 to the SRAM 3.
Transfer program PG7 and the rewriting data received from the personal computer 10 are edited on the SRAM3 and written to the flash memory 1, and an end display and an error display are given to the display means 8 when the rewriting to the flash memory 1 is completed. Error processing program PG9 to be executed
And a restart processing program PG10 for restarting the next processing at the end of rewriting.

Among these, the programs transferred to the SRAM 3 by the first transfer program PG4 are a check program PG6 and a second transfer program PG.
7, editing program PG8, error processing program PG
9 and a restart processing program PG10, which are referred to as a second rewriting program PG11. On the other hand, as shown in FIG. 2B, the configuration of the SRAM 3 is other than a program area (first area) in which the second rewrite program PG11 transferred from the flash memory 1 is stored and a protection area of the flash memory 1. And a data area (second area) in which transfer data from another sector area is stored.

Next, the data rewriting operation of the present electronic device will be specifically described with reference to the flowchart of FIG. First, when rewriting the data in the flash memory 1,
After creating rewrite data on the personal computer 10, CPU
2 and the RS-232C signal line 9 are connected, and the start key 5 is pressed. Then, the CPU 2 executing the program of the flash memory 1 and performing the normal process makes a determination of the detection of the start key 5 in step S1. When the depression of the start key 5 is detected, the normal process is interrupted and the flash memory 1 The protected area rewrite start program PG3 therein is executed, and it is determined in step S2 whether or not there is a connection with the personal computer 10.

When the connection with the personal computer 10 is detected, the CPU 2 causes the first transfer program PG in the protected area to be detected.
4 is executed, and the second rewrite program PG11 is transferred to the program area of the SRAM 3 in step S3. After that, the CPU 2 starts executing the second rewriting program PG11 transferred to the SRAM 3 by executing the protected area processing shift program PG5 in step S4.

In this case, the CPU 2 first executes the checking program PG6 in the second rewriting program PG11 to transmit a reception ready signal to the personal computer 10 via the RS-232C signal line 9 in step S5.
In response to the transmission of the reception ready signal, the personal computer 10 transmits rewrite data. The rewrite data transmitted from the personal computer 10 is data including the rewrite data itself and the address of the rewrite data (the address of the flash memory 1). With this configuration, the personal computer 10 can store the flash memory 1
When the data is rewritten, only the changed data can be transmitted without transmitting all the data, so that the data transmission time can be reduced. Also in the present apparatus, the reception time of the rewritten data is shortened, and only the changed data need be rewritten. Therefore, the data rewriting time can be reduced.

The CPU 2 receives the rewriting data from the personal computer 10 in step S6. Then, in step S7, it is determined whether or not the received rewrite data is correct by performing a checksum calculation of the data. Here step S
As a result of the determination in step 7, if it is determined that the regular rewriting data cannot be received, a resend request is sent to the personal computer 10 in step S8, and the process returns to step S6. Then, the rewriting data retransmitted from the personal computer 10 is received. If the rewrite data can be received as a result of the determination in step S7, the process proceeds to step S9, and after confirming that the received data is not the end code indicating the transmission of the rewrite data, the CPU 2 transfers it to the SRAM 3. The second transfer program PG7 is executed.

By executing the second transfer program PG7, all the data of the sector of the flash memory 1 corresponding to the corresponding address of the received data is transferred to the data area of the SRAM 3 in step S10. Thereafter, the CPU 2 executes the editing program PG8 to execute step S.
At 11, a data editing process is performed in which the corresponding data in the data area of the SRAM 3 is rewritten to the received rewriting data.
Further, in step S12, the data "00" or "FF" H (hexadecimal) is written in the corresponding sector of the flash memory 1 to erase it. Further, in step S13, the edit data in the data area of the SRAM 3 is transferred and written in the erased corresponding sector.

After that, the error processing program PG9 transferred to the SRAM 3 is executed, and the flash memory 1
It is checked whether or not the data has been normally written by performing a checksum operation on the data. That is,
The checksum of the corresponding sector in the flash memory 1 before erasing is compared with the checksum calculation result of the edited data newly written in the corresponding sector. If a checksum error occurs, the error is stored in a separate area of the SRAM 3. Set a flag. Thus, the flash memory 1
Is partially rewritten to one of the sectors.

After that, the CPU 2 returns to step S5 and executes the checking program PG6 of the SRAM 3 again to receive the rewriting data regarding the next sector transmitted from the personal computer 10 side and check the received data. Then, by re-executing the second transfer program PG7, the data of the sector of the flash memory corresponding to the corresponding address of the received data is SR-processed in step S10.
By transferring the data to the data area of AM3 and re-executing the editing program PG8, the data rewriting process of steps S11 to S13 is similarly performed, and the data writing error and the like are also checked.

In this way, by executing the rewriting program PG11 of the SRAM 3, the data of each sector of the flash memory 1 is sequentially rewritten into the data transmitted from the personal computer 10 side. And the personal computer 10
When the end code indicating the end of data rewriting is transmitted from the side and the "end code" in step S9 is determined to be "Y", the CPU 2 executes the error processing program PG9, and writes the error flag in a separate area of the SRAM3. It is determined whether or not is set. If the error flag is set, an error display is displayed on the display means 8, and if the error flag is not set, a write end display is displayed on the display means 8 (step S14). As the display means 8, there is a tone generating means in addition to the LED and LCD. Further, when such a writing error occurs, an error signal is transmitted to the personal computer 10 side to display an error on the personal computer 10. After that, the CPU 2 executes the restart processing program PG10 transferred to the SRAM 3 to return to the normal processing in step S15.

As the restart process PG10 after the writing process is completed, in addition to the method of returning to the normal process as in the present embodiment, the Foch dog which the CPU 2 regularly performs during the execution of the program. By stopping access to the circuit 6, the watchdog circuit 6
There is a method of activating the reset circuit 7 to reset the CPU 2 and restore the program of the flash memory 1. In this case, the CPU 2 executes the initial program of the flash memory 1 and then executes the program of each sector. After the writing process is completed, C
There is also a method of putting the PU 2 in a standby state, resetting the CPU 2 from the reset circuit 7 by a power-on reset based on turning off the power of the electronic device, and returning the CPU 2 to the program of the flash memory 1.

As a method of activating the rewriting program, in addition to pressing the start key 5, a method of immediately transferring and executing the rewriting program to the SRAM 3 when the CPU 2 detects the connection with the personal computer 10, When a "rewrite program transfer" command is received from an external device such as
There is a method of transferring to the AM3 and executing it.

Further, in the present embodiment, the rewriting program is always stored in the non-rewritable protected area of the flash memory 1, but it may be stored in another rewritable sector, and the personal computer 10 An external device such as the above may be transmitted to and stored in the SRAM 3, and the point is that the rewriting program is stored in the SRAM 3 when rewriting the data in the flash memory 1. Therefore, the rewriting program may be stored in the SRAM 3 at the initial time other than the rewriting time of the flash memory. The rewriting program SRA
When data is stored in M3, a checksum operation is performed on this data.
Is loaded into the SRAM 3. In the present embodiment, data is rewritten for each sector of the flash memory 1. However, if the capacity of the SRAM 3 is made larger than the capacity of the flash memory 1, all data in the flash memory 1 can be rewritten collectively. Is also possible.

[0026]

As described above, according to the present invention, the data rewritable SRAM and the external device for transmitting the change data such as the program data are provided, and the control means is activated by a predetermined condition to the CPU. The rewriting program of the first area of the SRAM is executed to transfer the data of the non-volatile memory to the second area of the SRAM, the non-volatile memory is erased, and the non-volatile memory based on the changed data from the external device. Since the rewriting is performed, the data can be rewritten while the data in the non-volatile memory is changed, for example, with the flash memory, which is the non-volatile memory, mounted on the printed circuit board or the like.
Further, when rewriting data, it is only necessary to rewrite only the changed data portion without rewriting all the data, so the data rewriting efficiency can be improved.

Further, the external device has the rewriting program stored in the first area of the SRAM, and the transfer program for receiving the rewriting program from the external device in the non-volatile memory and transferring the rewriting program to the first area. Is stored, it is not necessary to make the rewriting program resident in the SRAM. Further, since the rewriting program and the transfer program for transferring the rewriting program to the first area of the SRAM are stored in the nonvolatile memory, the data can be rewritten immediately without using an external device. In addition, the correctness of the data rewriting of the nonvolatile memory is checked, and an error is displayed on the display means when the check result indicates an error. Therefore, the correctness of the data rewriting can be accurately recognized.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of an electronic device of the present invention.

FIG. 2 is a diagram showing a flash memory and an S constituting an electronic device
FIG. 2 is a diagram illustrating a configuration of a RAM.

FIG. 3 is a flowchart illustrating a data rewriting operation of a CPU of the electronic device.

[Explanation of symbols]

1 ... Flash memory, 2 ... CPU, 3 ... SRAM, 4
... address decoder, 5 ... start key, 6 ... watchdog circuit, 7 ... reset circuit, 8 ... display means, 9 ... R
S-232C signal line, 10 ... PC.

Claims (6)

[Claims] 1. A rewriting device for rewriting data in an electronic device comprising a non-volatile memory that stores data and can rewrite the data, and a CPU that accesses the non-volatile memory and performs a predetermined process. A rewritable volatile memory having a first area for storing a program and a second area for transferring and storing the data; and an external device for transmitting change data of the data, The CPU is activated under a predetermined condition to cause the CPU to execute the rewriting program of the first area to transfer the data of the non-volatile memory to the second area and erase the non-volatile memory, and based on the change data, An electronic device comprising: a control unit that rewrites a nonvolatile memory. 2. The external device according to claim 1, wherein the external device has the rewrite program stored in a first area of the volatile memory, and receives the rewrite program from the external device in the nonvolatile memory. An electronic device for storing a transfer program for transferring data to a first area. 3. The electronic apparatus according to claim 1, wherein the rewriting program and a transfer program for transferring the rewriting program to a first area of the volatile memory are stored in the nonvolatile memory. 4. The non-volatile memory according to claim 1, wherein the nonvolatile memory includes a plurality of blocks.
An electronic device characterized in that data can be partially rewritten. 5. The display device according to claim 1, wherein said display means, a check means for checking whether or not data rewriting of said nonvolatile memory is correct, and a check result of said check means result in an error. Means for displaying an error on the display means. 6. The non-volatile memory according to claim 1, further comprising:
An electronic device comprising restart means for returning the process of U to the program execution process of the nonvolatile memory.