JPH08166251A - Odometer - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain an odometer for an automobile capable of easily resetting mileage storage and display at any time while the ignition switch is opened without troublesome operation. [Structure] Connected to a storage means 5 for storing mileage data and capable of updating the stored contents, a display 6 for displaying mileage data, a power supply line from a main power source 13 via an ignition switch 12, and An odtrip drive circuit 2 having a reset input terminal RST for resetting the contents of the storage means 5 in response to the input of the reset potential and a switch 3 for giving a reset potential to the reset input terminal RST are provided, and the switch 3 is referred to as a power line switch 3A. The power supply line switch 3A switches the power supply from the main power supply 13 directly to the odtrip drive circuit 2, and the reset switch 3B switches the reset potential applied to the reset input terminal RST.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an odometer for an automobile,
In particular, the present invention relates to an odometer that can store and display a traveling distance from an arbitrarily set starting point and can easily reduce the traveling distance and the display stored at an arbitrary time point to zero.

[0002]

2. Description of the Related Art Odometers for automobiles, which store and display measured traveling distances starting from an arbitrarily set starting point, have replaced conventional mechanical structures with electronic structures in recent years. A block configuration of such an electronic odometer 20 is shown in FIG. The conventional electronic odometer 20 includes an odtrip drive circuit 21 and
Non-volatile memory 5, display 6, reset switch 2
It consists of 2. The od trip drive circuit 21 is supplied with power from the main battery 13 via the ignition switch 12 and the diode 10. Further, the ignition circuit 11 is supplied with power from the main battery 13 via the ignition switch 12.

The odrip drive circuit 21 determines the current mileage based on the detection value relating to the mileage sent from a wheel sensor or the like (not shown), temporarily stores it in the built-in RAM 8, and further, this travel. The distance is written and recorded in the non-volatile memory (NVM) 5 at a predetermined interval, or the non-volatile memory (NVM) 5 is stored in the RAM 8 in accordance with the opening of the ignition switch 12.
In addition to recording and writing, the display 6 is driven to display the traveling distance on the display 6. The RAM 8 which is a volatile memory may be configured to be backed up by the RAM holding battery 7 when the ignition switch 12 is opened. The odtrip drive circuit 21 includes a reset terminal RST. When the reset terminal RST becomes the ground potential, the odtrip drive circuit 21 will be
The contents of the AM 8 or the nonvolatile memory 5 are reset to a zero value. As a result, the display on the display 6 becomes zero. That is, the odometer 21 is reset to zero by dropping the reset terminal RST to the ground potential.

[0004]

However, since the conventional odometer 20 as described above has a structure in which power is supplied to the odtrip drive circuit 21 via the ignition switch 12, for example, the ignition is performed when the engine is stopped by refueling or the like. When the switch 12 is turned off (opened), power is not supplied to the odtrip drive circuit 21,
Therefore, the odtrip drive circuit 21 does not operate. Therefore, even if the reset switch 22 is operated while the ignition switch 12 is turned off, the nonvolatile memory 5 cannot be reset (zeroed). Therefore, in order to reset the odometer 21, after the ignition switch 12 is closed to restart the engine and the odtrip drive circuit 21 is re-energized, the reset switch 22 must be operated again to reset the nonvolatile memory 5. The operation was troublesome.

The present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to set the ignition switch at any time and even when the ignition switch is opened.
An object of the present invention is to provide an odometer for an automobile that can easily reset and store the traveled distance without any troublesome operation.

[0006]

SUMMARY OF THE INVENTION An odometer according to the present invention for achieving the above-mentioned object is a storage means for storing traveling distance data and capable of updating the stored contents, and a display for displaying the traveling distance data. And an odrip drive circuit connected to the main power supply through an ignition switch and having a reset input terminal for resetting the contents of the storage means with the input of a reset potential, and a switch for applying a reset potential to the reset input terminal. In the odometer provided, the switch is composed of a power line switch and a reset switch, the power line switch switches the power supply from the main power source directly to the odtrip drive circuit to a conducting or non-conducting state, the reset switch Supply or cut off the reset potential applied to the reset input terminal Characterized by being configured to switch the state. Alternatively, the power supply line switch and the reset switch are both configured to be simultaneously switched by a single operation. Alternatively, a delay circuit is provided between the reset switch and the reset input terminal.

[0007]

In the odometer according to the present invention, even when the ignition switch is opened and power is not supplied to the odtrip drive circuit, the power line switch is operated to directly connect the odtrip drive circuit from the main battery. The supply line is established and the odtrip drive circuit operates. Further, when the reset switch is operated, the odtrip drive circuit resets the contents of the storage means, and thus the indicator is also reset. As a result, the traveling distance memory and display can be easily reset to zero without a troublesome operation. Further, since the power supply line switch and the reset switch are both operated by one operation, zero resetting can be easily performed without troublesome operation. Furthermore, since the delay circuit delays the signal from the reset switch and inputs it to the reset terminal, the reset operation is performed when the odtrip drive circuit completely rises after the power is supplied, and thus a reliable reset is performed.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, the structure of the present invention will be described. FIG. 1 is a block diagram showing a connection between an odometer according to the present invention, a main battery as a main power source, and an ignition switch circuit. In the figure, 13 is a main battery, which is an odometer 1 and an ignition circuit 1 according to the present invention.
1 constitutes a main power source for applying a voltage. The ignition circuit 11 is connected to the main battery 13 by closing the ignition switch 12. The odometer 1 according to the present invention includes an odtrip drive circuit 2.
A NVM (storage means) 5 which is a non-volatile memory for recording the traveled distance based on the signal from the odrip drive circuit 2, and a display 6 for displaying the traveled distance based on the display signal from the odtrip drive circuit 2. , Switch 3.

The switch 3 is a power line switch 3A for directly inputting power to the power input terminal PW of the odrip drive circuit 2 from the main battery 13 via the diode 9.
And a reset switch 3B for inputting a reset potential to the reset terminal of the odtrip drive circuit 2. The power line switch 3A and the reset switch 3B are configured to operate independently or interlock with each other. Therefore, the odometer 1 has a main battery 13
There are two power lines from. The first system is supplied from the main battery 13 through the ignition switch 12 and the diode 10 to the odtrip drive circuit 2 in the odometer 1, and the second system is directly supplied from the main battery 13 in the odometer 1. The power is supplied to the odtrip drive circuit 2 via the power line switch 3A and the diode 9.

The odtrip drive circuit 2 receives the power from the main battery 13 via the first system or the second system at the terminal PW to operate, and also operates the NVM.
Power is supplied to the (storage means) 5, the display 6, and the like. That is, while the engine is operating with the ignition switch 12 closed, power is supplied from the first system via the ignition switch 12. Further, when the engine is stopped and the ignition switch 12 is open, the power supply of the second system can be received via the power supply line switch 3A.

The odrip drive circuit 2 determines the current traveling distance based on the detected value relating to the traveling distance sent from a wheel sensor (not shown) or the like, and the RAM 8 which is a volatile memory having the traveling distance built therein. Temporarily stored in (storage means), and at a predetermined interval, NVM5
Write and record on the ignition switch 1
2 is opened, RAM8 (storage means) from NVM
5 has a function of writing and recording the data on the display 5, and a function of driving the display 6 to display the traveling distance on the display 6. The RAM 8 that is a volatile memory may be configured to maintain the memory even when the main power supply is cut off by backing up the RAM 8 by the RAM holding battery 7. Also,
The RAM 8 may be provided inside the odtrip drive circuit 2 or may be provided outside the odtrip drive circuit 2. An E ² PROM is used as the NVM 5 that retains the record relating to the traveling distance even when the power is cut off.
In addition, in the present embodiment, the NVM 5 is provided outside the odtrip drive circuit 2, but in addition to this, for example, when the odtrip drive circuit 2 is composed of one chip,
The VM 5 can also be provided inside.

The reset switch 3B is connected to the reset terminal RST of the odtrip drive circuit 2 and the ground, respectively. When the reset switch 3B is closed by operation, the reset terminal RST becomes the ground potential. Further, the reset switch 3B and the odtrip drive circuit 2
Alternatively, the delay circuit 4 may be provided between the reset terminal RST and the reset terminal RST.

FIG. 2 is a flowchart of the processing operation of the odtrip drive circuit 2 in the odometer 1 shown in FIG. The operation of the odometer 1 will be described below with reference to FIG. First, when the ignition switch is closed and in the on state (step S1), the odometer 1 follows the conventional trip operation (step S9). When the ignition switch is open and in the off state, and the switch 3 is operated to turn on the power line switch 3A (step S2), the odometer 1 is powered by the main battery 13 via the power line switch 3A. When the power is supplied (step S3) and the reset switch 3B is closed (step S4), the odo trip drive circuit 2 resets the trip data recorded in the RAM 8 or the NVM 5 (step S5), and thus the display also. It is reset (step S6). Next, when the switch 3 is opened and the reset switch 3B is also closed (step S7), the power supply from the main battery 13 via the power line switch 3A is stopped (step S8).

As a result of the above operation, the storage and display of the traveling distance can be easily reset to zero without a troublesome operation. Also, if the power line switch 3A and the reset switch 3B are interlocking type, both can be operated at once by one operation,
The operation is further simplified and facilitated. Further, in the case of the configuration in which the delay circuit 4 is provided, the signal from the reset switch 3B can be delayed and input to the reset terminal RST, so that the reset operation is performed when the odtrip drive circuit 2 completely rises after the power is supplied. Therefore, a reliable reset operation is executed.

[0015]

As described above, the odometer according to the present invention is provided with the power supply line switch that establishes the power supply line for directly supplying power from the main battery to the odtrip drive circuit, so that the ignition switch is open. The odtrip drive circuit can be operated even when power is not supplied to the odtrip drive circuit. That is, the odometer can be zeroed at any time. And,
Since the power line switch and the reset switch are both operated by one operation, there is an effect that the contents and display of the storage means can be easily reset to zero without a troublesome operation.
Furthermore, the delay circuit delaying the signal from the reset switch and inputting it to the reset terminal allows the reset operation to be performed when the odtrip drive circuit completely rises after the power is supplied, and thus a reliable reset can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a connection between an odometer according to an embodiment of the present invention and a main power supply circuit and a start switch circuit.

FIG. 2 is a flowchart of a processing operation of the odtrip drive circuit shown in FIG.

FIG. 3 is a block diagram showing a connection between a conventional odometer and a main power supply circuit and a start switch circuit.

[Explanation of symbols]

 1 Odometer 2 Odd trip drive circuit 3 Switch 3A Power line switch 3B Reset switch 4 Delay circuit 5 Non-volatile memory (NVM) 6 Display 7 RAM holding battery 8 RAM 9, 10 Diode 11 Ignition circuit 12 Ignition switch 13 Main battery

Claims (3)

[Claims] 1. A storage means for storing mileage data and updating the stored contents, an indicator for displaying the mileage data, a main power supply connected via an ignition switch, and a reset potential input. In an odtrip drive circuit having a reset input terminal for resetting the contents of the storage means, and an odometer having a switch for applying a reset potential to the reset input terminal, the switch includes a power line switch and a reset switch. The power supply line switch switches the power supply from the main power supply directly to the odtrip drive circuit to a conducting or non-conducting state, and the reset switch switches a reset potential applied to the reset input terminal to a supplying or blocking state. An odometer that is characterized by 2. The odometer according to claim 1, wherein both the power line switch and the reset switch are simultaneously switched and operated by a single operation. 3. A delay circuit is provided between the reset switch and the reset input terminal.
Or the odometer described in 2.