JPH06131267A - Storage device for on-vehicle electrical equipment - Google Patents

Abstract

PURPOSE:To provide the storage device for on-vehicle electrical equipment which can eliminate the possibility that a CPU rewrites the contents of an electrically rewritable nonvolatile memory owing to malfunction. CONSTITUTION:This device is equipped with the electrically rewritable EEPROM 4 (nonvolatile memory), the CPU 3 which reads and writes information cut of and in the EEPROM 4, and a service check terminal 6 which is turned OFF in a normal travel of the vehicle and places in operation only at the time of factory shipping or vehicle maintenance; when the service check terminal is in operation, the CPU 3 is permitted to rewrite the EEPROM 4, but when the service check terminal is not in operation, the CPU 3 is inhibited from rewriting the EEPROM 4 even if performing rewriting operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention stores information peculiar to a vehicle such as an automobile in a non-volatile memory such as an EEPROM and rewrites the stored contents of the non-volatile memory at the time of factory shipment or vehicle maintenance. The present invention relates to a storage device for goods.

[0002]

2. Description of the Related Art In a conventional vehicle-mounted electric component using a microcomputer (CPU), vehicle setting data is written in a non-rewritable non-volatile memory (ROM), and engine control of an engine or the like is performed by using the setting data. Was going on. However, recently, more precise control is performed according to the characteristics of the vehicle, so that the electrically rewritable EEP
A method of writing data in a manufacturing factory using a ROM has been adopted. Furthermore, because control is performed that includes individual vehicle differences, vehicle-specific information (for example, vehicle weight and
A method of rewriting the presence / absence of options / vehicle number) at the vehicle manufacturing line or service factory is being considered.

FIG. 3 shows the configuration of a conventional storage device for on-vehicle electrical equipment. In FIG. 3, in a vehicle manufacturing line or a service factory, when the vehicle tester 31 sends write data and write instructions, which are information peculiar to the vehicle, to the control unit 32, the writing algorithm in the CPU 33 causes the EEPROM 34 to write the data. Write data can be stored.

[0004]

However, in the above-mentioned conventional storage device for the on-vehicle electrical equipment, when the CPU 33 malfunctions due to some cause (traveling in a strong electric field, submersion of the vehicle, etc.), the CPU 33 stores in the CPU 33. As long as the write algorithm is built-in, the possibility of writing wrong data to the EEPROM 34 is not zero. If incorrect data is written in the area in which important data is recorded, there is a problem that it not only causes a great inconvenience to the user, but also may cause a very dangerous state in some cases. With respect to the on-vehicle electrical equipment having the first reliability, the above-described conventional usage in which the risk rate is not zero could not be put into practical use.

The present invention solves such a conventional problem, and even if the CPU malfunctions, the EEP is unnecessary.
It is an object of the present invention to provide an excellent storage device for in-vehicle electrical equipment that can reduce the possibility of rewriting the contents of ROM to zero.

[0006]

In order to achieve the above object, the present invention provides an electrically rewritable non-volatile memory,
The nonvolatile computer is provided with a microcomputer for reading and writing information from the nonvolatile memory, and a service check terminal which is in a non-operating state during normal traveling of the vehicle and is in an operating state only at the time of factory shipment or vehicle maintenance. -When the service check terminal is in the operating state, rewriting of the non-volatile memory is permitted by the microcomputer, and when the service check terminal is in the non-operating state, even if the microcomputer is rewritten. Even if the operation is performed, rewriting of the non-volatile memory is prohibited.

[0007]

Therefore, according to the present invention, when the service check terminal is in the non-operating state, the rewriting of the non-volatile memory is prohibited even if the rewriting operation is performed by the microcomputer. Even if the microcomputer performs a rewrite operation due to an erroneous operation due to some cause, the possibility of unnecessarily rewriting the contents of the nonvolatile memory can be reduced to zero.

[0008]

EXAMPLES Examples of the present invention will be described below with reference to FIGS.
Will be described with reference to.

FIG. 1 shows the configuration of the first embodiment. In FIG. 1, reference numeral 1 denotes a vehicle tester, and write data and a write instruction, which are information unique to the vehicle, are sent to the control unit 2. 3 is a micro computer (C
PU), which has a built-in algorithm for writing data to the EEPROM 4 and reading the write data stored in the EEPROM 4. Reference numeral 5 is a WC terminal for controlling prohibition or permission of writing from the outside of the EEPROM 4, and when the WC terminal 5 is LOW (GND), EEP
ROM4 is writable, otherwise EEP
Writing to the ROM 4 is prohibited. A service check terminal 6 is in a non-operating state when the vehicle is normally traveling, and is in an operating state only at the time of factory shipment or vehicle maintenance (during service). This service check terminal 6 is a service terminal generally used by many automobile manufacturers. For example, the service check terminal 6 is located in the hood of a vehicle.
The CS signal) is input to the electric component, and the electric component can be checked.

Next, the operation of the first embodiment will be described. In FIG. 1, vehicle-specific information (for example, vehicle weight /
When writing the option 4 or not) to the EEPROM 4, first set the service check terminal 6 to the operating state (service state) with a short pin etc.
Since the WC terminal 5 provided in the OM4 becomes LOW (GND), the EEPROM 4 becomes writable. Next, the vehicle tester 1 sends the write data and the write instruction, which are information peculiar to the vehicle, to the CPU 3. At this time, E
Since the EPROM 4 is in the writable state, the write data is E
It is stored in the EPROM 4. Further, since the stored contents written in the EEPROM 4 can be confirmed by the vehicle tester 1 via the CPU 3, if the wrong data is stored due to an operation error of the vehicle tester 1 or an erroneous operation of the CPU 3, a service is provided. It can be found by a man.

When the vehicle is in the user's hand, it is normally
Since the screw check terminal 6 is in the non-operating state and the WC terminal 5 is not LOW, the writing in the EEPROM 4 is prohibited. As a result, even if the CPU 3 performs the rewriting operation due to an erroneous operation due to some cause (traveling in a strong electric field, submersion of the vehicle, etc.), there is no possibility of unnecessarily rewriting the contents of the EEPROM 4.

If the user of the vehicle mistakenly activates the service check terminal 6, the WA
Since the RNING lamp (not shown) is turned on, the user does not continue to drive the vehicle.

As described above, according to the first embodiment,
When the vehicle is shipped from the factory or when the vehicle is serviced, the service check terminal 6 is activated and the vehicle tester 1 writes vehicle-specific information in the EEPROM 4. When the vehicle is in the user's hand, the service check terminal 6 is turned on. Since the writing is prohibited in the EEPROM 4 by setting the non-operating state, even if the CPU 3 performs the rewriting operation due to a malfunction due to some cause, the possibility of unnecessarily rewriting the contents of the EEPROM 4 can be reduced to zero. It is possible.

FIG. 2 shows the configuration of the second embodiment. In FIG. 2, the same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. 7 is a parking brake terminal, which is L when the vehicle is parked.
It becomes OW (GND) and issues a parking signal. 8 is an OR circuit, which is a service check signal (SCS signal)
And the parking signal is input.

Next, the operation of the second embodiment will be described. In FIG. 2, when the service check terminal 6 is brought into an operating state (service state) with a short pin or the like, OR
Since the WC terminal 5 becomes LOW (GND) through the circuit 8, the operation similar to that in the first embodiment causes unnecessary E
The possibility of rewriting the contents of the EPROM 4 can be reduced to zero. Further, when the parking signal is issued by the parking brake terminal 7, the OR is performed in the same manner as above.
Since the WC terminal 5 becomes LOW (GND) through the circuit 8, the operation similar to that in the first embodiment causes unnecessary E
The possibility of rewriting the contents of the EPROM 4 can be reduced to zero.

In the first and second embodiments, if the WC terminal 5 is not LOW (GND), EE
Although the PROM 4 is write-protected, the writing signal line of the EEPROM 4 may be cut off when the service check signal (SCS signal) or the parking signal is not issued.

[0017]

As is apparent from the above embodiments, the present invention provides an electrically rewritable non-volatile memory such as an EEPROM and a micro computer for reading and writing information from the non-volatile memory. A service check terminal that is inactive during normal running of the vehicle and that is in operation only at the time of factory shipment or vehicle maintenance. When the service check terminal is in operation, the microcomputer is When the rewriting of the non-volatile memory is permitted and the service check terminal is in the non-operating state, the rewriting of the non-volatile memory is not permitted even if the rewriting operation is performed by the microcomputer. Even if the microcomputer rewrites due to a malfunction due to some cause, it is unnecessary It has the effect that the possibility of rewriting the contents of the memory can be made zero.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a storage device for an on-vehicle electrical component according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a storage device for an on-vehicle electrical component according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a storage device of a conventional vehicle-mounted electric component.

[Explanation of symbols]

 1 Vehicle Tester 2 Control Unit 3 CPU 4 EEPROM 5 WC Terminal 6 Service Check Terminal 7 Parking Brake Terminal

Claims (3)

[Claims] 1. An electrically rewritable non-volatile memory, a micro computer for reading and writing information from the non-volatile memory, and a non-operating state during normal running of the vehicle, which is set at the time of factory shipment or vehicle. It has a service check terminal that operates only during maintenance, and when the service check terminal is in operation, rewriting of the nonvolatile memory is permitted by the microcomputer and the service check terminal is A storage device for an on-vehicle electrical component, wherein rewriting of a non-volatile memory is prohibited even when the microcomputer performs a rewriting operation when in a non-operating state. 2. The in-vehicle electrical component according to claim 1, wherein rewriting of the nonvolatile memory is permitted by a signal generated when the parking brake is operated, in combination with the service check terminal or as a substitute for the service check terminal. Storage device. 3. When the service check terminal is in a non-operating state or when the parking brake is not operating, the signal line for writing in the non-volatile memory is cut off to prohibit rewriting of the non-volatile memory. A storage device for an on-vehicle electrical component according to claim 1 or 2.