JP2002268907A - Memory controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a memory controller in which work efficiency is improved in the case of rewriting data in a flash memory and also development, management and quality of software are improved. SOLUTION: Initialization of hardware is performed by selection and execution of initialization codes to conform to a kind of the hardware after discriminating the kind of the hardware. In addition, a bootstrap program, the respective initialization codes and a system control program are independently arranged in a flash ROM in their once deletion units.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a memory control device and a memory control method using a flash memory in which a first storage area and second and third storage areas are divided and managed in block units. The present invention relates to a memory control device and a memory control method suitable for a general device in which a controller for embedded use is mounted and a processor controls a device.

[0002]

2. Description of the Related Art In recent years, flash memories have been frequently used as storage media. The flash memory has the advantage that, although it is a nonvolatile memory, it can erase and write data, and can easily update information and change programs. As a result, demand for flash memory is growing in fields such as embedded devices and mobile phones. However, conventionally, when writing to a flash memory, it is necessary to control the writing of new data after erasing existing data without fail in a predetermined capacity unit (block). In addition, flash memories are often provided with protection bits such as lock bits for preventing erroneous erasure and electrical protection mechanisms using hardware. Therefore, in order to perform rewriting, a dedicated rewriting control program corresponding to a flash memory and hardware to be used has been required.

A control program for erasing and writing a flash memory can use the flash memory itself as a storage medium, and can also be used in another medium. However, conventionally, since a system program for device control and the like are usually created as one file when a program is created, due to the nature of flash memory, when rewriting a device control program or a write control program, it is almost impossible. The program must be written after erasing the entire area of the flash memory.

[0004] Conventionally, programs for hardware initialization and the like are independently created exclusively for hardware, and stored as binary codes in a flash memory. For this reason, depending on the development and product variations, even if there is a slight change in the hardware specifications, it is necessary to correct the initialization part, and a dedicated program has been created for each different hardware. However, in embedded systems, even when the hardware is slightly different, the system control program is often used in common. However, since the hardware initialization program cannot be shared with programs for other hardware, conventionally, as a means for achieving commonality, 1
It was necessary to create a program that switches the processing by determining the hardware configuration in one program.

[0005]

However, in the flash memory, it is necessary to perform data erasure and write control in a predetermined capacity unit, and there is a problem that correct data is not written when overwriting is performed. .

Also, when rewriting data, the entire area of the flash memory is erased in order to rewrite the data into a rewrite control program corresponding to the hardware. There was a problem that work was not performed smoothly.

Further, since complicated processing is performed by a complicated program source as a means for sharing a system control program, there is a problem that it is difficult to manage and restore the program, and it is difficult to maintain the quality of the flash memory. Was.

The present invention has been made to solve the above-mentioned problems, and the object of the present invention is roughly divided into two points.

First, when a program stored in a flash memory is executed, a binary code portion suitable for the hardware to be used is selected and executed with respect to a hardware-dependent portion such as a hardware initialization program. The purpose of the present invention is to improve the efficiency and productivity of development, production, and the like, by increasing the processing speed and sharing programs.

The second point is that by dividing the code part and the system control program part depending on the hardware, and constructing and writing in accordance with the block unit of the flash memory, failure in rewriting and time for rewriting are reduced. The purpose is to avoid such a problem.

[0011]

[Means for Solving the Problems]

According to a first aspect of the present invention, there is provided a memory control apparatus for writing data to a flash memory and writing data to and deleting data from the flash memory in which writing and erasing of data are performed in block units. Wherein a rewrite program, a bootstrap program, a hardware initialization program, and a hardware-independent system control program are independently written in a block of the flash memory, which is a once-erased unit. . With this configuration, a code portion and a system control program portion depending on hardware can be divided, and data to be erased and written can be limited.

According to a second aspect of the present invention, the hardware initialization program has a plurality of initialization code sections each composed of an object code, and the initialization code section and a hardware-independent system control program are respectively provided in the flash memory. It is a memory control device arranged for each block size. According to a second aspect of the present invention, a configuration of hardware to be initialized is determined by executing a bootstrap program, the initialization code portion is selected, and an object code corresponding to the hardware is activated, This is also a memory control method in which hardware initialization is performed. With this configuration, when executing a program stored in the flash memory, it is possible to select and execute an initialization code portion suitable for the hardware to be used with respect to a hardware-dependent portion such as a hardware initialization program.

According to a third aspect of the present invention, there is provided the memory control device according to the first or second aspect, further comprising a rewriting program that is sequentially executed by starting from the flash memory or another storage medium. With this configuration, rewriting can be performed by starting the flash memory itself, and rewriting from another storage medium is also possible.

According to a fourth aspect of the present invention, in the memory control device of the third aspect, the bootstrap program which requires rewriting when the rewriting program started from the flash memory itself or another storage medium is executed. A hardware initialization program or the system control program is erased and rewritten in units of any corresponding blocks of the flash memory. With this configuration, data can be erased and written according to the block unit of the flash memory.

According to a fifth aspect of the present invention, in the memory control device of the third aspect, a header code for determining an address or allocation of each block of the flash memory corresponding to the data to be rewritten is included in the object code of the flash memory. It is characterized by being added or embedded. With this configuration, it is possible to write the object codes arranged in an arbitrary block in any order as data necessary for executing the rewriting program in each of the corresponding blocks.

[0017]

1 to 3 show a preferred embodiment of a memory control device according to the present invention.

FIG. 1 is a block diagram showing an overall configuration of an example in which a memory control device is applied to a printing system. Controllers are CPU1, flash ROM2, RAM3,
And an external I / F 4 and a printer unit 5. The CPU 1 reads a binary code from the flash ROM 2 and executes memory control described later. RAM
Reference numeral 3 denotes a temporary memory, and a flash ROM 2
When a part of is expanded and executed, when the system is started and executed, and in this example, the printer unit 5 is configured, it is used for holding print data.

FIG. 2 shows the flow of processing in this system. When this system is started from the flash ROM 2, the instruction code of the bootstrap unit is
1, the minimum setting S1 of the CPU 1, the ASIC, and other hardware is performed, and then the confirmation S2 of the hardware is performed. When the hardware is confirmed, a hardware initialization program to be used is determined and selected S3, S4 or S5.

Next, the corresponding code from the initialization program stored in the flash ROM 2 is expanded in the RAM 3 and the program is executed. At this time, each initialization program may be compressed,
3 It is possible to decompress when developing. On the RAM 3, the hardware initialization program is executed at a high speed,
Initialization and diagnosis of hardware are performed. Upon normal termination, the system control program is started (S6).

FIG. 3 shows mapping of object codes in the flash ROM 2. As shown in FIG. 3, a plurality of hardware initialization units 1, 2, and 3 are written after the bootstrap unit, and these are selectively activated based on the hardware determination result in S2.

A system control program is written after the hardware initialization unit, and when the hardware initialization is completed, the system control program is started.
By configuring the control device in which the hardware initialization portion is shared in this way, it is possible to avoid the complexity and quality reduction in software development, production, and management.

The flash R, such as updating the system control program or modifying the hardware initialization program,
When rewriting the OM2, data to be rewritten is prepared, and the corresponding address and size checksum of the flash ROM 2 are added or embedded as a header.
Write. Thereby, the minimum necessary erasing and writing operations are realized, and the working efficiency is improved.

[0024]

According to the invention of each claim, since the data required for erasing and writing is minimized, the time required for erasing and writing data can be shortened and the failure of data writing can be reduced. , The production efficiency can be improved. In addition, the rewriting program can be made common and the non-common parts can be made independent, and the development, management, and quality of software can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of a memory control device according to the present invention.

FIG. 2 is an object mapping of a flash ROM in the embodiment of the memory control device according to the present invention;

FIG. 3 is a flowchart of a memory control program in the embodiment of the memory control device according to the present invention.

[Explanation of symbols]

 1 CPU 2 Flash ROM 3 RAM 4 External I / F 5 Printer

Claims (5)

[Claims] 1. A memory control device for writing and erasing data in a flash memory in which writing and erasing of data are performed in block units and erasing data from the flash memory, comprising: a rewriting program; a bootstrap program; A memory control device characterized in that an encrypted program and a hardware-independent system control program are independently written in a block of the flash memory which is a unit of erasure once. 2. The hardware initialization program has a plurality of initialization code sections each composed of an object code, and the initialization code section and a hardware-independent system control program are arranged for each block size of the flash memory. A memory controller that is initialized, a configuration of hardware to be initialized is determined by execution of a bootstrap program, the initialization code portion is selected, and an object code corresponding to the hardware is activated, A memory control device wherein hardware initialization is performed. 3. The memory control device according to claim 1, further comprising a rewrite program that is sequentially executed by starting from said flash memory or another storage medium. 4. The memory control device according to claim 3, wherein
When the rewriting program started from the flash memory itself or another storage medium is executed, the bootstrap program, the hardware initialization program, or the system control program that requires rewriting may be any of the flash memory. A memory control device characterized by being erased and rewritten in a corresponding block unit. 5. The memory control device according to claim 3, wherein
A memory control device in which a header code for determining an address or assignment of each block of a flash memory corresponding to data to be rewritten is added to or embedded in an object code of the flash memory.