JP2002106408A - Electronic controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a serial communication line being activated by an external device at a start of communication with the external device by means of a wake-up signal detecting means, transmit a power-start signal to a power supply circuit, and start an electronic controller for a vehicle. SOLUTION: The electronic controller for a vehicle comprises a central processing device, a ROM connected to the central processing device, an external device and a serial communication port. Furthermore, a connector part that can be connected to the external device, the serial communication line for connecting the serial communication port to the connector part, and a branched part at a halfway point of the serial communication line are respectively provided. The electronic controller detects that the serial communication line is activated by the external device after the external device is connected to the connector part by means of the wake-up signal detection means that is connected to the branched part and also the power supply circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic control unit for a vehicle, and more particularly to an electronic control unit for a vehicle having a serial communication port capable of serial communication with an external device outside the vehicle.

[0002]

2. Description of the Related Art In recent years, electronic control of vehicles has been advanced.
Electronic engine control ECU (ECM: Engine)
Control Module), Transmission Control ECU (TCM: Transmission)
Many ECUs such as Control Module) and ECU for controlling antilock brake system (ABS)
(Engine control unit) is mounted on the vehicle.

[0003] These ECUs appropriately control each device by transmitting a command signal to a corresponding device.

At present, many of the on-vehicle electronic controllers are equipped with a serial communication function. By transmitting and receiving data to and from an external device using the serial communication function, a failure diagnosis after shipment from the market and an assembly line are required. Program writing to the on-vehicle electronic controller is performed.

[0005] The main use of serial communication is for failure diagnosis in which, when a failure occurs in a vehicle, data stored in each ECU is read out to clarify the cause of the failure. Currently, in the United States, EU, Japan, etc., four-wheeled vehicles and vehicle-mounted electronic controllers related to exhaust gas (mainly EC
M, TCM) and an external vehicle failure diagnostic device (tester) connected by serial communication, and outputting exhaust gas-related failure diagnostic data (such as a code for identifying a failure) to the external vehicle failure diagnostic device. Mandatory by law.

[0006] Due to these restrictions, the setting of the serial communication function of the vehicle has rapidly spread. In general, in addition to the output of data required by regulations, a large number of data output by a vehicle maker that is determined to be useful for identifying a failure are output.

In addition to the failure diagnosis, an on-board electronic controller and an external program device are connected by serial communication through an assembly line of a vehicle manufacturer, and the software and constants of the on-vehicle electronic controller are exchanged from the external program device. The data is transferred to the on-board electronic controller, and the on-board electronic controller memory (flash ROM, EEPROM
M is used) and software and constants are written.

In order to realize this, the on-vehicle electronic controller communicates with an external program device, and the ROM (flash ROM,
It is necessary to have a minimum program for writing software and constants to an EEPROM.

The electronic control unit for a vehicle is disclosed in
000-101655.
An electronic control device disclosed in this publication includes a microcomputer having at least one serial communication module, a rewritable nonvolatile memory connected to the microcomputer via a serial communication line, a nonvolatile memory and a serial communication line. And at least one input / output module connected in parallel via the buffer, and a buffer for temporarily storing transmission data to the nonvolatile memory, the microcomputer communicates with the input / output module at a predetermined timing, The contents of the buffer are checked at the timing when communication with the input / output module is not executed, and when transmission data is stored in the buffer, communication with the non-volatile memory is performed via the serial communication line, and the ECU (electronic control) is executed. Update data during normal control of Without being affected by interruption or the like of the source voltage, (rewritable) EEPROM without spending extra time it reflects the non-volatile memory.

[0010] Here, the hardware configuration of serial communication of the conventional on-vehicle electronic controller will be described. In FIG. 8, reference numeral 404 denotes a vehicular electronic control device (also referred to as an "on-vehicle electronic controller". , 406 are external devices,
Reference numeral 408 denotes a connector unit (also referred to as a “connection device”) for connecting the vehicle electronic control device 404 and the external device 406;
Reference numeral 0 denotes an on-vehicle sensor; 412, an actuator such as a fuel injection valve; 414, another control device (also referred to as a "controller"); 416, a power supply (also referred to as a "battery");
Is an ignition (also referred to as "IG") switch.

The vehicle electronic control unit 404 mounted on the vehicle includes a first communication port 404A which is a serial communication port for performing data communication with an external device 406 by serial communication, and an input processing circuit 404E described later. CPU 404B, which is a central processing unit for calculating an optimal control amount for target control based on signals from the CPU and outputting a control signal based on the calculation result, and a block rewritable ROM for storing control programs and data (If programmed at the factory, flash memory or EEP
ROM) 404C, a RAM 404D for storing data for the CPU 404B to perform calculations, and the onboard sensor 4
Input processing circuit 4 for inputting signals from 10 and processing the waveform
04E, an output control circuit 404F that receives a control signal from the CPU 404B and drives the actuator 412,
A second communication port 404G for performing communication with another control device 414 and a power supply circuit 404H are provided.

The external device 406 includes an external device communication port (not shown) for performing data communication with the vehicle electronic control device 404, an external device CPU (not shown), and the vehicle electronic control device 404. A storage medium (not shown) in which a new program or data file is stored, an external device side ROM (not shown), an external device side RAM (not shown), and the like are provided.

The connector section 408 includes a first connector section 408-1 on the vehicle side and a second connector section 408- on the external device side.
A first serial communication line (also referred to as a "first serial communication signal line") 420 for connecting the first communication port 404A, which is the serial communication port, to the vehicle-side first connector unit 408-1. In addition, a second serial communication line (also referred to as “second serial communication signal line”) 422 for connecting an external device side communication port (not shown) of the external device 406 and the external device side second connector unit 408-2 is provided. An external device 406 can be connected to the electronic control unit 404.

Further, as shown in FIG. 8, a power supply 416 and an ignition switch 418 located on the vehicle side are provided in the power supply circuit 404H of the electronic control unit 404 for the vehicle. The power supply 416 is connected to the power supply line 42.
4 and the ground line 426, the connector portion 4
08 to the external device 406.

Then, the first and second serial communication lines 420 and 422 through which actual signals are transmitted, and the ground line 4
If you have two, you can use serial communication,
Generally, a power supply line 424 for supplying power from the vehicle to the external device 406 is often provided.

The power supply circuit 404H includes a power supply 4
When the ignition switch is turned off, the power is supplied only to some circuits such as the backup RAM, but the power is not supplied to the CPU and the communication port. It has become. However, when the ON signal of the ignition switch is turned on, power is supplied to all devices of the vehicle-mounted electronic controller, and the vehicle electronic control device 404 is activated.

When programming by the assembly line, a flash ROM is used as the ROM, and only a minimum necessary program for programming is already programmed in a part of the ROM, and the engine control program is communicated with the remaining program. Downloaded to ROM area.

[0018]

Conventionally, when an on-vehicle electronic controller communicates with an external device to exchange information, an ignition switch of a vehicle is turned on to start up the on-vehicle electronic controller, and a desired electronic controller is started. After performing communication, set the ignition switch of the vehicle to OF
F is needed.

In this method, for example, when a program is written to an on-vehicle electronic controller at a factory using serial communication, the following inconveniences arise. (1) It takes a lot of time to perform ON / OFF of the ignition switch. (2) Controllers and electric systems other than the on-vehicle electronic controller are also activated when the ignition switch is turned on. That is, in a factory, there are many cases in which a manufacturing process is still in progress and a failure (such as a failure) occurs when the system is started. In addition, even in the case of the same production model, there are many cases where the assembling / defective state is different in each vehicle. When the ignition switch is turned on, sufficient consideration such as checking a check sheet or the like is required. For this reason, the writing of the program to the in-vehicle electronic controller has been limited to the final step of the manufacturing process.

Further, in this system, for example, when a failure is diagnosed by connecting a tester to a vehicle having a problem in the market, there are the following disadvantages. (1) In order to collect data of the on-vehicle electronic controller, it was necessary to turn on an ignition switch. In this case, only data from the start to the stop of the engine could be obtained. That is, most of the engine malfunctions at the time of starting occur at the time of starting, and it is necessary to investigate the state before the engine is started.

[0021]

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned disadvantages, the present invention provides a central processing unit, a ROM connected to the central processing unit, and a serial communication capable of serial communication with an external device outside the vehicle. An electronic control device for a vehicle having a port, a connector portion connectable to the external device, a serial communication line connecting the serial communication port and the connector portion, and a branch portion in the middle of the serial communication line. Is connected to this branch,
And a wake-up signal detection unit connected to a power supply circuit, and after the external device is connected to the connector unit, the wake-up signal detection unit detects that the external device has activated the serial communication line. It is characterized by the following.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION
After connecting the external device to the connector unit, the wake-up signal detection unit detects that the external device has activated the serial communication line, transmits a power supply start signal to the power supply circuit, and starts the vehicle electronic control device. It is possible.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 7 show an embodiment of the present invention. 2 and 3, reference numeral 2 denotes a vehicle, and reference numeral 4 denotes a vehicle electronic control device (also referred to as “vehicle electronic controller”).
In addition, as the vehicle electronic control device, there are ECM, TCM, etc.), 6 is an external device, 8 is a connector unit (also referred to as a “connection device”) for connecting the vehicle electronic control device 4 and the external device 6, 10 is a vehicle sensor, 12 is an actuator such as a fuel injection valve, and 14 is another control device (“controller”).
, 16 is a power source (also called “battery”), 1
Reference numeral 8 denotes an ignition (also referred to as "IG") switch.

The vehicle electronic control unit 4 mounted on the vehicle 2 includes a first communication port 4A which is a serial communication port for performing data communication with an external device 6 by serial communication, and an input processing circuit described later. CPU 4B, which is a central processing unit that calculates an optimal control amount for the target control based on the signal from 4E, and outputs a control signal based on the calculation result, and a block rewritable block that stores control programs and data. ROM (flash memory or EEPROM if programmed at the factory) 4C
RAM4 for storing data for PU4B to perform calculations
D, an input processing circuit 4E for inputting a signal from the in-vehicle sensor 10 to perform waveform processing, and an output control circuit 4F for driving the actuator 12 in response to a control signal from the CPU 4B.
, A second communication port 4G for performing communication with another control device 14, and a power supply circuit 4H.

The external device 6 includes an external device communication port (not shown) for performing data communication with the vehicle electronic control device 4, an external device CPU (not shown), and the vehicle electronic control device 4. Storage medium (not shown) in which new program and data files are stored, external device ROM
(Not shown), an external device-side RAM (not shown), and the like.

The connector section 8 comprises a first connector section 8-1 on the vehicle side and a second connector section 8-2 on the external device, and the first communication port 4A which is the serial communication port.
A first serial communication line (also referred to as a “first serial communication signal line”) 20 for connecting the external device 6 to the vehicle-side first connector section 8-1, and an external device-side communication port (not shown) of the external device 6 and the external device Side second connector section 8-2
And a second serial communication line (also referred to as a “second serial communication signal line”) 22 for connecting the external device 6 to the vehicle electronic control device 4.

Further, as shown in FIG. 3, a power supply 16 located on the vehicle 2 side and an ignition switch 18 are connected and provided in the power supply circuit 4H of the electronic control unit 4 for a vehicle. The power supply 16 is connected to the external device 6 via the power supply line 24 and the ground line 26 via the connector unit 8.

At this time, the vehicle-side first connector portion 8-
A wake-up signal detecting means 30 connected to the branch section 28 and connected to the power supply circuit 4H. After being connected to the connector section 8, the external device 6 connects the first and second serial communication lines 2 to each other.
The wake-up signal detecting means 30 detects that 0 and 22 have been activated.

More specifically, the power supply circuit 4H includes:
Power is supplied from the power supply 16, the ignition switch 18 is turned off, and the wake-up signal detecting means 3 is turned on.
When the start request signal from 0 is OFF, power is supplied only to some circuits such as the backup RAM, but the first communication port 4A which is a serial communication port and the CPU 4
Since power is not supplied to B, the system is in a sleep state.

Naturally, the ignition switch 18 is turned on.
When a signal is input, power is supplied to all the devices of the vehicle electronic control device 4 mounted on the vehicle 2 to activate the vehicle electronic control device 4 and also operate the serial communication function. The ignition switch 18 is OFF
However, when the external device 6 activates the first and second serial communication lines 20 and 22 (the state in which the potential difference from the ground level becomes a certain value or more), the wake-up signal detection means 30 , The potential difference between the first and second serial communication lines 20 and 22 with respect to the ground level is detected, and a start request signal to the power supply circuit 4H is turned on to supply power to all devices of the vehicle electronic control device 4. Then, the vehicle electronic control unit 4 is started.

Also, when the ignition switch 18
At the time of FF, the wake-up signal detecting means 30 turns off the start request signal to the power supply circuit 4H when a communication command is not transmitted within a predetermined time after detecting the signal, that is, after a fixed time from the end of communication. The power supply is restricted, and the vehicle electronic control unit 4 is stopped, that is, the power supply is stopped.

Here, a description will be given of an example of the potential of a communication line in a state where a signal does not come from a tester (see FIG. 4) and an example of a potential of a communication line in a state where a signal is transmitted from a tester (see FIG. 5).

In the example of the potential of the communication line where no signal comes from the tester shown in FIG.
However, depending on the system, the voltage in the communication pause state may not be 0 V (HIGH) or may be negative. However, in any case, the potential does not change in the communication pause state.

In the example of the potential of the communication line in the state where the signal is transmitted from the tester in FIG. 5, the wake-up signal detecting means 30 detects the first potential change from 0 V (LOW) in the communication pause state. Then, the activation request signal to the power supply circuit 4H is turned ON. Again, set the communication pause state to 0
After V (LOW) has continued for a predetermined time, the activation request signal to the power supply circuit 4H is turned off.

The external device 6 can be constituted by a failure diagnosis device.

When the external device 6 is constituted by a failure diagnosis device, the external device 6 is used for failure diagnosis,
It has a function of displaying and storing data mainly transmitted from the vehicle 2 via the communication line.

The power source may be a built-in battery, but in most cases, power is supplied from the power supply line 24 of the first connector 8-1 on the vehicle side.

In this case, in particular, the ignition switch 18
The greatest advantage is that data can be collected and stored even when the power is OFF, and therefore, even when the engine is stopped (when the alternator is not generating power), power consumption by the failure diagnosis device that is the external device 6 is prevented. Therefore, it is preferable that the data collection of the engine stop be provided with a timer start that turns on all the functions of the failure diagnosis device that is the external device 6 only at the time of communication (the data collection while the engine is stopped needs to be more frequent as the engine is running). Absent).

At this time, the vehicle electronic control unit 4 outputs the specified data requested by the failure diagnosis device which is the external device 6.

The program for the vehicle electronic control unit 4 is executed in the following procedure. (1) The external device-side second connector 8-2 of the failure diagnosis device, which is the external device 6, is connected to the vehicle-side first connector 8-1. (2) Start up a diagnostic data collection / storing program for the failure diagnostic device, which is the external device 6. (3) Thereafter, the operator leaves the system until the predetermined number of days or data is full and there is a display / alarm thereof.

The external device 6 can be constituted by a program writing device.

When the external device 6 is constituted by a program writing device, the external device 6 is a manufacturing device installed on an assembly line.

Even when not connected, a power supply supplied from the vehicle 2 via a system that constantly outputs a communication initialization signal and repeats until there is a response or the vehicle-side first connector 8-1. There is a system that detects the potential of the line 24 and outputs a communication initialization signal.

Various types of models are flowing in the assembly line, and software to be programmed and constants are different for each type. Which software and constant to select depends on the assembly line system. A bar code that can identify the model attached to the vehicle 2 is read by a bar code reader, and the information is written in the external device 6 as a program writing program. To the device to determine software and constants, or to make a model-specific connection on the vehicle harness side of the vehicle electronic control unit 4, and the vehicle electronic control unit 4 recognizes the connection state and There is a method of specifying the information, transmitting the information from the vehicle electronic control device 4 to the program writing device which is the external device 6, and determining software and constants.

At this time, software and constants are programmed in the vehicle electronic control device 4 programmed in the assembly line for all models to which the vehicle electronic control device 4 can be applied. Only software and constants, such as communication and the minimum required for programs, are programmed, and only shift data and constants are programmed. There are systems that are premised on being programmed on an assembly line. Note that a flash ROM or an EEPROM is used as a device to be programmed.

Next, the operation will be described with reference to the control flowchart of FIG.

First, the wake-up signal detecting means 3
0, the first and second serial communication lines 20, 22
To determine whether or not the potential of the “H” is “H” (10
2) is performed, and if this determination (102) is NO,
In the wake-up signal detection means 30, the first and second
The process proceeds to the judgment (104) as to whether or not the potential of the serial communication lines 20 and 22 is "L", and the judgment (1
If 02) is YES, the power supply circuit 4H supplies power to all the devices of the vehicle electronic control device 4, activates the vehicle electronic control device 4 (106), and returns to the determination (102).

It is determined whether or not the wake-up signal detecting means 30 detects that the potentials of the first and second serial communication lines 20 and 22 are "L" (104).
Is NO, the process directly returns to the determination (102), and if the determination (104) is YES, the power supply circuit 4H stops power supply to each device of the vehicle electronic control unit 4 (108). Returning to the determination (102).

When the external device 6 is constituted by a failure diagnosis device, the ON / OFF of the ignition switch 18
At the time of F, as shown in FIG. 6, the failure diagnosis device as the external device 6 is started by a timer (202), and a wake-up signal is transmitted from the failure diagnosis device as the external device 6 to the vehicle electronic control device 4 (FIG. 6). 204). At this point, communication has not yet been established.

The wake-up signal detecting means 30 comprises:
A wake-up signal (potential difference) of the first and second serial communication lines 20 and 22 is detected, a start request signal to the power supply circuit 4H is turned on, and power is supplied to all the devices of the vehicle electronic control device 4, and Electronic control unit 4 is O
N, that is, start (206).

At this point, the function of the communication port of the vehicle electronic control unit 4 is activated.

Further, the failure diagnosis device, which is the external device 6, transmits a communication initialization signal to the vehicle electronic control device 4 again, and the vehicle electronic control device 4 confirms that the communication has been established. A response is returned to the communication initialization signal in order to notify the failure diagnosis device which is the device 6.

The failure diagnostic device, which is the external device 6, requests the vehicle electronic control device 4 for desired data, that is, diagnostic data, and receives the diagnostic data from the vehicle electronic control device 4; (208).

Further, the failure diagnosis device which is the external device 6 includes:
When the collection and storage of the requested data is completed, the state shifts to the communication pause state ("L") and the OFF state of the main function (for power saving) (210).

The wake-up signal detecting means 30 comprises:
Detecting that the signal has become “L” for a certain period of time from the end of communication, turning off a start request signal to the power supply circuit 4H, restricting power supply, and supplying power to each device in the electronic control unit 4 for a vehicle. The supply is stopped to stop the vehicle electronic control unit 4 (212).

Various data (various sensor information such as outside air temperature, water temperature, etc.) can be stored over a long period of time even when the engine is stopped by the above-mentioned power saving function of the failure diagnosis device which is the external device 6 and the above-mentioned power saving function of the vehicle electronic control device 4. It can be collected and stored.

Further, when the external device 6 is constituted by a program writing device, as shown in FIG.
The external device 6 is connected to the vehicle-side first connector portion 8-1 of the vehicle 2 which has entered the programming process on the assembly line, and the external device-side second connector portion 8-2 of the program writing device is connected (302).

Then, a wake-up signal is transmitted from the program writing device, which is the external device 6, to the vehicle electronic control device 4 (304). At this point, communication has not been established yet.

The wake-up signal detecting means 30
A wake-up signal (potential difference) of the first and second serial communication lines 20 and 22 is detected, a start request signal to the power supply circuit 4H is turned on, and power is supplied to all the devices of the vehicle electronic control device 4, and Electronic control unit 4 is O
N, that is, start (306).

At this point, the function of the communication port of the vehicle electronic control unit 4 is activated.

The program writing device, which is the external device 6, transmits a communication initialization signal to the vehicle electronic control device 4 again, and the vehicle electronic control device 4 confirms that communication has been established. In order to notify the program writing device which is the device 6, a response is returned to the communication initialization signal.

At this point, the program writing device, which is the external device 6, requests the vehicle electronic control device 4 for a controller identification number (308).

The program writing device, which is the external device 6, transmits a program and a constant corresponding to the controller identification number to the vehicle electronic control device 4, and the vehicle electronic control device 4 transmits the program to the internal flash ROM or the like. EEP
Write to the ROM (310).

When the writing is completed, a recognition sign (lamp lighting, buzzer alarm) is issued on the vehicle 2 side or the program writing device side which is the external device 6 (312).

When the worker disconnects the second connector 8-2 on the external device side and enters a communication pause state, and thereafter the communication line becomes "L" for a certain period of time after the end of the communication, the wake-up is performed. The signal detection unit 30 turns off the start request signal to the power supply circuit 4H, restricts the power supply, stops the power supply to each device in the vehicle electronic control device 4, and turns off the vehicle electronic control device 4. Stop (31
4).

Thus, one vehicle electronic control unit 4
When communication between the external device 6 and the external device 6 is started, the wake-up signal detecting means 30 detects that the external device 6 has activated the first and second serial communication lines 20 and 22, so that the power supply circuit 4 </ b> H is powered. A start signal can be transmitted to start the vehicle electronic control unit 4, and it is not necessary to turn on the ignition switch 18 just to turn on the power of one vehicle electronic control unit 4. Except for one vehicle electronic control unit 4 that is in communication with the vehicle 6, no other vehicle-mounted controller is activated, which is practically advantageous.

Also, when the ignition switch 18
At the time of FF, the wake-up signal detecting means 30 turns off the start request signal to the power supply circuit 4H when a communication command is not transmitted within a predetermined time after detecting the signal, that is, after a fixed time from the end of communication. By limiting the power supply and stopping the vehicle electronic control unit 4, that is, stopping the power supply, it is possible to reliably prevent the battery from running down, and to contribute to the improvement of the product power.

Furthermore, if the external device 6 is constituted by a failure diagnosis device, even when the engine is stopped, the failure diagnosis device, which is the external device 6, diagnoses the failure of the vehicle electronic control unit 4 and collects data. This can contribute to the early detection and resolution of the cause of the failure, and further to the improvement of reliability. In addition, most of the engine malfunctions occur when the vehicle electronic control unit 4 is started before the engine is started. Since the failure diagnosis can be performed from the start of the vehicle electronic control device 4, the state from the start of the vehicle electronic control device 4 to the start of the engine, which was conventionally impossible to diagnose, can be diagnosed, which is practically advantageous. is there.

Further, if the external device 6 is constituted by a program writing device, the ignition switch for starting the vehicle electronic control device 4 which is necessary for writing a program in the vehicle electronic control device 4 is required. 18 can be reduced, and if the wake-up signal detecting means 30 is provided, a program can be written anywhere in the manufacturing process of the factory, and the degree of freedom in manufacturing process layout increases. That is, writing at the optimal position is possible,
In addition, only one vehicle electronic control unit 4 that needs to write a program can be started. When the ignition switch 18 is turned on, the system is not assembled. Can be prevented from being transmitted, which can contribute to an improvement in assemblability and a reduction in the failure rate.

Note that the present invention is not limited to the above-described embodiment, and various application modifications are possible.

For example, in the embodiment of the present invention, the electronic control unit for a vehicle has only an input function, that is, a function written only by an external device. However, the electronic control unit for a vehicle has only a data input function. In addition, a special configuration may be adopted in which an output function is also added.

That is, the electronic control unit for a vehicle has a function of inputting data from an external device and also has an output function of transmitting data to another electronic control unit for a vehicle.

In this case, even if there is no external device, if there is a vehicle of the same type having an output function, data transmission to another vehicle electronic control device becomes possible, and writing work can be performed easily. , If the data after learning control is output, the specifications can be aligned,
Moreover, it can cope with emergency evacuation, which is practically advantageous.

If a display function is added in addition to the output function, it is possible to compare data between vehicles, display a faulty part by the display function, and perform quick and reliable fault diagnosis.

[0076]

As described above in detail, according to the present invention, there is provided a central processing unit, a ROM connected to the central processing unit, and a serial communication port capable of serial communication with an external device outside the vehicle. In a vehicle electronic control device,
Provide a connector unit that can be connected to an external device, provide a serial communication line that connects the serial communication port and the connector unit, provide a branch part in the middle of this serial communication line,
A wake-up signal detection unit connected to the branch unit and connected to the power supply circuit is provided, and after the external device is connected to the connector unit, it is determined by the wake-up signal detection unit that the external device has activated the serial communication line. The wake-up signal detecting means detects that the external device has activated the serial communication line at the start of communication between one vehicle electronic control device and the external device. It is possible to start the vehicle electronic control unit by transmitting a power supply start signal to the vehicle electronic control unit, and it is not necessary to turn on the ignition switch only to turn on the power supply of one vehicle electronic control unit. Except for one vehicle electronic control unit in communication, other on-board controllers are started. No, which is advantageous in practical use.

[Brief description of the drawings]

FIG. 1 is a control flowchart of a vehicle electronic control device according to an embodiment of the present invention.

FIG. 2 is a schematic left side view of the vehicle.

FIG. 3 is a hardware configuration diagram of serial communication of the vehicle electronic control device;

FIG. 4 is a diagram showing an example of a potential of a communication line in a state where no signal comes from a tester.

FIG. 5 is a diagram illustrating an example of a potential of a communication line in a state where a signal is transmitted from a tester.

FIG. 6 is a flowchart when an external device is configured by a failure diagnosis device.

FIG. 7 is a flowchart when an external device is configured by a program writing device.

FIG. 8 is a hardware configuration diagram of serial communication of a vehicle electronic control device according to the prior art of the present invention.

[Explanation of symbols]

Reference Signs List 2 vehicle 4 vehicle electronic control unit 4A first communication port 4B CPU 4C ROM 4D RAM 4E input processing circuit 4F output control circuit 4G second communication port 4H power supply circuit 6 external device 8 connector section 8-1 vehicle-side first connector Part 8-2 External device side second connector part 10 In-vehicle sensor 12 Actuator 14 Other control device (also referred to as "controller") 16 Power supply (also referred to as "battery") 18 Ignition (also referred to as "IG") switch 20 1 serial communication line (also referred to as “first serial communication signal line”) 22 second serial communication line (also referred to as “second serial communication signal line”) 24 power supply line 26 ground line 28 branching unit 30 wake-up signal detecting means

Claims (5)

[Claims] An electronic control unit for a vehicle, comprising: a central processing unit; a ROM connected to the central processing unit; and a serial communication port capable of serial communication with an external device outside the vehicle. A connector part,
A serial communication line for connecting the serial communication port and the connector is provided, a branch is provided in the middle of the serial communication line, and a wake-up signal detecting means connected to the branch and connected to a power supply circuit is provided. ,
An electronic control unit for a vehicle, wherein after the external device is connected to the connector section, the wake-up signal detecting means detects that the external device has activated the serial communication line. 2. The vehicular electronic control device according to claim 1, wherein the wake-up signal detection means stops power supply when a communication command is not transmitted within a predetermined time after detecting the signal. 3. The electronic control unit for a vehicle according to claim 1, wherein the external device comprises a failure diagnosis device. 4. The electronic control unit for a vehicle according to claim 1, wherein said external device comprises a program writing device. 5. The vehicle electronic control device according to claim 1, wherein the vehicle electronic control device has not only a data input function but also an output function.