JPH08328845A - ROM control program rewriting method - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] The flash ROM mounted on the board and built into the product can be easily rewritten including its boot block. [Structure] When rewriting the boot program written in the flash ROM and the control program for the CPU with the upgrade data stored in the external storage means (ROM board), the address of the flash ROM is the address of an unused area in the memory. ,
For example, after changing to (800000H) to (BFFFFFH), the specific area (000000H) to (3FFF)
FFH) fetches the version upgrade data from the ROM board, and flash R with the same version upgrade data
The control program including the boot program in the OM is rewritten, and then the address of the flash ROM that has been upgraded is specified area (000000H) to
Return to the address of (3FFFFFH).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rewriting a ROM control program, and more particularly to a ROM writer including the contents of a ROM mounted on a board and already incorporated in a product, including its boot loader program. The present invention relates to a method for rewriting a control program of a ROM that can be easily rewritten without depending on.

[0002]

2. Description of the Related Art A ROM is exclusively for reading data, but a PROM (programmable
In e read only memory, data can be written and saved on the user side.

If the PROM is further classified, there are a fuse ROM that can be written only once and an EPROM that can be erased and rewritten. The EPROM is convenient in that the data can be rewritten arbitrarily, but the data is erased by, for example, irradiation of ultraviolet rays, and a dedicated EP ROM writer is required for writing the data. Therefore, it is difficult to rewrite it when it is already mounted on the board and incorporated in the product.

On the other hand, there is a flash ROM that can erase data by an electric signal.
Usually, the flash ROM is divided into some (for example, eight) blocks, one of which is used as a boot block, and other blocks are rewritten by the boot program (basic software).

[0005]

As described above, according to the flash ROM, the boot program can read data from, for example, a floppy disk (FD) and rewrite the contents of other blocks. However, since the boot block must be written by the ROM writer before mounting on the board, it is difficult to rewrite the boot block after mounting on the board, which hinders version upgrade. There was an occasion.

The present invention has been made to solve such a conventional problem, and an object thereof is to easily write a flash ROM mounted on a substrate and incorporated in a product, including its boot block. Another object of the present invention is to provide a method for rewriting a ROM control program that can be replaced.

[0007]

In order to achieve the above object, the present invention is a specific area including a head address of a memory which is mounted on a main body board together with a CPU and whose reading and writing are managed by the CPU. An electrically erasable flash ROM is assigned to
Program written in the CPU and the above CPU
In rewriting the control program for the version update data stored in the external storage means, after changing the address of the flash ROM to the address of an unused area in the memory, the update data from the external storage means is stored in the specific area. The flash RO with the same version update data.
It is characterized in that the control program including the boot program in M is rewritten, and then the upgraded address of the flash ROM is returned to the address of the specific area.

In this case, the above address switching is performed by the address selector. That is, when the external storage means is a ROM board such as an EPROM, the address of the flash ROM in the specific area is stored in the memory by inserting the ROM board into a connector provided on the main body substrate. Of the unused area, and the specific area is designated as a data writing area from the ROM board. Then, after rewriting the data, R
When the OM board is detached from the connection connector, the address of the flash ROM is returned to the address of the specific area again. The external storage means may be a floppy disk.

Further, after the upgrade data is fetched from the external storage means to the specific area, and after the version upgrade data is fetched to the specific area,
After rewriting the contents of the flash ROM, it is preferable to perform a checksum of both of these data.

On the other hand, when displaying the version of the flash ROM on the monitor screen, the system version number of the control program and the boot version number of the boot program may be displayed separately.
Further, it is preferable in view of management of the main body program to display the current number and the new number together for each of the system version and the boot version.

When storing the upgrade data in the external storage means, a header area is provided in a part of the storage area, and identification data such as model identification code, checksum data and version number is stored in the header area. It is preferable to write it in. This makes it possible to accurately recognize the version upgrade data and to easily manage the version number.

Furthermore, an external storage device that can be written on the main body substrate is provided, and the flash RO is executed by the CPU.
It is preferable that version-up data be created based on the program information in M and the version-up data can be written to an external storage medium such as a floppy disk via the external storage device. According to this, 1
If you upgrade a single product, the upgrade data can be copied from that product.

[0013]

When the version is upgraded, the new version data is written in a ROM board such as an EPROM as a preparatory step. Then, when the ROM board is inserted into the connector provided on the main board,
The address selector changes the address of the flash ROM to the address of the unused area in the memory, and then the version upgrade data is fetched from the ROM board to the specific area. Then, the control program including the boot program in the flash ROM is rewritten with the same version upgrade data, and after the completion, the ROM board is removed from the connector, so that the address of the upgraded flash ROM is in the specific area. Will be returned to.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a main body substrate 10 incorporated in a product such as a waveform recorder. Various circuit patterns are actually formed on the main body substrate 10, and resistors, capacitors, various semiconductors, etc. are mounted, but here, for convenience, the CPU 11 is used.
Only the memory 12 whose reading and writing are managed by the CPU 11 is shown. Further, the main body substrate 10 is provided with a connector 13 to which a ROM board 20 for version upgrade is connected, and a floppy disk drive 14 for exchanging data with a floppy disk 30 as an external storage medium. . It is assumed that the ROM board 20 has version-up data written by the ROM writer.

FIG. 2 shows the memory 1 viewed from the CPU 11 side.
Two address maps are shown. The same figure (a) is RO
The address map in the initial case where the M board 20 is not connected to the connector 13 shows that the total memory capacity is 16M from (000000H) to (FFFFFFH).
B, and in this embodiment, the flash ROM has a start address (000000H) to (3FFFFFH) in the flash ROM.
Is allocated to the area up to.

In this embodiment, (400000)
H) to (7FFFFFH) are, for example, SRAM and I /
It is used as the O port address area, and the remaining (800,000)
H) to (FFFFFFH) are not used.

On the other hand, when the ROM board 20 is connected to the connector 13, the area of the flash ROM is, for example, (800000H) to (BFFFFFH) in the unused area as shown in FIG. 2B. ), And was used as a flash ROM area until then (000000
ROM board 20 in the area from 0H) to (3FFFFFH)
The version upgrade data of is written.

Then, all areas (blocks) including the boot block of the flash ROM are rewritten with the version-up data, and after confirmation, RO
The area of the flash ROM that has been upgraded by removing the M board 20 from the connector 13 is shown in Figure (a).
As shown in, the data is returned to the area of (000000H) to (3FFFFFH).

An example of the switching circuit (address selector) for switching the address in this way is shown in FIG.
The switching circuit 40 includes a decoder 41 and a selector section 42.
And a specific pin of the connector 13, which is 1 in this example.
Depending on whether the pin number is "H" level or "L" level, RO
The presence of the M board 20 is detected.

That is, when the ROM board 20 is not connected, the 1st pin is at the "H" level, but the ROM
When the board 20 is connected, its 1st pin is connected to the GND of the same ROM board 20, so that it shifts to the “L” level.

The select input B of the decoder 41 has CP
A23, which is the most significant bit (MSB) of the 24-bit address signal, is input from U11 to select input A
A22 of the next most significant bit (MSB-1) is input to. An address valid signal is inverted and input to the enable input (inversion input) G.

On the other hand, the output Y0 of the decoder 41 is (000
000H) to (3FFFFFH) address area, output Y1 is (400000H) to (7FFFFFH) address area, and output Y2 is (800000H) to (BFFF).
FFH) area, output Y3 is (C00000H) to (F
FFFFFH) area.

The selector section 42 has an inverter circuit 42a connected to the first pin, two invert NAND circuits 42b and 42c, and this invert NAND circuit 42.
Inverting OR circuit 4 with each output of b and 42c as input
2d and.

One input of the invert NAND circuit 42b is connected to the first pin, and the other input is connected to the decoder 41.
Output Y2 of is connected. The output of the inverter circuit 42a is connected to one input of the invert NAND circuit 42c, and the output Y0 of the decoder 41 is connected to the other input.

With this address switching circuit 40, as shown in FIG.
In the address map of FIG. 2, the area of the flash ROM when the ROM board 20 is not connected to the connector 13 (see FIG. 11A), the area of the flash ROM when the ROM board 20 is connected to the connector 13 and the ROM The board area (see FIG. 11B) is set respectively.

First, the case where the ROM board 20 is not connected will be described.
0H)-(3FFFFFH) is accessed, A2
3, A22 and the inversion signal of the address valid are both L, so that Y0 = L and Y2 = H. At this time, since the 1st pin is hung at H, the output of the inverter circuit 42a is L, and therefore one of the invert NAND circuit 42a
Since the output of b is L and the output of the other invert NAND circuit 42c is H, the flash ROM area is L.
The ROM board area is also L, but since the ROM board is not connected, these two areas do not overlap.

Subsequently, the CPU 11 (800,000H)
~ (BFFFFFH) is accessed, A23, A
Since both 22 and the address inversion signal are L, Y0 = H and Y2 = L. Since the 1st pin is "H", the output of one invert NAND circuit 42b becomes H, and the other invert NAND circuit 42c becomes Y0 = H.
Output becomes H, and neither region becomes L.

Next, the case where the ROM board 20 is connected will be described. CPU11 is (000000
H)-(3FFFFFH) is accessed, A2
3, A22 and the inversion signal of the address valid are both L, so that Y0 = L and Y2 = H. At this time, the output of one of the invert NAND circuits 42b becomes H, because the 1st pin has changed to L and Y2 = H. Also, the output H of the inverter circuit 42a and Y0 = L cause the output of the other inverter NAND circuit 42c to become H. As a result, the flash ROM area is H and Y0 =
Since the ROM board area becomes L due to L, the ROM board area is accessed.

Then, the CPU 11 (800000H-
BFFFFFH), A23 = H,
Since the inversion signal of A22 and address valid becomes L,
Y0 = H and Y2 = L. Since the first pin is L and Y2 = L, the output of one of the invert NAND circuits 42b becomes L. At this time, the output T of the inverter circuit 42a is H, and since Y0 = H, the output of the other inversion NAND circuit 42c is H. Therefore, the flash ROM area becomes L, and the same flash ROM area is accessed. For reference, the function table of the decoder 41 is shown in the following table.

[0030]

[Table 1]

Next, according to the flow charts of FIGS. 4 and 5, a flash ROM using the ROM board 20.
The procedure for version upgrade is explained. FIG. 4 is a general flow chart. First, the power is turned on and a hidden command is input to start the version upgrade operation by the ROM board 20 shown in FIG. The hidden command can be obtained, for example, by simultaneously pressing the SYSTEM key and the STATUS key of the operation unit (not shown).

In the flowchart of FIG. 5, first, a screen for version upgrade is displayed on the monitor. An example of the display is shown in FIG. 6, but in this embodiment, the system version of the control program and the boot version of the boot program are separate, and the current version number and the new version number to be updated from now on. And are displayed respectively. In addition, there is also a message prompting you to upgrade.

Then, when the version up YES key is pressed, the above (000000) is read from the ROM board 20.
H) to (3FFFFFH) area, the version upgrade data is read, the checksum is taken, ROM
It is compared with the checksum of board 20. If the checksum is OK, then the contents of the flash ROM in the area (800000H) to (BFFFFFH) are rewritten by the version upgrade data.

Then, the checksum of the rewritten flash ROM is taken, and (000000H) to
The checksum of the ROM board 20 in the (3FFFFFH) area is compared, and if OK, an end message is displayed on the monitor screen until the end key operation is made.
The version upgrade is confirmed when the end key operation is performed. Then, by removing the ROM board 20 from the connector 13, the flash R is upgraded.
OM address is the original area (000000H) ~
It is returned to (3FFFFFH).

In the above embodiment, the version-up data is R
This is an example in which the flash ROM is stored in the OM board 20, but the flash ROM can also be upgraded by storing the version upgrade data in a floppy disk.

Thus, according to the present invention, the flash R
Although it is possible to upgrade the OM including its boot block, it is also possible to copy this upgrade data and give it to other similar equipment. An example thereof is shown in the flowchart of FIG. That is, on the assumption that the contents of the flash ROM are rewritten with the new version upgrade data as described above, the CPU 11 simultaneously presses the hidden command key, for example, the FD key and the cursor key after the power is turned on, so that the CPU 11 creates the version upgrade data. Enter the mode.

As a result, the program information in the flash ROM is converted into version upgrade data. As the conversion method, for example, the bit data of the flash ROM may be directly transferred or the data may be arbitrarily compressed. Thereafter, the version upgrade data is written in the floppy disk 30 as an external storage medium via the floppy disk drive 14. In this way, the contents of the flash ROM mounted in other products can be rewritten on the floppy disk 30 by using the floppy disk 30 as a ROM writer.

In this way, the floppy disk 30
Even if you write the version upgrade data to,
Even if the version-up data is written to the ROM board 20 by the ROM writer, a header area is provided as shown in FIG. It is preferred to write identification data such as data and version number. This is preferable for more surely writing the version upgrade data and managing the version number.

[0039]

As described above, according to the present invention,
Even after being mounted on a board and incorporated into a product, the contents of the flash ROM, including its boot block (boot program), can be rewritten (version up) very easily.

Further, since the system version of the control program and the boot version of the boot program are individually displayed on the monitor screen, version management can be appropriately performed.

Furthermore, since the device main body has the version upgrade data creation function, it is possible to create version upgrade data for other devices by using that one device main body as a parent, and a separate ROM. There is no need to prepare a writer.

In addition, when creating the version-up data, a header area is separately provided, and identification information such as a model identification code is stored in the area, so that the version-up data can be recognized more accurately. , It is possible to prevent wrong version upgrade for different models.

[Brief description of drawings]

FIG. 1 is a schematic diagram schematically showing a configuration of a main body substrate incorporated in, for example, a waveform recorder to which the present invention is applied.

FIG. 2 is a schematic diagram showing an address map of a memory viewed from a CPU.

FIG. 3 is a block diagram showing an example of a configuration of an address selector.

FIG. 4 is a main flowchart when rewriting data in a flash ROM.

FIG. 5 is a specific flowchart for rewriting the data in the flash ROM by the ROM board.

FIG. 6 is an explanatory diagram showing a display example of a monitor screen at the time of version upgrade.

FIG. 7 is a flowchart in a version upgrade data creation mode.

FIG. 8 is a schematic diagram showing a header area provided when storing version-up data in a ROM board or the like and showing an ID code or the like stored in the header area.

[Explanation of symbols]

 10 Main Board 11 CPU 12 Memory 13 Connector 14 Floppy Disk Drive 20 ROM Board 30 Floppy Disk

Claims (9)

[Claims] 1. A flash ROM, which is mounted on a main body board together with a CPU and whose reading and writing is managed by the CPU, is assigned to an electrically erasable flash ROM in a specific area including a start address of the memory. ROM
Program written in the CPU and the above CPU
In rewriting the control program for the version update data stored in the external storage means, after changing the address of the flash ROM to the address of an unused area in the memory, the update data from the external storage means is stored in the specific area. The flash RO with the same version update data.
A method of rewriting a control program of a ROM, characterized in that a control program including a boot program in M is rewritten, and then the upgraded address of the flash ROM is returned to the address of the specific area. 2. The external storage means is an R such as an EPROM.
It consists of an OM board, and the main board has the R
A connection connector for the OM board and an address selector for the memory are provided, and the address selector receives the ROM board connection signal from the connection connector and transfers the address of the flash ROM in the specific area to the unused area in the memory. In addition to changing the address, the specific area is designated as a data writing area from the ROM board, and when the ROM board is removed from the connection connector, the address of the flash ROM is returned to the address of the specific area. RO according to claim 1, characterized in that
Rewriting method of M control program. 3. The method according to claim 1, wherein the external storage means is a floppy disk. 4. The R according to claim 1, wherein after the version-up data is fetched from the external storage means to the specific area, a checksum of both is performed.
OM control program rewriting method. 5. The control program for the ROM according to claim 1, wherein after the contents of the flash ROM are rewritten with the version-up data taken into the specific area, a checksum of both is performed. Rewriting method. 6. The system version number of the control program and the boot version number of the boot program are separately displayed when the version of the flash ROM is displayed on the monitor screen. A method for rewriting the control program of the ROM described in 1. 7. The version number of the flash ROM is updated, and the current number and the new number are displayed together for each of the system version and the boot version. A method for rewriting the control program in the described ROM. 8. When storing the upgrade data in the external storage means, a header area is provided in a part of the storage area, and identification data such as a model identification code, checksum data and version number is written in the header area. RO according to claim 1, characterized in that
Rewriting method of M control program. 9. An external storage device writable on the main body substrate is provided, version upgrade data is created by the CPU based on program information in the flash ROM, and the version upgrade data is stored in a floppy disk via the external storage device. The method for rewriting a control program in a ROM according to claim 1, wherein the method is writable to an external storage medium such as a disk.