JPS6269119A - Odometer for vehicle - Google Patents

Abstract

PURPOSE:To display the total travel distance of a vehicle with good accuracy at all times by detecting vehicle velocity of the vehicle and operating repeatedly and integrating the travel distance of the vehicle based on the detected result. CONSTITUTION:The titled odometer is provided with a vehicle velocity detection means 1 to detect the vehicle velocity of the vehicle and produce a series of pulse signals having frequency in proportion to the detected result, a distance arithmetic means 2 to operate repeatedly the actual travel distance of the vehicle in response to each pulse signal in order, a temporary storage means 3 (3a-3d), a fixed storage means 4 (4a-4c), a discrimination means 5 and the 1st and the 2nd erasion and write means 6 and 7. Then, the means 4 erases stored data of one side of the 2nd and the 3rd storage parts 4b and 4c and writes the stored data of one side of the 2nd and the 3rd storage regions 3b and 3c in the storage part of the one side based on an erasion and write signal from the means 6. Further, the stored data of the other side of the 2nd and the 3rd storage part 4b and 4c are erased and the stored data of one side of the 2nd and the 3rd regions 3b and 3c are written in the storage part of the other side based on the erasion and write signal from the means 7. In this way, an error of the storage contents is correctly rewritten.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a vehicle odometer, and particularly to a vehicle odometer that detects the speed of a vehicle and repeatedly calculates and integrates the distance traveled by the vehicle based on the detection result. , and relates to a vehicular mileage needle adapted to display these integration results.

[Prior art]

Regarding this type of odometer, Japanese Patent Application Laid-Open No. 59-1072
As disclosed in the No. 07 publication, a non-volatile memory is used, and the storage area of this non-volatile memory is designated as the first. The distance traveled by the vehicle is divided into a second and third storage area, and each time the mileage of the vehicle reaches a certain value, it is sequentially stored in the third storage area, and each time the third storage area overflows, the first or third storage area is The memory content of the second memory area is increased by 11, and the memory content of the third memory area is cleared, and when the memory content continues, the newer one of the memory content of the first and second memory areas is output. There is something I tried to do.

[Problem that the invention seeks to solve]

However, in such a configuration, when storing data in the first or second storage areas ↑ and a, these two storage areas are further divided into three storage area parts, and one of the two storage areas is Since the same memory contents are written in the three storage areas, and when the same memory contents are written one after another, a majority vote is taken of the storage contents in each of these three storage areas. There is, of course, a limit to the reduction in capacity, and there is also the problem that the error in the stored contents becomes small below a certain value and becomes unsatisfactory.

Therefore, in order to cope with this problem, the present invention provides a vehicle mileage system that corrects errors in the contents of q as accurately as possible while suppressing the storage capacity of the nonvolatile storage means to the minimum necessary. This is an attempt to provide a measurement plan.

[Means for solving problems]

In solving this problem, the structural features of the present invention are as follows:
As illustrated in FIG. 1, a vehicle speed detecting means 1 detects the speed of the vehicle and generates a series of pulse signals having a frequency proportional to the detection result; a first storage area 3a that repeatedly stores the calculated mileage when it is less than a predetermined unit distance value; a temporary storage means 3 having second and third storage areas 3b, 3c for storing the total sum of the calculated mileage, and a fourth storage area 3d for storing the total sum of the calculated mileage; storage area 3
a, 3b, and 3c, respectively.
．． A non-volatile storage means 4 having second and third storage sections 4a, 4b, 4c, storage data of the first storage section 4a and a second
and the data stored in one of the third storage units 4b and 4c is the sum of the data stored in Section 4, 1. When the data differs from the storage data in the q area 3d, the second
and a determining means 5 which generates a match signal if the difference between the stored data in the third storage units 4b and 4c matches the predetermined unit distance value, and generates a mismatch signal if they do not match, and a discriminator 5 which responds to the match signal. When the data stored in the first storage area 3a is zero, the data 1a in one of the second and third storage sections 4b and 4c is erased and an erase/write signal necessary for correctly writing is generated. a writing means 6, and second and third storage units 4b, 4c when the storage data in the first storage area 3a is zero or the maximum value less than the predetermined unit distance value in response to the mismatch signal 3;
a second erasing/writing means 7 for generating an erasing/writing signal necessary for erasing and correctly writing data stored on the other side;
The non-volatile storage means 4 erases the data stored in one of the second and third storage sections 4b and 4c based on the erase/write signal from the first erase/write means 6, and stores data in the second storage section. and third
The data stored in one of the storage areas 3b and 3c is written, and the data stored in the other storage area 4b and 4c is erased based on the erase/write signal from the second erase/write means 7. One of the second and third storage areas 3b and 3e (1. The reason lies in the fact that α data is written.

[Effect]

However, by configuring the present invention in this way, the first storage section 4 of the non-volatile storage means 4 may be damaged due to some reason.
When the sum of the stored data of a and the stored data of one of the second and third storage sections 4b and 4c is different from the stored data of the fourth storage area 3d of the temporary storage means 3, the determination means 5
generates a match signal, when the stored data in the first storage area 3a is zero, the nonvolatile storage means 4 responds to the erase/write signal from the first erase/write means 6 to erase the second and third storage sections. 4b
, 4c is stored in the second and third storage areas 3.
Rewrite with the stored data of either b or 3c. On the other hand, if the discrimination means 5 generates a mismatch signal, the nonvolatile storage means 4 erases data from the second erasure/writing means 7 when the stored data in the first storage area 3a is zero or the maximum value less than the predetermined unit distance value. In response to the write signal, the second and third storage units 4b, 4c
The other storage data is stored in the second and third storage areas 3b.

Rewrite with data stored in one of 3C.

In this way, if there is an error in the storage contents of the nonvolatile storage means 4, the second and third storage sections 4b.

Based on the comparison of each storage data of 4C, both storage units 4b
, 4c can be correctly rewritten with the data stored in one of the second and third storage areas 3b and 3c in relation to the data stored in the first storage area 3a. According to the stored contents, the total distance traveled by the vehicle can always be displayed accurately. Furthermore, since such effects can be achieved with two storage units, the first and second storage units 4b and 4c, it is also useful for reducing the storage capacity of the nonvolatile storage means 4.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
The figure shows a block circuit diagram of a vehicle odometer according to the present invention. The odometer includes a vehicle speed sensor 10, a waveform shaping circuit 20 connected to the vehicle speed sensor 10, and a constant voltage circuit 30 connected to the DC power supply B and ignition switch TO of the vehicle. , detects the actual speed of the vehicle and generates a series of pulse signals having a frequency proportional to the detection result.

The waveform shaping circuit 20 sequentially shapes the waveform of each pulse signal from the vehicle speed sensor 10 and generates a shaped pulse signal.

The constant voltage circuit 30 has a pair of diodes 31, 32, a pair of transistors 33, 34, and a booster circuit 35, and the diode 31 has its anode connected to the positive side terminal of the DC power supply B via the ignition switch IG. On the other hand, the diode 32 is connected to the DC power supply B at its anode.
connected directly to the positive terminal of the The transistor 33 is connected at its collector to the positive terminal of the DC power supply B through each resistor 33a, 33b and the diode 32, and this transistor 33 responds to a self-holding signal generated from the microcomputer 40 as described below. conducts only while this self-holding signal is generated.

Transistor 34 connects diode 32 at its emitter
The base of this transistor 34 is connected to the cathode of the diode 32 via a resistor 33b, and to the collector of the transistor 33 via a resistor 33a. Thus, transistor 34 becomes conductive in response to the conduction of transistor 33. The booster circuit 35 receives a DC voltage from the DC power supply B through the ignition switch IC and the diode 31, or receives a DC voltage from the DC power supply B through the diode 32 and the transistor 34, and generates a boost signal.

The microcomputer 40 is always connected to the DC power supply B.
The microcomputer 40 is activated by receiving a power supply voltage, and stores a main control program and external and internal interrupt control programs stored in advance in its built-in ROM as shown in FIGS. 5 to 16. The flowcharts are executed in cooperation with the waveform shaping circuit 20 and the nonvolatile memory 50, and during this execution, the transistor 33, the nonvolatile memory 50, and the digital display 70 are
Various arithmetic operations necessary for controlling the drive circuit 60 are performed as described in the operation description below.

However, the interrupt timing of the external interrupt control program is determined by the input timing of each shaped pulse signal from the waveform shaping circuit 20 to the microcomputer 40. Further, the interrupt timing of the internal interrupt control program is determined by a predetermined time period (e.g., 8
ms) is determined by the end of timing. The timer starts counting the predetermined time at the same time as the timer is reset, and is reset when the timer ends.

In addition, the RAM built into the microcomputer 40 has four storage sections 40a and 40, as shown in FIG.
0 b, 40 c, and 40 d are provided, and the storage section 40a is made up of 24 memory cells, and stores the total mileage of the vehicle in 24-bit total mileage data ODO.
It is temporarily stored as . Storage section 40
b consists of eight memory cells, and is configured to temporarily store values less than a predetermined mileage (256 km) of the vehicle as 8-bit first mileage data. Also, a re-storage unit 40c.

40d consists of 16 memory cells, and the memory section 4
0c is an integral multiple of the predetermined mileage of the vehicle, 16
The storage unit 40d temporarily stores the second mileage data l (MO) of the 16 bits, and also stores the integral multiple of the above-mentioned predetermined mileage as the third mileage data HM of the 16 bits.
It is temporarily stored as 1.

The nonvolatile memory 50 consists of a main storage section 50a and a pair of auxiliary storage sections 50b and 50c.
a and both auxiliary storage units 50b and 50C become writable and erasable in response to the power supply voltage from the DC power supply B and the boost signal from the booster circuit 35, and also respond to the power supply voltage from the DC type power supply B and the booster signal from the booster circuit 35. The written contents are stored and retained regardless of the presence or absence of the boost signal. In such a case, the main part 9 50a contains 256 entries 1. It consists of a cells, and is configured to write and erase values less than the predetermined mileage in a non-volatile manner as main mileage data MM of 16 bits x 16 words. The auxiliary storage section 50b is composed of 16 memory cells, and is configured to non-volatilely write and erase an integral multiple of the predetermined mileage as 16 bits of auxiliary mileage data SMO. Further, the auxiliary storage unit 50c has 16
consisting of several memory cells, with an integral multiple of the predetermined traveling distance,
It is designed to be written and erased in a non-volatile manner as 16-bit auxiliary mileage data SMI.

The drive circuit 60 receives a power supply voltage from the DC power supply B and becomes active, and under the control of the microcomputer 40 generates a drive signal representing the total distance traveled by the vehicle. The digital display 70 digitally displays the total travel distance in response to a drive signal from the drive circuit 60.

In this embodiment configured as above, if the vehicle is started by closing the ignition switch IG,
The booster circuit 35 of the constant voltage circuit 30 receives the power supply voltage from the DC type HB through the ignition switch IG and the diode 31 and generates a boost signal, and the nonvolatile memory 50 receives the power supply voltage from the DC power supply B and receives the power supply voltage from the booster circuit 35. Upon receiving the boost signal, the drive circuit 60 enters a write/erase enabled state, and the drive circuit 60 receives a power supply voltage from the DC power supply B through the ignition switch IG and enters the operating state.

Further, when the microcomputer 40 moves to the initialization routine 90 of the main control program that has already been started in step 80 according to the flowchart in FIG. Based on the power supply voltage via the ignition switch IG from
Generates a self-holding signal and also outputs an error flag ERR.
FLG is reset to O, and in step 92, the main storage section 50a and both auxiliary storage sections 50b of the nonvolatile memory 50,
50c is read out and stored in each memory section 40b of the RAM.
, 40c, and 40d, respectively. In such a case, the main mileage data MM in the main memory section 50a is stored in the memory section 40b as the first mileage data LM, and the auxiliary mileage data SMO in the auxiliary record fa section 50b is stored in the memory section 40C as the second mileage data LM. The auxiliary mileage data SMI stored in the auxiliary storage section 50e is stored as the mileage data I (MO) and is stored in the storage section 40d as the third mileage data HMI.

Moreover, as mentioned above, when the self-holding signal is output from the microcomputer 40, the transistor 33 of the constant voltage circuit 30 becomes conductive, and in response! - The transistor 34 becomes conductive and allows the supply voltage to be applied from the DC power supply B to the booster circuit 35 via the diode 32. This means that the generation of the self-holding signal from the booster circuit 35 is independent of the opening of the ignition switch IG,
means that it is maintained under the power supply voltage from the

However, at the current stage, the RAM storage section 40C
The second mileage data HMO in the storage section 40d and the third mileage data in the storage section 40d
If the mileage data HMI is equal, the microcomputer 40 determines "rYES" in step 93 of the initialization routine 90 (see FIG. 6), and sets the control flag FLGLRAM=0000000 in step 93a.
0 (=O), and in step 93b, the second
The mileage data HMO is multiplied by 256, the first mileage data LM in the storage unit 40b is added to this multiplication result, and the addition result is stored in the RAM as the total mileage data ODO.
The data is temporarily stored in the storage unit 40a.

Next, in step 100 of the main control program, the microcomputer 40 generates the total mileage data ODO in the storage section 40a as a display signal, and in response to this, the drive circuit 60 generates a drive signal, and the digital display 70 digitally displays the contents of the drive signal (total mileage data 0DO) as the total mileage of the vehicle at the current stage. Thereafter, when the main control program proceeds to the memory control routine 110 (see FIGS. 5 and 8),
In step 111, the microcomputer 40 determines that timer data TMRAM≠0 (in step 91, TM
In the next step 120 (see FIG. 5), it is determined as rNOJ based on ERRFLG=0 in step 91, and in step 130, The determination is "NO" based on the power supply voltage from the DC power supply B via the ignition switch IG. In addition, the timer data TMRAM
represents the time required to erase or write data stored in the nonvolatile memory 50.

At this stage, when a shaped pulse signal is generated from the waveform shaping circuit 20 in cooperation with the vehicle speed sensor 10, the microcomputer 40 executes an interrupt of the external interrupt control program in step 200 according to the flowchart of FIG. In step 201, a predetermined unit distance is added to the traveling distance DX, and the addition result is updated as DX. In such a case, the predetermined unit distance corresponds to the cycle of the pulse signal from the vehicle speed sensor 10, and the RO of the microcomputer 40 corresponds to the period of the pulse signal from the vehicle speed sensor 10.
It is stored in M in advance.

Moreover, the mileage DX in such step 201
The addition and updating of is repeated in response to the forming pulse signals sequentially generated from the waveform shaping circuit 20, and when the determination in step 202 becomes rYESJ, the microcomputer 4
0 is calculated by subtracting 1 (km) from the latest mileage DX in step 201 in step 202b.
In step 202C, the total mileage data O
Add 1 (corridor) to DO, update it as ODO, and store it in the storage unit 40.
Temporarily stored in a. After that, if the update result ODO in step 202c is an integral multiple of 256 (km),
In step 203, the microcomputer 40
It is determined as YESJ, and the control flag FLGRAM is set to 00011111 in step 203a. On the other hand, the update result ODO in step 202c is 2.
If it is not an integral multiple of 56 (km), the microcomputer 40 determines rNOJ in step 203, and sets the control flag FLGR in step 203b.
Set AM=OO100O00. Note that the above-described interrupt execution of the external interrupt control program is repeatedly performed in response to each shaping pulse signal from the waveform shaping circuit 20.

Also, as mentioned above, timer data TMRAM=112(
ms), the timer of the microcomputer 40 is reset and starts counting the predetermined time.

Thereafter, when the timer finishes counting, the microcomputer 40 starts interrupt execution of the internal interrupt control program in step 210 according to the flowchart of FIG.
In step 2tta, 8 (ms) is subtracted from the timer data TMRAM in step 91, and this subtraction result is stored as TMRAM, and in step 212
At step 211, it is determined that it is rNOJ.

Further, the subtraction update of the timer data TMRAM in step 211a is repeated in response to the end of the repeated time measurement of the timer, so that the timer data TMRAM=O
Then, the determination at step 212 becomes rYESJ. Note that the above-described interrupt execution of the internal interrupt control program is performed every time the timer ends.

When the main control program reaches step 111 (see FIG. 8) of the memory control routine 110 under the timer data TMRAM=O, the micro combinator 40 determines rYEsJ at step 111, and step 112 , erase/write flag EWFLG
=0 (assumed to have been initialized in step 7 step 91), it is determined that it is rNOJ. At this stage, the control flag FLGRAM is set to step 20 of the external interrupt control program.
3a (or 203b), the microcomputer 40 determines that it is rNOJ in step 113, and in step 113a, the main travel distance in the main storage section 50a of the nonvolatile memory 50 is Data MM
is read out and stored in the storage section 40b of the RAM as the first mileage data LM, the auxiliary mileage data SMO in the auxiliary storage section 50b is read out and stored in the storage section 40C as the second mileage data 14M0, and The auxiliary mileage data SMI in the section 50c is read out and stored in the storage section 40d as third mileage data i-(M1).

However, at this stage, the control flag FLG
If the RAM is the value (00011111) in step 203a (see FIG. 5), the microcomputer 40 advances the memory control routine 110 to the first subroutine 5RI (see FIGS. 8 and 9) through step 113b. . Then, the microcomputer 40 executes step 114 of the first subroutine SRI.
, the third mileage data HMI in the storage unit 40d reads “
256'', and this multiplication result is stored in the first
The mileage data LM and l (km) are added, and the addition result is set as confirmation data A.

If the confirmation data A set in this way does not match the total mileage data ODO in the storage section 40a, the microcomputer 40 sets rNOJ in step 114a.
It is determined that the error flag ERRF is set in step 114b.
Set LG=1. This means that there is an error in each of the RAM storage units 40a, 40b, and 40d. On the other hand, the determination in step 114a is "
If YESJ, the microcomputer 40 generates an SMO erasure start signal necessary to start erasing the auxiliary mileage data SMO in the auxiliary storage section 50b of the nonvolatile memory 50 in step 114C, and then proceeds to step 114d.
, the control flag FLGRAM is -00001.
Set it to 111. Furthermore, the nonvolatile memory 50 starts erasing the storage contents of the auxiliary storage section 50b in response to the SMO erasure start signal from the microcomputer 40.

As described above, when the execution of the first subroutine SRI ends in step 114b or 114d, the microcomputer 40 executes the memory control routine 110.
At step 114c (see FIG. 8), the timer data T
Set MRAM=112 (ms), step 1
At step 14f, the erase/write flag EWFLG is set to 1. The execution of the first subroutine SRL is as described above (,
When the process ends with ERRFLG=1 in step 114b, the microcomputer 40 determines rYEsJ in step 120 of the main control program, and returns the main control program to the initialization routine 90.

Then, the microcomputer 40 performs step 91.
(See Figure 6), the error flag E RRFLG=O
In step 92, the non-volatile memory 50 is reset.
Each of the stored data MM and SMO in the main storage unit 50a and both auxiliary storage units 50b and 50c.

The SMI is read out and stored in each RAM memory section 40b, 40c,
Each entry is stored in 40d as ↑, LP-Y LM, HMO, and HMI, respectively. Therefore, based on ODO≠A in step 114a, the second mileage data HMO is changed to the third mileage data HMO.
If it matches the mileage data HMI, the microcomputer 40 determines rYESJ at step 93, performs calculations at each step 93a and 93b in the same manner as described above, and determines 0DO=256 XHM at step 100.
O+LM is generated as a display signal, and in response to this, the digital display 70 digitally displays the total travel distance in cooperation with the drive circuit 60.

On the other hand, if the determination in step 93 is rNOJ, the microcomputer 40 determines the second mileage data HMO and the third mileage data HMO in step 94.
It is determined whether the difference from MI is "l". If the determination in step 94 is rYEsJ,
The microcomputer 40, in step 95,
It is determined whether the first mileage data LM in the storage unit 40b of M is zero. If the determination in step 95 is rYEsJ, the microcomputer 40 sets the control flag FLGRAM=00000011 in step 95a, and in step 95b, the microcomputer 40 sets the second mileage data H in the storage section 40c
MO is multiplied by r256J, and the multiplication result is stored in the RAM storage unit 40a as total mileage data ODO. On the other hand, if the determination in step 94 is rNOJ, the microcomputer 40 determines that the control flag FLGRAM=00000111 in step 95C.
In step 95d, the same calculation as that in step 95b is performed, and the result of this calculation is stored in the storage section 40a.

Further, if the determination in step 94 described above is "NO", the microcomputer 40
6 (see FIG. 7), the same determination as that in step 95 is made. Therefore, if the determination in step 96 is rYEsJ, the microcomputer 40 controls the control flag FL in step 96a.
Set GRAM=00000011 and step 96
At b, the second mileage data HMO is multiplied by r256J, the first mileage data LM is added to this multiplication result, and the addition result is stored in the RAM storage section 40a as the total mileage data ODO. On the other hand, if the determination in step 96 is "NO", the microcomputer 4
In step 97, it is determined whether the first mileage data LM in the storage section 40b is 255 (km).

When the determination in step 97 is rYEsJ, the microcomputer 40 sets the control flag FLGRAM=OO011111 in step 97a,
In step 97b, 1 (kffl) is added to the third mileage data HMI in the storage section 40d, this addition result is multiplied by r256J, and this multiplication result is stored in the storage section 40a as the total mileage data ODO. . On the other hand, if the determination in step 97 is rNOJ, the microcomputer 40 sets the control flag FLGRAM=OOO00000 in step 97c, and sets the maximum total mileage OD Oma in step 97d.
Set x to ODO.

Thereafter, when the main control program proceeds to the memory control routine 110 when the timer data TMRAM=0 as described above, the microcomputer 40 determines rYEsJ in step 111, and in step 112, the process in step 114f is performed. r based on EWFLG=1
It is determined as YESJ, and in step 112a, a write/erase signal necessary for writing or erasing in the nonvolatile memory 50 is generated, and in step 112b, EWFLG is reset to 0. Furthermore, in response to a write/erase signal from the microcomputer 40, the nonvolatile memory 50 stops erasing its stored contents.

At this stage, the control flag FLGRAM=0
0001111 (see step 114d in FIG. 9), the microcomputer 40 executes step 1.
In step 113a, the storage contents of the nonvolatile memory 50 are stored in the RAM, and the memory control routine 110t-
Step 113b is advanced to the second subroutine SR2. Then, in step 115 of the second subroutine SR2, the microcomputer 40 multiplies the third mileage data HMI in the storage section 40d by r25.6J, and uses this multiplication result as the first mileage data in the storage section 4Ob. LM and 1 (ka+) are added, and the addition result is set as confirmation data A.

If the confirmation data A set in this way does not match the total mileage data ODO in the storage unit 40a, the microcomputer 40 selects "NO" in step 115a.
It is determined that the error flag ERRF is set in step 115b.
LG=1 and cent. This means that there is an error in each of the RAM storage units 40a, 40b, and 4Qc. On the other hand, the determination in step 115a is "
If YESJ, the microcomputer 40 generates a 5M0N inclusive start signal necessary for starting the auxiliary mileage data SMO into the auxiliary storage section 50b of the nonvolatile memory 50 in step 115C, and proceeds to step 115d. , control flag FLGRAM=0000011
Set it to 1.

In addition, the nonvolatile memory 50 is connected to the microcomputer 40.
The auxiliary storage unit 50b responds to the SMO write start signal from
↑, the second mileage data HMO in part 9 40e begins to be used as the auxiliary mileage data SMO.

As described above, when the execution of the second subroutine SR2 ends in step 115b or 115d, the microcomputer 40 executes the memory control routine 110.
At step 114e, timer data TMRAM=1
12 (ms), and the erase/write flag EWFLG-1 is set in step 114f. The execution of the second subroutine SR2 is performed in step 11 as described above.
If it ends with 5b, the microcomputer 4o
is determined to be rYEsj at step 120 of the main control program, and the initialization routine 9o is executed in the same manner as described above.

Also, as described above, the timer data l" M RAM
= 0, the main control program starts the memory controller [tl
When proceeding to the routine 110, the microcomputer 40 determines rYEsJ in step 111, and in step 112, the EWFL in step 114f is determined.
Based on G=1, rYESJ is determined, and in step 112a, a write/erase signal necessary for writing or erasing in the nonvolatile memory 50 is generated, and in step 112b, EW
Reset FLG to 0. Also, in response to a write/erase signal from the microcomputer 40, the nonvolatile memory 5
0 stops writing the memory contents.

At this stage, the control flag FLGRAM=0
0000111 (see step 95C in FIG. 6 or step 115d in FIG. 10), the microcomputer 40 determines rNOJ in step 113, and in step 113a, the nonvolatile memory 50 The memory contents are stored in the RAM, and the memory control routine 110 is advanced to the third subroutine SR3 via step 113b. Then, in step 116 (see figure ffi11), the microcomputer 40 stores the second mileage data HM in the constant reference storage section 40c.
O is multiplied by r256J, and this multiplication result is stored in the storage unit 40a.
It is determined whether or not the total mileage data matches the total mileage data 000 within.

If the determination in step 116 is rYEsJ, the microcomputer 4o sets 1 to the third mileage data 14M1 of the recording section 40d in step 116a.
(km) is added W12, and whether or not this addition result matches the second mileage data (IMO) is determined on a monthly basis. However, if it is determined in step 116 or 116a that it is rNOJ, the microcomputer 4o
Error flag E RRFL G at step 116b
= 1 and Seso]・Do. If the determination in step 116a is YES, the microcomputer 40 sends an MM erasure start signal necessary to start erasing the main mileage data MM in the main storage section 50a of the nonvolatile memory 50 in step 116c. and step 1
At 16d, control flag FLGRAM=000
Cent 00011. Furthermore, in response to the MM erase start signal from the microcomputer 4o, the nonvolatile memory 50 starts erasing the stored contents of the main memory section 50a.

As described above, when the execution of the third subroutine SR3 ends in step 116b or 116d, the microcomputer 40 executes the memory control routine 110.
At step 114e, the timer data TMRAIvl=
112 (ms), and set the erase/write flags IF and WFLG to 1 using the steering knob 114f. When the execution of the third subroutine SR3 ends in step l16b as described above, the microcomputer 40 executes r in step l120 of the main control program.
YESJ and executes the initialization routine 90 as described above.
Execute the following.

Similarly to the above, when the main control program proceeds to the memory control routine 110 when the timer data TMRAM=0, the microcomputer 40 determines rYESJ in step 111, and in step 112, EWFLC=0 in step 114f. rY based on 1
EsJ is determined, and in step 112a, a write/erase signal necessary for writing or erasing in the nonvolatile memory 50 is generated, and in step 112b, EWFLG is reset to 0. Furthermore, in response to a write/erase signal from the microcomputer 40, the nonvolatile memory 50 stops writing its stored contents.

At this stage, the control flag FLGRAM=O
OOOOO11 (see step 95a in FIG. 6, step 96a in FIG. 7, or step 116d in FIG. 11), the microcomputer 40 determines "NO" in step 113, and in step 113a, Similarly to the above, the storage contents of the nonvolatile memory 50 are
Memory in AM and memory control routine 1
1O to the fourth subroutine SR via step 113b.
Proceed to step 4 (see Figures 8 and 12). Then, in step 117 of the fourth subroutine SR4, the microcomputer 40 multiplies the second mileage data HMO in the storage section 40c by r256J, and adds the first mileage data LM in the storage section 40b to this multiplication result. The result of this addition is designated as confirmation data A.

If the confirmation data A set in this way does not match the total mileage data ODO in the storage section 40a, the microcomputer 40 selects rNOJ in step 117a.
It is determined that the error flag ERRF is set in step 117b.
Set LG=1. On the other hand, if the determination in step 117a is YESJ, the micro combinator 40, in step 117C,
0 supplementary note 1. Auxiliary mileage data S into part a 50C
In response to the SMI erase start signal necessary to start erasing the MI, the nonvolatile memory 50 erases the stored data S in the auxiliary storage section 50c.
Start erasing MI.

As described above, when the execution of the fourth subroutine SR4 ends in step 117b or 117d, the microcomputer 40 executes the memory control routine 110.
At step 114e, timer data TMRAM=1
12 (ms), and the erase/write flag EWFLG is set to 1 in step 114f. Execution of the fourth subroutine SR4 is performed in step 117 as described above.
If the process ends in step b, the microcomputer 40 determines rYESJ in step 120 of the main control program, and executes the initialization routine 90 in the same manner as described above.

Similarly to the above, when the main control program proceeds to the memory control routine 110 when the timer data TMRAM=O, the microcomputer 40 determines in step 111 that rYEsJ, and in step 112, EWFLG in step 114f= rY based on 1
ESJ is determined, and in step 112a, a write/erase signal necessary for writing or erasing in the nonvolatile memory 50 is generated, and in step 112b, it is reset to EWFLG-0. Furthermore, in response to a write/erase signal from the microcomputer 40, the nonvolatile memory 50 stops erasing its stored contents.

At this stage, the control flag FLGRAM=0
0000001 (see step 117d in FIG. 12), the microcomputer 40 determines "NO" in step 113, and in step 113a, similarly to the above, the storage contents of the nonvolatile memory 50 are RA
Memory control routine 110
through step 113b and the fifth subroutine SR5 (
(See Figures 8 and 13). Then, in step 118 of the fifth subroutine SR5, the microcomputer 40 multiplies the second mileage data HMO in the storage unit 40c by r256J, and stores this multiplication result in the storage unit 40.
The first mileage data LM in b is added, and the addition result is set as confirmation data A.

If the confirmation data A set in this way does not match the total mileage data ODO in the storage section 40a, the microcomputer 40 sets rNOJ in step 118a.
It is determined that the error flag ERRF is set in step 118b.
Set LG=1. On the other hand, if the determination in step 118a is "YESJ", the microcomputer 4O, in step 118C,
0 auxiliary mileage data SMI into the auxiliary storage unit 50c
A write start signal necessary for starting writing is generated, and F L G RAM = 0 is set in step 118d. In addition, the non-volatile memory 50 stores the third mileage data HMI in the storage section 40d in the auxiliary storage section 50c in response to the SMI damage start signal. ili supplementary mileage data S
Start writing as MI.

As described above, when the execution of the fifth subroutine SR5 ends in step 118b or 118d, the microcomputer 40 executes the memory control routine 110.
At step 114e, timer data TMRAM=1
12 (ms), and in step 114f, the erase/write flag EWFLG-1 is set. The execution of the fifth subroutine SR5 is performed in step 1 as described above.
If it ends at 18b, the microcomputer 4
0 is rYEsj at step 120 of the main control program.
Then, the initialization routine 90 is executed in the same manner as described above.

Similarly to the above, when the main control program proceeds to the memory control routine 110 when the timer data TMRAM-〇 is reached, the microcomputer 40 determines in step 111 that rYEsJ, and in step 112, the EWFLG in step 114f= rY based on 1
EsJ is determined, and in step 112a, a write/erase signal necessary for writing or erasing in the nonvolatile memory 50 is generated, and in step 112b, EWFLG is reset to 0. Furthermore, in response to a write/erase signal from the microcomputer 40, the nonvolatile memory 50 stops writing its stored contents.

At this stage, the control flag F L G RA
If M=00000000 (see step 97C in FIG. 7 or step 118d in FIG. 13),
The microcomputer 40 issues rNO in step 113.
In step 113a, the memory contents of the non-volatile memo IJ 50 are stored in the RAM, and the memory control routine 110 is executed in step 11.
3b to the sixth subroutine SR6 (FIGS. 8 and 1)
(See Figure 4). Then, microcomputer 4
In step 119 of the sixth subroutine SR6, the third mileage data L (Ml is set to r2 in the storage section 40d)
56J, the first mileage data LM and 1 (km) in the storage section 40b are added to this multiplication result, and this addition result is set as confirmation data A.

If the confirmation data A set in this way does not match the total mileage data ODO in the storage section 40a, the microcomputer 40 sets rNOJ in step 119a.
”, and in step 119b, the error flag E) is set to RFLG=1. On the other hand, in step 119a
If the determination is rYESJ at step IL9c, the microcomputer 40 stores the nonvolatile memory 50 at step IL9c.
An MMi write start signal necessary to start writing into the main memory 50a is generated, and in step 119d FLGRAM=
Set it to oooooooooo. In addition, in response to the MM write start signal from the microcomputer 40, the nonvolatile memory 50 stores the first mileage data LM in the storage section 40b.
begins to be written into the main storage section 50a as main mileage data MM. After that, in step 112, rY
When EsJ is determined, the microcomputer 40 generates a write/erase end signal in the next step 112a, and in response to this, the nonvolatile memory 50 ends writing to the main storage section 50a.

As explained above, memory control routine 1
10 and the initialization routine 90, O
Based on the comparison between DO and A and the comparison between HMO and HMl, the control flag FLGRAM is controlled according to LM, and the control flag FLG that is controlled in this way is
The main memory section 50a of the non-volatile memory 50 based on RAM, both auxiliary memory 1. Since errors in the stored contents of the α sections 5Qb and soc can always be corrected almost correctly, the displayed contents of the digital display 70 can always be maintained with high precision.

After that, when the ignition switch IG is opened, the microcomputer 40 performs step 13o knee cr.
y E S J To: By FI, step 14 (H, 1
Based on m7FLGRΔM=O, it is determined that rYESJ, and in step 150, [YESj
Then, in step 160, the self-holding signal disappears, causing both l-transistors 33 and 34 to become non-conductive. At this time, the nonvolatile memory 50 retains the contents of ↑ and α immediately before both transistors 33 and 34 become non-conductive.

[Brief explanation of drawings]

FIG. 1 is a diagram corresponding to the structure of the invention described in the claims, FIG. 2 is a block diagram showing an embodiment of the invention, and FIG. 3 is a storage area of the RAM of the microcomputer shown in FIG. 2. 4 is a diagram showing the storage area of the nonvolatile memory shown in FIG. 2, and FIGS. 5 to 16 are flowcharts showing the operation of the microcomputer shown in FIG. 2. Explanation of symbols 10...Vehicle speed sensor, 40...Microcomputer, 40a to 40d...RAM storage section, 50...
Non-volatile memory, 50a...main culprit t, α part, 50b,
50c... Auxiliary storage unit.

Claims (1)

[Claims] a vehicle speed detection means for detecting the vehicle speed of the vehicle and generating a series of pulse signals having a frequency proportional to the detection result; and a distance calculation means for repeatedly calculating the actual traveling distance of the vehicle in response to each of the pulse signals sequentially. , a first storage area that repeatedly stores the calculated mileage when it is less than a predetermined unit distance value, and second and third storage areas that store this each time the calculated mileage becomes an integral multiple of the predetermined unit distance value. temporary storage means having a storage area and a fourth storage area for storing the total sum of the calculated mileage; and first, second and third storage areas for storing each storage data in the first, second and third storage areas, respectively. non-volatile storage means having a third storage area, the sum of the storage data of the first storage area and the storage data of one of the second and third storage areas being different from the storage data of the fourth storage area; and determining means for generating a match signal if the difference between the stored data in the second and third storage units matches the predetermined unit distance value, and generating a mismatch signal if they do not match; a first storage area that generates an erase/write signal necessary for erasing and correctly writing data stored in one of the second and third storage areas when the data stored in the first storage area is zero;
erasing/writing means; in response to the mismatch signal, when the stored data in the first storage area is zero or a maximum value less than the predetermined unit distance value, the stored data in the other of the second and third storage units is deleted; a second erasing/writing means that generates an erasing/writing signal necessary for erasing and writing correctly; Erasing data stored in one of the second and third storage sections, writing data stored in one of the second and third storage areas in the same storage section, and erasing data from the second erasing/writing means The data stored in one of the second and third storage areas is erased based on a write signal, and the data stored in one of the second and third storage areas is written in the other storage area. A vehicle odometer featuring: