JP6071113B2 - Network system - Google Patents

Description

  The present invention relates to a network system including a plurality of electronic control devices.

  In offices and vehicles, a network system in which an electronic control device (also referred to as a control unit or ECU) and a communication terminal are connected is constructed. A lot of various ECUs are mounted on vehicles in accordance with computerization and high functionality.

  In particular, the ECU connected to the in-vehicle network system reduces the load on the battery by switching between two operation modes: a normal mode for normal operation and a sleep mode that consumes less power than the normal mode. . That is, when an activation signal is input to the ECU in the sleep state, the ECU transits to the normal mode (wakes up), and various controls are performed. After the control ends or when a sleep signal is input, the ECU transits to the sleep mode.

  For example, a technology is disclosed in which when an ignition switch is in an off state, an ECU that is not required for operation is set to a sleep mode, and the sleep mode of each ECU is canceled by turning on an operation switch (see Patent Document 1).

  In addition, using an interface that is normally provided on the external device side such as a TV, even when the external device is turned off (sleep mode), incoming calls to the mobile phone The technique which can alert | report via is disclosed (refer patent document 2).

Japanese Patent Laid-Open No. 04-283140 JP 2011-091699 A

Renesas Microcomputer M16C Family / M16C / 50 Series User's Manual: Hardware

  In Patent Document 1, the master ECU transmits a wake-up frame to all the connected slave ECUs for connection confirmation, and the slave ECU changes from the sleep state to the wake-up state once, and the response frame return it. Thereafter, the microcomputer in each slave ECU drives the actuator based on the communication data or external input. At this time, the slave ECU without communication data or external input returns to the sleep state. For this reason, there is a problem that power consumption for starting up the slave ECU simply for connection confirmation is wasted.

  Similarly, Patent Document 2 also transmits a wake-up command for connection confirmation. Therefore, if the incoming call is interrupted during the transition from the sleep state to the wake-up state, power consumption may be wasted. is there.

  Against the background of the above problems, an object of the present invention is to provide a network system that can check the state of a device connected to a network with low power consumption.

Means for Solving the Problems and Effects of the Invention

  A network system for solving the above problems includes a master control unit and a slave control unit group including at least one slave control unit that is communicably connected to the master control unit, and the master control unit is a slave. For all slave control units included in the control unit group, a master side transmission unit that transmits one state request signal for confirming the connection state is included, and the slave control unit is determined in advance by the slave control unit. An operation mode control unit that switches and controls a plurality of operation modes, and a slave side reception unit that receives a status request signal. When the slave side reception unit receives the status request signal, the operation mode control unit A slave that maintains the operation mode and transmits a response signal to the status request signal. Further comprising a side transmitting unit.

  With the above configuration, the slave control unit can transmit a response signal to the master control unit regardless of the operation mode of the slave control unit. Therefore, unlike the prior art, it is not necessary to transmit a response signal after the slave control unit in the sleep state wakes up, and an increase in current consumption can be suppressed. Further, since the master control unit can transmit a status request signal regardless of the operation mode of the slave control unit, the status of the slave control unit can be confirmed in a shorter time when necessary.

The figure which shows the structural example of the network system of this invention. The figure which shows the structural example of slave ECU. The flowchart explaining a response signal transmission process. The figure which shows the transmission timing of a status request and a response signal. The flowchart explaining a state confirmation process. The figure which shows another example of the transmission timing of a status request and a response signal. The flowchart explaining another example of a state confirmation process.

  The network system of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of the network system NS of the present invention. The network system NS is configured, for example, in a vehicle and connected to a communication network (hereinafter referred to as a LAN) 50. The master ECU 1 (master control unit of the present invention) and slave ECUs (10, 20, 30, 40: The slave control unit of the present invention: a generic name of these in the case where no symbol is added.

  In the example of FIG. 1, a slave ECU group is constituted by four slave ECUs. The slave ECU group only needs to include at least one slave ECU.

  In the network system NS, the slave ECU receives a communication frame transmitted from the master ECU 1, and the slave ECU performs predetermined operation control based on the content of the communication frame.

  Each of the master ECU 1 and the slave ECU is a clock generated by a known CR oscillation circuit (104, 114, 214, 314, 414) or a crystal oscillation circuit (105, 115, 215, 315, 415: the oscillation circuit of the present invention). Operates based on the signal. Details of the clock generation circuit are described in Non-Patent Document 1, for example.

  The CR oscillation circuit generates a clock signal having a relatively low frequency. The crystal oscillation circuit generates a clock signal having a higher frequency than the CR oscillation circuit.

  As shown in FIG. 1, the master ECU 1 includes at least a microcomputer 2 (a microcomputer and a state confirmation unit of the present invention) and a communication I / F 3 (a master side transmission unit and a master side reception unit of the present invention). A configuration in which a switch group, a sensor group, and an actuator group are connected as in a slave ECU described later may be used.

  The microcomputer 2 includes a well-known CPU core 101, a memory 102, peripheral circuits (not shown) such as a timer, and a clock generation circuit 103. Various functions of the master ECU 1 are realized by the CPU core 101 executing a master ECU control program stored in the memory 102 based on the clock signal generated by the clock generation circuit 103.

  The clock generation circuit 103 includes a CR oscillation circuit 104 and a crystal oscillation circuit 105 to which an oscillator 106 external to the microcomputer 2 is connected. Based on a switching command from the microcomputer 2, a clock signal from any of the oscillation circuits Is output.

  The communication I / F 3 is a communication interface circuit for performing data communication with the slave ECU via the LAN 50.

  FIG. 2 shows a configuration example of the slave ECU 10. The other slave ECUs (20, 30, 40) have the same configuration. The slave ECU 10 includes a microcomputer 11 (operation mode control unit of the present invention), an input circuit 13, a driver circuit 14, and a communication I / F 15 (slave side reception unit and slave side transmission unit of the present invention).

  Connected to the slave ECU 10 is a switch group 21 on which a user inputs an operation, for example, a sensor group 22 including a rotation sensor, a pressure sensor, a temperature sensor, and the like, for example, an actuator group 31 including a motor, a solenoid, and the like.

  The microcomputer 11 includes a well-known CPU core 111, a memory 112, peripheral circuits (not shown) such as a timer, and a clock generation circuit 113. Various functions of the slave ECU 10 are realized by the CPU core 111 executing the slave ECU control program stored in the memory 112 based on the clock signal generated by the clock generation circuit 113.

  The clock generation circuit 113 includes a CR oscillation circuit 114 and a crystal oscillation circuit 115 (which may be a ceramic oscillation circuit using a ceramic oscillator) to which an oscillator 116 external to the microcomputer 11 is connected. Based on the command, a clock signal from one of the oscillation circuits is output.

  The input circuit 13 performs signal processing such as waveform shaping and A / D conversion of input signals from the switch group 21 and the sensor group 22. The driver circuit 14 drives and controls the actuator group 31. The communication I / F 15 is a communication interface circuit for performing data communication with other ECUs via the LAN 50.

  With the above-described configuration, the slave ECU 10 (and other slave ECUs as well) can receive control commands from the master ECU 1 received via the LAN 50 or data acquired from other slave ECUs, the switch group 21 acquired via the input circuit 13, An operation control command value is calculated based on the operation states of the sensor group 22 and the actuator group 31, and drive control of the actuator group 31 is performed via the driver circuit 14.

  The master ECU 1 and the slave ECU operate based on the clock signal generated by the crystal oscillation circuit in the normal mode, which is a normal operation mode, and in the sleep mode, which is an operation mode that consumes less power than the normal mode. It operates based on the clock signal generated by the oscillation circuit.

  In the sleep mode, the slave ECU 10 is supplied with power to at least the microcomputer 11 and the communication I / F 15 and can communicate with the master ECU 1.

  The configuration of FIG. 2 corresponds to “the operation mode includes a normal mode that is a normal operation mode and a sleep mode that consumes less power than the normal mode”. With this configuration, even when the slave control unit is in the sleep mode, the response signal can be transmitted without shifting to the normal mode, so that an increase in power consumption can be suppressed.

  In addition, the configuration of FIG. 2 indicates that “the slave control unit includes a microcomputer that controls the operation of the slave control unit, and the microcomputer includes an oscillation circuit that oscillates using an oscillator connected to the microcomputer; A CR oscillation circuit that oscillates at a frequency determined based on the capacitance value of the capacitor and the resistance value of the resistor, and the slave control unit operates based on the clock signal output from the oscillation circuit in the normal mode, and sleep mode Corresponds to the one that operates based on the clock signal output from the CR oscillation circuit.

  In general, it is known that the power consumption of a CR oscillation circuit is less than that of an oscillation circuit using an oscillator (a crystal oscillator or a ceramic oscillator). With the above configuration, it is possible to suppress an increase in power consumption when a response signal is transmitted in the sleep mode.

  The response signal transmission process included in the slave ECU control program executed by the microcomputer 11 of the slave ECU 10 will be described using the slave ECU 10 as an example with reference to FIG. Note that the master ECU 1 transmits a state request signal that requests transmission of the state of the slave ECU at a predetermined timing regardless of the operation mode of the slave ECU.

  First, when a predetermined sleep mode transition condition (timeout, external command, etc.) is established, the normal mode is shifted to the sleep mode (S11). Next, when the status request signal from the master ECU 1 is received (S12: Yes), it is determined whether or not a response timing for transmitting a response signal for responding to the received status request signal has arrived. At this time, the wake-up operation is not performed. The response timing will be described later. When the response timing has arrived (S13: Yes), a response signal is transmitted to the master ECU 1 (S14).

  The above-described configuration corresponds to “the slave side transmission unit transmits a response signal when a predetermined response timing arrives after the slave side reception unit receives the state request signal”. With this configuration, even in a configuration in which one status request for all slave control units is transmitted from the master control unit, any slave control unit is selected based on the response timing (that is, the response signal reception timing at the master control unit). Can be identified as a response signal from

  Thereafter, when the wake-up request from the master ECU 1 is received (S15: Yes), the sleep mode is shifted to the normal mode (S16).

  In the above example, the operation in the sleep mode is taken as an example, but the response signal transmission process in the normal mode is configured to skip steps S11, S15, and S16.

  In the example of FIG. 1, in the master ECU 1, the slave ECU 30, and the slave ECU 40, the respective crystal oscillation circuits are operating (that is, the normal mode). Further, in the slave ECU 10 and the slave ECU 20, the respective CR oscillation circuits are operating (that is, the sleep mode). In this state, when the master ECU 1 transmits a state request signal to all the slave ECUs, all the slave ECUs can transmit a response signal without switching the operation mode.

  FIG. 4 shows the data communication state of each ECU when the response signal transmission process of FIG. 3 is executed. For the master ECU 1, transmission / reception is collectively shown for convenience, but in actuality, the configuration is such that full-duplex communication or half-duplex communication can be performed. Each ECU outputs an H level when data is not transmitted (also referred to as an idle state). The master ECU 1 transmits an L level signal at time T0 as a state request signal for all slave ECUs.

  The slave ECU detects the time (L level) from the detection of a change in the transmission signal of the master ECU 1 from the H level to the L level (that is, the fall) until the change from the L level to the H level (ie, the rise). When the L level time exceeds a predetermined value (for example, T0 × 0.8), it is determined that it is a state request.

  The slave ECU determines that the response timing has arrived when a predetermined time has elapsed from the time when the rising of the state request signal is detected, and transmits the L level signal at time T (the low level signal of the present invention) as a response signal. . The response timings of the slave ECUs (10, 20, 30, 40) are D11, D21, D31, and D41, respectively.

  In the above example, the determination criterion for the arrival of the response timing is the rise of the state request, but it may be the fall of the state request.

  The response timings (D11 to D41) are set to different times for each slave ECU, and are stored in the memory (112 etc.) in advance. The response timing may be obtained by multiplying an identification number for identifying the slave ECU by a predetermined coefficient.

  The above-described configuration corresponds to “the response timing is determined to be different from the response timing of other slave control units”. Since this configuration does not superimpose response signals from other control units, the master control unit can accurately receive response signals from all slave control units.

  For example, as in the relationship between the slave ECU 10 and the slave ECU 20, the slave ECU 20 starts transmitting the response signal before the transmission of the response signal of the slave ECU 10 is completed (that is, before the rising of the response signal is output). To do. In the example of FIG. 4, the slave ECU 20 starts to transmit a response signal when the time D <b> 21 elapses after detecting the rise of the state request from the master ECU 1. D21 = D11 (response timing of slave ECU 10) + D0 (predetermined delay time) is set. D0 is preferably smaller than the L level time T described above. Thereby, transmission of the response signal of the slave ECU 20 starts before transmission of the response signal of the slave ECU 10 ends.

  Similarly, the relationship between the slave ECU 20 and the slave ECU 30 and the relationship between the slave ECU 30 and the slave ECU 40 are the transmission of the response signal when the time D0 has elapsed from the response timing of the slave ECU that started transmission of the response signal first. Is set to start.

  Thereby, the response signal received by the master ECU 1 becomes an L level signal at time T1. Time T1 is expressed as D0 (delay time of slave ECU 20) + D0 (delay time of slave ECU 30) + D0 (delay time of slave ECU 40) + T (L level time of response signal of slave ECU 40).

  The above-described configuration is as follows: “The slave side transmission unit outputs a low level signal as a response signal for a predetermined time, and the response timing is determined by the slave side before the other slave control unit finishes transmitting the response signal. This is equivalent to “the transmission unit is determined to start transmission of the response signal”. With this configuration, the response signal from the slave control unit group becomes one low level signal. When there is a slave control unit that does not transmit a response signal, the state (for example, length) of the low-level signal changes. Based on this, the master control unit can check the state of the slave control unit group. it can.

  The master ECU 1 can receive the response signal as described above transmitted from the slave ECU and check the state of each slave ECU. Hereinafter, the state confirmation process included in the master ECU control program executed by the microcomputer 2 of the master ECU 1 will be described with reference to FIG.

  This process is: “Master control unit is a master side receiving unit that receives a response signal, and a state confirmation unit that checks the connection status of the slave control unit group based on the duration of the response signal received by the master side receiving unit. And “including”. With this configuration, it is possible to identify which slave control unit is not transmitting the response signal.

  First, a status request is transmitted to each slave ECU (S31). At the same time, when the transmission of the status request is finished, a timer for measuring the elapsed time since the end of the transmission is activated. And it waits for the fall detection of a response signal.

  When the falling edge of the response signal is not detected (S32: No), the above-mentioned elapsed time is compared with a predetermined reference time. When the elapsed time is less than the reference time (S38: No), the process returns to step S32 and waits for detection of the falling edge of the response signal. On the other hand, when the elapsed time exceeds the reference time (S38: Yes), this process ends.

  The reference time is assumed to be T1 in FIG. 4 or a predetermined value added to T1.

  Next, when the fall of the response signal is detected (S32: Yes), measurement of the L level time of the response signal is started (S33). Next, when the rising of the response signal is detected (S34: Yes), the measurement of the L level time is ended (S35).

  Next, the above-described elapsed time is compared with the reference time. When the elapsed time is less than the reference time (S36: No), it is determined that all the response signals have not been received, and the process returns to step S32 to wait for detection of the falling edge of the response signal. On the other hand, when the elapsed time exceeds the reference time (S36: Yes), the state of the slave ECU is confirmed according to the reception state of the response signal as follows (S37).

If the response signal is not received when the elapsed time exceeds D11 (that is, the falling edge of the response signal is not detected), it is determined that the slave ECU 10 is not operating normally.
If the response signal is not received when the elapsed time exceeds D21, it is determined that the slave ECU 20 is not operating normally.
If the response signal is not received when the elapsed time exceeds D31, it is determined that the slave ECU 30 is not operating normally.
If the response signal is not received when the elapsed time exceeds D41, it is determined that the slave ECU 40 is not operating normally.

  Note that the state of not operating normally includes abnormal operation of the slave ECU, disconnection of the LAN 50, disconnection of the slave ECU, and the like. Further, if the identification information of each slave ECU and the response timing (D11, D21, D31, D41) are stored in the memory 102 of the master ECU 1 in association with each other, the slave ECU that cannot receive the response signal can be specified. . This configuration is “the state confirmation unit stores the response timing in advance and identifies the slave ECU that does not transmit the response signal based on the state of the response signal received by the master side reception unit and the response timing”. It corresponds to.

  FIG. 6 shows another example of the data communication state of each ECU when the response signal transmission process of FIG. 3 is executed. The idle state of each ECU, the state request from the master ECU 1, and the state request at the slave ECU are the same as those in FIG.

  The slave ECU determines that the response timing has arrived when a predetermined time has elapsed from the time when the rise of the state request is detected, and transmits an L level signal at time T (low level signal of the present invention) as a response signal. The response timings of the slave ECUs (10, 20, 30, 40) are D12, D22, D32, and D42, respectively.

  As in FIG. 4, the rising edge of the state request is used as a reference, but the falling edge of the state request may be used as a reference. As for the response timing (D12 to D42), different times are set for each slave ECU, and are stored in the memory (112 or the like) in advance. The response timing may be obtained by multiplying an identification number for identifying the slave ECU by a predetermined coefficient.

  For example, as in the relationship between the slave ECU 10 and the slave ECU 20, after the transmission of the response signal of the slave ECU 10 is completed (that is, after the rising of the response signal is output), after a predetermined time has elapsed, Slave ECU20 starts transmission of a response signal. The response timing D22 of the slave ECU 20 is set as D22 = D12 + T + D1. D1 is preferably set smaller than the L level time T described above. D1 corresponds to the interval I1.

  Similarly, the relationship between the slave ECU 20 and the slave ECU 30 and the relationship between the slave ECU 30 and the slave ECU 40 are also the time D1 (respectively, the interval D1 after the transmission of the response signal of the slave ECU that started the transmission of the response signal ends). The transmission of the response signal is set to start when I2, I3) have elapsed.

  Thus, an H level signal at time D1 is output between the response signals of the slave ECUs.

  The above-described configuration is as follows: “The slave-side transmitter outputs a low-level signal as a response signal for a predetermined time, and the response timing is a predetermined interval after the other slave control units finish transmitting the response signal. This is equivalent to “determined to start transmitting its own response signal after a lapse of time”. With this configuration, when there is a slave control unit that does not transmit a response signal, the interval time changes, so the master control unit can check the state of the slave control unit group based on this.

  The state confirmation process included in the master ECU control program executed by the microcomputer 2 of the master ECU 1 in the state of FIG. 6 will be described with reference to FIG.

  This process is: “The master control unit checks the connection status of the slave control unit group based on the master side receiver that receives the response signal and the number of intervals of the response signal received by the master side receiver. Part ". With this configuration, it is possible to identify which slave control unit is not transmitting the response signal.

  First, a status request is transmitted to each slave ECU (S51). At the same time, when the transmission of the status request is finished, a timer for measuring the elapsed time since the end of the transmission is activated. Then, it waits for the response signal to fall.

  When the falling edge of the response signal is not detected (S52: No), the above-described elapsed time is compared with a predetermined reference time. When the elapsed time is less than the reference time (S61: No), the process returns to step S52 to wait for detection of the falling edge of the response signal. On the other hand, when the elapsed time exceeds the reference time (S61: Yes), the process proceeds to step S59.

  The reference time is assumed to be, for example, a predetermined value added to D42 + T or D42 + T in FIG.

  Next, when the falling edge of the response signal is detected (S52: Yes), it waits for the rising edge of the response signal. When the rising of the response signal is detected (S53: Yes), measurement of the H level time (that is, the interval time) is started (S54).

  Next, the above-described elapsed time is compared with the reference time. When the elapsed time is less than the reference time (S55: No), the next response signal falling detection is awaited. When the fall of the next response signal is detected (S56: Yes), the measurement of the H level time is ended (S57). Then, the measurement count of the H level time (that is, the interval time) is updated (S58). Then, the process returns to step S53.

  On the other hand, when the elapsed time exceeds the reference time (S55: Yes), the process proceeds to step S59.

  In step S59, the number of measurements of the H level time is compared with a reference value for the number of measurements. In the example of FIG. 6, the reference value is 3.

Next, the state of the slave ECU is confirmed according to the number of times of H level time measurement as described below (S60).
-When the number of measurements is equal to the reference value, it is determined that all slave ECUs are operating normally.
-When the number of measurements is not equal to the reference value, it is determined that one of the slave ECUs is not operating normally. Although the slave ECU that is not operating normally cannot be identified, it can be detected that there is some abnormality in the LAN 50 under the master ECU 1.
-When the number of measurements is zero, it is determined that all slave ECUs are not operating normally.

  Similarly to the configuration of FIG. 5, if the identification information of each slave ECU and the response timing (D12, D22, D32, D42) are stored in the memory 102 of the master ECU 1 in association with each other, the number of measurements is the reference value. When not equal to, a slave ECU that cannot receive the response signal can be identified based on the timing at which the L level signal could not be detected. This configuration corresponds to “the state confirmation unit stores the response timing in advance and identifies the slave ECU that does not transmit the response signal based on the detection state and response timing of the interval received by the master side reception unit”. .

  Although the embodiments of the present invention have been described above, these are merely examples, and the present invention is not limited to these embodiments, and the knowledge of those skilled in the art can be used without departing from the spirit of the claims. Various modifications based on this are possible.

1 Master ECU (Master Control Unit)
2 Microcomputer (status check part)
3 Communication I / F (master side transmitter, master side receiver)
10, 20, 30, 40 Slave ECU (slave control unit group, slave control unit)
11 Microcomputer (microcomputer, operation mode control unit)
15 Communication I / F (slave side receiver, slave side transmitter)
50 Communication network (LAN)
104, 114, 214, 314, 414 CR oscillation circuit 105, 115, 215, 315, 415 Crystal oscillation circuit (oscillation circuit)
103 clock generation circuit 113 clock generation circuit NS network system

Claims (6)

A master control unit;
A slave control unit group including at least one slave control unit, communicatively connected to the master control unit, and
The master control unit is
For all slave control units included in the slave control unit group, including a master side transmission unit that transmits one state request signal for confirming the connection state,
The slave control unit is
An operation mode control unit for switching and controlling a plurality of predetermined operation modes of the slave control unit;
A slave side receiving unit for receiving the state request signal;
Including
When the slave side receiving unit receives the state request signal, the operation mode control unit maintains the current operation mode,
A slave side transmitter for transmitting a response signal to the state request signal;
Further seen including,
The slave side transmission unit outputs a low level signal as the response signal for a predetermined time when a predetermined response timing arrives after the slave side reception unit receives the state request signal. ,
The network system according to claim 1, wherein the response timing is determined such that the slave side transmission unit starts transmission of a response signal before another slave control unit ends transmission of the response signal . The master control unit is
A master side receiving unit for receiving the response signal;
Based on the duration of the response signal received by the master side receiving unit, a state confirmation unit that confirms the connection state of the slave control unit group,
The network system according to claim 1, comprising: A master control unit;
A slave control unit group including at least one slave control unit, communicatively connected to the master control unit, and
The master control unit is
For all slave control units included in the slave control unit group, including a master side transmission unit that transmits one state request signal for confirming the connection state,
The slave control unit is
An operation mode control unit for switching and controlling a plurality of predetermined operation modes of the slave control unit;
A slave side receiving unit for receiving the state request signal;
Including
When the slave side receiving unit receives the state request signal, the operation mode control unit maintains the current operation mode,
A slave side transmitter for transmitting a response signal to the state request signal;
Further including
The slave side transmission unit outputs a low level signal as the response signal for a predetermined time when a predetermined response timing arrives after the slave side reception unit receives the state request signal. ,
The network system is characterized in that the response timing is determined such that transmission of its own response signal is started after a predetermined interval time has elapsed since another slave control unit ends transmission of the response signal . The master control unit is
A master side receiving unit for receiving the response signal;
Based on the number of intervals of the response signal received by the master side reception unit, a state confirmation unit for confirming the connection state of the slave control unit group,
The network system according to claim 3 , comprising: The network system according to any one of claims 1 to 4, wherein the operation mode includes a normal mode that is a normal operation mode and a sleep mode that consumes less power than the normal mode . The slave control unit includes a microcomputer that controls the operation of the slave control unit,
The microcomputer includes an oscillation circuit that oscillates using an oscillator connected to the microcomputer, and a CR oscillation circuit that oscillates at a frequency determined based on a capacitance value of a capacitor and a resistance value of a resistor,
6. The slave control unit according to claim 5, wherein the slave control unit operates based on a clock signal output from the oscillation circuit in the normal mode, and operates based on a clock signal output from the CR oscillation circuit in the sleep mode . Network system.

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