JPH10198568A - Flash memory writing device and method - Google Patents

Abstract

(57) [Problem] To provide a flash memory writing device and a method thereof capable of coping with various flash memories at low cost. A host system (2) holding data to be written to a flash memory (11) and a loader program for erasing and writing the flash memory (11).
And a RAM for storing, in the target system 1, predetermined data supplied from the flash memory 11 and a host system for updating data to the flash memory 11
13, the type of the flash memory 11 is identified, a loader program corresponding to the identified type is transferred from the host system 2 to the RAM 13, and the flash memory 1 is assigned according to the transferred loader program.
1 is erased and written.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to flash memory rewriting for controlling updating of a flash memory on a target system from a host system.

[0002]

2. Description of the Related Art Conventionally, a flash memory rewriting circuit described in Japanese Patent Application Laid-Open No. Hei 5-233478 is known. FIG. 3 shows the configuration of a conventional flash memory writing system.
1 is a flash memory, 13 is a RAM, 12 is a CPU for controlling the entire target system, 14 is an external communication I / F for communicating with a host system, and 15 is a program for executing erasing / writing of the flash memory 11. Loader ROM for storing, 2 for host system, 22 for RO holding data to be written to flash memory 11
The M data storage device 3 is a communication medium that is a medium for executing communication between the target system 1 and the host system 2.

FIG. 4 is a flowchart for explaining an erasing / writing operation to the flash memory 11 in the system configured in FIG. Hereinafter, the erase / write operation to the flash memory 11 will be described with reference to the flowcharts of FIGS. First, the target system 1 is initialized by the reset in step (a). next,
In step (b), it is determined whether to update the contents of the flash memory 11 (execute the loader program).
If the loader program is not executed, step (c)
To run a normal program. To execute the loader program, the following routine is executed.

That is, in step (d), the type of the flash memory 11 is identified. Specifically, when the host system 2 issues a type identification command to the flash memory 11 and accesses a predetermined address of the flash memory, the type is output from the flash memory, thereby identifying the type. From the type of the flash memory 11 found in step (e), the address of the corresponding loader program (loader ROM 1
Branching to 5), the flash memory 1 in step (f)
1 and the host system 2 is deleted in step (g).
The contents of the ROM data storage device 22 are transferred to the RAM 13 via the external communication I / F 14 and the contents of the RAM 13 are written to the flash memory 11 in step (h). Then, in step (i), the flash memory 1
1, data is written to all addresses to be written, and the contents are read at the same time to read the original data (RA
M13), the writing is completed if they match (verify processing). When the capacity of data to be written to the flash memory 11 is larger than the capacity of the RAM 13, the contents of the flash memory 11 can be updated by repeatedly executing the above steps (g) and (h). Through the above operation, the contents of the flash memory 11 can be erased and the contents of the ROM data storage device 22 can be written to the flash memory 11.

[0005]

As described above, in the conventional flash memory writing method, a loader ROM for storing a loader program for executing erasing / writing of the flash memory is required in the target system unit, and different types of flash memories are used. In the case of supporting a memory, a plurality of types of loader programs are required for each type, so that the capacity of the loader ROM is increased and the scale and cost of the target system unit are increased.

[0006]

According to the present invention, a loader ROM storing a loader program for executing erasing / writing of a flash memory is removed from a target system, and a loader storage device is provided in a host system. The contents of the loader storage device are transferred to the RAM in the target system so that the program can be executed on the RAM.

According to the present invention, a loader ROM is not required in the target system, so that the size and cost of the target system can be reduced, and a flash memory writing device capable of supporting loader programs for various flash memories in the host system. Can be provided.

[0008]

1 is a block diagram showing a configuration of a flash memory writing apparatus according to a first embodiment of the present invention; FIG. 2 is a block diagram showing a configuration of a flash memory writing apparatus according to a first embodiment of the present invention; The system unit has a RAM that stores a flash memory and predetermined data supplied from a host system unit for updating data in the flash memory, identifies a type of the flash memory, and responds to the identified type. A loader program is transferred from the host system unit to the RAM, and the flash memory is erased and written in accordance with the transferred loader program. It can be handled by the system part, Loader RO is over the target system part
Since M is unnecessary, the scale and cost of the target system unit can be reduced.

According to a second aspect of the present invention, there is provided a flash memory writing apparatus according to the first aspect, wherein the type of the flash memory is identified and a loader program corresponding to the identified type is transmitted from the host system unit to the target system unit. The loader control ROM for processing the transfer to the RAM and branching to the address of the transferred loader program on the RAM is provided in the target system unit, and the loader program in the host system unit is changed. Alone, it is possible to support different types of flash memories, so that writing to different types of flash memories can be performed without changing the target system unit.

According to a third aspect of the present invention, there is provided a flash memory writing method, comprising: a host system unit for storing data to be written to the flash memory; a loader program for executing erasing and writing of the flash memory; A RAM that stores a flash memory in the target system unit and predetermined data supplied from a host system unit for updating data to the flash memory, and an identification and identification of the type of the flash memory. A loader control ROM for processing transfer of a loader program corresponding to the type from the host system unit to the RAM of the target system unit and branching to an address of the transferred loader program on the RAM; System part is a communication medium Connected, and identifies the type of the flash memory, transfers a loader program corresponding to the identified type from the host system unit to the RAM through the communication medium, and sets a start address of the transferred loader program. Branching, erasing the flash memory according to the loader program, and
The present invention is characterized in that ROM data is transferred from a host system through the communication medium and predetermined data is written in a flash memory, and a loader program for a wide variety of flash memories can be handled by the host system unit. Since the loader ROM is not required, the size and cost of the target system can be reduced.

(Embodiment 1) An embodiment of the present invention described in claims 1, 2 and 3 of the present invention will be described below with reference to FIGS. 1 and 2. FIG. FIG. 1 shows a configuration of a flash memory writing system, 1 is a target system, 11 is a flash memory, 13 is a RAM, and 12 is a CP for controlling the entire target system.
U and 14 are external communication I / s for communicating with the host system.
F, 16 are loader control ROM, 2 is host system,
21 is a loader storage device for storing a program for executing erasing / writing of the flash memory 11, 22
Is R holding data to be written to the flash memory 11
The OM data storage device 3 is a communication medium that is a medium for executing communication between the target system 1 and the host system 3.

FIG. 2 is a flow chart for explaining an erasing / writing operation to the flash memory 11 in the system configured in FIG. Hereinafter, an erasing / writing method for the flash memory 11 will be described with reference to FIGS. First, the target system 1 is initialized by the reset in step (a). Next, in step (b), it is determined whether to update the contents of the flash memory 11 (execute the loader program). If the loader is not executed, a normal program is executed in step (c). When executing the loader, the following routine is executed.

That is, in step (d), the type of the flash memory 11 is identified. Specifically, a type identification command is issued to the flash memory 11 (data for outputting the type is written to a predetermined address) to identify the type. Next, a loader program corresponding to the type of the flash memory 11 determined in step (e) is transferred from the loader storage device 21 to the RAM 13 via the external communication I / F 14 and, in step (f), Branch to the start address of the loader program existing in the RAM 13. The above (d), (e),
The processing of (f) is executed by a program in the loader control ROM 16.

Then, the program from the next step (g) onward is executed on the RAM 13. In step (g), the contents of the flash memory 11 are erased, and in step (h), the host system 2 and the external communication I / F 14 are erased.
The contents of the ROM data storage device 22 are stored in the RAM
13 and writes the contents of the RAM 13 to the flash memory 11 in step (i). Then, in step (j), data is written to all addresses to be written in the flash memory 11, and at the same time, the contents are read and compared with the original data (the contents of the RAM 13) to match (verify). Then, the writing is completed. When the capacity of the data to be written to the flash memory 11 is larger than the capacity of the RAM 13, the contents of the flash memory 11 can be updated by repeatedly executing the above steps (h) and (i).

By the above operation, the flash memory 11
Can be erased and the contents of the ROM data storage device 22 can be written. In addition, when a different type of flash memory 11 is used in the target system 1, the loader ROM capacity needs to be increased in the target system 1 in the related art.
In the present invention, the loader control ROM 16 having a small capacity enough to carry out the processes of the steps (d), (e) and (f) is mounted on the target system 1 so that the host system 2
By changing the contents of the loader storage device 21 of this type, it is possible to deal with another type of flash memory, so that the target system 1 does not need to be changed.

In the above description, the loader control ROM
16 executes the transfer of the loader program and the branch to the RAM 13, the loader control ROM 16 stores the CPU program even if it is stored in the flash memory 11 in advance.
Of course, it can be implemented even if it exists in the area 12. Note that the flash memory can be erased in a batch, since the loader control ROM 16 controls the loader control operation and the RAM 13 executes the loader program as described above.

[0017]

As described above, according to the present invention, the loader ROM is not required in the target system, the scale and cost can be reduced, and the loader for a variety of flash memories can be changed in the target system. Therefore, when the target system is mass-produced (rewriting the flash memory), it is possible to provide a flash memory writing device that can reduce the cost and simplify the manufacturing process.

[Brief description of the drawings]

FIG. 1 is a block diagram of a flash memory writing device according to an embodiment of the present invention.

FIG. 2 is a flowchart of a flash memory writing method according to the embodiment of the present invention;

FIG. 3 is a system configuration diagram of a conventional flash memory writing device.

FIG. 4 is a flowchart of a conventional flash memory writing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Target system 2 Host system 11 Flash memory 12 CPU 13 RAM 14 External communication I / F 15 Loader ROM 16 Loader control ROM 21 Loader storage device 22 ROM data storage device

Claims (3)

[Claims] 1. A host system unit for holding data to be written to a flash memory and a loader program for executing erasing and writing of the flash memory, and a flash memory and a host system unit for updating data in the flash memory. A target system unit having a RAM for storing predetermined data to be processed, identifying a type of the flash memory, transferring a loader program corresponding to the identified type from the host system unit to the RAM, A flash memory writing device for erasing and writing the flash memory according to a transferred loader program. 2. Identifying a type of a flash memory, transferring a loader program corresponding to the identified type from a host system unit to a RAM of a target system unit,
2. The flash memory writing device according to claim 1, wherein a loader control ROM for processing a branch to an address of the transferred loader program on the RAM is provided in the target system unit. 3. A host system section for holding data to be written to a flash memory, a loader program for executing erasing and writing of the flash memory, and a target system section. A RAM for storing predetermined data supplied from a host system unit for updating data to the flash memory, and a type of the flash memory and a loader program corresponding to the identified type are transmitted from the host system unit to the target system unit. A loader control ROM for processing transfer to the RAM and branching to the address of the transferred loader program on the RAM, wherein the host system unit and the target system unit are connected by a communication medium; Identify flash memory type Transferring a loader program corresponding to the identified type from the host system unit to the RAM through the communication medium, branching to a start address of the transferred loader program, and erasing the flash memory according to the loader program. And writing predetermined data to the flash memory by transferring information data to be written from the host system unit through the communication medium.