JPH05231873A - Electronic odometer - Google Patents

Abstract

PURPOSE:To improve the reliability of the electronic odometer against burst errors in bits by additionally providing a nonvolatile memory and deciding the arranging order of data at every address so that the digits of data at adja cent addresses cannot become equal to each other by only writing high-order digits of integrated travel distances as data at each address and utilizing the addresses themselves for the low-order digits of the integrated travel distances. CONSTITUTION:High-order digits (for example, four digits, namely, 100-km units when a six-digit display is used) of an integrated travel distance are written at each address 00-99 of a nonvolatile memory 5 and the integrated travel distance is displayed by using the data of an address, namely, four high-order digits and the two digits of the address. In the memory 5, the arranging order of data is decided at every address so that the digits of the data at adjacent addresses cannot become equal to each other and, even when a burst error occurs in bits, the same digit does not become an error at adjacent addresses and the data can be surely discriminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic odometer, and more particularly to an improved odometer.

[0002]

2. Description of the Related Art Conventionally, when an electronic odometer of this type is used as, for example, an odometer of a vehicle, it is necessary to keep past accumulated mileage even when a battery abnormality (voltage drop, disconnection, etc.) occurs. Therefore, a non-volatile memory is used (Japanese Patent Laid-Open Nos. 57-198810 and 59-1).
96414).

[0003]

When the data of the accumulated travel distance is held in the non-volatile memory, whether or not it is possible to surely determine whether or not erroneous data (error) is written in the non-volatile memory. There was a problem with the reliability of the data. That is, in the above determination, it is easier to find erroneous data as the amount of written data is larger (because erroneous data has a value that is far from other correct data). Since data is written for each unit traveled distance, there is a large difference between the minimum value and the maximum value (latest value) of correct data, and it is difficult to find erroneous data.

Therefore, the applicant writes only the upper digit of the mileage as data in each address of the non-volatile memory and displays the lower digit by using the address itself so that the number of writing to the non-volatile memory can be determined. Reduce and
In principle, since there are only two types of data at each address, we have proposed a technique that can improve reliability by facilitating the detection of erroneous data with disjoint values (Japanese Patent Laid-Open No. 62-201312).
(See the official gazette).

FIG. 6 is an address table of the non-volatile memory M according to the prior art of the present applicant.
For each of the 00 addresses, each address holds the upper 4 digits of the mileage in a binary number, each digit has 4 bits, and one address has 16 bits of b1 to b16. Each address has 00 to 99 and bit b1. b16 is a decoder D
Writing and reading are performed by 1 and D2. In the same figure, it can be seen that the latest value is the address 56 "123456 Km".

As shown in FIG. 7, when noise occurs at the 57th signal line of the decoder D1 and a burst error occurs at the address 56, the data at the address 56 has a value that is far from the data at the addresses 55 and 57 before and after it. Therefore, the discovery of this burst error is relatively easy.

However, as shown in FIG. 8, when the 16th noise of the signal line of the decoder D2 causes noise and a burst error of the bit b16 occurs, the data of the most significant digit of all addresses 00 to 99 is changed, resulting in an error. This burst error cannot be found only by the discriminating means that finds the data from the difference from other correct data, and therefore the latest value is erroneous "923456."
It becomes "Km".

It is an object of the present invention to provide a more reliable electronic odometer which is resistant to bit-unit burst errors by adding a new writing method to the applicant's previous technique. And

[0009]

In order to solve the above-mentioned problems, the present invention counts the signals from the distance detecting means and stores the upper digit of the total traveling distance for each unit traveling distance in each address of the nonvolatile memory. An electronic odometer for writing and holding the lower digit of the integrated mileage, using the address itself of the non-volatile memory, moving to the next address for each unit mileage, and writing and holding the data. In the above, the arrangement order of the data is determined so that the digits of the data of the addresses adjacent to each other of the addresses of the nonvolatile memory are not aligned.

[0010]

The arrangement order of the data is determined so that the digits of the data of the adjacent addresses are not aligned for each address of the non-volatile memory, and even if a burst error occurs in the bit unit, the same digit of the data of the adjacent address has an error. And the data can be easily identified.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments of the accompanying drawings.

FIG. 1 is a block diagram in which the electronic mileage gauge according to the present invention is used as an odometer of a vehicle. A distance sensor 1 which is a distance detecting means and includes an auxiliary circuit such as a waveform shaping circuit is It is provided on the wheel or axle of the vehicle, and outputs a pulse signal for each rotation speed, which is used as a distance input of the microcomputer 2 as a control means. The microcomputer 2
It receives a distance input, counts the number of pulses, writes the data in the non-volatile memory 5 via the decoders 3 and 4 for each predetermined unit traveling distance (for example, 1 km), and displays the fluorescence as a display means via the driver 6. Display output to a digital display 7 including a display element such as a tube is performed by a predetermined method. In addition, 8 is a vehicle-mounted battery.

A method of writing to the non-volatile memory 5 and outputting the display to the display 7 will be described with reference to the address table of the first embodiment shown in FIG.

In the non-volatile memory 5, the upper digits of the accumulated traveling distance (for example, the upper 4 digits when displaying 6 digits, that is, 100 Km unit) are stored in the addresses 0 to 99 by the decoders 3 and 4, and the data of the addresses 00 to 99 is set to 1. Type or two types (in the present embodiment, 2 of "1, 2,3,4" and "1, 2,3,3")
Type) is written every 100 km, and the microcomputer 2 sends a display output to the driver 6 based on this data and the display 7 displays the latest value. The writing and display output methods so far are It is based on the same idea as the above-mentioned prior technology of the applicant.

However, in the present invention, the nonvolatile memory 5
The data arrangement order is determined for each address so that the data of the lower address is moved by one digit (4 bits) to the left with respect to the data of the previous address, and is written. The microcomputer 2 controls so that the arrangement sequence of 00 to 03 is repeated at addresses 04 to 99. Then, when obtaining the integrated traveling distance, the microcomputer 2 performs a predetermined process (for example, a special process while converting the data of the addresses 00 to 99 of the nonvolatile memory 5 according to the data arrangement order determined by each address). Kaisho 62-2013
No. 12, page 3, upper right column, line 12 to same page lower right column, 19th line
Line)).

In FIG. 2, when the microcomputer 2 determines that the latest value is the data at the address 56 by the above-mentioned predetermined processing, the microcomputer 2 determines that the data at the address 56 is "1.2.
"3.4" is read, and this data is converted according to the arrangement order of the data of the address 56 (the arrangement order of the data of the address 56 does not need to be rearranged similarly to the address 00).
Then, the converted data “1, 2, 3, 4” and address 56
Based on the above, the total traveled distance "123456 Km" is obtained.

As shown in FIG. 3, when the 16th noise on the signal line of the decoder 4 causes a burst error of the bit b16, the most significant digit data of all addresses 00 to 99 is changed. For example, the data of addresses 55 to 57 are "C. 1 .2 .3""9 2 .3 .4""A".
・ 3 ・ 3 ・ 1 」, but when these are converted,
・ 3 ・ C "," 9 ・ 2 ・ 3.4 "," 1 ・ A ・ 3/3 ", and the 4th digit, 1st digit, and 2nd digit are different values (errors) due to the relationship between front and back. Therefore, the discovery of this burst error, which was considered difficult in the past, can be performed relatively easily. To correct the data, for example, the value of the corresponding digit of the preceding address is rewritten.

Further, as shown in FIG. 4, when the fourth noise of the signal line of the decoder 4 causes a burst error of the bit b4, the fourth digit data of all addresses 00 to 99 is changed. For example, the data of addresses 55 to 57 are "4.1.2B""12.3C""2.3".
It is "3.9", but when converted, these are "1.2B.
"4""1 .2 .3 .C""9 .2 .3 .3", and the relationship between the front and back shows that the 3rd digit, 4th digit, 1st digit are values that are far apart (error), This burst error, which has been considered difficult in the past, can be relatively easily found. To correct the data, for example, the value of the corresponding digit of the preceding address is rewritten.

FIG. 5 shows a second embodiment of the present invention, in which the even-numbered addresses 01, 03, ..., 99 of the nonvolatile memory 5 in the block diagram of FIG. 1 have odd-numbered addresses. The arrangement order of the data is determined for each address so that the data of 00, 02, ..., 98 can be written by moving to the left by two digits (8 bits). It is performed in the same manner as the first embodiment shown in 2-4.

In each of the above embodiments, the burst error in address units will not be described in detail, but the error condition is the same as in the conventional example (see FIG. 7), and the finding thereof is also relatively easy. To be done.

The addresses 00 to 0 of the nonvolatile memory 5 are also included.
It goes without saying that the arrangement order of the 99 pieces of data is not limited to the above-mentioned embodiment and can be arbitrarily set.

Furthermore, although the odometer has been described in each of the above-mentioned embodiments, it goes without saying that it can also be used as a trip meter.

[0023]

Industrial Applicability The present invention is an electronic odometer that writes the data of the upper digit of the accumulated mileage into a nonvolatile memory and displays the accumulated mileage by using this data and the address of the nonvolatile memory. , The arrangement order of the data is determined so that the digits of the data of the adjacent addresses are not aligned for each address of the nonvolatile memory, and even if a burst error occurs in bit units, the same digit of the data of the adjacent addresses may cause an error. It is possible to provide an electronic odometer with improved reliability, which can be corrected by comparing data of adjacent addresses.

[Brief description of drawings]

FIG. 1 is a block diagram in which the present invention is used as an odometer.

FIG. 2 is a data table of the nonvolatile memory according to the first embodiment of the present invention.

FIG. 3 is a data table for explaining a burst error of the nonvolatile memory according to the same embodiment.

FIG. 4 is a data table for explaining another burst error of the nonvolatile memory according to the same embodiment.

FIG. 5 is a data table of a nonvolatile memory according to a second embodiment of the present invention.

FIG. 6 is a data table of a conventional nonvolatile memory.

FIG. 7 is a data table for explaining a burst error of the nonvolatile memory of the above.

FIG. 8 is a data table explaining another burst error of the nonvolatile memory of the same as above.

[Explanation of symbols]

 1 distance sensor (distance detection means) 2 microcomputer (control means) 3,4 decoder 5 non-volatile memory 6 driver 7 indicator (display means)

Claims (1)

[Claims] 1. A signal from a distance detecting means is counted, and the upper digit of the accumulated traveling distance is written and held as data in each address of a nonvolatile memory for each unit traveling distance, and the lower digit of the accumulated traveling distance is stored in the nonvolatile memory. In the electronic odometer that uses the address itself of the non-volatile memory and moves to the next address for each unit mileage and writes and holds the data, An electronic odometer, wherein the arrangement order of the data is determined so that the digits of the data of the address are not aligned.