JP2533055Y2 - Vehicle mileage accumulator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle mileage integrating device using a non-volatile memory as storage means for recording the mileage of a vehicle.

[0002]

2. Description of the Related Art A vehicle has an odometer that integrates and displays the distance the vehicle has traveled in the past and a trip meter that can be reset as appropriate and displays the distance traveled after the reset. It is installed as.

Conventionally, an odometer generally has a mechanical counter which has a plurality of character wheels and displays the mileage by sequentially carrying the characters from the lower-order character wheel according to the traveling of the vehicle. . However, with the recent digitization of vehicle instruments, the display of the vehicle odometer has been replaced by an electronic display such as a fluorescent display tube instead of a mechanical counter. When the electronic display is used as described above, the mileage information is stored in a non-volatile memory so that the mileage information is not lost even when the power is turned off. It is a common practice to read mileage information from a computer and display it on a display.

FIG. 8 is a block diagram showing a conventional example of a vehicle mileage recording device having a nonvolatile memory. In FIG. 8, reference numeral 1 denotes a microcomputer (CPU) which operates according to a predetermined control program. ROM 11 for storing programs, and RAM 12 as volatile memory for storing various data generated in the course of operation
And In the RAM 12, a pointer address storage unit 12a, a point data storage unit 12b, a counter value storage unit 12c, and a distance counter 12d are formed.

[0005] The pointer address storage unit 12a stores address data indicating the position where data is to be recorded when data is recorded in the nonvolatile memory 3 described later, and the point data storage unit 12b stores the nonvolatile memory 3 specified by the pointer. The data stored at the middle address is stored, and the counter value storage unit 12c stores the count value in the counter area in the nonvolatile memory 3, and these constitute a mileage storage area. And the distance counter 12
d counts the pulse signal from the rotation sensor 2.

The rotation sensor 2 is connected to an output rotation system of the transmission via a rotation connection member (not shown), and generates a pulse signal having a frequency proportional to the traveling speed according to the traveling of the vehicle. input.

Reference numeral 3 denotes a non-volatile memory which can hold the recorded contents without a power source and which records mileage data obtained by integrating mileage.
Is C based on the pulse signal input from the rotation sensor 2.
The travel distance data is updated each time the PU 1 detects that the vehicle has traveled a predetermined distance, for example, 1 km.

Reference numeral 4 denotes a display for displaying the integrated traveling distance calculated by the CPU 1 based on the traveling distance data stored in the traveling distance storage area in the RAM 12. The display 4 is operated by the display driver 5. Driven.

The nonvolatile memory 3 is composed of 116 × 8 bits as shown in FIG.
, A data area 3a is formed, and the remaining addresses 113 to 116 form a counter area 3b. In the counter area 3b, there are three counters 3b each having 8 bits.
₁ counter 3b ₂ are formed.

The method of writing the vehicle mileage data into the nonvolatile memory 3 having the above-described configuration is performed as shown in FIGS. In the nonvolatile memory 3, FIG.
As shown in (a), hexadecimal FFs are recorded in both the data area 3a and the counter area 3b.
In this state, 0 indicating the address 0 is stored in the pointer address storage unit 12a. Thereafter, when the vehicle starts traveling and the CPU 1 detects that the vehicle has traveled a predetermined distance, for example, 1 km, based on the content of a distance counter 12d that counts a pulse signal from the rotation sensor 2, FIG.
As shown in (b), the data “F” currently recorded at the address 0 indicated by the pointer address storage unit 12a.
After the data "00" obtained by adding +1 to "F" is recorded, the address 1 is designated to the pointer address storage unit 12a by +1. By repeating the above operation sequentially, the vehicle becomes 11
At the time when the vehicle travels for 4 km, as shown in FIG. 10 (c), data “01” obtained by adding +1 to data “00” is recorded at address 0, and +1 is added to the pointer address storage unit 12a to indicate the address 1. To

Thereafter, the vehicle is further driven, and
When the vehicle travels for 8928 km, as shown in FIG. 10D, the final address 112 of the data area 3a of the nonvolatile memory 3 is changed.
"FF" is recorded in hexadecimal notation,
Data “00” obtained by adding +1 to the data “FF” that has been recorded so far is written to the _three counters 3b _{1 to} 3b 3 in the counter area 3b. And one more vehicle
When the vehicle travels km, as shown in FIG. 9 (e), +1 data is recorded at the address pointed to by the pointer address storage unit 12a, and +1 is added to the pointer address storage unit 12a to indicate the address 1.

The travel distance can be obtained by reading the data recorded as described above and performing the following equation. Traveling distance = 28928 × [(counter value) +1] + 113 × [(data of nonvolatile memory address specified by pointer address storage unit) +1] + (pointer address) km (A)

Further, as described above, the nonvolatile memory 3 is configured to be rewritten in units of 8 bits, so that each address of the data area 3a can be rewritten once only for 113 km.
Can be integrated. Then, assuming that the rewriting permissible frequency of the nonvolatile memory 3 is 10000 times, it is possible to accumulate the vehicle traveling distance up to 10000 × 113 = 11300000 km. For example, 10
When the distance integration of 00000 km is performed, it becomes possible by rewriting 8850 times.

[0014] Note that when it constitutes a counter area 3b by three counters 3b ₁ ～3B _3, which if applied reset the CPU1 in the middle of rewriting counter area, the next power rises, Three counters can be used to perform the correction process using the principle of majority decision,
This increases the reliability of the counter value.

[0015]

As described above, the data in the nonvolatile memory is rewritten each time the vehicle travels a predetermined distance. When the nonvolatile memory is rewritten, if the count value of the counter area is also rewritten at the same time,
If the CPU is turned off, large erroneous data is recorded as mileage.

The occurrence of erroneous recording will be described with reference to FIG.
A specific example will be described. FIG. 11A shows that the data values of addresses 0 to 111 of the data area 3a of the nonvolatile memory 3 are F
It is assumed that F and 112 are FE and the data value of the counter area 3b is FF. That is, the traveling distance is 2892
Assume that it was 7 km.

In this state, when the distance counter 1d counts a predetermined distance of 1 km, the data value of the nonvolatile memory 3 is rewritten, and as shown in FIG.
The data values of 112 are all FF, the data values of counters 1１〜３3 are 0, and 28928 km is recorded as the running distance.

FIG. 11B shows a case where the rewriting is completed normally. If the power of the CPU is turned off during this rewriting process, the process is interrupted, and FIG. 11C or FIG. ) Is stored. That is, FIG.
The case of 1 (c) is a process of rewriting the nonvolatile memory, first rewriting the data area, and then rewriting the counter area. In this case, if the power of the CPU is turned off after rewriting the data FE of the address 112 to FF, the data in the counter area is recorded in the state of FF, and the traveling distance becomes 0 km.

FIG. 11D shows a case where the rewriting of the non-volatile memory is performed by first rewriting the counter area and then rewriting the data area. In this case, the data in the counter area is rewritten to 00 from FF and then to CP
When the power supply to U is turned off, the data at address 112 becomes FE
State is recorded, and the mileage is 57
855 km. Therefore, an incorrect record is stored in both cases of FIG. 11C and FIG. 11D when the rewriting process of the nonvolatile memory by the CPU is performed. The power was turned off like this
When the wrong record is stored in the non-volatile memory
When the power is turned on, based on the record in the non-volatile memory
Store correct mileage data in mileage in volatile memory
Reset to the area and correct based on this mileage data.
Display the new accumulated mileage on the display
Become.

Therefore, in view of the above-mentioned conventional problems, the present invention is designed so that the power supply is cut off when rewriting the data of the non-volatile memory in which the mileage is recorded, and erroneous recording in the non-volatile memory is performed.
Stored from non-volatile memory when power is turned on
Even if this wrong record is read, the volatile memory
It is an object of the present invention to provide a vehicle mileage recording device improved so that correct mileage data can be reset in a section .

[0021]

In order to solve the above-mentioned problems, a vehicle mileage recording device according to the present invention is shown in FIG.
As shown in the basic configuration diagram, a pointer address storage unit 12a that is incremented by one each time the vehicle travels a predetermined distance, a point data storage unit 12b that is incremented by one each time the vehicle travels a predetermined distance, and initialized when the vehicle reaches a maximum value, Every time the point data in the point data storage unit 12b reaches the maximum value, +1
Volatile memory 1 having a stored counter value storage unit 12c
2, a calculating means 13 for calculating the traveling distance based on the contents of the pointer address storage section 12a, the point data storage section 12b and the counter value storage section 12c, and the point data storage designated by the address based on the contents of the pointer address storage section 12a. A non-volatile memory 3 having a data area 3a in which data corresponding to the contents of the section 12b is written and a counter area 3b in which data corresponding to the contents of the counter value storage section 12c are written; The pointer address storage unit 12
the data area 3 addressed by the contents of a
The data corresponding to the content of the point data storage unit 12b is written at the position a, and the counter value storage unit 1
Each time 2c is incremented by one, the contents are added to the counter area 3b.
Writes the writing means 14 reads out the data from said area of said nonvolatile memory 3 when the ignition switch is turned on from off, to the read data to
In vehicle travel distance adding device and a resetting means 15 for resetting the contents of the storage portion of the volatile memory 12 on the basis, from the counter area 3b the first and second counter area 3b _1, 3b ₂ The writing means 14 writes the contents of the counter value storage means 12c in the _first counter area 3b1 when the counter value storage means 12c is incremented by one when the vehicle has traveled a predetermined distance, and writing data corresponding to the contents of the point data storage section 12b to the position of the data area 3a addressed indicated by the contents of said pointer address storage unit 12a, finally the counter value storage section to the second counter area 3b ₂ 12c, and the resetting means 15 reads the first and second data read from the nonvolatile memory 3. When the difference between the data value of the counter area _3b 1, 3b ₂ is 1, 0 to the pointer address storage unit 12a, a maximum value in said point data storage unit 12b, the mosquito
It is characterized in that the contents of the first counter area are respectively written in the counter value storage section .

[0022]

With the above configuration, the pointer address storage unit 1
2a, the data which is incremented by +1 every time the vehicle travels a predetermined distance, the point data storage unit 12b increments by +1 each time the vehicle travels a predetermined distance, the data which is initialized when the maximum value is reached, and the counter value storage unit 12c. Since data which is incremented by one each time the point data reaches the maximum value is stored, the calculating means 12 can calculate the traveling distance based on these data.

The data area 3a of the nonvolatile memory 3
The data corresponding to the contents of the point data storage unit 12b addressed by the contents of the pointer address storage unit 12a and the data corresponding to the contents of the counter value storage unit 12c to the counter area 3b of the nonvolatile memory 3 are written by the writing unit 14. Since each of them is written, the volatile memory 12 is turned off by turning off the ignition switch.
Is not held normally, the resetting means 15
Can read data from the area of the nonvolatile memory 3 when the ignition switch is turned on from off and reset the contents of the storage section of the volatile memory 12.

In addition, the counter area 3b has the first and the second
And consists of counter area 3b _1, 3b _2, the write means 14, when the vehicle counter value storage unit 12c when the run the predetermined distance is +1, the counter value storage unit 12c in the first counter area 3b ₁ Write the contents of
Then write data corresponding to the address of the data area 3a indicated by the contents of the pointer address storage section 12a to the contents of point data storage section 12b, finally the contents of the second counter area 3b ₂ in the counter value storage unit 12c Write.

[0025] Therefore, even if the power supply during a write operation to the counter area 3b of the non-volatile memory 3 is the cross-sectional, normally whether the writing has been completed the first and second counter area 3b _1, 3 b It can be known from the difference between the data values recorded in ₂ and the ignition switch is turned on from off
When reset, the resetting means 15
The read first and second counter areas 3b ₁ , 3b ₂
When the data value difference is 1, the pointer address storage unit 12
0 for a, maximum value for point data storage unit 12b, count
Write the contents of the first counter area to the
The resetting means 15 causes the non-volatile memory 3
Volatile memory even if there is an error in the data value read from
Can be reset to the correct value.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an embodiment of the vehicle mileage accumulating apparatus according to the present invention. In FIG. 2, the same reference numerals are given to the same parts as those of the conventional apparatus described above with reference to FIG. 8, and the detailed description thereof will be omitted. .

In the embodiment of the present invention, a counter area 3b is formed in the nonvolatile memory 3 in addition to the data area 3a. Each of the counter areas 3b is the same as the counter area 3b described above with reference to FIG. counter area of the first及of three counters A3b ₁ and the second counter area B3b ₂ is formed, has been modified work CPU1 performed in this context. Incidentally, the non-volatile memory 3 is composed of 8 bits, the address of the address area 3a in 112 address from address 0, the counter area A3b ₁ and counter area B3b ₂ is 113 addresses 115 address and 116 address respectively address - 118 It shall be configured.

That is, the CPU 1 operates as a distance counter 12d.
When it is determined that the vehicle has traveled 1 km based on the count value, the data is written into the nonvolatile memory 3 using the data in the pointer address storage unit 12a, the point data storage unit 12b, and the counter value storage unit 12c in the travel distance storage area. While performing the operation, in particular, the non-volatile memory 3 in the counter area A3b ₁ and counter area B3b ₂ counter is counted up, the contents of the nonvolatile memory 3 before writing as shown in FIG. 3 (a) It is when it is.

[0029] In this state, when the 1km running is performed, first, the three counters of the counter area A3b ₁ to +1, then the address 112 three counter data from the FF counter area B3b ₂ of However, when writing is performed normally, the nonvolatile memory 3
Is as shown in FIG. 3B. Then, the writing operation may not be completed because the battery is removed during the writing operation, and in such a case,
The contents of the non-volatile memory 3 are as shown in FIG.

[0030] However, as the difference between the counter area contents of A3b ₁ and counter area B3b ₂ in the nonvolatile memory 3 is at the 1, it has been counted up, the address 0
All the data up to 112 can be regarded as FF. Therefore, the contents of the nonvolatile memory 3 are as shown in FIGS.
In any case of (d), the traveling distance is 28928 km.
Can be obtained as

The details of the operation outlined above are described in detail by the CPU 1
This will be described below with reference to the flowchart of FIG. The CPU 1 starts operating when the power is turned on, and in the first step S1, performs initialization necessary for the CPU 1 to perform the subsequent work.

Thereafter, the flow advances to step S2 to determine whether or not an ignition switch (IGN) not shown is turned on. When the ignition switch is turned on, the data of the traveling distance storage area in the RAM 12 is normally secured. Therefore, the determination in step S2 is YE
In the case of S, that is, when the ignition switch is on, the process proceeds to step S3, and it is determined whether or not a 1 km running flag F set by an external interrupt process described later is 1. If the determination in step S3 is YES, that is, if the 1-km running flag F is 1, the process proceeds to step S4 to perform a writing process to the nonvolatile memory 3 by a subroutine described later, and then returns to step S2. The data stored in the mileage storage area is used to display the mileage on the display 4 by timer interruption.

When the determination in step S2 is NO, that is, when the ignition switch is turned off, in step S5, the CPU 1 is set to a standby state in which the operation of the CPU is stopped in order to minimize the consumption of the battery which is a power supply. Wait for the ignition switch to be turned on. When the CPU 1 is in the standby state, there is no guarantee that the data of the traveling distance storage area in the RAM 12 is normally held. Therefore, when the determination in step S6 is YES, that is, when the ignition switch is turned on, the process proceeds to step S7 to reset the traveling distance storage area in the RAM 12 based on the contents of the nonvolatile memory 3 by a subroutine described later. I do.

The above-described external interrupt processing is performed every time a pulse signal is input from the rotation sensor 2. As shown in the flowchart of FIG. 5, the distance counter 12d is incremented by 1 in the first step S8a, and in the subsequent step S8b It is determined whether or not the count value of the distance counter 12d is a value corresponding to traveling 1 km. This step S8
When the determination of b is NO, the process immediately returns to the original flowchart of FIG. 4. When the determination is YES, the process proceeds to step S8c, where the 1km travel flag F is set to 1, and the subsequent step S8
At d, the distance counter 12d is initialized, and the process returns to the original flowchart of FIG.

The process of writing to the nonvolatile memory 3 in step S4 is performed by a subroutine shown in FIG.
That is, in this process, it is determined whether or not the content of the point address storage unit 12a is 112 in the first step S4a. When the determination in step S4a is NO, the process proceeds to step S4b, where data obtained by adding +1 to the point data in the point data storage unit 12b of the mileage storage area is written in the data area 3a in the nonvolatile memory 3.

Thereafter, the process proceeds to step S4c, where the content of the point address storage unit 12a is incremented by one.
Proceeding to 4d, the contents of the pointer address storage unit 12a become 1
13 is determined. If the determination in step S4d is NO, the process returns to the original flowchart in FIG.
On the other hand, when the determination in step S4d is YES, that is, when the contents of the pointer address storage unit 12a are 113, the process proceeds to step S4e, where the pointer address storage unit 12a
a is initialized, that is, set to 0, and the subsequent step S4f
In step (1), the content of the point data storage unit 12b is incremented by 1, and the process returns to the original flowchart of FIG.

If the determination in step S4a is YES
In other words, when the content of the pointer address storage unit 12a is 112, the process proceeds to step S4g, where it is determined whether the content of the pointer data storage unit 12b is FE. If the determination in step S4g is YES, that is, if the contents of the point data storage
In step S4h, the process proceeds to step S4h, where the counter value storage unit 1
+1 is added to the content of 2c. Then, proceed to step S4i,
Here write the contents of the counter value storage unit 12c in the counter area A3b ₁ in the nonvolatile memory 3, to check whether the successfully written reads the written content. Next, the process proceeds to step S4j, where the point data storage unit 12b is stored in the data area 3a of the nonvolatile memory 3.
Write +1 to the contents of. The write in the next step S4k, the contents of the counter value storage unit 12c in the counter area A3b ₂ in the nonvolatile memory 3,
The written contents are read to check whether or not the contents have been normally written, and then the process proceeds to step S4e.

The process of resetting the traveling distance storage area in the RAM 12 based on the contents of the nonvolatile memory 3 in step S7 is performed by a subroutine shown in FIG. That is, in this process, the contents of the nonvolatile memory 3 are read in the first step S7a. Then step S
Proceed to 7b difference in the content of the read out counter area A3b ₁ and counter area B3b ₂ determines whether or not 1. When the judgment at step S7b NO, that proceeds to step S7c when the difference between the contents of the counter area A3b ₁ and counter area B3b ₂ is not 1, the pointer address and point data based here on the value read in step S7a Is calculated and stored in the pointer address storage unit 12a and the point data storage unit 1
After that, the process proceeds to step S7e.

[0039] When the determination in step S7b is YES, i.e. counter area A3b ₁ and counter area B3
difference in content of b ₂ proceeds to step S7d when is 1, wherein the non-volatile memory in step S7a
3 based on the contents read out, the distance data is determined to be all FF, the pointer address storage unit 12a is set to 0, the point data storage unit 12b is set to FF , and the counter value
Proceeds to step S7e from the pay portion 12c in the first content of the counter area A3b _1. In step S7e, the pointer address, the point data, and the counter
After calculating the travel distance based on the above equation (A), the process returns to the original flowchart of FIG. Step S above
Immediately after the ignition switch is turned on, the distance data calculated in 7e is displayed on the display 4 by the timer interrupt processing.
Used to display the mileage.

If the power of the CPU 1 is cut off and the process is interrupted during the execution of the write process S4 as described above, erroneous data may be stored in the nonvolatile memory 3. A specific example will be described with reference to FIG. FIG. 3 (a)
In the address 0 of the address area 3a of the nonvolatile memory 3,
Data to 111 are FF, FE is recorded in the address 112, counter area A3b ₁ and counter area B3b ₂
Are all recorded as FF.

Then, after traveling a predetermined distance, the above-mentioned write processing to the nonvolatile memory is performed, and the first counter area A
If the power of the write processing after the end CPU became disconnection to, as shown in FIG. 3 (c), the recorded value of the counter area A3b ₁ is 0, and the other remains in the recording state of FIG. 3 (a) Becomes When the power is turned off after the writing of the next address area is completed, the data value of the address 112 is rewritten to FF, as shown in FIG. Note that FIG.
(A) shows a case where the processing is completed without interruption .

As can be understood from FIG. 3, since the processing is not interrupted and the data values recorded in the counter area A and the counter area B are equal , the counter area A3b ₁
The difference between the contents of the counter area B3b ₂ are equal to a 1
If not, it is determined that there was an interruption, and
To adopt the contents of the counter area A3b _1. Therefore, non-volatile by interruptions in reconfiguration process in the flowchart of FIG. 7
Even if the data in the memory 3 is incorrect,
At the time of setting, the correct data is used for volatile data
It can be reset in each storage unit of the memory .

[0043]

As described above, according to the present invention, the counter area in the non-volatile memory is composed of the first and second counter areas. writing to the counter area, then write the data, and finally writes the second counter area, even when the power supply during a write operation to the cross-sectional, whether the first and second normally write is completed You can know from the difference between the data values stored in the second counter area, power
If the wrong record is read when it is turned on, it is correct
The mileage data can be reset .

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a vehicle mileage integrating device according to the present invention.

FIG. 2 is a configuration diagram of an embodiment of a vehicle mileage integrating device according to the present invention;

FIG. 3 is an explanatory diagram for explaining a schematic operation of the apparatus in FIG. 2;

FIG. 4 is a flowchart showing tasks performed by a CPU in the apparatus of FIG. 2;

FIG. 5 is a flowchart of an external interrupt process performed by a CPU in the apparatus of FIG. 2;

FIG. 6 is a flowchart showing details of a part of the flowchart of FIG. 4;

FIG. 7 is a flowchart showing details of another part of the flowchart in FIG. 4;

FIG. 8 is a configuration diagram illustrating an example of a conventional device.

9 is a diagram illustrating a configuration of a nonvolatile memory of the device in FIG. 8;

FIG. 10 is an explanatory diagram for explaining a recording operation of a nonvolatile memory of the device of FIG. 8;

FIG. 11 is an explanatory diagram for explaining a problem of a conventional device.

[Explanation of symbols]

Reference Signs List 12 volatile memory (RAM) 12a pointer address storage unit 12b point data storage unit 12c counter value storage unit 13 arithmetic unit (CPU) 14 writing unit (CPU) 15 resetting unit (CPU) 3 nonvolatile memory 3a data area 3b counter Area 3b ₁ First counter area 3b ₂ Second counter area

Claims (1)

(57) [Scope of request for utility model registration] 1. A pointer address storage unit that is incremented by one each time the vehicle travels a predetermined distance, a point data storage unit that is incremented by one each time the vehicle travels a predetermined distance, and is initialized when the vehicle reaches a maximum value, and in the point data storage unit. A volatile memory having a counter value storage unit that is incremented by one each time the point data reaches a maximum value, and a calculation unit that calculates a mileage based on the contents of the pointer address storage unit, the point data storage unit, and the counter value storage unit. A non-volatile memory having a data area addressed by the contents of the pointer address storage section to which data corresponding to the contents of the point data storage section is written, and a counter area to which data corresponding to the contents of the counter value storage section are written Every time the vehicle travels a predetermined distance, the contents of the pointer address storage unit are used. Writing means for writing data corresponding to the contents of the point data storage unit to the position of the data area designated by the address, and writing the contents to the counter area each time the counter value storage unit is incremented by one; Resetting means for reading data from the area of the nonvolatile memory when the switch is turned on from off and resetting the contents of the storage section of the volatile memory based on the read data. In the distance accumulator, the counter area includes a first counter area and a second counter area, and the writing unit stores the first counter area when the counter value storage unit is incremented by one when the vehicle travels a predetermined distance. Write the contents of the counter value storage section to the The data corresponding to the contents of the point data storage unit is written at the position of the data area instructed, and the contents of the counter value storage unit are finally written to the second counter area. When the difference between the data values of the first and second counter areas read from the memory is 1, the pointer address storage unit stores 0, the point data storage unit stores the maximum value , and the counter value storage unit stores the first value.
A vehicle mileage accumulating device, wherein the contents of the counter areas are written.