JP3235834B2 - Vehicle electronic control unit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle electronic control device including a one-chip microcomputer.

[Related Art] In recent years, microcomputers have been mounted on vehicles such as automobiles, and since then, various control functions such as engine control have been dramatically improved.

The microcomputer mounted on this car is CP
In contrast to general-purpose microcomputers composed of several chips such as U, ROM, RAM, peripheral I / O, etc., many adopt a one-chip microcomputer in which each element is integrated in one IC. If the built-in ROM contains
Usually, a mask ROM is used.

This mask ROM is suitable for mass production and has high reliability because programs and data are written at the wafer manufacturing stage of ICs, but it has little cost advantage in small production, and other control parts that are performed in parallel In the event of a specification change due to a system change or improvement due to the development of a new mask, it is necessary to change the mask design in order to rewrite the program and data once written, which adds a new period (several months) and extra cost. In addition, the one-chip microcomputer itself in stock is wasted and causes an increase in product cost.

To cope with this, Japanese Patent Application Laid-Open No. 60-159353 discloses that a first memory consisting of a writable PROM that retains data even when the power is turned off is externally connected to a one-chip microcomputer to operate an automobile. There is disclosed a technique in which a control program for controlling various operating units to be controlled is stored, and control data is stored in a second memory including a non-writable mask ROM inside the one-chip microcomputer.

[Problems to be Solved by the Invention] However, once the specifications are fixed and the debugging is completed, the control program for the vehicle is applied to vehicles having similar specifications by changing control data different for each vehicle. In this case, if the control data is stored in the mask ROM, not only the change becomes impossible, but also it becomes difficult to quickly respond to a small-scale specification change even in the same vehicle model.

In addition, when the same control program common to many types of vehicles is stored in the PROM, the cost is significantly disadvantageous for the mask ROM.Additionally, attaching the PROM externally to the one-chip microcomputer reduces the number of assembly steps. In addition to the increase in the number of parts, a large number of man-hours are required from the viewpoint of parts management, leading to an increase in cost.

[Object of the Invention] The present invention has been made in view of the above circumstances, and a single microcomputer can be applied in common to many types of vehicles. It is an object of the present invention to provide an electronic control unit for a vehicle that can respond to the cost and reduce the cost.

[Means for Solving the Problems] In order to achieve the above object, the invention according to claim 1 retains data even when power is turned off and a first memory in which data cannot be written, and rewrites this data. An electronic control unit for a vehicle comprising a microcomputer having a second memory, wherein the microcomputer is different from the first memory, which stores common specification data common to each vehicle type including a control program, for each vehicle type. It is characterized by comprising a one-chip microcomputer incorporating the second memory storing control data.

According to a second aspect of the present invention, in the first aspect of the present invention, the first memory for storing common specification data common to each vehicle type including a control program is constituted by a mask ROM, and control data for each vehicle type is provided. The second to memorize
Is characterized in that the memory is constituted by a ROM capable of electrically rewriting data as a one-time program compatible ROM.

[Operation] In the electronic control device for a vehicle according to the first aspect, the first memory in which data cannot be written to the one-chip microcomputer and the second memory in which data can be rewritten while holding data even when the power is turned off. The first memory, in which data cannot be written, stores common specification data common to each vehicle type including the control program, and retains the data even when the power is turned off and can rewrite the data. The control data different for each vehicle type is stored in the second memory, and the one-chip microcomputer constitutes a vehicle electronic control device. Then, the common specification data including the unchangeable control program stored in the first memory is used in common for each vehicle type, and the control data for each rewritable vehicle type stored in the second memory is used. The control corresponding to the vehicle type is executed.

According to the second aspect of the present invention, the first memory is masked.
A common specification data, which is composed of a ROM and is common to each vehicle type including a control program, is stored in the first memory by a masking process in a manufacturing stage. Further, the second memory is constituted by a ROM capable of electrically rewriting data as a one-time program compatible ROM as a one-time program compatible ROM, and control data that differs for each vehicle type is stored by one-time program compatible write at the time of shipment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The drawing is a configuration diagram of an electronic control device according to the present invention,
In the figure, reference numeral 1 denotes an electronic control unit (ECU) mounted on a vehicle such as an automobile.

The ECU 1 performs, for example, an air-fuel ratio control (fuel injection control) of the engine, an ignition timing control, etc., and an input processing circuit 3 for processing input signals from various sensors, switches, etc., with the one-chip microcomputer 2 as a center. , An A / D converter 4 for converting an analog input signal from sensors into a digital signal, an output processing circuit 5 for driving various actuators, a power supply circuit 6, and the like.

The one-chip microcomputer 2 includes a CPU 6, a mask ROM 7, a RAM 8, a timer 9, an electrically rewritable PROM (EEPROM) 10, a counter 11, and an I / O port 1.
2 and the like are integrated in one chip, and these elements are connected to each other by a data bus 13 and an address bus 14.

The A / D converter 4 may be built in the one-chip microcomputer 2.

The one-chip microcomputer 2 has a mask RO
In a first memory such as M7, control programs such as fuel injection control and ignition timing control common to each vehicle type and fixed data common to each vehicle type such as operation constants are stored. In the second memory, for example,
Control data unique to each vehicle type, such as a basic fuel injection amount map, an ignition timing map, and a control constant, is stored.

Data common to each vehicle type including this control program is stored in advance in the mask ROM 7 at the stage of manufacturing the one-chip microcomputer 2, and the one-chip microcomputer 2 stores the control program and each Only the fixed data common to the vehicle types is stored in the mask ROM 7, and the EEPROM 10 does not store any meaningful data.

In other words, in the one-chip microcomputer 2 for control, only data common to each vehicle type is determined before being mounted on the car and shipped to the market. By storing the information in the mask ROM 7 in the manufacturing step 2, the cost can be reduced.

On the other hand, the data unique to each model is subject to specification changes during the period from the development stage to the actual production and shipment, and for models whose specifications have not been finalized, It is impossible to store data at the stage of manufacturing the one-chip microcomputer 2.

Therefore, such a vehicle-specific data is stored in the EEPROM in the one-chip microcomputer 2 when the product is shipped.
By writing the information into 10, the present invention can be applied to many types of vehicles, and finally, the one-chip microcomputer 2 can have different contents for each type of vehicle. As a result, the development period is shortened, the cost can be reduced because an external PROM is not required, and the number of man-hours for managing parts can be reduced because all the one-chip microcomputers 2 in stock are the same. it can.

In this case, the data specific to the vehicle model need only be written once at the time of product shipment. Such PROMs include one-time program ROMs (OTPROMs) such as fuse-cut type and diode destruction type ROMs. PROM (UVEPROM), which can erase and rewrite data with ultraviolet rays, meaning that data will not be written again after product shipment, or electrically erase and rewrite data as in EEPROM 10 above PROMs that can be used are also available as ROMs for one-time programs.

The EEPROM 10 does not require special equipment such as a large amount of ultraviolet ray generation source, and can be more cost-effective to handle than the UVEPROM.

In the ECU 1 having such a configuration, signals of various sensors and switches are taken into the one-chip microcomputer 2 via the input processing circuit 3, and
The digital signal converted by the A / D converter 4 is taken into the microcomputer 2.

In the one-chip microcomputer 2, the CP
In U6, the signals of various sensors and switches are subjected to data processing in accordance with the control program stored in the mask ROM 7, and for example, the engine speed is calculated and stored in the RAM 8.

Next, using the engine speed and the intake air amount or the suction pipe pressure as parameters,
The basic fuel injection amount map stored in the EEPROM 10 is searched to set the basic fuel injection amount, and the basic fuel injection amount and the engine speed are used as parameters, and stored in the EEPROM 10 corresponding to the vehicle type. Search the ignition timing map and set the basic ignition timing.

After that, the basic fuel injection amount and the basic ignition timing are corrected by parameters related to the operating state of the engine from sensors and switches, and are output from the output port of the I / O port 12 via the output processing circuit 5 at a predetermined timing. And outputs it to various actuators such as an injector and an igniter to perform fuel injection control, ignition timing control, and the like.

[Effect of the Invention] As described above, according to the first aspect of the present invention,
A first memory in which data cannot be written and a second memory in which data can be written and the data can be rewritten even when the power is turned off, is built in the one-chip microcomputer; Then, a common common specification data for each vehicle type including a control program is stored, and control data different for each vehicle type is stored in a second memory capable of holding the data even when the power is turned off and rewriting the data. Since the electronic control unit for a vehicle is configured by a one-chip microcomputer, one microcomputer can be applied to many types of vehicles, and the number of management steps can be significantly reduced, thereby reducing costs. Also, in the case of mass production of multiple models, it is possible to cope with the situation by storing only the control data unique to the model in the second memory, and it is possible to flexibly cope with it and achieve a significant cost reduction. be able to.

In addition, even if a small-scale specification change occurs, such as a change in the content of control data during the development of the vehicle or a change in the content of control data for improvement, the data can be rewritten in the second memory in which data can be rewritten. Since different control data is stored in
It is sufficient to rewrite only the control data in the second memory, and it is possible to deal with it quickly and easily.

According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, the first memory is constituted by a mask ROM, and common specification data including a control program and common to each vehicle type is produced. The first memory is stored in the first memory by the masking process described above, and the second memory is constituted by a ROM capable of electrically rewriting data as a ROM corresponding to a one-time program. Can be stored by writing the one-time program at the time of shipment, which makes it possible to cope with the production of multiple models very easily, and to achieve both the cost merit and the reduction of man-hours. Have.

[Brief description of the drawings]

 The drawing is a configuration diagram of an electronic control device according to the present invention. 1. Electronic control device 2. One-chip microcomputer 7. First memory (mask ROM) 10. Second memory (EEPROM)

Continuation of front page (56) References JP-A-60-159353 (JP, A) JP-A-1-280892 (JP, A) JP-A-2-25344 (JP, U)

Claims (2)

(57) [Claims] An electronic control device for a vehicle, comprising: a microcomputer having a first memory in which data cannot be written and a second memory capable of holding data even when the power is turned off and rewriting the data. The microcomputer includes a first memory storing common specification data common to each vehicle type including a control program, and a second memory storing control data different for each vehicle type.
An electronic control unit for a vehicle, comprising a one-chip microcomputer incorporating the above-mentioned memory. 2. The first memory for storing common specification data common to each vehicle type including a control program is constituted by a mask ROM, and the second memory for storing control data for each vehicle type is one-time. 2. The electronic control unit for a vehicle according to claim 1, wherein the ROM corresponding to the program is constituted by an electrically rewritable ROM.