JPH074503Y2 - Vehicle mileage recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a vehicle mileage recording device using a non-volatile memory as a storage means for recording the mileage of a vehicle.

[Conventional technology]

The vehicle is equipped with an odometer that accumulates and displays the distance traveled by the vehicle in the past and a trip meter that can be appropriately reset and that displays the traveled distance after the reset, as odometers. .

Conventionally, a odometer generally has a mechanical counter which has a plurality of character wheels and which sequentially displays the mileage by sequentially carrying the character wheel of the lower digit according to the traveling of the vehicle.
However, with the recent computerization of vehicle measuring instruments, vehicle odometers are being displayed using electronic display devices such as fluorescent display tubes instead of mechanical counters. When using the electronic display in this way, 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 generally practiced to read the traveling distance information from the device and display it on a display.

In a conventional vehicle odometer, a non-volatile memory for holding mileage information is used in a 64 x 16 bit configuration,
As shown in FIG. 6 (a), addresses 0 to 63 are given. As shown in the figure, the initial value is "FFFF" in hexadecimal, and every 1 km thereafter, in binary number from address 0 to address 63, as shown in FIG. 6 (b), "0000". Data is written, and as shown in FIG. 6 (c), when the vehicle travels 64 km and the address indicated by the pointer becomes 0 again, the written data is incremented by +1.
Then, the operation of rewriting the incremented data in units of 16 bits is repeated.

Further, when the traveling distance is obtained based on the traveling distance data recorded in the nonvolatile memory as described above, the traveling distance is calculated by the following formula.

Traveling distance = 64 × [(data in the nonvolatile memory indicated by the pointer) +1] + (pointer address) km That is, in the example of FIG. 6C, 64 × [(0) +1]
+ (1) = 65km.

[Problems to be solved by the device]

As described above, the conventional non-volatile memory rewrites data consisting of 4 hexadecimal digits in 16-bit units. Generally, the non-volatile memory has an allowable rewriting frequency of about 10,000 times. Since the vehicle mileage can only be accumulated up to 64 x 10000 = 640000 km, there was a limit to the mileage that can be accumulated.

Therefore, in view of the above-mentioned conventional problems, it is an object of the present invention to provide a vehicle mileage recording apparatus capable of accumulating more mileages within a storage update allowance range of a nonvolatile memory. .

[Means for Solving the Problems]

In order to solve the above problems, the vehicle mileage recording apparatus according to the present invention has an address pointer 1c which is incremented by 1 every time a vehicle travels a predetermined distance and data is updated, as shown in the basic configuration diagram of FIG. And a non-volatile memory 3 for recording the mileage of the vehicle having an address area 3a which is addressed by the address pointer 1c, and an address designated by the address pointer 1c each time the vehicle travels a predetermined distance. +1 for recorded data
In the vehicle mileage recording device, the address area is provided with a recording means 1e for recording the +1 data at an address designated by the address pointer 1c.
It is characterized in that a counter area 3b, in which the data incremented by 1 is recorded when the data recorded in 3a reaches the maximum value, is formed in the nonvolatile memory 3.

[Operation] In the above configuration, the address area is provided in the nonvolatile memory 3.
When the data recorded in 3a reaches the maximum value, a counter area 3b in which +1 data is recorded is formed, and even if the mileage that can be recorded by the data of each address in the address area 3a is small, With this combination, a large mileage can be recorded, and the number of addresses can be increased accordingly. Therefore, the number of times of rewriting at each address can be reduced, and a large mileage can be recorded with the rewriting allowable frequency of the nonvolatile memory 3. become.

〔Example〕

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

FIG. 2 is a block diagram showing a configuration of a vehicle mileage device according to the present invention. In FIG. 2, reference numeral 1 denotes a microcomputer (CP which operates according to a predetermined control program).
U), which is a ROM 1a for storing a control program, a RAM 1b for storing various data generated in the course of operation, and an address pointer 1c for designating an address at which data is recorded when recording data to be described later in the memory. , A distance counter that counts pulse signals from a rotation sensor 2 described later
1d, has a traveling distance storage area 1e for storing the calculated traveling distance, and has an address pointer 1c and a distance counter.
The 1d and the traveling distance storage area 1e can be configured by utilizing a predetermined area of the RAM 1b, but are shown separately from the RAM 1b. Reference numeral 2 denotes a rotation sensor connected to the output rotation system of the transmission via a rotation connecting member (not shown),
The rotation sensor 2 generates a pulse signal having a frequency proportional to the traveling speed according to the traveling of the vehicle, and inputs this to the CPU 1. Reference numeral 3 is a non-volatile memory capable of holding the recorded contents without a power source and for recording traveling distance data obtained by accumulating traveling distances. The non-volatile memory 3 stores a pulse signal input from the rotation sensor 2. Based on this, the CPU 1 updates the traveled distance data every time it detects that the vehicle has traveled a predetermined distance, for example, 1 km. Reference numeral 4 denotes a display device that displays the travel distance calculated by the CPU 1 based on the travel distance data stored in the travel distance storage area in the RAM 1b. The display device 4 is driven by the display driver 5.

The non-volatile memory 3 is, as shown in FIG.
128 x 8 bit configuration, address space from 0 to 124
3a, and the remaining 125 to 127 constitute counter areas 3b. The counter area 3b, 3 two counters 3b ₁ ~ counter 3b ₃ is formed consisting of 8 bits each.

The method of writing the vehicle travel distance data into the nonvolatile memory 3 having the above-described configuration is performed as shown in FIGS. 3 (a) to 3 (e).

In the non-volatile memory 3, hexadecimal FFs are initially recorded in both the address area 3a and the counter area 3b as shown in FIG. Address pointer 1c in this state
Indicates the address 0. After that, the vehicle starts traveling, and when the CPU 1 detects that the vehicle has traveled a predetermined distance, for example, 1 km, based on the pulse signal from the rotation sensor 2, the address pointer 1c indicates, as shown in FIG. 3 (b). To the data “FF” currently recorded at address 0
Address pointer after recording the data "00"
Address 1 is given to 1c at +1. When the vehicle has traveled 126 km by repeating the above operation in sequence,
As shown in FIG. 3 (c), data "00" is stored at address 0.
The data "01" is incremented by 1 and then the address pointer 1c is incremented by 1 to indicate the address 1.

After that, when the vehicle further travels and the vehicle travels 32000 km, "FF" is recorded in hexadecimal notation at the final address 124 of the address area 3a of the nonvolatile memory 3 as shown in FIG. 3 (d). Then, the data "00" which is obtained by adding ₁ to the data "FF" recorded until then is written in the _three counters 3b1 to 3b3 of the counter area 3b. Then, when the vehicle further travels 1 km, as shown in FIG. 3 (e), the data obtained by incrementing the address designated by the address pointer 1c by 1 is recorded, and the address pointer 1c is incremented by 1 to obtain the address 1
To instruct.

The traveling distance can be obtained by reading the data recorded as described above and performing the following formula.

Mileage = 32000 x [(counter value) + 1] + 125 x
[(Non-volatile memory data indicated by the pointer) +1] +
(Pointer address) km By rewriting the non-volatile memory 3 in units of 8 bits as described above, the distance of 125 km can be accumulated by rewriting each address of the address area 3a once. Like And the non-volatile memory 3
If the permissible rewriting frequency is 10,000, then 10,000 × 12
It is possible to add up the vehicle mileage up to 5 = 1250000 km. For example, when integrating the distance of 1000000 km, 800
It is possible to rewrite it 0 times.

In the case it constitutes a counter area 3b by three counters 3b ₁ ～3B _3, which took reset the CPU1 in the middle of rewriting counter area, then when the power rises, three counters Can be used to perform a correction process using the principle of majority voting, which can increase the reliability of the counter value.

The operation of the vehicle mileage recording apparatus outlined above is
A detailed description will be given below with reference to the flow charts of FIGS. 4 and 5 showing the work performed by the CPU 1 in the figure in accordance with a predetermined control program.

The CPU1 starts its operation when its power is turned on, and in the first step S1, the CPU1 performs the initialization necessary for the subsequent work. After that, if the RAM 16 is backed up in step S2, the three mileage storage areas are compared using the principle of majority decision to obtain mileage data. If the data is not backed up or the compared data is unreliable, the data is read from the non-volatile memory 3, and in the subsequent step S3, the travel distance is calculated based on the read data based on the above-described arithmetic expression. The mileage is calculated, and the calculated mileage is stored in each of the three mileage storage areas in the RAM 1b. The mileage stored in the mileage storage area in the RAM 1b is used to output the mileage display data to the display driver 5 for displaying the mileage on the display 4 in the display process performed by the timer interrupt. It

Also, every time a pulse signal is input from the rotation sensor 2, the process proceeds to step S4, and external interrupt processing is performed. If the determination in step S4 is YES, the process proceeds to step S5, where, for example, C
Distance counter 1d configured in a predetermined area of RAM1b in PU1
Then, in step S5, it is determined whether or not the value of the distance counter 1d has reached a value corresponding to 1 km traveling. When the determination in step S5 is NO, the external interrupt processing is skipped and normal processing is performed. YES in step S5
If so, the process proceeds to step S6, the flag is set to 1, the distance counter is initialized, and the external interrupt process is ended. On the other hand, in step S8, this flag is determined and waits until flag = 1, and if the determination in step S8 is YES, step S7
Then, the process for rewriting the data in the non-volatile memory 3 currently designated by the address pointer 1c is performed.

The data rewriting process in step S7 is performed by executing the subroutine shown in FIG. 5 and increments the values of the three traveling distance storage areas by +1.

First, in step S7a, the nonvolatile memory 3 is set to the write enable state, and then in step S7b, the above-mentioned step S7 is performed.
In 2, the data stored in the RAM 1b is added to the data at the address of the non-volatile memory 3 designated by the current address pointer 1c by +1 to write the data to the currently designated address. After that, in step S7c, the nonvolatile memory 3 is set to the write-protected state, and then the next step S7d
In step S7c, data is read from the address to which the data was written. Then in step S7e,
It is determined whether the data written in step S7b and the data read in step S7d are the same. If the result of this determination is that they are not equal, steps S7a 'to 7e'
In step S7a to 7e, the same work as described above is performed. If the result of the determination in step S7e 'is not the same, in step S7f an error display is displayed on the display unit 4 and the series of work is completed.

Further, as a result of the determination in step S7e or 7e ′, if they are equal, the process proceeds to step S7g, where it is determined whether or not the address 124 is designated by the address pointer 1c, and if this determination is NO. The process proceeds to step S7h to increment the address pointer 1c by +1 and then returns to the original main routine. If the determination in step S7g is YES, the process proceeds to step S7i, where the address pointer 1c is set to 0, and then the process proceeds to step S7j to increment the write data by 1. After that, in step S7k, it is determined whether or not the data at the address 124 pointed to by the address pointer 1c is "FF". If the determination in step S7k is NO, the process returns to the main routine. When the determination in step S7k is YES, the process proceeds to step S7l, and the nonvolatile memory 3 is put in the writing state. Continued respectively +1 contents of the counter 3b ₁ ~3b ₃ in step S7m～S7o, and then return the nonvolatile memory 3 in the next step S7p write-protected state to the main routine.

〔effect〕

As described above, according to the present invention, when the data recorded in the address area reaches the maximum value in the non-volatile memory, the counter area in which the incremented data is recorded is formed, so that each address area is formed. Even if the mileage that can be recorded by the address data is small, a large mileage can be recorded in combination with the counter area, and the number of addresses can be increased accordingly, so the number of times of rewriting of each address can be reduced, It becomes possible to integrate more mileage within the range of the rewriting allowable frequency of the non-volatile memory.

[Brief description of drawings]

1 is a block diagram showing a basic configuration of a vehicle mileage recording apparatus according to the present invention, FIG. 2 is a block diagram showing an embodiment of a vehicle mileage recording apparatus according to the present invention, and FIG. 3 is a vehicle traveling according to the present invention. Explanatory diagram for explaining the operation of the distance recording device, FIGS. 4 and 5 are flowcharts showing the work performed by the CPU in FIG. 2, and FIG. 6 is a method of recording the traveling distance by the conventional recording device. FIG. 1c ... Address pointer, 1e ... CPU (recording means), 3
... Nonvolatile memory, 3a ... Address area, 3b ... Counter area.

Claims (1)

[Scope of utility model registration request] 1. An address pointer which is incremented by +1 every time the vehicle travels a predetermined distance, a non-volatile memory for recording a travel distance of the vehicle having an address area addressed by the address pointer, and a predetermined distance of the vehicle. A vehicle mileage recording device comprising a recording means for incrementing the data recorded at the address designated by the address pointer every time the vehicle travels and recording the incremented data at the address designated by the address pointer. In the vehicle mileage recording device, a counter area is formed in the non-volatile memory in which, when the data recorded in the address area reaches a maximum value, +1 data is recorded.