JPS6338112A - Odometer device - Google Patents

Abstract

PURPOSE:To improve the reliability of a device without making its system complex by outputting binary run distance data which is obtained by integrating the run distance of a vehicle as the high-order digit data and the low-order digit data, and storing them in the 1st and the 2nd storage means. CONSTITUTION:A run distance arithmetic output means 1 outputs the binary run distance which is obtained by integrating specific distance every time the vehicle runs by the specific distance as the high-order digit data and low-order digit data, and also outputs a driving signal for displaying the run distance. Information stored in the 2nd storage means 5 is rewritable many times and either of the high-order or low-order digits of the run distance inputted from the means 1 are stored. Information in the 1st storage means 3, on the other hand, is rewritable only once and this means 5 has a higher function for holding information and is equipped with a retrieval means for retrieving addresses for information storage and stores the other digits of the run distance inputted from the means 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to, among measuring instruments installed in a vehicle, particularly an odometer device that displays a cumulative value of mileage.

(Technical background of the invention and its problems) In recent years, the computerization of measuring devices installed in vehicles has been rapidly put into practical use in response to technological advances in memory cables (for example, in automotive technology, 38. Fall 2.1984 P
185-P186). FIG. 6 shows a control section 27 of an odometer device in such a conventional vehicle measuring device. For example, every time the vehicle travels 0.1 km, a pulse signal is input from the heavy speed pulse 43 to the microcomputer 31, and the microcomputer 31 integrates the pulse signal based on the pulse signal and then stores it in the EEPROM (ODO memory circuit) 3.
3, the accumulated mileage is written therein, and the accumulated mileage is displayed on the display panel 41 via the display drive circuit 39.

By the way, E E P used in this Hitff
The ROM 33 is used to prevent the stored cumulative mileage from being erased if the power is accidentally cut off or the voltage of a battery (not shown) drops significantly.

However, although this EEPROM 33 is used to prevent the cumulative mileage from being erased, that is, to improve the reliability of the cumulative mileage, for example, as the mileage of the vehicle increases, the number of writes to the EEPROM 33 increases accordingly. As a result, the durability of the memory deteriorates, and there is a risk that the cumulative mileage displayed on the display panel 41 may be displayed differently from the actual cumulative mileage.

As a countermeasure, it has been considered to use a so-called highly reliable EPROM with a high data retention function in place of the EEPROM 33. Using this EPROM increases the data retention function, so the display panel 41
The cumulative mileage displayed will be an accurate value, and the reliability of the cumulative mileage will certainly improve. However, when writing the cumulative mileage to the EPROM, an address (hereinafter referred to as a physical address) is used to write the cumulative mileage.

), but the provision of a search circuit or counter for searching the physical address to be written into the EPROM complicates the system, and an improvement has been desired.

(Object of the Invention) The present invention has been made in view of the above, and its object is to provide an odometer device with improved reliability without complicating the system.

(Summary of the Invention) In order to achieve the above object, the present invention calculates the number of digits of the binary mileage obtained by accumulating the predetermined distance each time the vehicle travels a predetermined distance. A mileage calculation output means 1 which outputs a driving signal for displaying the mileage while outputting the lower digits separately, and the information to be stored can be rewritten any number of times and is input from the mileage calculation output means 1. A second storage means 5 for storing one of the upper and lower digits of the mileage; A first digit which is provided with a search means for searching for an address at which the information is to be written and stores the other of the upper and lower digits of the mileage inputted from the mileage calculation output means 1;
The gist is that it has a storage means 3.

(Example of the invention) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 2 is a block diagram showing the control section of the odometer device of the present invention.

In the figure, reference numeral 43 indicates a vehicle speed pulse, which outputs a pulse signal to the control circuit 7 every time the vehicle travels a predetermined distance, for example, 0.1 klll. The control circuit 7 has a microcomputer and calculates the traveling distance based on the pulse signal from the vehicle speed pulse 43, and writes it into the EEPROM ll every time the cumulative traveling distance reaches 1 km.
A drive signal is output to the drive circuit 15. On the other hand, ft? Each time the 4-calculated travel distance reaches 000 km, it is written in EPt'' (0M9) and outputs a drive signal to the first drive circuit 13, which will be described later.

For example, in the EPROM 9, the cumulative mileage for every 1000 kli is written sequentially from the bit indicated by the physical address, that is, the 100 bit end that displays the 0 digit on the display 17, and the 81st mileage of the upper digit (0 digit), which has been written the least number of times, is written. It remembers distance. Here, writing data to the EPROM 9 is performed by applying a high voltage to the transistor and injecting electrons into the floating gate and storing them therein, while erasing is performed by emitting electrons when the floating gate is irradiated with ultraviolet light. This is done by

On the other hand, the EEPROM 11 is controlled by the control circuit 7 to
The cumulative mileage is a binary number (IIQll, 111
1I) and then added in a memory cell having an digit bit to store the lower digits (m digits) of the cumulative travel distance. Here, the lower digits (m
The number of bits required for a lower digit (10"), which is expressed in a decimal number, is 2λ to represent it in a binary number, and this number of bits is obtained from the following formula 1 % (). Also, EEPROM II is Prepare kxl bit as redundant memory, for example lkm turtle's fi'
When the jl mileage is incremented by 1 and the length bit string is rewritten 0 times, up to S+n-1 digits can be displayed on the display 17. Here, S is the following formula % Formula % (2) Note that EEPROM ll uses a thin oxide film, and when the electric field at the interface becomes strong, electrons pass through the so-called tunneling effect, which causes the memory cell to be injected or released into the floating gate. The information is stored as 1QIZ111''.

The first drive circuit 13 outputs a display signal to the display 17 when a drive signal is inputted from the control circuit 7, for example every 1100 Qk, to display the upper digit (0 digit) of the cumulative mileage displayed on the display 17, which will be described later. On the other hand, the second drive circuit 15 outputs a display signal to the display 17 when a drive signal is input from the control circuit 7 to the lower digits (m digits) of the cumulative mileage displayed on the display 17, for example, every 1 km. It is.

The display device 17 is, for example, a thin film EL panel, etc., and is provided according to the number of digits (ffl+t1 digit) for displaying the cumulative mileage, and a display signal is input from the first drive circuit 131'3 and the second drive circuit 15. The cumulative mileage is digitally displayed.

Next, the operation of this embodiment will be explained using the processing flowchart shown in FIG.

Every time the vehicle travels a predetermined distance, for example, 0.1 km, a vehicle speed pulse 43rd pulse signal is input to the control circuit 7, and the micro combi coater of the control circuit 7 performs addition based on the pulse signal (steps 100 to 3). 110).

Step 1 when the added cumulative mileage reaches 11v
If the cumulative traveling distance does not reach 1 km, the process returns to step 1°O where a pulse signal is input (step 120).

Proceeding to step 130, the control circuit 7 converts the calculated mileage into a binary number and then inputs it into EEPRO~111 and adds the accumulated mileage, and outputs a drive signal to the second drive circuit 15 to display the display 17. The cumulative mileage 3 is displayed (steps 130 to 150).

When the added cumulative mileage reaches 11,000k, the program proceeds to step 170 and writes to the EPROM 9, while if the cumulative mileage does not reach 11,000k, the program returns to step 100 where a pulse signal is input (step 160).
).

Proceeding to step 170, the control circuit 7 outputs EPR○N・1.
In order to write 1 to the bit indicated by the physical address 9 or write 1 to the next bit, the physical address is incremented by 1 and a drive signal is output to the first drive circuit 13, after which the process returns to step 100 (step 170 ~190
).

By repeating the above operations while the vehicle is running, it is possible to improve the reliability of the cumulative mileage displayed on the display 17 by using the EPROM 9, which has a high data retention function in the upper digits with fewer writes. Saro. Shita, E P
Since only the upper digits of ROM 9 are used, r'EPRO
Compared to using the upper digit and the lower digit (r of V digit) of M11, the system does not become complicated because the counter etc. for searching the physical address can be downsized. Furthermore,
By improving the manufacturing process, the system of the control section of this odometer equipment was changed to control circuit 7. EPROM9. EEPROM
It is also possible to create a single chip in which 1 and 1 are integrated.

FIG. 4 is a block diagram showing another embodiment of the present invention, and its feature is that an EPROM 9 with high data retention capacity is used to store the lower digits of the cumulative mileage mentioned above. The purpose is to use EEPROMll to store the information.

Thereby, the reliability of the lower digits of the cumulative mileage can be improved without complicating the system. Note that the other configurations are exactly the same as in the above example.

FIG. 5 is a circuit diagram showing still another embodiment of the present invention, and its features include a backup battery 25 in place of the EEPROM, so that data can be written even after the power is cut off. It uses a non-continuous memory that holds 3 mileage plans with C~10S RA>119.

As a result, the same hill effect (817) as in the above embodiment can be obtained. Note that the other configurations are the same as in the above embodiment.

(Effects of the Invention) As explained above, according to the present invention, each time the vehicle travels a predetermined distance, the distance traveled in binary numbers obtained by integrating the predetermined distance is stored as information. a second storage means that is rewritable and stores one of the upper and lower digits of the mileage; The first storage means has a search means for searching for the address at which the information is to be written (a first storage means for storing the other of the upper and lower digits of the mileage), which makes the system complicated. Reliability can be improved without having to

[Brief explanation of drawings]

FIG. 1 is a claim correspondence diagram showing this invention, FIG. 2 is a block diagram showing this invention, FIG. 3 is a processing flow chart showing the operation, and FIG. 4 is a block diagram showing another embodiment of this invention. FIG. 5 is a circuit diagram showing still another embodiment of the present invention, and FIG. 6 is a configuration diagram showing a conventional odometer device. 1... Mileage calculation output means 3... First storage means 5... Second storage means 7...
Control circuit 9...EPROM11...EEPROM
13...First drive circuit 15...Second drive circuit Agent Patent attorney Tamotsu Miyoshi Male lineage 1χ Figure 2 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] A drive signal that outputs the number of digits of the binary mileage obtained by integrating the predetermined distance each time the vehicle travels a predetermined distance into upper and lower digits, and displays the mileage. a mileage calculation output means for outputting the mileage calculation output means; and a second memory that is capable of rewriting the stored information any number of times and stores one of the upper and lower digits of the mileage inputted from the mileage calculation output means. and a function of being able to write the information to be stored only once and retaining the information is the second function.
a first storage means, which is higher than the storage means and has a search means for searching for an address at which the information is to be written, and stores the other of the upper and lower digits of the mileage inputted from the mileage calculation output means; An odometer device comprising: