JP3280216B2 - Electronic integrator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic integrator capable of measuring and displaying a traveling distance, and more particularly to an electronic integrator having improved reliability.

[0002]

2. Description of the Related Art Conventionally, when this kind of electronic integrator is used as, for example, an odometer of a vehicle, it is necessary to hold past traveling data even when a battery abnormality (voltage drop, battery disconnection, etc.) occurs. Therefore, a non-volatile memory is used (see Japanese Patent Application Laid-Open No. 59-196414).

In such a configuration, when the traveling data is stored in a non-volatile memory as a storage means, it is determined whether or not it is possible to reliably determine whether or not erroneous data (error) has been written to the non-volatile memory. There was a problem with the reliability of the running data. In other words, in the case of performing the above determination, it is easy to find erroneous data as the traveling data written is larger (because the erroneous data is a value far apart from other normal data). Since the traveling data is written for each unit traveling distance, there is a large difference between the minimum value and the maximum value (latest value) even in the positive data,
Finding wrong data is difficult.

Therefore, the applicant of the present invention writes only the upper digit of the traveling distance in each address of the non-volatile memory as traveling data, and uses the address itself for the lower digit.
In addition to reducing the number of times of writing to the non-volatile memory, there is basically only two types of running data at each address, and has proposed a method that enhances the reliability of facilitating the detection of erroneous data with distant values ( Tokuhei 5-65010
Reference).

FIG. 7 is an allocation diagram showing the configuration of the nonvolatile memory M in the earlier application filed by the present applicant.
For each of the 100 addresses, each address has 4 bits for each digit to hold the upper 4 digits of the mileage in binary, and each address has 16 bits b1 to b16,
The addresses 00 to 99 and the bits b1 to b16 are written and read by the decoders D1 and D2 (or an encoder or a combination of a decoder and an encoder). In the figure, it can be seen that the latest traveling data is "1.2.3 3.3" of the address 56 and the latest traveling distance is "123356 km".

[0006]

As shown in FIG. 8, when noise occurs at the 57th signal line of the decoder D1 at the time of writing and an error occurs in the address 56, the running data at the address 56 becomes Address 55, 5 before and after
7, the burst error is relatively easy to find.

[0007] However, as shown in FIG.
In the case of writing, if the noise is put on the first signal line of the decoder D2 and an error occurs in the bit b1, the running data of the least significant digit changes, and only the discrimination method of finding out from the difference between the erroneous data and the positive data Cannot detect this burst error, and the latest value of the mileage is incorrectly “12335”.
5 km "and an error of 1 km occurs.

An object of the present invention is to provide an electronic integrator that is resistant to bit-unit errors and has improved reliability by adding a newer writing method to the prior art of the present applicant.

[0009]

According to the present invention, there is provided a vehicle driving apparatus comprising: a counting means for counting a signal from a distance detecting means; Using the address itself, the lower-order digit of the integrated travel distance is used to shift to the next address for each unit travel distance, and the travel data is written and retained, and the latest value is displayed by digital display means. In the electronic integrator, the running data is written and held as a 4-bit binary number in each of the high-order digits , and the binary number is 3 out of the 4-bit value in the numerical value adjacent to the converted value. The bits are converted by a different conversion method, and the travel data is converted in the inverse of the conversion method and displayed on the display means.

[0010] The present invention for solving the above problems, each of the upper digit of the hexadecimal number by converting the accumulated running distance
It is a digit .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Signals from a distance sensor 1 are counted, and the upper four digits of an integrated travel distance are EE for each unit travel distance.
The travel data is written and held at each address of the PROM 5, and the lower two digits of the integrated travel distance are shifted to the next address for each unit travel distance by using the address itself, and the travel data is written and held at the display 5. In the electronic integrator that displays the latest value, the running data is written and held as a 4-bit binary number in each digit, and the binary number is a conversion value in which 3 bits out of 4 bits are different in the numerical value adjacent to the converted value. The driving data is converted by the method, and the traveling data is converted in the inverse manner of the above-described conversion method and displayed on the display 5. Even if an error occurs in the bit, the numerical value obtained by the inverse conversion is based on those of the preceding and following addresses. Since the value is far from the value, it is instantly known that the error occurs.

The converted numerical value is the upper four digits of a hexadecimal number obtained by converting the integrated mileage, and the lower one digit uses the address itself, so that the address can be reduced and the storage means can be reduced in capacity. Get better.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. 1 to 4 relate to the first embodiment, and FIGS. 5 and 6 relate to the second embodiment.

FIG. 1 is a block diagram in the case where the electronic integrator according to the present invention is used as an odometer of a vehicle. The distance sensor 1 which is a distance detecting means and includes an auxiliary circuit such as a waveform shaping circuit is shown in FIG. It is installed on the wheel or axle of the vehicle, and outputs a pulse signal in accordance with traveling, and uses it as a distance input to the microcomputer 2 as control means. The microcomputer 2 receives the distance input, counts the number of pulses, and writes and reads the running data of the EEPROM 5 as the storage means via the decoders 3 and 4 as the input / output means at every predetermined unit running distance (for example, 1 km). In the latter case, display output to a digital display means including a display element such as a fluorescent display tube is performed by a predetermined method via a driver 6 which is a driving means. Reference numeral 8 denotes a vehicle battery.

A method of writing to the EEPROM 5 and outputting a display to the display 7 will be described with reference to an assignment diagram shown in FIG.

The EEPROM 5 uses the decoders 3 and 4 to display the upper digits (for example, the upper 4 digits of a 6-digit display, ie, 100 km unit) at one of two types of travel data at addresses 00 to 99 at addresses 00 to 99. Type (In the present embodiment, two types of "1.2.3.3.2" and "1.2.33.3"
The microcomputer 2 sends a display output to the driver 6 based on the traveling data, and the display 7 displays the latest value. It is based on the same concept as the above-mentioned prior art of the applicant.

In the present invention, the decoders 3 and 4 use the EEP
There is a difference in that the travel data is converted from a decimal number to a binary number and written into the ROM 5 and that the travel data is inversely converted and read. That is, as shown in FIG. 3, instead of the general conversion method ((a) in FIG. 3), in a numerical value adjacent to a decimal number which is a numerical value to be converted, a binary number is a conversion method in which 3 bits out of 4 bits are different. The conversion is performed by using ((b) in the figure), and this conversion is performed by the microcomputer 2. When the travel distance is to be obtained, the travel data stored at addresses 00 to 99 of the EEPROM 5 is converted from a binary number to a decimal number by inverse conversion of the above conversion method, and a predetermined process (for example, Japanese Patent Publication No.
No. 65010, column 4, lines 27-42).

In FIG. 2, when the microcomputer 2 determines that the latest value is the traveling data of the address 56 by the above-described predetermined processing, the microcomputer 2 sets
The running data of b1 "0111 ・ 1100 ・ 1011 ・ 1
From “011”, “1.2.33.3” is obtained by the inverse conversion of the conversion method of FIG. 3B, and based on this and the address 56, the traveling distance is displayed on the display 7 as “123356 km”.

Here, as shown in FIG.
When writing noise, the first noise on the signal line of the input / output means 4 causes an error in the bit b1, and the running data “0111 · 1100 ·
From “1011 · 1010”, “1 · 2 · 3 · 6” is obtained by inverse conversion of the conversion method of FIG. 3B, and this value is obtained by the value “1.2.3.3” of the address 55 or the address 57. Is found to be a far apart value (error) having a large difference as compared with the value "1.2.3.2", and it is possible to relatively easily find a bit error which has conventionally been considered difficult. Then, for the bits b4 to b1 in which the large difference has occurred, the address 56 and the addresses 5 located before and after the address 56 are determined.
Comparing with 5 and 57, "1010" of address 56
Although 3 bits match "1011" of address 55, but only 2 bits match "1100" of address 57, "1010"
It is assumed that it is determined that was to be written into the "1011" is probability to correct, the correct travel distance on the display unit 7 with rewritten to "12
3356 km "is displayed.

FIG. 5 shows another embodiment of the present invention, in which the traveling distance is converted into a hexadecimal number, and the EEPRO is used.
M5 converts the upper 4 digits converted to hexadecimal numbers of the traveling distance into the addresses 0 to F by the decoders 3 and 4 to the addresses 0 to F, respectively.
Is one type or two types (in this embodiment, "1.
E · 2 · 3 ”and“ 1 · E · 2 · 2 ”), and the microcomputer 2 sends a display output to the driver 6 based on the running data, Indicates the latest value. That is, when the traveling distance is "12
"3,47 km", converted to hexadecimal, "1 · E ·
2.3.7 ", and the upper four digits" 1.E.2.3 "are written to address 7. Therefore, the traveling data at addresses 0 to 7 is "1E.2.3", and the addresses 8 to F are "1E2.2".

Writing and reading to and from the EEPROM 5 are specifically performed by the conversion method shown in FIG. 6, so that the bits b4 to b1 are "1" at the addresses 0 to 7.
011 "and" 1100 "for addresses 8 to F. As described above, in a numerical value adjacent to a hexadecimal number which is a converted numerical value, a binary number is converted by using a conversion method (FIG. 6) in which 3 bits out of 4 bits are different from each other to obtain data indicating a numerical value “3”. Even if there is a 1-bit error, it does not become a neighboring number “2” (it does not become a neighboring value “4”),
Conversely, even if there is a 1-bit error in the data indicating the numerical value “2”, the adjacent numerical value is not “3” (neither is the adjacent numerical value “1”), but is “123”, which is the correct running distance.
447 km ".

According to this embodiment, the number of addresses is smaller than that of the above embodiment, and the EEPROM 5 has a small capacity, which can contribute to cost reduction.

In each of the above-described embodiments, details of the error in the address unit are not described in detail, but the situation of the error is the same as that of the conventional example (see FIG. 8), and the discovery of the error is relatively similar to the conventional example. Easy to do.

The method of converting a converted value (decimal or hexadecimal) into a binary number is described in FIG.
Alternatively, it is needless to say that the binary number is not limited to the one shown in FIG. 6 and can be set arbitrarily. is necessary.

The input / output circuit may be constituted by an encoder or a combination of a decoder and an encoder in addition to the decoders 3 and 4 used in each of the above embodiments, or a control means (microcomputer 2) Performs a conversion (including an inverse conversion) between a converted numerical value and a binary number, it can be configured with a simplified input / output circuit.

Further, in each of the above embodiments, the odometer has been described, but it is needless to say that the odometer can be used as a trip meter.

[0027]

According to the present invention, the signal from the distance detecting means is counted, and the upper digit of the integrated mileage is written and held at each address of the storage means as running data for each unit mileage, and the lower order of the integrated mileage is stored. Digit using the address itself, in the electronic integrator that shifts to the next address for each unit travel distance, writes and holds the travel data, and displays the latest value on digital display means,
In the running data , each of the high-order digits is written and held as a 4-bit binary number, and the binary number is converted by a conversion method in which 3 bits of the 4 bits are different in a numerical value adjacent to the converted value, The travel data is inversely converted to the conversion method and displayed on the display means,
Even if an error occurs in a bit, the numerical value obtained by inverse conversion based on the error is a value that is far from those of the previous and next addresses, so it is instantly known that the error is an error, and therefore, it is resistant to errors in bit units, reliability Can be increased.

The converted numerical value is each of the upper digits of the hexadecimal number obtained by converting the accumulated mileage, and requires a small number of addresses, requires only a small storage capacity, and contributes to cost reduction. .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating the configuration of a first embodiment of the present invention.

FIG. 2 is an assignment diagram for explaining a configuration of an EEPROM in the embodiment.

FIG. 3 is a table for explaining conversion between decimal numbers and binary numbers in the embodiment.

FIG. 4 is an assignment diagram for explaining a bit error in the embodiment.

FIG. 5 is an assignment diagram for explaining bit errors in a second embodiment of the present invention.

FIG. 6 is a table for explaining conversion between a hexadecimal number and a binary number in the embodiment.

FIG. 7 is an assignment diagram for explaining the configuration of a conventional EEPROM.

FIG. 8 is an allocation diagram for explaining a bit error in the above.

FIG. 9 is an assignment diagram for explaining another bit error in the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Distance sensor (distance detection means) 2 Microcomputer (control means) 3, 4 Decoder (input / output means) 5 EEPROM (storage means) 6 Driver (drive means) 7 Display (display means)

Claims (2)

(57) [Claims] 1. A signal from a distance detecting means is counted, and an upper digit of an integrated traveling distance is written and held as traveling data at each address of a storage means for each unit traveling distance, and a lower digit of the integrated traveling distance is stored in the address. utilizing itself, in electronic odometer which displays the most recent value in the digital display means while writing holds the traveling data shifts to the next said address for each of the unit travel distance, the travel data the upper Each digit of the digit is written and held as a 4-bit binary number, and the binary number is converted by a different conversion method in which 3 bits out of the 4 bits in the numerical value adjacent to the value to be converted. An electronic integrator, wherein the method is reversed and displayed on the display means. 2. The electronic integrator according to claim 1, wherein the converted numerical value is an upper digit of a hexadecimal number obtained by converting the integrated traveling distance.