JPH1097459A - Eeprom initializing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the initialization time of a mass-storage EEPROM. SOLUTION: A write area of each page of the EEPROM is provided with a management area A. At the initialization, a 1st page is initialized first and its page management area A-1 is set to 'initialization completion'. When a write event of the EEPROM is generated thereafter, information is written to a data area B-1 first. When the page becomes full, the management area A-1 is set to 'writing completion', a next page is initialized, and its management area A-2 is set to 'initialization completion'. Thus, whenever write information is generated, it is written to a data area which is already initialized and a next page is initialized in advance. The initialization time is very short as compared with an information write time, so the initialization time of the EEPROM is only the initialization time of the starting page eventually and greatly shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an initialization method for an EEPROM, and more particularly to an initialization method for a large-capacity EEPROM in which a writing area is divided into a plurality of pages.

[0002]

2. Description of the Related Art Since the initial state of this type of EEPROM (non-volatile rewritable program read-only memory) is not guaranteed, the stored contents must be initialized before the EEPROM is used. Figure 4 shows the EEPR
FIG. 3 is a configuration diagram showing a configuration of an OM data write area. Conventionally, in order to initialize the EEPROM, an operation of writing an initial value for each page, which is a unit write area, shown in FIG.

[0003]

As described above, the conventional EE
In the initialization method of the PROM, initialization is first performed for all pages. In the EEPROM, after a write operation is performed once, there is a fixed write disable time until the next write. The time interval required until the next writing becomes possible is much larger than the time required for the writing process to the EEPROM.

In a conventional EEPROM initialization method, 1
After writing the initial data to the page, a series of processes such as writing the initial data to the next page at regular time intervals are repeated for all pages. Therefore, the entire initialization time is (write time + time interval required for the next write) × the total number of pages. For example, the time interval required for the next write in an EEPROM having a storage capacity of 512 Kbytes and one page of 128 bytes. Is about 41 ms when writing time is approximately 0 ms and writing time is approximately 0.
A second initialization time is required, which takes a long time.

[0005]

SUMMARY OF THE INVENTION An EEPROM initialization method according to the present invention uses an EEPROM in which a writing area is divided into a plurality of unit writing area pages and initialized for each page.
In the initialization method of (1), first, the first page is initialized and stored. When information to be stored is generated, the information is stored in the first page, and when the page is full, the initialization of the second page is performed. After the information is sequentially stored in each page, the next page is initialized and stored.

Further, the unit write area of each page is divided into a management area and a data area, and when initialization is completed in the management area, a flag indicating that fact is written and information to be stored in the data area is written. May be written.

[0007]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a configuration of a write area of an EEPROM according to an embodiment of the present invention. FIG. 2 is a flowchart showing the initialization method of the first page in FIG. 1, and FIG. 3 is a flowchart showing the information writing and initialization method in FIG.

As shown in FIG. 1, the EEPROM has a management area A and a data area B in each page of a unit writing area, and has a capacity of m pages. First, FIG.
As shown in the flowchart, the first page of the EEPROM is initialized and the "initialized" flag is written in the management area A-1 (S21). EEPRO only by this processing
The initialization process for M is completed (S22).

Next, information to be stored in the device is generated, and E
FIG. 3 shows a case where the writing process to the EPROM is performed. When a write event to the EEPROM occurs (S3
1) Write information to be stored in the EEPROM in the data area B-1, and write a "written" flag in the management area A-1 (S32). Thereafter, the next page is initialized, and an “initialized” flag is written in the management area A-2 (S33).

Similarly, when a write event to the n-th page occurs, information to be written is written to data Bn, a "written" flag is written to management area An, and then page n + 1 is initialized. The "initialized" flag is written in the management area A- (n + 1). In this way, by repeating the initialization of the next area every time the information to be written to the EEPROM is generated, the entire area finally used is initialized.

[0011]

As described above, the EEPR of the present invention
The OM initialization method initializes the first page, and initializes the subsequent pages after writing information on the initialization-completed page, and then initializes the next page. On the other hand, since the initialization time is a short time, the initialization time of the EEPROM is consequently only the initialization time for the first page, so that there is an effect that the time can be greatly reduced.

[0012]

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a write area of an EEPROM according to an embodiment of the present invention;

FIG. 2 is a flowchart illustrating a method of initializing a first page of the EEPROM of FIG. 1;

FIG. 3 is a flowchart showing a method of writing and initializing information in the EEPROM of FIG. 1;

FIG. 4 is a configuration diagram showing a configuration of a writing area of a conventional EEPROM.

[Explanation of symbols]

 None

Claims (2)

[Claims] 1. An EEPROM which is used when a writing area is divided into pages of a plurality of unit writing areas and initialized for each page.
In the initialization method of M, first, the first page is initialized and stored. When information to be stored is generated, the information is stored in the first page, and when the page is full, the second page is initialized. A method of initializing an EEPROM, wherein information is sequentially stored in each page, and then the next page is initialized. 2. The information to divide a unit write area of each page into a management area and a data area, write a flag indicating that the initialization has been completed in the management area, and store the flag in the data area. 3. The method according to claim 1, wherein
The initialization method of the described EEPROM.