JP2006039969A - Method for retaining data in memory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lower required capacity of memory while securing reliability of memory. <P>SOLUTION: In writing data to memory, an arbitrary value is written in the most significant position, required information is written in mid-positions, and a value created on an arbitrary condition based on the arbitrary value is written in the least significant position. Further, the arbitrary condition is made the mirror value of the arbitrary value written in the most significant position. In addition, a plurality of pieces of information are made to be written repeatedly, and the arbitrary value is made to be obtained by counting up or counting down using a value which is larger than the number of repeating by 1 at most. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a data storage method for writing data to a memory of a microcomputer.

In a memory for arbitrary writing for a RAM or EEPROM of a microcomputer, there is a possibility that data may be damaged due to fluctuations in the power supply voltage supplied, influence of noise, and the like. Correspondingly, when preserving important data in RAM, EEPROM, etc., writing is performed by setting a mirror value (reciprocal number) to the value to be written in RAM. When performing RAM reading, a method is generally known in which a value is used while confirming whether or not the relationship between the data location and the reciprocal number matches and confirming that the RAM is not broken.
JP 2003-343342 A (see [0023]) JP 2002-317687 A (see [0054], [0055])

  Since it has a mirror value for the data capacity to be written, twice as much memory is required. For example, as shown in FIG. 6, when 16-bit data “1234” is stored, a mirror value “EDCB” of “1234” is additionally written. At this time, the data to be written is “1234EDCB”, and 32 bits are required. If the total amount of data to be written is large, more memory is required, leading to increased costs for the microcomputer and memory.

  An object of the present invention is to reduce the necessary memory capacity while ensuring the reliability of the memory.

  The technical measures taken in order to solve the above-mentioned problems are as follows: when writing data to the memory, arbitrary values are written at the highest level, necessary information is written at the intermediate position, and the lowest level is written at the highest level. A value created under an arbitrary condition based on an arbitrary value was written. According to this, in addition to the necessary information, it is sufficient to add 8 bits of the most significant 4 bits and the least significant 4 bits.

  Furthermore, the arbitrary condition is set to an arbitrary mirror value written at the top. According to this, the lowest data can be easily created.

  Furthermore, a plurality of pieces of information are repeatedly written, and an arbitrary value is obtained by counting up or down using a value up to one more than the number of repetitions. According to this, it becomes possible to know where the latest data is by looking at the connection of the data written at the top or bottom.

  According to the present invention, it is possible to reduce the necessary memory capacity while ensuring the reliability of the memory.

  Embodiments according to the present invention will be described with reference to the drawings.

  FIG. 1 shows an example in which six consecutive 4-bit data = 24 bits are written. As a memory of the microcomputer, a RAM or an EEPROM is assumed. Here, the highest arbitrary value (here, “1”) is written. Next, data to be stored (here, “FFFFFF”) is written. Finally, an arbitrary mirror value (here, “E”) written at the top is written at the bottom. By this series of writing, 32-bit information is retained, but originally the necessary data is 24 bits. In order to confirm the reliability of the memory value written and held, it is determined whether the highest value (here “1”) and the lowest value (here “E”) have a mirror value relationship. Check it.

  According to this method, necessary information that can be stored can be stored up to 24 bits by the same 32-bit memory as in the conventional technique of FIG.

  Next, an embodiment for storing a plurality of information will be described with reference to FIGS.

  An area of 32 bits × 6 tables (= 192 bits) is prepared as the RAM of the microcomputer (see FIG. 2). When the first information is written, the value “1” is written at the top of the first table, then the 24-bit information is written, and finally the mirror value “E” of the value “1” is written at the bottom. (See FIG. 3). When the next information is written, the value “2” is written at the top of the second table, then the 24-bit information is written, and finally the mirror value “D” of the value “2” is written at the bottom. Write. In this way, the highest value is counted up one by one and data is written to the next table. In the last sixth table, the value “6” is written at the top, then the 24-bit information is written, and finally the mirror value “9” of the value “6” is written at the bottom ( (See FIG. 4).

  After writing the last table, the process returns to the first table first, and new information is overwritten. Here, the maximum value to be written at the top is set to a value one more than the number of tables. Therefore, since there are 6 tables here, the maximum value is 7. Next to the maximum value, the value is returned to 1 and then counted up.

  According to this condition, the seventh write is the first table, the value “7” is written at the top, then the 24-bit information is written, and finally the mirror value of the value “2” is written at the bottom. 8 ”is written. The eighth write is the second table, the value “1” is written at the top, then the 24-bit information is written, and finally the mirror value “E” of the value “1” is written at the bottom ( (See FIG. 5). Thereafter, data is continuously stored under this condition.

  As shown in FIG. 5, at the stage of writing for the eighth time, the highest value is “7” → “1” → “3” → “4” → “5” → “6” in order from the first table. It has become. Since there is no regularity only between the second table and the third table under the condition that the highest value is counted up from 1 to 7, the data stored in the second table is the latest data. You can see that there is.

  In the above embodiment, the length of data to be stored may be changed as appropriate.

  In the above embodiment, hexadecimal data (0 to F) is used and the mirror value of the highest value is written at the lowest value, but other counting methods may be used.

  In addition to the mirror value, the value to be written at the bottom may be a number incremented by a specific number.

  In the above embodiment, when a plurality of pieces of information are stored, the highest value is counted up one by one. However, it may be changed to count down one by one. In this case, the highest value is switched in the order of “7” → “6” → “5” → “4” → “3” → “2” → “1” → “7”. Also, the value to be written first may be an arbitrary value instead of “1” or “7”.

It is a block diagram which shows the memory structure of the embodiment of this invention. It is a block diagram which shows the memory structure of another embodiment of this invention. In FIG. 2, it is a block diagram which shows the memory structure after performing the 1st write. In FIG. 2, it is a block diagram which shows the memory structure after performing the 6th write. In FIG. 2, it is a block diagram which shows the memory structure after performing the 8th write. It is a block diagram which shows the memory structure in a prior art.

Explanation of symbols

1 1st table 2 2nd table 3 3rd table 4 4th table 5 5th table 6 6th table

Claims (3)

Write any value at the top,
Write the necessary information in the middle position,
A method of retaining data in a memory, wherein a value created under an arbitrary condition based on an arbitrary value written at the highest level is written at the lowest level. 2. The method for retaining data in a memory according to claim 1, wherein the arbitrary condition is an arbitrary mirror value written at the highest level. 2. The method for retaining data in a memory according to claim 1, wherein a plurality of information is repeatedly written, and an arbitrary value is counted up or down using a value up to one more than the number of repetitions.

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