JPH04317149A - Management system for eeprom - Google Patents

Abstract

PURPOSE:To manage EEPROM as consumption articles, to pay attention to the use limit of data writing, to automatically allocate other areas even if a part of a memory is destroyed and to effectively use the area. CONSTITUTION:The areas of the memory are made into blocks. The number of access times and the areas of link destination are mentioned in a minute management table (DBMT) 2 for respective blocks, and a block management table (BMT) 1 manages the use situation. A storage content is automatically moved to the link destination if need. Data is made to correspond to area management. A head block number, a data head pointer and a data size are provided for prescribed positions.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to electrically erasable programmable nonvolatile memory used in one-chip microcomputers, etc.
and Programmable Read Onl
Regarding the management method of E2Memory (hereinafter abbreviated as E2PROM), in particular,
This relates to a 2PROM management method.

0002

[Prior Art] E2PROM erases data by irradiating it with ultraviolet light, whereas so-called EPROM erases data by irradiating it with ultraviolet light.
Data can be erased electrically, and it is attracting attention as a memory element for one-chip microcomputers and IC cards. E
Since 2PROM is a consumable item, it needs to be managed in the same way as floppy disks and hard disks, but so far it has not been given much attention. Directory management and file allocation table management are performed on floppy disks and hard disks, so the same access methods are only considered.

0003

[Problem to be Solved by the Invention] By the way, when accessing E2PROM on a real-time OS or UNIX, access must be performed in the same way as normal memory using a memory-mapped input/output section. Accessing the E2PROM using this method poses the following problems. That is, (1) when the E2PROM becomes inaccessible, it cannot be assigned to another area, and the E2PROM
cannot be treated as consumables.

(2) It is impossible to track the usage status of memory access and manage the durability.

(3) Since the E2PROM area is limited in size, it must be used more effectively than normal memory access methods, and each area must be able to be registered freely, but in conventional methods, it is not fixed. It has been assigned.

The present invention was devised in view of these problems, and it is possible to count the number of data writes, to take note of the usage limit as a consumable item, and to automatically restore memory even if part of the memory is destroyed. It is an object of the present invention to provide a management method for an E2PROM that can allocate other areas and make effective use of the areas.

[0007]

[Means for Solving the Problems] A means for solving the above problems in the present invention is to block memory areas and use them in a management system for electrically erasable programmable non-volatile memory (EEPROM). Area management includes a block management table that manages the status, a detailed block management table that links the number of accesses and areas for each block, and describes the destination to which the memory contents will be transferred when necessary, and the first block for each data. This is based on a memory management system that includes data management that includes a general management table that includes numbers and data sizes, and a detail management table that includes data header pointers and check data.

[0008]

[Operation] The present invention changes the management method of E2PROM, which was conventionally treated in the same way as ordinary ROM and PROM, to one that is more similar to that of a floppy disk or hard disk.
This is to accommodate various types of access. for that,
In the present invention, a memory area is divided into blocks, and the associated area management and data management are performed. The area management of the present invention consists of a block management table and a detailed block management table.The block management table describes the usage status of each block, and the detailed block management table shows the number of accesses and linked destinations for each block. Are listed. This connects the areas and transfers the stored contents to the other party when necessary. Data management also corresponds to this, by recording the first block number and data size of each data in the general management table, and storing the data start pointer and check data in the detail management table, so that access, block acquisition, and movement can be easily performed. We are prepared.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram of area management according to the present invention. In the present invention, memory is made into fixed-sized blocks,
Block management table (hereinafter referred to as
(referred to as BMT) 1 is provided as shown in the figure. BMT1 indicates "in use", "system use", "empty area", or "fault has occurred (unusable)" for blocks 1 to block n.
etc. are set for each situation. Each block of BMT1 has a detailed block management table (hereinafter referred to as DBMT).
Managed by 2. DBMT2 is placed at the beginning of each block, and in (1) in the figure, the number of the next block to be connected to the block is set, and (2) is the number of the block before being connected to the block. The number of accesses to the block is set in (3). In this example, E2PR is
Acquire the desired area of OM and if there are multiple blocks,
By setting a link in (2), it is possible to acquire an area. Furthermore, when a failure occurs within one block, an empty block is acquired and the link of the block where the failure occurs is transferred to the newly acquired block. To release the area, make the block an empty area and remove the link. When accessing a block, the block access count is increased and an error notification is issued when the durability count is exceeded.

FIG. 2 is an explanatory diagram of data management according to the present invention. In the present invention, the area is managed using the method shown in FIG. 1, but in order to do so, each data needs to be set as shown below. In this embodiment, data management consists of general management and detail management, and the general management table (
(hereinafter referred to as GDMT) 21, as shown in Figure (a), the setting status (setting or not), the number of the first block, the data size (number of acquired blocks), the number of detail items (m
) etc. are set. Detail management table (hereinafter referred to as D
As shown in Figure (b), the data head pointer, detail data size, block check code (BCC), etc. are set in the DMT 22 (referred to as DMT). E2PR
When writing data to OM, data is written after registering the GDMT number, number of detail items, and data size, and furthermore, BCC data is created and the written data is checked. Also in the case of data reading, a check is performed using BCC data.

The following effects are evident in this embodiment.

(1) Since it is possible to count the number of accesses to the E2PROM and manage the number of times data is written, it is possible to be careful when the usage limit as a consumable item is exceeded and prepare for replacement.

(2) If the E2PROM is destroyed and writing becomes impossible, another area is automatically allocated and the E2PROM is
Even if a part of the 2PROM is destroyed, the entire 2PROM does not become unusable and normal operation is possible.

(3) Since the area is not fixedly assigned by data and can be used freely, the area can be used effectively.

(4) Excellent portability to other programs, E
It can be applied not only to 2PROM but also to various consumable devices.

[0016]

[Effects of the Invention] As explained above, according to the present invention, the number of data writes can be counted, the usage limit as a consumable item can be taken into account, and even if part of the memory is destroyed, other areas can be automatically restored. It is possible to provide an E2PROM management method that can effectively utilize allocated areas.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of area management of the present invention.

FIG. 2 is an explanatory diagram of data management of the present invention.

[Explanation of symbols]

1...BMT, 2...DBMT, 21...GDMT, 22...D
DMT.

Claims (1)

[Claims] Claim 1: In a management system for electrically erasable programmable non-volatile memory (EEPROM), memory areas are divided into blocks, and access counts and areas are linked for each block to a block management table that manages their usage status. , an area management table that includes a detailed block management table that describes the destination to which the memory contents are transferred when necessary, a general management table that includes the first block number and data size for each data, a data start pointer, and check data. 1. A management method for an EEPROM, comprising: a detail management table including a data management table;