JP6010207B2 - Communications system - Google Patents

Description

  The present invention relates to a power management technique in a communication network, and more particularly to a technique effective in reducing power consumption of a semiconductor integrated circuit device used in a communication network system that communicates via a CAN (Controller Area Network) bus.

  Cars are equipped with many ECUs (Electric Control Units) that control various information systems such as navigation systems and audio, powertrain systems such as engines and chassis, and body systems such as air conditioners, headlights, and door locks. ing.

  For example, CAN is widely used as a communication network protocol for connecting these ECUs. ECUs mounted on automobiles are classified into ECUs that are always controlled, such as engines, brakes, and airbags, and ECUs that need to be operated only when an event such as opening / closing of a sunroof occurs. In the CAN, when the automobile starts the engine, all ECUs are turned on thereafter.

  Further, as a data propagation technique in this type of communication network, for example, a method of storing data or using a CAN bus without using a CAN protocol for performing diagnosis (see Patent Document 1), a wired LAN, or the like. Regardless of the communication protocol, there is known one that enables data communication by UART (Universal Asynchronous Receiver Transmitter) (see Patent Document 2).

JP-T-2004-535742 JP 2006-20038 A

  However, the present inventor has found that the communication technology using the communication network protocol as described above has the following problems.

  ECUs mounted on automobiles are, for example, ECUs that are constantly controlled (engines, brakes, airbags, etc. are constantly controlled) (for example, events such as opening / closing of sunroofs) It is divided into ECUs that need to be operated only when the event occurs (the occurrence frequency of events to be transmitted and received messages is relatively low).

  In the case of an ECU that requires operation only when an event occurs, power consumption can be reduced by turning on the ECU only when the event occurs. However, as described above, after the engine is started, all the ECUs are turned on, and many ECUs always consume power.

  Electricity used in automobiles is made with an alternator (alternator) that is powered by the power of the engine, so if the power consumption is low, the load on the alternator will decrease, and gasoline consumption will also decrease. As power consumption increases, there is a problem that the power generation load of the automobile increases and the fuel efficiency of the automobile decreases.

  The number of ECUs mounted on automobiles is increasing year by year, and the electric power consumed by these ECUs is also increasing. As a result, there is a risk that the fuel consumption of the automobile will be greatly reduced.

  On the other hand, ECUs required for safe operation of automobiles such as engines and brakes communicate relatively frequently via a communication network, and hindering such communication is safe for automobiles. It will also interfere with operation. From this point of view, it is necessary to perform communication that does not hinder the safe operation of the vehicle when communication to such an ECU is performed while suppressing communication from the emergency ECU.

  An object of the present invention is to provide a technique capable of significantly reducing the power consumption of an automobile by optimally controlling the power supply of each ECU connected to a communication network.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  The present invention provides a communication protocol interface serving as an interface of a first communication protocol input via a communication bus, a controller for controlling an actuator or the like based on a message input via the communication protocol interface, A first regulator that supplies power to the communication protocol interface; and a second regulator that supplies / stops power to the controller and an actuator controlled by the controller based on a control signal output from the communication protocol interface The communication protocol interface is configured to generate a control signal based on a message of a second communication protocol transferred from the communication bus and different from the first communication protocol.

  Moreover, the outline | summary of the other invention of this application is shown briefly.

  In the present invention, the communication protocol interface determines whether the message transferred via the communication bus is a message of the first communication protocol or a message of the second communication protocol, and the first communication In the case of a protocol message, a protocol determination unit that transmits the message to the controller, and when the protocol determination unit determines that the message is a message of the second communication protocol, the message is input, and the identification number in the message is set. And detecting whether the detected identification number and the identification number individually assigned to the semiconductor integrated circuit device match, and if they match, a control signal for operating the second regulator Is provided with an ID determination unit that outputs.

  Further, the present invention includes a timer for measuring an idle time of the controller when a power supply voltage is supplied to the controller, and the controller shuts off the power to the ID determination unit when the controller idle time elapses for an arbitrary time. An instruction signal is output, and the ID determination unit outputs a control signal for stopping the operation of the second regulator when receiving the power-off instruction signal.

  Furthermore, the present invention includes a power supply operation information storage unit that stores operation information indicating whether the communication protocol interface has operated or stopped the second regulator, and the ID determination unit includes: When the second regulator is operated or when the second regulator is stopped, the operation is stored in the power supply operation information storage unit.

  Further, according to the present invention, the controller stops communication according to the first communication protocol so that all the semiconductor integrated circuit devices performing communication according to the first communication protocol stop communication according to the first communication protocol. After outputting a message via the communication bus and stopping communication of the semiconductor integrated circuit device, the communication bus is connected to any semiconductor integrated circuit device that wants to participate in communication according to the first communication protocol. A message of the second communication protocol is transferred through the second regulator to operate a second regulator of any of the semiconductor integrated circuit devices.

  Further, according to the present invention, the semiconductor integrated circuit device that has stopped communication using the first communication protocol resumes communication using the first communication protocol after an arbitrary time set in the communication stop message has elapsed. To do.

  Further, according to the present invention, the semiconductor integrated circuit device that has stopped communication according to the first communication protocol transfers a message that causes the communication protocol interface to operate the second regulator according to the second communication protocol. The operation of the second regulator is stopped.

  Furthermore, the present invention provides a system activation message for causing the controller to operate the first regulator according to the second communication protocol, to activate the semiconductor integrated circuit device, and to start communication according to the first communication protocol. When the semiconductor integrated circuit device that is plugged in exists, it is determined whether or not there is a plugged in semiconductor integrated circuit device from the activated semiconductor integrated circuit device. The operation recognition information including at least the identification number is acquired by the first communication protocol in the plugged-in semiconductor integrated circuit device.

  Further, according to the present invention, when the semiconductor integrated circuit device is operated by an external trigger, the second regulator does not stop power supply to the controller and the actuator, the controller enters a standby state, and the communication protocol The interface is configured to accept a message according to the second communication protocol.

  Further, according to the present invention, when the controller detects an external trigger and transitions from a standby state to an operating state, the controller transfers an activation notification signal for notifying that the semiconductor integrated circuit device has been activated by the external trigger to the communication bus. Is.

  Further, according to the present invention, when the controller detects an external trigger and transitions from a standby state to an operating state, the communication protocol interface is set so that communication according to the first communication protocol is started. When an inquiry about whether or not the semiconductor integrated circuit device has been activated is generated, the activation is notified.

  In the present invention, the first communication protocol is a vehicle communication protocol, and is a communication protocol mainly used as an in-vehicle network such as CAN or FlexRay.

  In the present invention, the second communication protocol is a communication protocol used mainly for communication between semiconductor integrated circuits such as UART, or a communication protocol used dependently as an in-vehicle network such as LIN (Local Interconnect Network). It is made up of. Or the structure of a communication message is the same as that of CAN or FlexRay, but consists of communication protocols with different communication frequencies.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  (1) Since the power supply can be stopped when the operation of the controller and the actuator is unnecessary, the power consumption of the semiconductor integrated circuit device can be greatly reduced.

  (2) Further, by stopping communication between ECUs or stopping the operation of the semiconductor integrated circuit in the ECU in a predetermined case, not only the improvement of power consumption and fuel consumption but also the improvement of the safety performance of the automobile can be achieved. Can be planned.

It is a block diagram which shows an example of the connection form of the in-vehicle network by Embodiment 1 of this invention. It is a block diagram which shows an example of a structure in the CAN transceiver / receiver provided in ECU of FIG. It is explanatory drawing which shows an example of the communication format transferred via the CAN bus by Embodiment 1 of this invention. It is explanatory drawing which shows an example of the UART data format of FIG. It is a flowchart which shows an example of operation | movement in ECU of FIG. 5 is an operation flowchart illustrating an example of communication between a master ECU and a slave ECU according to Embodiment 1 of the present invention. It is explanatory drawing which shows an example of the baud rate of CAN communication when the CAN transceiver / receiver of FIG. 2 performs filtering. It is a block diagram which shows the other example of a structure in the CAN transceiver / receiver of FIG. It is an operation | movement flowchart which shows an example of communication with master ECU and slave ECU by Embodiment 2 of this invention. 10 is a flowchart showing an example of the operation of a master ECU in FIG. 9. It is a flowchart which shows an example of operation | movement of the slave ECU which is participating in the CAN communication in FIG. It is a flowchart which shows an example of operation | movement in the slave ECU which is not participating in the CAN communication in FIG. It is an operation | movement flowchart which shows an example of communication with master ECU and slave ECU when ECU by Embodiment 3 of this invention is plugged in. It is a flowchart which shows an example of operation | movement of master ECU at the time of operation | movement of FIG. It is a flowchart which shows an example of operation | movement of the existing slave ECU at the time of operation | movement of FIG. It is a flowchart which shows an example of operation | movement of the plugged-in slave ECU at the time of operation | movement of FIG. It is a flowchart which shows an example of operation | movement in which master ECU by Embodiment 4 of this invention confirms whether slave ECU is participating in CAN communication.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

(Embodiment 1)
1 is a block diagram showing an example of a connection form of an in-vehicle network according to Embodiment 1 of the present invention, and FIG. 2 is a block diagram showing an example of a configuration of a CAN transceiver / receiver provided in the ECU of FIG. 3 is an explanatory diagram showing an example of a communication format transferred via the CAN bus according to the first embodiment of the present invention, FIG. 4 is an explanatory diagram showing an example of the UART data format of FIG. 3, and FIG. 6 is a flowchart showing an example of the operation in the ECU of FIG. 2, FIG. 6 is an operation flowchart showing an example of communication between the master ECU and the slave ECU according to Embodiment 1 of the present invention, and FIG. 7 is a diagram of the CAN transceiver / receiver of FIG. FIG. 8 is an explanatory diagram showing an example of a baud rate of CAN communication when performing filtering, and FIG. 8 is a diagram of the configuration of the CAN transceiver / receiver of FIG. Is a block diagram showing an example.

  In the first embodiment, the connection form of the in-vehicle network of the automobile has a configuration in which a plurality of ECUs 1, 1a, 1b are connected to each other via a CAN bus Bc serving as a communication bus, as shown in FIG. These ECUs 1, 1a, and 1b are, for example, semiconductor integrated circuits that control various types of information systems such as navigation systems and audio, power train systems such as engines and chassis, and body systems such as air conditioners, headlights, and door locks. It is a control device having. The ECUs 1, 1a, 1b are connected to actuators Ac controlled by the ECUs 1, 1a, 1b, respectively. However, an ECU to which an actuator is not connected may be used.

  The ECU 1 includes a CAN transceiver / receiver 2, regulators 3 and 4, and an MCU (Micro Controller Unit) 5 serving as a controller. The ECU 1 (, 1a, 1b) is connected to the CAN bus Bc via the CAN transceiver / receiver 2. A CAN protocol differential signal, which is a first communication protocol, or a UART protocol differential signal, which is a second communication protocol, is transferred to the CAN bus Bc.

  The CAN transceiver / receiver 2 serving as an electrical interface for communication converts the differential signal input via the CAN bus Bc into a digital signal, and converts the digital signal output from the MCU 5 into a differential signal to convert it into a CAN bus. In addition to outputting to Bc, it is determined whether the communication protocol of the differential signal input through the CAN bus Bc is the CAN protocol or the UART protocol. When the determination result is the UART protocol, the UART data is analyzed. Based on this, the regulator 4 is controlled.

  The regulator 3 serving as a first regulator is a regulator that regulates a power supply voltage supplied from, for example, a battery of an automobile and supplies it as an operating power supply for the CAN transceiver / receiver 2.

  The regulator 4 serving as the second regulator regulates the power supply voltage supplied from the vehicle battery or the like based on the control output from the CAN transceiver / receiver 2 and supplies it as the operation power supply for the MCU 5 and the actuator Ac. It is a regulator.

  The MCU 5 includes a CAN interface 6, a communication control unit 7, a RAM (Random Access Memory) 8, a timer 9, an interrupt controller 10, a CPU (Central Processing Unit) 11, and a ROM (Read Only Memory) 12. The communication control unit 7, RAM 8, timer 9, CPU 11, and ROM 12 are connected to each other via an internal bus Bs.

  Further, when a message is transmitted to another ECU using either the CAN protocol or the UART protocol, the MCU 5 transmits a digital signal of the message to be transmitted and information indicating which protocol is to be transmitted to the CAN transceiver / receiver. 2 to send.

  The CAN interface 6 is an interface between the MCU 5 and the CAN bus Bc. The communication control unit 7 controls communication with other ECUs according to the CAN protocol. The RAM 8 is used for temporary storage of data, for example, temporary storage of data received from the CAN network and data transmitted to the CAN network.

  The timer 9 counts up a timer clock, sets a desired time, and outputs a timer counter signal when a certain time is reached. When there is a program to be executed with priority over the program being executed, the interrupt controller 10 controls interruption of the program being executed and execution of the interrupt program. When the interrupt program ends, the interrupted program resumes. Normally, the interrupt controller 10 controls internal interrupts from inside the MCU 5 and external interrupts from outside the MCU 5.

  For example, when no data is received from the CAN network for a certain period of time, a time-out signal output from the timer 9 is received, an interrupt program is generated, and an interrupt processing signal is output.

  The CPU 11 manages all the control in the MCU 5. The ROM 12 mainly stores an operation program for the MCU 5. The operation program is, for example, a CAN communication program, an actuator control program, a power shutoff processing program, or the like.

  Although the configuration of the ECU 1 has been described here, the other ECUs 1a and 1b have the same configuration as the ECU 1.

  FIG. 2 is a block diagram showing an example of a configuration in the CAN transceiver / receiver 2.

  As shown in the figure, the CAN transceiver / receiver 2 includes a transceiver / receiver 13, a select circuit 14 serving as a protocol determination unit, a UART circuit 15, an ID determination circuit 16 serving as an ID determination unit, and a register 17 serving as a power supply operation information storage unit. And an on-chip oscillator 18.

  The CAN transceiver / receiver 2 is connected to the MCU 5 as described above. An actuator Ac is connected to the MCU 5, and the MCU 5 drives and controls the actuator Ac.

  The transceiver / receiver 13 converts a differential signal input via the CAN bus Bc into a digital signal, converts a digital signal output from the MCU 5 into a differential signal, and outputs the differential signal to the CAN bus Bc.

  The select circuit 14 determines the protocol of the signal received from the CAN bus Bc by the following method.

  In the case where communication using the CAN protocol and communication using the UART protocol can be superimposed, for example, different communication frequency bands (CAN protocol communication is performed in a high frequency band and UART protocol communication is performed in a low frequency band). There are known techniques such as non-contact IC cards and power line communication for performing communication by superimposing signals in such different frequency bands, and these techniques may be adopted as appropriate.

  At the time of reception, signals received from the CAN bus Bc are separated by AM demodulation, and protocol signals in respective analog signal states are converted into digital signals. At the time of transmission, the digital signal of the message is converted into an analog signal of a communication frequency band according to the protocol based on information indicating which protocol is to be transmitted, and the converted analog signal is superimposed by AM modulation and is applied to the CAN bus Bc. Output.

  Alternatively, when the communication using the CAN protocol and the communication using the UART protocol are separated in time, the transceiver / receiver 13 performs analog-to-digital conversion on the signal received from the CAN bus Bc, and the select circuit 14 in the subsequent stage performs any communication. The received protocol is discriminated according to the timing to be performed, the digital signal of the message from the MCU 5 is converted from digital to analog at the time of transmission, and the analog signal is sent to the CAN bus Bc according to which communication timing is performed. Output. By performing both temporal separation and frequency separation, it becomes possible to further ensure protocol separation.

  The select circuit 14 determines whether the digital signal input via the transceiver / receiver 13 is a CAN protocol or a UART protocol, and outputs the digital signal to the MCU 5 in the case of the CAN protocol. In the case of the UART protocol, switching control is performed so that the digital signal is output to the UART circuit 15.

  The selection circuit 14 determines whether the received digital signal is a CAN protocol or a UART protocol based on the above-described frequency difference or predetermined transmission / reception timing information.

  In the case of transmission, the select circuit 14 transmits to the transceiver / receiver 13 a digital signal of a message input from the MCU 5 and information indicating which protocol is to be transmitted, or which protocol is to be transmitted. Based on the indicated information and predetermined transmission / reception timing information, the digital signal of the message input from the MCU 5 is transmitted to the transceiver / receiver 13 at a predetermined timing.

  The UART circuit 15 determines whether or not the digital signal input via the select circuit 14 matches the UART format, and if it matches, outputs the digital signal to the ID determination circuit 16. To do.

  The ID determination circuit 16 detects the CAN ID that is the identification number of the input digital signal, determines whether the CAN ID is the same as the CAN ID assigned to each ECU, and if so, the regulator 4 An enable signal EN, which is a control signal, is output.

  The register 17 stores information indicating that the regulator 4 is in the ON state by the ID determination circuit 16. The on-chip oscillator 18 generates an operation clock signal in the CAN transceiver / receiver 2.

  FIG. 3 is an explanatory diagram showing an example of a communication format transferred via the CAN bus Bc.

  When communication is started, a UART format wait message 19 is transferred to the first first message, and then a UART format CAN ID message 20 is transferred to the second message. Thereafter, the CAN frame 21 in the CAN format is transferred, and CAN communication is started.

  FIG. 4 is an explanatory diagram showing an example of a UART data format transferred in the first message and the second message.

  The wait message 19 of the first message is a startup message, and includes an SOF (Start Of Frame) 19a indicating the start of a frame, for example, an arbitrary data bit 19b consisting of 8 bits, a parity bit 19c, and the end of data. The stop bit 19d shown in FIG.

  The CAN ID message 20 of the second message is composed of an SOF 20a indicating the start of a frame, for example, a data bit 20b consisting of 8-bit CAN ID, a parity bit 20c, and a stop bit 20d indicating the end of data. .

  Here, the wait message 19 is used for start-up waiting time processing for securing a necessary time after the on-chip oscillator 18 starts oscillating until the oscillation becomes stable. If the time until the oscillation stabilizes is sufficiently shorter than the time from when the CAN ID message is received until the CAN frame 21 is received, it is omitted and the CAN ID message 20 is transferred. Good.

  In the data bit 20b, not only the CAN ID but also one-to-one communication (communication between the master ECU and a specific ECU), simultaneous communication (communication between the master ECU and all other ECUs), or a group Information for setting a communication mode such as communication (communication between the master ECU and an ECU belonging to a specific group) may be included.

  In this master ECU, when a certain ECU transmits a message to another ECU, the sender ECU becomes the master ECU from time to time, but a specific ECU becomes the master fixedly. Also good.

  Next, the operation of the ECU 1 according to the present embodiment will be described using the flowchart of FIG.

  First, when the transceiver / receiver 13 of the CAN transceiver / receiver 2 receives a message via the CAN bus Bc (step S101), the transceiver / receiver 13 receives the message of the differential signal received via the CAN bus Bc. The digital signal is converted and output to the select circuit 14.

  The select circuit 14 determines whether the input signal is a CAN format message or a UART format message (step S102), and if it is a CAN format message, outputs the message to the MCU 5.

  Then, the MCU 5 determines whether or not the input message specifies the CAN ID of the ECU 1 itself (step S103), and if it is the CAN ID of the ECU 1, executes processing of the message (step S104).

  In the process of step S102, if the message is in the UART format, the message is output to the UART circuit 15. The UART circuit 15 determines whether the input message matches the UART format, and outputs the message to the ID determination circuit 16 when it matches.

  The ID determination circuit 16 determines whether or not the input message specifies the CAN ID of the ECU 1 (step S105). If the received message is the CAN ID of the ECU 1, the ID determination circuit 16 determines the enable signal EN as a regulator. 4 to turn on the regulator 4 to supply power to the ECU 5 and the actuator Ac (step S106). At this time, the ID determination circuit 16 performs a process of writing information indicating that the regulator 4 is in the ON state to the register 17.

  Thus, by writing information indicating that the regulator 4 is in the ON state to the register 17, there is an instruction to turn on the regulator 4 by a UART format message in a state where power is already supplied to the MCU 5. Even in this case, the process of turning on the regulator 4 by the ID determination circuit 16 can be omitted.

  When information indicating that the regulator 4 is in the ON state is written in the register 17, the timer 9 starts counting up and monitors the idle time of the CAN bus Bc. When the idle time has passed an arbitrary time, the MCU 5 outputs a power shutdown instruction signal SD to the ID determination circuit 16.

  When receiving the power cutoff instruction signal SD, the ID determination circuit 16 outputs an inactive enable signal EN to the regulator 4, turns off the regulator 4, and stops the power supply of the MCU 5 and the actuator Ac. At this time, the ID determination circuit 16 deletes information indicating that the regulator 4 is in the ON state from the register 17.

  Alternatively, the ID determination circuit 16 may output the inactive enable signal EN to the regulator 4 by the ECU serving as the master transmitting a power-off message to the ECU that is not operating.

  FIG. 6 is an operation flowchart illustrating an example of communication between the ECU 1a serving as a master ECU and the ECU 1 serving as a slave ECU.

  First, when the ECU 1a transmits a message to the ECU 1b (step S201), the CAN transceiver / receiver 2 of the ECU 1 does not turn on the regulator 4 and supplies power to the MCU 5 of the ECU 1 because the message is for the ECU 1b. Do not feed and start / message transfer.

  Subsequently, when the ECU 1a transmits, for example, the wait message 19 (FIG. 3) which is the first message in the UART format to the ECUs 1 and 1b (step S202), the CAN transceiver / receiver 2 of the ECUs 1 and 1b is activated.

  Thereafter, the CAN ID message 20 (FIG. 3) of the second message is input. If this CAN ID message 20 is addressed to, for example, the ECU 1 and the ECU 1b, the CAN transceiver / receiver 2 of the ECUs 1 and 1b The power is supplied to the MCU 5 and the actuator Ac of the ECU 1 and to the MCU 5 and the actuator Ac of the ECU 1b (step S203).

  When a CAN protocol message addressed to the ECU 1 is input, the ECU 1 performs message processing (step S204). When a CAN protocol message addressed to the ECU 1b is input, the MCU 5 of the ECU 1 processes the message. It is determined that it is not necessary, and the message is discarded (step S205).

  In step S205, when the CAN transceiver / receiver 2 also has a CAN ID filtering function, the message can be discarded without transferring the message to the MCU 5.

  Thereafter, when an arbitrary idle time of the ECU 1 elapses, the power cut-off instruction signal SD is output from the MCU 5 to the ID determination circuit 16, the regulator 4 is turned off by the ID determination circuit 16, and the power of the MCU 5 and the actuator Ac is turned on. A blocking process is executed (step S206).

  Thereby, according to the present embodiment, power is supplied only to the ECU in which CAN communication is performed, and power supply to the MCU and the actuator Ac in the ECU in which communication is not performed is stopped. The power consumption can be greatly reduced.

  Next, a filtering technique for identifying a UART frame and a CAN frame transmitted via the CAN bus Bc will be described. Here, an example of operation when 500 kps, for example, is used as the communication baud rate according to the CAN protocol will be described.

  If the baud rate of CAN communication is 500 kps, 1 bit is 2 μs. The CAN frame does not continue the same level for longer than 5 bits due to the stuffing function defined in the CAN protocol.

  Therefore, if 'Lo' continues for longer than 10 μs, it is determined that the signal is not a CAN frame SOF signal, and the signal is detected as a UART SOF.

  As shown in FIG. 7, the CAN transceiver / receiver 2 samples data at intervals of 1 μs, for example, when a falling edge is detected in the received signal. From the falling edge, the 11th sample is 10 μs. In the case of 'Lo' from the falling edge to the 12th sample, UART SOF detection is performed.

  In the UART mode, the CAN transceiver / receiver 2 ignores the CAN frame, and after detecting the UART SOF, connects the received data to the UART circuit 15 (FIG. 2) and starts UART reception.

  Then, the ID determination circuit 16 (FIG. 2) determines whether or not the CAN ID included in the UART frame and the CAN ID of the own ECU match, and if they match, the selection circuit 14 (FIG. 2). Connects the connection path to the MCU 5 (CAN mode) and inputs / outputs subsequent data to / from the MCU 5.

  Next, a CAN ID setting technique will be described.

  The CAN ID is set in, for example, the transceiver / receiver 2. For example, the CAN transceiver / receiver 2 incorporates a nonvolatile semiconductor memory exemplified as a flash memory.

  Then, the CAN ID is written into the nonvolatile semiconductor memory using a flash writer or the like. Further, not only the CAN ID is written in advance by a flash writer or the like, but, for example, when the system is started, the ECU that is the master starts all ECUs by all ECU start signals that are system start messages. Frames are transmitted, CAN IDs are acquired in the order of transmission, and stored in the nonvolatile semiconductor memory.

  In the existing communication protocol of CAN, any ECU that wishes to send a message can start sending a message if no other ECU is sending a message on the network.

  At the stage of CAN ID acquisition, any ECU cannot identify its own ECU and send a message to the master ECU, and sends a CAN ID acquisition request message using an existing communication protocol.

  In this case, a plurality of ECUs transmit CAN ID acquisition request messages, resulting in signal congestion on the network, and the master ECU may not receive the messages correctly.

  When the ECU that has transmitted the CAN ID acquisition request message detects that signal congestion has occurred on the network, the ECU once stops transmitting the message and resends the CAN ID acquisition request message after a predetermined time has elapsed. By repeating the above, CAN IDs are obtained sequentially.

  The CAN transceiver / receiver 2 may be preinstalled with a CAN ID in hardware, or may be configured to set the CAN ID using an external resistor R1 as shown in FIG. 8, for example.

  In this case, the CAN transceiver / receiver 2 is configured to include a voltage dividing resistor 22 and an A / D converter 23. The power supply voltage VDD is connected to one connection portion of the resistor R1, and one connection portion of the resistor 22 is connected to the other connection portion of the resistor R1.

  A reference potential VSS is connected to the other connection portion of the resistor 22. A connection portion between the resistor R1 and the resistor 22 is connected to an input portion of the A / D converter 23, and an output portion of the A / D converter 23 is connected to the register 17.

  The voltage divided by the resistor R1 and the resistor 22 is converted into digital data by the A / D converter 23, and the digital data is stored in the register 17, whereby the CAN ID is set. Therefore, CAN ID is set by the voltage value divided by the resistor R1 and the resistor 22.

  In addition, the CAN ID may be stored in a memory or the like provided in the MCU 5, and the CAN ID may be set in the CAN transceiver / receiver 2 by the MCU 5.

(Embodiment 2)
9 is an operation flowchart showing an example of communication between the master ECU and the slave ECU according to Embodiment 2 of the present invention, FIG. 10 is a flowchart showing an example of the operation of the master ECU in FIG. 9, and FIG. FIG. 12 is a flowchart showing an example of the operation of the slave ECU not participating in the CAN communication in FIG. 10.

  In the second embodiment, in the in-vehicle network of the automobile shown in FIG. 1 of the first embodiment, a technology for starting the communication by starting an ECU to which power is not supplied (communication by the CAN protocol is not performed). Will be described.

  FIG. 9 is an operation flowchart illustrating an example of communication between the ECU 1 serving as a master ECU and the ECUs 1a and 1b serving as slave ECUs.

  In FIG. 9, ECU1 and ECU1a are performing CAN communication, and after that, ECU1b which is not performing CAN communication is started, and operation | movement until it makes CAN communication is shown. Further, the left side of FIG. 9 shows the state of the register 17 (FIG. 2) provided in the ECU 1.

  From left to right of the register 17, state data in the ECU 1, ECU 1 a, and ECU 1 b are stored, and “1” indicates a state participating in CAN communication (hereinafter referred to as CAN mode). '0' indicates a state in which communication by the UART protocol is possible (hereinafter referred to as UART mode).

  In a state where the ECU 1 and the ECU 1a are performing CAN communication (step S301), if the ECU 1b also needs to participate in CAN communication for some reason, the ECU 1 is connected to all the ECUs that are performing CAN communication (in this case, the ECU 1a). ), A CAN communication stop frame serving as a communication stop message is transmitted (step S302).

  At this time, since the ECU 1a is in the CAN mode and the ECU 1b is in the UART mode, the data indicating the state of the ECU 1a in the register 17 is “1”, and the data indicating the state of the ECU 1b is “0”. .

  The CAN communication stop frame is not defined by the CAN protocol, and is therefore determined by the contents of the frame in the communication system. And so on.

  By setting all bits of ID (identifier) in the frame to “0” as the CAN communication stop frame, even if other ECUs are sending messages, the priority is adjusted and the highest priority is given on the CAN bus. All of the ECUs can receive this frame.

  And all ECUs (ECU1a) which are performing CAN communication will stop CAN communication, if a CAN communication stop frame is received (step S303).

  When the CAN communication is stopped, for example, the transmission of the CAN frame is stopped for an arbitrary period instructed by the ECU 1, and the pattern that automatically returns to the CAN communication when the period elapses, the CAN communication is stopped, and the MCU 5 ( Various patterns are conceivable, such as a pattern in which the power of FIG. 1) is turned off, the CAN transceiver / receiver 2 (FIG. 1) transitions to a mode for performing communication using the UART protocol, and transitions to a standby state.

  In FIG. 9, the CAN communication stop frame transmitted by the ECU 1 is a pattern in which the ECU 1a automatically returns to CAN communication when an arbitrary period instructed by the ECU 1 elapses.

  When the CAN communication is automatically restored, the CAN transceiver / receiver 2 stands by in a state where the CAN communication can be performed, and the MCU 5 is not turned off.

  Subsequently, the ECU 1 uses the technique described in the first embodiment to activate the ECU 1b that is to newly participate in CAN communication using UART protocol communication (steps S304 and S305).

  When the ECU 1b is activated, the ECU 1b participates in CAN communication, and data indicating the state of the ECU 1b in the register 17 is rewritten from “0” to “1”.

  When an arbitrary period instructed by the ECU 1 elapses, the ECU 1a automatically recovers (step S306), and all of the ECU 1, ECU 1a, and ECU 1b are participating in CAN communication (step S307). .

  As a method of stopping the CAN communication by the master ECU, in addition to stopping the CAN communication of the slave ECU by the CAN frame as described above, for example, when using optical communication or the like, a stop signal is set to a normal stop signal. It is also possible to superimpose it on the signal.

  In addition, instead of the ECU 1 outputting the CAN communication stop frame in step S302, the ECU 1b may be activated by communication of the UART protocol (referred to as step S302 ').

  In this case, the ECU 1a detects that the ECU 1 is communicating with the UART protocol, and the ECU 1a is controlled not to perform CAN communication during the communication period. When such an operation is performed, it is possible to make a transition to step S307 after performing step S302 '.

  FIG. 10 is a flowchart illustrating an example of an operation in the ECU 1 serving as a master when starting an ECU that does not perform CAN communication and starting CAN communication.

  First, when there is an ECU that does not participate in CAN communication, the ECU 1 determines whether or not the ECU needs to be activated (step S401). If it is determined that it is necessary to activate an ECU that does not participate in CAN communication, the ECU 1 determines whether the in-vehicle network system is in CAN communication (step S402).

  When the CAN communication is not being performed, a process of step S404 described later is executed. When the CAN communication is being performed, the ECU 1 transmits a CAN communication stop frame to all the ECUs participating in the CAN communication (step S403). ), The CAN communication of the ECU is stopped.

  When the CAN communication of all ECUs participating in the CAN communication is stopped, the ECU 1 activates the ECU 1b that is newly desired to participate in the CAN communication using the UART protocol communication (step S404).

  In this case, as described in the first embodiment, a UART format wait message is transferred to the first first message, and then a UART format CAN ID message is transferred to the second message.

  When the ECU to be activated is activated in the process of step S404, the CAN frame 21 in the CAN format is transferred and CAN communication is started (step S405).

  FIG. 11 shows an ECU 1a that is a slave ECU that performs CAN communication when starting an ECU 1 that does not perform CAN communication and activates an ECU 1b that does not perform CAN communication. It is a flowchart which shows an example of the operation | movement in.

  First, the ECU 1b determines whether or not the CAN transceiver / receiver 2 is in the CAN mode (step S501). In the CAN mode, the ECU 1b determines whether or not a CAN communication stop frame has been transmitted from the master ECU 1. Judgment is made (step S502).

  If the CAN communication stop frame has not been transmitted from the ECU 1, an execution process corresponding to normal CAN protocol communication is performed (step S503). When a CAN communication stop frame is transmitted from the ECU 1, based on the instruction, the CAN transceiver / receiver 2 of the ECU 1a turns off the power of the MCU 5 and stops communication using the CAN protocol (step S504).

  Then, after maintaining the state of step S504 for an arbitrary period instructed by the ECU 1 (step S505), the CAN transceiver / receiver 2 turns on the power of the MCU 5 and returns to communication by the CAN protocol (step S506). .

  Here, in the process of step S504, it is assumed that the MCU 1 of the ECU 1a is turned off by the instruction from the ECU 1 to stop the communication by the CAN protocol, but the instruction of the ECU 1 is not limited to this, but the power of the MCU 5 of the ECU 1a is also stopped. Processing that stops only communication using the CAN protocol without turning off the server may be used.

  FIG. 12 is a flowchart illustrating an example of an operation in the ECU 1b when the ECU 1 serving as a master activates the ECU 1b that is not in the CAN mode and starts CAN communication.

  First, the ECU 1b determines whether the CAN transceiver / receiver 2 is in the CAN mode or the UART mode (step S601). If the CAN transceiver / receiver 2 is in the CAN mode, an execution process corresponding to the normal CAN protocol communication time is determined. Is performed (step S602).

  In the process of step S601, in the case of the UART mode, it is determined whether or not a message in the UART format for starting the ECU has been received (step S603).

  When the message is received in the process of step S603, the ECU 1b determines whether or not the received message is a message addressed to the own ECU (1b) (step S604). Based on the message, the CAN transceiver / receiver 2 of the ECU 1b turns on the power of the MCU 5, and causes the ECU 1b to participate in CAN communication (step S605).

  As described above, the technology for starting and starting the ECU that is not supplied with power (communication by the CAN protocol is not performed) is effective for reducing damage in an emergency or preventing secondary disasters. In such a case, the message communication in the UART format in FIGS. 10 to 12 may be performed by signal superposition using different frequency bands so as not to disturb the communication in the CAN format. While performing CAN communication required for safe driving of a vehicle such as a brake and an airbag, it is possible to stop unnecessary ECU communication and activate an ECU that needs to participate in communication.

  When a radar ECU that monitors the surroundings of an automobile detects an abnormal approach of another vehicle, the seat belt is fixed before the collision occurs by activating the ECU that controls the airbag and seat belt in preparation for the occurrence of a collision accident. In addition, the airbag can be inflated immediately before / after the occurrence of the collision to reduce physical damage to the occupant. Or the approach to the pedestrian etc. of the own vehicle is detected, brake control ECU is started and deceleration control is performed, and the damage given to a pedestrian etc. can be reduced.

  For example, in the case of a fuel cell vehicle, when a gas leak such as hydrogen gas is detected at the time of a collision (the master ECU and the gas sensor ECU communicate), the master ECU controls each sunroof, window, slide door, air conditioner, etc. By starting the ECU, it is possible to ventilate the interior of the vehicle and prevent the vehicle from being filled with hydrogen gas and causing a fire or explosion.

  Further, in the case of a hybrid vehicle or an electric vehicle, if the ECU that performs power control in the event of a collision does not participate in CAN communication, the power control system ECU is activated and the battery and the battery peripheral device are connected to the fan. (And radiator) can be used for emergency cooling to prevent fire due to battery ignition.

  In addition, the corresponding ECU is activated in the event of a collision, etc., in addition to notifying the occurrence of an accident by lighting a room lamp, blinking a hazard lamp, sounding a horn, reporting by telematics, etc. When the door is locked Unlock the door for evacuation, etc.

(Embodiment 3)
FIG. 13 is an operation flowchart showing an example of communication between the master ECU and the slave ECU when the ECU according to the third embodiment of the present invention is plugged in. FIG. 14 is an operation flowchart of the master ECU during the operation of FIG. FIG. 15 is a flowchart showing an example of the operation of the existing slave ECU during the operation of FIG. 13, and FIG. 16 is a flowchart showing an example of the operation of the plugged-in slave ECU during the operation of FIG. It is.

  In the third embodiment, in the in-vehicle network of the automobile shown in FIG. 1 of the first embodiment, when the ECU is newly plugged in, the ECU information that becomes the operation recognition information of the plugged-in ECU is stored in the master. A technique for notifying the ECU will be described.

  Here, “plug-in” means that an ECU that did not exist at the time when the CAN was operating previously is newly connected to the CAN, for example, by adding or replacing a car navigation system. .

  FIG. 13 is an operation flowchart illustrating an example of communication between the ECU 1 serving as a master ECU and the ECUs 1a and 1b serving as slave ECUs when the ECU is newly plugged in. Here, in FIG. 13, it is assumed that the ECU 1b (FIG. 1) is a newly plugged-in ECU.

  The master ECU 1 is in a state where power is supplied to the MCU 5 and the CAN transceiver / receiver 2, and the slave ECU 1a is in a standby state in which the CAN transceiver / receiver 2 is in the UART mode. It is turned off. In the plugged-in ECU 1b, the CAN transceiver / receiver 2 is in a standby state in the UART mode, and the power supply of the MCU 5 is turned off.

  In FIG. 13, the slave ECUs 1a and 1b are both ECUs that perform an intermittent operation. Further, on the left side of the figure, the state of the register 17 (FIG. 2) provided in the ECU 1 is shown. From the left to the right of the register 17, the respective state data in the ECU 1, ECU 1a, and ECU 1b are stored. Yes. “1” in the register 17 indicates the CAN mode, and “0” indicates the UART mode.

  First, the ECU 1 transmits all ECU activation signals for activating all ECUs to all ECUs via the CAN bus Bc by using the UART frame (step S701).

  This all ECU activation signal is composed of, for example, two messages. The first message is a message indicating that all the ECUs are activated in the CAN ID message 20 of FIG. 4, and the second message is the activation information. It is a signal that means a message for acquisition.

  In the ECUs 1a and 1b, by receiving all ECU activation signals, the CAN transceiver / receiver 2 is activated in the CAN mode, and the power of the MCU 5 is turned on (step S702).

  Subsequently, the ECU 1 inquires whether there is a newly plugged-in ECU (step S703), and the plugged-in ECU 1b obtains ECU information (CAN ID, operation information, etc.) of its own ECU 1b based on a request from the ECU 1. It transmits to ECU1 by a CAN frame (step S704).

  Thereafter, the ECU 1 also requests ECU information from the remaining ECU 1a (step S705), and acquires the ECU information (step S706). When an arbitrary time elapses, the CAN transceiver / receiver 2 of the ECUs 1a and 1b enters a standby state in the UART mode, and the power of the MCU 5 of the ECUs 1a and 1b is turned off (step S707).

  The ECU 1 repeats the activation of the ECU 1a (step S708) and the activation of the ECU 1b (step S709) for each arbitrary period based on the ECU information acquired in the processes of steps S704 and S706.

  FIG. 14 is a flowchart showing an example of the operation of the ECU 1 serving as a master during the operation of FIG.

  First, the ECU 1 transmits all ECU activation signals to all ECUs (ECUs 1a and 1b) via the CAN bus Bc using the UART frame (step S801), and activates the CAN mode. Subsequently, the ECU 1 requests ECU information from the plugged-in ECU 1b and other existing ECUs 1a through the CAN frame (step S802).

  When the ECU 1 acquires ECU information from all ECUs, the ECU 1 stores the acquired ECU information in a buffer or the like (step S803). The ECU 1 determines whether or not the intermittent time of the ECU 1a has elapsed (step S804), and when the intermittent time has elapsed, the ECU 1 is activated by the UART frame and starts CAN communication with the ECU 1a (step S805). .

  In the process of step S804, if the intermittent time of the ECU 1a has not elapsed, the ECU 1 determines whether or not the intermittent time of the ECU 1b has elapsed (step S806), and when the intermittent time has elapsed, the ECU 1b The CAN communication with the ECU 1b is started (step S807).

  FIG. 15 is a flowchart showing an example of the operation of the existing ECU 1a serving as a slave during the operation of FIG.

  First, the ECU 1a determines whether or not the CAN transceiver / receiver 2 is in the UART mode (step S901). If the CAN mode is the CAN mode, the ECU 1a performs an execution process in accordance with normal CAN protocol communication (step S902).

  In the process of step S901, in the case of the UART mode, it is determined whether the UART frame received from the master ECU 1 is addressed to the own ECU 1a or all ECU activation signals (step S903).

  When the UART frame is addressed to the own ECU 1a or all ECU activation signals, the CAN transceiver / receiver 2 shifts to the CAN mode and turns on the power of the MCU 5 (step S904). If the UART frame is not addressed to the own ECU 1a or the whole ECU activation signal, the process returns to step S901.

  Subsequently, the ECU 1a determines whether or not there is a request for acquiring ECU information of the ECU 1a from the ECU 1 (step S905). If there is no request for acquisition of ECU information from the ECU 1a, the process of step S902 is executed.

  When there is a request for acquiring ECU information, the ECU 1a checks whether the CAN bus Bc is in an idle state for an arbitrary period (step S906). If the CAN bus Bc is in an idle state, the ECU 1a sends the ECU information of the ECU 1a to the ECU 1 using a CAN frame. Transmit (step S907).

  Then, the ECU 1a shifts the CAN transceiver / receiver 2 to the UART mode and waits for an activation message from the ECU 1 (step S908). When the activation message is received from the ECU 1 (step S909), it is determined whether the message is addressed to the ECU 1a (step S910). When the message is addressed to the ECU 1a, the ECU 1a turns on the power of the MCU 5, and The mode is changed (step S911), and the process of step S902 is executed.

  FIG. 16 is a flowchart showing an example of the operation of the plugged-in ECU 1b serving as a slave during the operation of FIG.

  First, the ECU 1b determines whether or not the CAN transceiver / receiver 2 is in the UART mode (step S1001). If the CAN transceiver / receiver 2 is in the CAN mode, the ECU 1b performs an execution process according to communication of the normal CAN protocol (step S1002). In the case of the UART mode, it is determined whether the UART frame received from the master ECU 1 is addressed to the own ECU 1b, all ECU activation signals, or an acquisition request to the plugged-in ECU (step S1003).

  If the UART frame is addressed to the ECU 1b, all ECU activation signals, or an acquisition request to the plugged-in ECU, the CAN transceiver / receiver 2 shifts to the CAN mode and turns on the power of the MCU 5 (step S1004).

  Subsequently, the ECU 1b determines whether there is an ECU information acquisition request from the ECU 1b (step S1005). When there is no ECU information acquisition request from the ECU 1b, the process of step S1002 is executed.

  If there is an ECU information acquisition request in the process of step S1005, the ECU 1b confirms whether the acquisition request is an ECU information acquisition request to the plugged-in ECU (step S1006), and then sends it to the plug-in ECU. In the case of the ECU information acquisition request, the ECU 1b determines whether or not the own ECU 1b is a plug-in ECU (step S1007).

  Further, in the process of step S1006, if it is not a request for acquiring ECU information to the plugged-in ECU, the ECU 1b executes a process of step S1008 described later, and determines in the process of step S1007 that the ECU is not a plug-in ECU. If so, the process of step S1002 is executed.

  If it is determined that the ECU 1b is a plug-in ECU, the ECU 1b checks whether the CAN bus Bc is in an idle state for an arbitrary period (step S1008). If the ECU 1b is in an idle state, the ECU 1b sends the ECU information of the ECU 1b to the ECU 1. The frame is transmitted (step S1009).

  Subsequently, the ECU 1b shifts the CAN transceiver / receiver 2 to the UART mode and waits for an activation message from the ECU 1 (step S1010). When the ECU 1b receives the activation message from the ECU 1 (step S1011), the ECU 1b determines whether the message is addressed to the ECU 1b (step S1012). If the message is addressed to the ECU 1b, the ECU 1b turns on the power of the MCU 5. Then, the mode is shifted to the CAN mode (step S1013), and the process of step S1002 is executed.

  The existing ECU (ECU 1a) connected to the CAN network and the added ECU (ECU 1b) may perform the following processing not shown in the flow of FIGS.

  In response to the ECU 1 and the ECU 1a transmitting the ECU information of the ECU (step S706 in FIG. 13), the ECU 1b stores the ECU information of the ECU 1 and the ECU 1a in a nonvolatile memory in the ECU 1b.

  Further, in response to the ECU 1b transmitting the ECU information of the ECU 1b to the ECU 1 (step S704 in FIG. 13), the ECU 1a stores the ECU information of the ECU 1b in a nonvolatile memory in the ECU 1a.

  When the ECU 1a or ECU 1b becomes the master ECU in place of the ECU 1, it is redundant to perform the processing of FIG. 14 in order to obtain the ECU information of the ECU 1a or ECU 1b, and the existing ECU 1b exists when the plug-in ECU 1b exists. All of the ECUs are shared in the information acquisition process of the plug-in ECU 1b, and the plug-in ECU similarly shares the information of all the existing ECUs in the information acquisition process.

  With this process, all ECUs connected to the CAN network hold the ECU information of the other ECUs, and the operation information acquisition process of the other ECUs is performed regardless of which ECU becomes the master ECU. It is possible to perform intermittent operation control of other ECUs.

  The above-described technology is effective for an ECU that is newly plugged in when a function that has been newly added as an option of the automobile is retrofitted.

  For example, when a rear wiper provided in a rear window of an automobile is attached by retrofitting, the body master ECU transmits all ECU start signals via the CAN bus when the power is turned on, and all ECUs Start up.

  The plugged-in ECU transmits ECU information of the plugged-in ECU to the master ECU in response to a request from the master ECU. In this case, since the plugged-in ECU is an ECU that operates the rear wiper that operates intermittently, for example, the CAN ID and the intermittent operation information of the rear wiper are transmitted as the ECU information.

  When the master ECU detects the information that the operation of the rear wiper is turned on, the master ECU activates the plugged-in ECU that controls the rear wiper according to the information.

  Here, the ECU for controlling the rear wiper has been described as an example, but the same processing is performed when various ECUs such as a navigation system and audio are added.

  In addition, since the plugged-in ECU is newly added to the optimized in-vehicle network system, if a problem occurs in the system, the probability of causing a failure is higher than that of the existing ECU. There is a possibility.

  Therefore, when a problem occurs, the necessity to verify the plug-in ECU first can be recognized. In this case, a preset CAN ID (for example, ID1 to ID16) is allocated to the existing transceiver and the CAN transceiver / receiver 2 is allocated, and other CAN IDs are allocated to the plug-in ECU. When a CAN ID other than a preset CAN ID is distributed via the CAN bus, it can be recognized as a plug-in ECU.

(Embodiment 4)
FIG. 17 is a flowchart illustrating an example of an operation in which the master ECU according to the fourth embodiment of the present invention confirms whether the slave ECU participates in CAN communication.

  In the fourth embodiment, in the in-vehicle network of the automobile shown in FIG. 1 of the first embodiment, when a slave ECU is activated by an external trigger, the slave ECU is activated relative to the master ECU. A technique for notifying the user will be described.

  FIG. 17 is a flowchart illustrating an example of an operation in which the ECU 1 serving as a master confirms whether the slave ECUs 1a and 1b are participating in CAN communication.

  In FIG. 17, it is assumed that the ECU 1b can be activated by an external trigger, and the state of the register 17 (FIG. 2) provided in the ECU 1 is shown on the left side of FIG. From left to right of the register 17, state data in the ECU 1, ECU 1 a, and ECU 1 b are stored. “1” in the register 17 indicates the CAN mode, and “0” indicates the UART mode. Yes.

  First, the ECU 1 inquires whether or not each of the ECUs 1a and 1b is activated by communication using the CAN protocol (step S1101). Here, since the ECU 1a is activated, the ECU 1a notifies the ECU 1 that it is activated (step S1102). As a result, the data indicating the state of the ECU 1a of the register 17 is “1”.

  Thereafter, when the ECU 1b is activated by an external trigger (step S1103), the MCU 5 of the ECU 1b activates the CAN transceiver / receiver 2 (step S1104). Then, the ECU 1 inquires again whether each of the ECUs 1a and 1b is activated by communication using the CAN protocol (step S1105).

  Receiving this, the ECU 1a notifies the ECU 1 that it is activated (step S1106). Since the ECU 1b is also activated, the ECU 1 is notified of the activation (step S1107). Thereby, the data indicating the state of the ECU 1a in the register 17 and the data indicating the state of the ECU 1b are each '1'.

  Since the ECU that can be activated by an external trigger needs to detect the external trigger, the MCU 5 is not turned off and is in a standby state, and the CAN transceiver / receiver 2 is activated by the external ECU from the master ECU in the UART mode. Wait for a message to activate a possible ECU.

  The master ECU inquires whether each slave ECU is activated every arbitrary time, and the ECU activated by an external trigger is directed to its own ECU, all ECU activation signals, or newly activated In any case, respond to the inquiry.

  Thereafter, the slave ECU may instruct whether to wait in the CAN mode or shift to the UART mode in accordance with an instruction from the master ECU.

  In addition, the master ECU may instruct whether the ECU activated by the external trigger waits in the CAN mode or shifts to the UART mode together with the inquiry.

  Further, the ECU itself activated by the external trigger can notify the master ECU of the activation.

  When the MCU 5 is activated by an external trigger, the MCU 5 activates the CAN transceiver / receiver 2. Subsequently, the MCU 5 performs control so as to transmit the Lo signal via the CAN bus for an arbitrary period (for example, about 1 ms), and notifies the master ECU that the ECU has started.

  The notification by the Lo signal is a one-shot transmission so that retransmission is not repeated when a CAN frame output from another ECU collides with the Lo signal from the ECU. Or in order to prevent the collision with the CAN frame which another ECU outputs, you may make it communicate using a different frequency band.

  When the master ECU detects that one of the slave ECUs is activated, the master ECU makes an inquiry to the slave ECU via communication using the CAN protocol, and obtains ECU information of the activated ECU. obtain.

  As an ECU that is activated by an external trigger, for example, there is an ECU that controls a memory sheet or the like. When the ECU is activated by a switch of the memory sheet, the activation is notified to the master ECU.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  For example, in the above-described embodiment, the ECU includes the two regulators 3 and 4 and is configured to perform ON / OFF control of the regulator 4 that supplies power to the MCU 5 and the actuator Ac by the enable signal EN. The power supply voltage may be supplied to the MCU 5 and the actuator Ac via a switch.

  In this case, the enable signal EN is a signal for ON / OFF control of the switch. When the switch is ON, power is supplied to the MCU 5 and the actuator Ac. When the switch is OFF, power is supplied to the MCU 5 and the actuator Ac. Will be stopped.

  In the above embodiment, the CAN is used as the communication network and the regulator power ON / OFF control is controlled by the UART protocol. However, for example, another communication network such as FlexRay is used as the communication network. The power supply of the regulator may be controlled by other protocols such as LIN.

  The present invention is suitable for low power consumption technology in a semiconductor integrated circuit device used in a communication system such as an automobile.

1 ECU
1a ECU
1b ECU
2 CAN transceiver / receiver 3 Regulator 4 Regulator 5 MCU
6 CAN interface 7 Communication control unit 8 RAM
9 Timer 10 Interrupt controller 11 CPU
12 ROM
13 transceiver / receiver 14 select circuit 15 UART circuit 16 ID determination circuit 17 register 18 on-chip oscillator 19 wait message 19a SOF
19b Data bit 19c Parity bit 19d Stop bit 20 CAN ID message 20a SOF
20b Data bit 20c Parity bit 20d Stop bit 21 CAN frame 22 Resistor 23 A / D converter R1 Resistor Bc CAN bus Ac Actuator Bs Internal bus

Claims (6)

A communication system in which a first electronic control device and a second electronic control device are connected by a communication bus,
The first and second electronic control units include a first communication protocol processing unit that processes a signal of the first communication protocol via the communication bus, and a second communication protocol that passes through the communication bus. A second communication protocol processing unit for processing a signal based on the ID information, and an active mode and a low power consumption mode as operation modes,
In the active mode, power is supplied to the first and second communication protocol processing units,
In the low power consumption mode, power supply to the second communication protocol processing unit is stopped,
The first electronic control unit transmits ID information indicating the second electronic control unit using the first communication protocol;
When the second electronic control device receives the ID information indicating the second electronic control device when in the low power consumption mode, the second electronic control device supplies power to the second communication protocol processing unit. Communications system. The communication system according to claim 1, wherein
The second electronic control unit includes an ID determination unit that determines whether the received ID information matches an ID of the second electronic control unit,
The ID determination unit is a communication system in which power is supplied in the low power consumption mode. The communication system according to claim 1 or 2,
The first electronic control device and the second electronic control device are configured to change the second communication protocol after the second electronic control device receives ID information indicating the second electronic control device. A communication system that performs communication using. The communication system according to claim 1 or 2,
The second electronic control unit includes a selection unit that selects one of the first communication protocol processing unit and the second communication protocol processing unit,
A communication system that selects the second communication protocol after receiving ID information indicating the second electronic control unit. The communication system according to claim 3,
A third electronic control unit having the same configuration as the second electronic control unit is connected to the communication bus;
The first electronic control unit is configured so that the first electronic control unit and the second electronic control unit communicate with each other using the second communication protocol. When in the low power consumption mode and the first electronic control device wants to start communication with the third electronic control device using the second communication protocol, a communication stop message using the second communication protocol A communication system for transmitting. The communication system according to claim 5, wherein
The first electronic control unit transmits ID information indicating the third electronic control unit using the first communication protocol after transmitting the communication stop message,
The third electronic control unit is a communication system that supplies power to the second communication protocol processing unit after receiving the ID information.

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