JP4225264B2 - Communication device - Google Patents

Description

  The present invention relates to a communication device including a communication unit (transceiver) connected to a network and capable of switching to a plurality of operation modes.

  Conventionally, a CAN (Controller Area Network) protocol, which is one of the CSMA / CD systems, is known as a communication protocol for a local area network (LAN) used in a vehicle.

  In this CAN protocol, an SOF (Start Of Frame) code indicating the start of a frame is used at the beginning of a frame to be used, and an identification (ID for identifying what message is assigned to the subsequent data area) ) Code is given. That is, each communication control device mounted on a network terminal constituting the LAN recognizes the start of a frame by receiving an SOF code, and identifies the frame type by using an ID code.

  In addition, the communication control apparatus having a frame to be transmitted starts frame transmission immediately if the network bus is not in use, and if the bus is in use, the bus is released (as soon as frame transmission is completed). , Start sending frames. As a result, when there are a plurality of communication control apparatuses that wish to transmit a frame, frame transmission starts simultaneously when the bus is released, so that a frame collision occurs on the bus.

  When such a frame collision occurs, the CAN protocol uses the above-described ID code to execute arbitration control that determines which frame is preferentially processed. In this arbitration control, the communication control apparatus that has transmitted the frame with the smallest ID code logical value obtains the transmission right. In general, a high priority ID code is assigned so that a frame to which a message requiring a quick response time is assigned is preferentially transmitted even if a collision with another frame occurs.

However, in each communication control device, the message transmission order is not necessarily determined in consideration of the message priority. Therefore, if the message transmission order of the low priority is the message transmission order of the high priority Earlier than that, low priority messages can delay the transmission of high priority messages. The present applicant has invented and applied for a communication control apparatus that can solve such problems (see Patent Document 1).
JP 2003-115852 A

  Incidentally, the CAN protocol is standardized by the International Organization for Standardization (ISO), and there are ISO 11898 (high speed CAN) and ISO 11519 (low speed CAN) standards.

  The low-speed CAN may be used as a communication protocol between communication control devices including a microcomputer that can receive power directly from a vehicle battery and operate regardless of the operating state of the engine. The microcomputer of such a communication control apparatus often has a low power consumption mode such as a sleep mode or a standby mode in order to reduce battery power consumption. In connection with this, some CAN transceivers that intervene between the network bus and the microcomputer and handle message transmission / reception processing also have a low power consumption mode (standby mode).

  On the other hand, the high-speed CAN is often used as a communication protocol between communication control devices that operate by receiving power supply via an ignition switch of a vehicle. For this reason, the microcomputer of the communication control device does not require the low power consumption mode, and therefore the low power consumption mode is unnecessary even in the CAN transceiver used in the communication control device. However, the CAN transceiver of the communication control apparatus using the high-speed CAN as a communication protocol may have a receive-only mode that enables only message reception.

  Thus, the operation mode used by the CAN transceiver may differ depending on the difference in the CAN protocol. When using different operation modes, since the connection form of the microcomputer of the communication control device and the CAN transceiver is different, conventionally, a control program for controlling the operation mode has been prepared individually. For this reason, the burden of creating a program is large, which causes a cost increase.

  The present invention has been made in view of the above points, and provides a communication device capable of controlling a transceiver by a common control program even when the transceiver is set to a different operation mode. Objective.

In order to achieve the above object, a communication device according to claim 1 is provided.
A communication unit that is connected to a network and transmits a message to the network and receives a message from the network;
A control unit that provides a message to be transmitted to the communication unit and acquires a message received by the communication unit,
The communication unit has at least one operation mode of a receive-only mode in which only message reception is possible and a low power consumption mode in which message transmission / reception is disabled, in addition to a normal operation mode in which message transmission / reception is possible, The operation mode of the communication unit is switched by a mode switching signal given from the control unit to the communication unit,
The control unit
Storage means for storing information related to the switchable operation mode of the communication unit by a mode switching signal;
Reference is made to information relating to the switchable operation mode stored in the storage means, and mode control means for controlling mode switching of the operation mode of the communication unit, and
An inspection device for inspecting the switchable operation mode of the communication unit is connected to the network, and a mode switching signal for the control unit to switch the operation mode of the communication unit is triggered by an inspection start signal from the inspection device. Based on the transmission / reception result of the message with the inspection apparatus in that state, the switchable operation mode of the communication unit is determined, and the determination result is stored in the storage means as information regarding the switchable operation mode. It is characterized by.

As described above, the invention described in claim 1 includes storage means for storing information related to the switchable operation mode of the communication unit. Therefore, by referring to the information stored in the storage means, it is possible to determine which operation mode can be switched, so the mode control means performs switching control to the switchable operation mode. be able to. Therefore, when the mode control means for controlling the switching of the operation mode of the communication unit is realized by the control program, it is not necessary to individually design the mode corresponding to the operation mode in the communication unit, and a common control program can be used. become.
Furthermore, in the first aspect of the present invention, an inspection device for inspecting an operation mode in which the communication unit can be switched is connected to the network, and the control unit is configured to use the inspection start signal from the inspection device as a trigger. A mode switching signal for switching the operation mode of the communication unit can be output, and the switchable operation mode of the communication unit can be determined based on the transmission / reception result of the message with the inspection device in that state, and the determination result can be switched. Information on the operation mode is stored in the storage means. Thereby, the information regarding the switchable operation mode of a communication part can be automatically memorize | stored in the memory | storage means of a control part only by connecting an inspection apparatus to a network.

  As described in claim 2, when executing the initialization process, the control unit refers to the information about the switchable operation mode stored in the storage unit, and whether or not the communication unit can switch to the receive-only mode. It is preferable to switch the communication unit to the receive-only mode when it is determined that switching is possible.

  When the initialization process is executed, an unintended transmission message may be output from the control unit to the communication unit. Therefore, when the communication unit can switch to the receive-only mode, such unintended message transmission can be prevented by switching to the receive-only mode.

  According to a third aspect of the present invention, when the control unit determines that the communication unit cannot be switched to the receive-only mode when executing the initialization process, whether or not the communication unit can be further switched to the low power consumption mode. When it is determined that switching is possible, it is preferable to switch the communication unit to the low power consumption mode. This is because unintended message transmission can be prevented by switching the communication unit to the low power consumption mode.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an ECU as a communication device connected to an in-vehicle LAN using a low speed CAN protocol. In this case, the communication speed is set to, for example, 250 kbps.

  As shown in FIG. 1, the ECU 1 includes a CAN controller 2 as a communication control device that controls communication with other ECUs according to the CAN protocol, and exchanges messages with other ECUs via the CAN controller 2. By doing so, the microcomputer 3 that executes various processes in cooperation with other ECUs, the CAN transceiver 4 for transmitting and receiving frames generated by the CAN controller 2 via the CAN bus, and the CAN transceiver 4 can be switched. And a memory 5 for storing information on the operation mode.

  As is well known, the CAN controller 2 includes a plurality of message boxes for storing messages transmitted and received between ECUs, frames the messages based on the stored values of the message boxes, and sends CAN messages via the CAN transceiver 4. Transmission control to transmit to the bus, reception control to receive a frame via the CAN transceiver 4 and extract a message, bus arbitration control (bit-by-bit non-destructive arbitration) when a frame collides on the bus, frame Communication control according to the CAN protocol, such as detection and notification of errors occurring in connection with transmission / reception of data, is executed.

  In FIG. 1, TX indicates an output terminal of a transmission frame of the CAN controller 2, and RX indicates an input terminal of a reception frame.

  In addition to the normal operation mode, the microcomputer 3 has a low power consumption mode that can reduce the power consumption by stopping the operation of the CPU and the oscillator. In other words, the low-speed CAN protocol may be used as a communication protocol between ECUs including a microcomputer that can receive power directly from a vehicle battery and operate regardless of the operating state of the engine. For this reason, the microcomputer 3 of the ECU 1 has a low power consumption mode such as a sleep mode or a standby mode in order to reduce the power consumption of the battery.

  When there is a message to be transmitted to another ECU, the microcomputer 3 identifies the ID code corresponding to the message from the content of the message, and these message and ID code are stored in the message register of the message box of the CAN controller 2 and Store in ID code register. At this time, the use specification register associated with each message box is set for transmission.

  In this way, when a message for transmission is stored in the message box of the CAN controller 2 by the microcomputer 3, the CAN controller 2 uses the stored value of the message box designated for transmission by the use designation register (( A frame is created based on the ID code and message) and transmitted through the CAN transceiver 4. The frame created at this time has an SOF (Start Of Frame) code indicating the start of the frame at the head, as described in the section of the prior art, and the ID code follows this SOF code. It will be granted.

  In addition, when there is a message to be received from another ECU, the microcomputer 3 designates the use specification register of the message box of the CAN controller 2 for reception, and an ID code corresponding to the message to be received is set in the message box. Store in ID code register.

  Then, as a reception control, the CAN controller 2 receives a frame that matches the ID code stored in the ID code register of the message box designated for reception, extracts a message from the received frame, and extracts the ID code. Store in the message register of the matched message box.

  After that, when the microcomputer 3 receives a notification that the frame has been received from the CAN controller 2 by an interrupt, a flag display, or the like, by reading the contents of the message register of the message box set for reception, A message from another ECU is received.

  The CAN transceiver 4 transmits and receives a signal that satisfies the electrical condition of a CAN bus defined in advance. The CAN transceiver 4 does not need to perform transmission / reception when the microcomputer 3 is set to the standby mode, for example, as a low power consumption mode. A low power consumption mode (for example, a standby mode) in which processing is disabled is provided.

  The operation mode of the CAN transceiver 4 is controlled by the microcomputer 3. That is, the standby (stand-by) terminal of the CAN transceiver 4 is connected to a standby instruction terminal (hereinafter referred to as STB terminal) of the microcomputer 3, and an operation mode switching signal of H level is sent from the microcomputer 3 to the standby terminal of the CAN transceiver 4. When input, the operation mode of the CAN transceiver 4 is switched from the normal operation mode to the standby mode.

  In FIG. 1, TXD indicates a transmission frame input terminal from the CAN controller 2, and RXD indicates a reception frame output terminal to the CAN controller 2. Further, C_H and C_L indicate connection terminals with the CAN bus in the CAN transceiver 4.

  The memory 5 is composed of a non-volatile memory such as an EEPROM, for example, and stores information related to a switchable operation mode in the CAN transceiver 4. For example, in the configuration shown in FIG. 1, since the CAN transceiver 4 can be switched to the standby mode, the memory 5 stores information indicating that the CAN transceiver 4 can be switched to the standby mode.

  Next, FIG. 2 is a block diagram showing a schematic configuration of the ECU connected to the in-vehicle LAN using the high speed CAN protocol. In this case, the communication speed is set to 500 kbps, for example.

  The difference in configuration between FIG. 1 and FIG. 2 is that in FIG. 1, the STB terminal of the microcomputer 3 and the standby terminal of the CAN transceiver 4 are connected, while in FIG. That is, a terminal (hereinafter referred to as RMI terminal) and a read-only mode terminal (hereinafter referred to as RM terminal) of the CAN transceiver 4 are connected. Other configurations and functions are the same as those in the example shown in FIG.

  In the configuration of FIG. 2, when an L-level mode switching signal is input from the RMI terminal of the microcomputer 3 to the RM terminal of the CAN transceiver 4, the operation mode of the CAN transceiver 4 is changed from the normal operation mode to another ECU. It is switched to the receive only mode that can only receive the message. Therefore, in the configuration of FIG. 2, the memory 5 stores information indicating that switching to the receive-only mode is possible.

  Here, some commercially available CAN transceivers 4 have a low power consumption mode and a receive only mode as an operation mode in addition to the normal operation mode (for example, TLE6250 manufactured by infineon).

  An example of switching between the plurality of operation modes will be described with reference to FIG. As shown in FIG. 3, when the input signal level to the standby terminal (Stand-by) of the above-mentioned CAN transceiver 4 is Low and the input signal level to the RM terminal is Hi, the CAN transceiver 4 is in the normal operation mode. Operates in (normal mode). From this state, when the input signal level to the standby terminal changes to Hi, the operation mode of the CAN transceiver 4 is switched to the standby mode which is the low power consumption mode. When the input signal level at the standby terminal is Hi, the operation mode of the CAN transceiver 4 is the standby mode regardless of the input signal level to the RM terminal.

  On the other hand, when the input signal level to the standby terminal is Low and the input signal level to the RM terminal is Low, the operation mode of the CAN transceiver 4 is switched to the receive-only mode. The transition to the receive-only mode can be performed from the normal mode and the standby mode.

  When such a CAN transceiver 4 having a plurality of operation modes is used in the communication apparatus shown in FIGS. 1 and 2, the connection form between the CAN transceiver 4 and the microcomputer 3 and the operation mode to be used differ depending on the CAN protocol. It will be. In this case, if a control program for controlling the operation mode of the CAN transceiver 4 is prepared individually, the burden of creating the program is large, which causes an increase in cost.

  Therefore, in the present embodiment, information related to the operation mode that can be switched in the CAN transceiver 4 is stored in the memory 5 connected to the microcomputer 3. For this reason, the microcomputer 3 can determine which operation mode the CAN transceiver 4 can be switched to by referring to the information stored in the memory 5. Therefore, the operation mode can be switched to the switchable operation mode. Control can be performed. Accordingly, a common control program can be used as a mode control program for controlling switching of the operation mode of the CAN transceiver 4.

  FIG. 4 shows a flowchart of an initialization routine for executing the initialization process of the ECU 1 as an example of switching the operation mode using a common mode control program. This initialization routine is executed, for example, at the time of power-on reset or when a reset signal is input from an operation monitoring circuit (not shown). In order to prevent unintended message transmission by executing the initialization process, the CAN transceiver 4 is switched to the receive only mode or the low power consumption mode.

  First, in step S100, it is determined with reference to the memory 5 whether the CAN transceiver 4 can be switched to the receive-only mode. As described above, when it is stored in the memory 5 that switching to the receive-only mode is possible, it is determined in step S100 that switching is possible, and the process proceeds to step S110. On the other hand, if it is determined in step S100 that switching to the receive-only mode is impossible, the process proceeds to step S120.

  In step S110, the operation mode of the CAN transceiver 4 is switched to the receive only mode by a mode switching signal. That is, an L level signal is output from the RMI terminal as a mode switching signal, and an L level signal is output from the STB terminal regardless of whether the microcomputer 3 and the CAN transceiver 4 are connected. As a result, the CAN transceiver 4 is switched to the receive only mode.

  In step S120, it is determined with reference to the memory 5 whether the CAN transceiver 4 can be switched to the low power consumption mode. As described above, when it is stored in the memory 5 that switching to the low power consumption mode is possible, it is determined in step S120 that switching is possible, and the process proceeds to step S130. On the other hand, if it is determined in step S120 that switching to the low power consumption mode is not possible, the process proceeds to step S140.

  In step S130, the operation mode of the CAN transceiver 4 is switched to the low power consumption mode by the mode switching signal. That is, an H level signal is output from the STB terminal as a mode switching signal. As a result, the CAN transceiver 4 is switched to the low power consumption mode. At this time, the signal level output from the RM terminal is arbitrary.

  If it is determined in both steps S100 and S120 that switching cannot be performed, the CAN transceiver 4 is in a state where the microcomputer 3 cannot switch the operation mode. In this case, the mode switching signal is not output to the CAN transceiver 4.

  In step S140, an initialization process of the ECU 1 is executed. As described above, when the CAN transceiver 4 can be switched to the receive-only mode at the time of executing the initialization process, the operation mode is switched to the receive-only mode, and the switch to the receive-only mode is performed. If it is not possible and switching to the low power consumption mode is possible, the mode is switched to the low power consumption mode. For this reason, there is a possibility that an unintended transmission message is output from the microcomputer 3 to the CAN transceiver 4 during the initialization process of the ECU 1, but by switching the CAN transceiver 4 to the receive only mode or the low power consumption mode, Such unintended message transmission can be prevented.

  When the initialization process of the ECU 1 is completed, the operation mode of the CAN transceiver 4 is switched to the normal mode in step S150.

  Next, a configuration and procedure for automatically storing information on the switchable operation mode in the CAN transceiver 4 in the memory 5 will be described with reference to FIGS. 5 and 6. FIG. 5 is a block diagram showing a configuration for storing information relating to the switchable operation mode of the CAN transceiver 4 in the memory 5, and FIG. 6 is a flowchart showing the procedure thereof.

  As shown in FIG. 5, the inspection device 6 is connected to the CAN bus. This inspection device 6 is for inspecting the switchable operation mode of the CAN transceiver 4. Specifically, the inspection device 6 gives an inspection start signal to the ECU 1 and measures a predetermined time from the start of the inspection. When a predetermined message is received from the ECU 1 during measurement of the predetermined time, a response message in response to the message is returned to the ECU 1. On the other hand, if a message from the ECU 1 is not received even when measurement for a predetermined time is completed, a message indicating that no message has been received is output to the ECU 1.

  When there are a plurality of switchable operation modes in the ECU 1, the inspection device 6 repeatedly transmits the above-described inspection start signal and message. Thereby, it is possible to check whether or not the operation mode can be used for each operation mode. Furthermore, since a plurality of ECUs are connected to the CAN bus, the inspection device 6 sequentially transmits an inspection start signal to each ECU.

  Processing contents executed in the microcomputer 3 of the ECU 1 in order to store in the memory 5 information related to the switchable operation mode when an inspection start signal is transmitted from the inspection device 6 will be described with reference to the flowchart of FIG. To do.

  In step S200, it is determined whether an inspection start signal has been received. If it is determined in this determination process that an inspection start signal has been received, the process proceeds to step S210. If it is determined that the inspection start signal has not been received yet, it waits until the inspection start signal is received.

  In step S210, a mode switching signal is output so that the CAN transceiver 4 can be switched to the low power consumption mode (standby mode). In a subsequent step S220, a predetermined message is transmitted to the inspection device 6.

  As described above, the inspection device 6 measures a predetermined time from the start of the inspection, and when receiving a predetermined message from the ECU 1 during the measurement, returns a response message in response to the message to the ECU 1. In step S230, it is determined whether or not this response message has been received. The predetermined time in step S230 is set longer than the predetermined time measured by the inspection device 6.

  When the ECU 1 receives the response message, since the CAN transceiver 4 has transmitted and received the message, it can be determined that switching to the low power consumption mode is not possible (step S250). Conversely, if the ECU 1 does not receive a response message, the ECU transceiver 1 does not receive a response message in spite of the fact that the ECU 1 and the inspection device 6 each transmitted a message, so the CAN transceiver 4 switches to the low power consumption mode. It is possible to determine that message transmission / reception has not been executed (step S240).

  Next, in step S260, in order to inspect another operation mode (receive only mode), reception of an inspection start signal is waited, and when an inspection start signal is received, the process proceeds to step S270.

  In step S270, a mode switching signal is output so that CAN transceiver 4 can be switched to the receive-only mode. In a subsequent step S280, a predetermined message is transmitted toward the inspection device 6.

  When the inspection device 6 receives a predetermined message from the ECU 1 during measurement for a predetermined time from the start of the inspection, the inspection device 6 returns a response message in response to the message to the ECU 1, and outputs a message indicating that if not received. . In step S290, it is determined whether the message received by ECU1 is a response message or a message indicating that no message has been received from ECU1.

  If the message received by the ECU 1 is a response message, since the CAN transceiver 4 has transmitted and received the message, it can be determined that switching to the receive-only mode is not possible (step S310). Conversely, when a message indicating that the message from the ECU 1 has not been received has been received, since the CAN transceiver 4 has only received the message, it can be determined that switching to the receive-only mode is possible (step S300).

  Finally, in step S320, the inspection result of each operation mode is stored in the memory 5 as information indicating the switchable operation mode.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made.

  For example, in the above-described embodiment, after the connection between the memory 5 and the microcomputer 3, information related to the switchable operation mode of the CAN transceiver 4 is stored in the memory 5 by the microcomputer 3. However, before the memory 5 is connected to the microcomputer 3, information regarding the switchable operation mode of the CAN transceiver 4 may be stored in the memory 5 in advance.

  In the above-described embodiment, the initialization routine has been described as an example of switching the operation mode of the CAN transceiver 4. However, for example, when the microcomputer 3 itself shifts to the low power consumption mode, the operation mode of the CAN transceiver 4 is changed. It can be applied in any case as long as switching is necessary.

It is a block diagram showing schematic structure of ECU as a communication apparatus connected to in-vehicle LAN using a low speed CAN protocol. It is a block diagram showing the schematic structure of ECU connected to in-vehicle LAN using a high speed CAN protocol. It is explanatory drawing for demonstrating an example of switching of the several operation mode in a CAN transceiver. It is a flowchart of the initialization routine for performing the initialization process of ECU1. It is a block diagram which shows the structure for memorize | storing in the memory the information regarding the switchable operation mode of a CAN transceiver. It is a flowchart which shows the processing content performed in a microcomputer in order to memorize | store the information regarding the switchable operation mode in a memory, when a test | inspection start signal is transmitted from a test | inspection apparatus.

Explanation of symbols

1 ECU
2 CAN Controller 3 Microcomputer 4 CAN Transceiver 5 Memory 6 Inspection Device

Claims (3)

A communication unit that is connected to a network and transmits a message to the network and receives a message from the network;
A control unit that gives a message to be transmitted to the communication unit and obtains a message received by the communication unit,
In addition to the normal operation mode in which messages can be transmitted and received, the communication unit has at least one operation mode of a receive only mode in which only message reception is possible and a low power consumption mode in which message transmission / reception is disabled. The operation mode of the communication unit is switched by a mode switching signal given from the control unit to the communication unit,
The controller is
Storage means for storing information related to the switchable operation mode of the communication unit by the mode switching signal;
Reference is made to information related to the switchable operation mode stored in the storage means, and mode control means for controlling mode switching of the operation mode of the communication unit , and
An inspection device for inspecting the switchable operation mode of the communication unit is connected to the network, and the control unit is configured to switch the operation mode of the communication unit using an inspection start signal from the inspection device as a trigger. Based on the transmission / reception result of the message with the inspection apparatus in the state that outputs the mode switching signal, the switchable operation mode of the communication unit is determined, and the determination result is information on the switchable operation mode. And storing in the storage means .   When executing the initialization process, the control unit refers to information on the switchable operation mode stored in the storage unit, determines whether the communication unit can be switched to the receive-only mode, and switches The communication apparatus according to claim 1, wherein when it is determined that the communication unit is possible, the communication unit is switched to a receive-only mode.   When the control unit determines that the communication unit cannot be switched to the receive-only mode when executing the initialization process, the control unit further determines whether or not the communication unit can be switched to the low power consumption mode. The communication apparatus according to claim 2, wherein the communication unit is switched to a low power consumption mode when it is determined.

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