Intermediary device

Abstract

A switching device (10) designed to switch data between several buses, wherein one or more nodes (51, 52, 61, 62, 63, 71, 72, 73) are connected to the respective buses, wherein at least one of the nodes is defined as a special node, the special node being designed to transition between several states, including a transmit-enabled state and a transmit-incapable state, wherein data transmission is possible in the transmit-enabled state, whereas data transmission is not possible in the transmit-incapable state, and wherein the special node transitions from the transmit-enabled state to the transmit-incapable state when a predetermined node transition time has elapsed since the occurrence of a predetermined event, the switching device comprising: several communication sections (16, 17, 18) designed to perform sending and receiving data and to transition between states including the transmit-enabled state and the transmit-disabled state, the communication sections being connected to the buses in a one-to-one relationship; and a state control section (S110, S220, S130, S140, S150) designed to cause a special communication section to transition from the transmit-enabled state to the transmit-disabled state when a switching transition time has elapsed since the occurrence of the predetermined event, wherein the special communication section represents at least one of the communication sections to which at least one of the buses connected to the special node is connected, and wherein the switching transition time is calculated by adding a predetermined additional time to the node transition time.

Description

Technical field

[0001] The present invention relates to a technique for transmitting data between multiple buses. State of the art

[0002] The communication system disclosed in JP 2002-026957A, for example, transitions from a transmit-enabled state, which enables a switching device to transmit data, to a transmit-incapable state, which prevents the switching device from transmitting data when there is no data to be transmitted. This configuration reduces the power consumption of the switching device. The switching device transmits data when it is in the transmit-incapable state. In this case, each node sends a wake-up frame, which is not the data to be transmitted, to the switching device when the switching device is in the transmit-incapable state.With this configuration, each node causes the switching device to transition from the transmit-unable state to the transmit-enabled state and sends the data to be switched.

[0003] JP 2016-158142A discloses a switching device designed to transmit data between multiple buses, wherein multiple nodes are connected to the respective buses, one of the nodes being defined as a special node, the special node being designed to transition between multiple states, including a transmit-enabled state and a transmit-incapable state, wherein data transmission is possible in the transmit-enabled state, while data transmission is not possible in the transmit-incapable state, and wherein the special node transitions from the transmit-enabled state to the transmit-incapable state when a predetermined node transition time has elapsed since the occurrence of a predetermined event, the switching device having multiple communication sections designed to perform sending and receiving data.where the communication sections are connected to the buses in a one-to-one relationship.

[0004] JP 2007-30 714 A discloses a communication system for a vehicle in which multiple networks are formed by dividing several control units into more than three groups and connecting the control units for each group via a communication cable. Gateway units (GWs) are provided between each network for forwarding data. Data from a low-power mode is transmitted after a specified time, and data from a high-power mode is transmitted to a variety of networks until the specified time has elapsed, even if one of the GW units, acting as a centrally controlled GW unit, receives data indicating the possibility of switching to the low-power mode. Summary of the invention

[0005] The issue described below was identified as a result of a detailed investigation by the inventor of this application. The inventor discovered that configuring the communication system described above as a whole becomes complicated because each node must have a configuration for activating the switching device.

[0006] According to one aspect of the present invention, it is advantageous if the communication system, which includes the switching device that mediates the data between the buses, has a simplified structure and prevents the switching device from being unable to mediate the data.

[0007] According to one aspect of the present invention, a mediating device comprises several communication sections and a state control section. The mediating device mediates the data between several buses, each of which is connected to one or more nodes.

[0008] At least one of the nodes is defined as a special node. This special node transitions between several states, including a transmit-enabled state and a transmit-disabled state. The transmit-enabled state allows the special node to send data. The transmit-disabled state prevents the special node from sending data. The special node transitions from the transmit-enabled state to the transmit-disabled state when a predetermined node transition time has elapsed since the occurrence of a predetermined event.

[0009] The communication segments perform data transmission and reception, transitioning between several states, including a transmit-enabled state and a transmit-disabled state. The communication segments are connected to the buses in a one-to-one relationship. The state control segment causes a specific communication segment to transition from the transmit-enabled state to the transmit-disabled state after a switching transition time has elapsed since the occurrence of a predetermined event. The switching transition time is a predetermined additional time added to a node transition time. The specific communication segment represents at least one of the communication segments to which at least one of the buses connected to the specific node is linked.

[0010] In the switching device, the switching transition time, during which the special communication segment changes from the transmit state to the transmit-incapable state, is set to be longer than the node transition time, during which the special node changes from the transmit state to the transmit-incapable state. While the special node is in the transmit state, the switching device, in this configuration, can prevent the special communication segment from changing to the transmit-incapable state. Thus, this configuration can simplify the structure of the communication system and prevent the switching device from being unable to relay the data sent by the special communication segment due to the switching device being in the transmit-incapable state.

[0011] The reference numerals in parentheses in the claims simply indicate a correspondence to specific devices described in the embodiments that provide an example of the present invention. That is to say, the technical scope of the present invention is not necessarily limited thereto. Brief description of the drawings Fig. Figure 1 is a block diagram showing a configuration of a communication system 1. Fig. Figure 2 is a diagram showing a state transition in a transceiver. Fig. Figure 3 is a flowchart showing node processing. Fig. Figure 4 is a flowchart showing gateway processing. Fig. Figure 5 is a diagram showing a timing diagram for the operation of a switching device. Embodiments for carrying out the invention

[0012] In the following, embodiments of the present invention are described with reference to the drawings. 1. First embodiment1-1. Configuration

[0013] The in Fig. The communication system 1 shown in Figure 1 is mounted on a vehicle, such as a passenger car. The communication system 1 includes a switching device 10 and several nodes 51, 52, 61, 62, 63, 71, 72, 73. Hereinafter, nodes 51, 52, 61, 62, 63, 71, 72, 73 will also be referred to as node 30 when all nodes 51, 52, 61, 62, 63, 71, 72, 73 are to be represented. Each of the nodes 30 will also be referred to as node 30.

[0014] The switching device 10 includes a controller 11, a bus-A transceiver 16, a bus-B transceiver 17 and a bus-C transceiver 18. The bus-A transceiver 16, the bus-B transceiver 17 and the bus-C transceiver 18 are collectively referred to as bus transceivers 16, 17, 18.

[0015] The Bus A transceiver 16 is connected to Bus A5, which is a communication line, and performs data transmission and reception with Bus A5. Nodes 51 and 52 are connected to Bus A5.

[0016] The Bus B transceiver 17 is connected to Bus B6, which is a communication line, and performs data transmission and reception with Bus B6. Nodes 61 and 62 are connected to Bus B6.

[0017] The Bus-C transceiver 18 is connected to Bus C7, which is a communication line, and performs data transmission and reception with Bus C7. Nodes 71, 72, and 73 are connected to Bus C7.

[0018] The switching device 10 communicates with the node 30 using any communication protocol via the corresponding bus 5, 6, 7. For example, a CAN protocol (CAN: Control Area Network; registered trademark) can be used as the communication protocol.

[0019] The switching device 10 and the node 30 generate and send frames including an event frame and a communication request frame according to the send request generated by the controller 11 and the management unit 31, and the communication request frame received via the respective buses 5, 6, 7.

[0020] The send request represents a command to send data generated by the controller 11 or the management unit 31 by executing any application. The event frame represents a frame of high importance, indicating, for example, a warning or a message. The communication request frame represents a request to send data from another node, including the switching device 10.

[0021] The controller 11 contains a known microcomputer comprising a CPU 12 and semiconductor memory (hereinafter referred to as memory 13), such as RAM, ROM, or flash memory. Various functions of the controller 11 are achieved by the CPU 12 executing a program stored in a non-volatile memory medium. The non-volatile memory medium represents a storage medium exclusively for electromagnetic waves. In this example, memory 13 corresponds to the non-volatile memory medium for storing a program. When the program is executed, a procedure is carried out according to the program. The number of microcomputers comprising the controller 11 can be one or more.

[0022] The controller 11 comprises a state transition function, a gateway processing function as described later, and a known mediation function that mediates the data, each provided as a configuration of a function achieved by the CPU 12 executing a program. The state transition function causes the state of the respective bus transreceivers 16, 17, 18 to change. A method for implementing these elements that constitute the controller 11 is not limited to software, and some or all of the elements can be achieved using one or more hardware elements.For example, if the above functions are to be achieved by an electronic circuit, which is hardware, the electronic circuit can be achieved by a digital circuit containing a large number of logic circuits, an analog circuit, or a combination of the digital circuit and the analog circuit.

[0023] As it is in Fig. As shown in Figure 2, the control unit 11, acting as a state transition function, causes the operating state of the respective bus transceivers 16, 17, 18 to change individually from a transmit and receive permission state, a receive permission state, and a transmit and receive prohibition state.

[0024] In the transmit and receive permission state, each of the bus transceivers 16, 17, 18 is able to transmit and receive the data.

[0025] In the receive-only state, each of the bus transceivers 16, 17, and 18 is unable to transmit data but is able to receive it. The power consumption in the receive-only state is lower than the power consumption in the transmit and receive-only state.

[0026] In the transmit and receive prohibited state, each of the bus transceivers 16, 17, and 18 is unable to transmit or receive data. The energy consumption in the transmit and receive prohibited state is significantly lower than the energy consumption in the receive permitted state.

[0027] As it is in Fig. As shown in Figure 2, the controller 11 causes the bus transceivers 16, 17, 18 to transition to the allow-receive state if they are in the allow-transmit state and a condition described in gateway processing is met. The controller 11 does not cause each of the bus transceivers 16, 17, 18 to transition from the allow-transmit state to the block-transmit state without overriding the allow-receive state.

[0028] It is now assumed that one of the bus transceivers 16, 17, 18 is in the receive-enabled state and a communication request is issued by a corresponding bus from buses 5, 6, 7. In this case, the controller 11 causes the corresponding transceiver 16, 17, 18, which is connected to the one bus 5, 6, 7 issuing the communication request, to transition to the transmit-and-receive-enabled state. "The communication request is issued" represents a case in which a data transmission request is issued to the switching device 10, a case in which a communication request frame is received from another node 30, and similar scenarios.

[0029] It is now assumed that the bus transceiver 16, 17, 18 is in the receive-allowed state and that no communication request is issued during a predetermined sleep time t2. In this case, the controller 11 causes the transceiver 16, 17, 18 to enter the transmit-and-receive-disabled state.

[0030] It is now assumed that one of the bus transceivers 16, 17, 18 is in the receive-blocked state and a communication request is issued by a corresponding bus 5, 6, 7. In this case, the controller 11 causes the corresponding transceiver 16, 17, 18, which is connected to the bus 5, 6, 7 that issues the communication request, to transition to the transmit-and-receive-allowed state. The controller 11 does not cause the bus transceiver 16, 17, 18 to transition from the transmit-and-receive-blocked state to the transmit-and-receive-allowed state without overriding the transmit-and-receive-allowed state.

[0031] As a switching function, the switching device 10 has a known function for switching data between the buses 5, 6, 7 to which the nodes 30 are connected. The controller 11 receives the communication request frame, which is sent by one node 30 connected to one bus 5, 6, 7 and is to be received by another node 30 connected to a different bus 5, 6, 7, via the corresponding bus transceiver 16, 17, 18. The controller 11 forwards the received communication request frame to one of the buses 5, 6, 7 that corresponds to the destination.

[0032] The following describes node 30. Since each of the nodes 30 has the same configuration and the same communication functions, node 51 is described as representative of the nodes 30.

[0033] As it is in Fig. As shown in Figure 1, node 51 contains a management unit 31 and a transceiver 32. The management unit 31 has a similar hardware configuration to the controller 11 of the switching device 10. Furthermore, the management unit 31 has similar data transmission and reception functions and state transition functions to the controller 11. As will be described later in the node processing section, the times at which the transition from the transmit / receive permission state to the receive permission state is set are different for the management unit 31 and the controller 11.

[0034] The transceiver 32 performs sending and receiving of data between buses 5, 6, 7 similarly to the bus transceivers 16, 17, 18 of the switching device 10. 1-2. Processing

[0035] The following describes the node processing performed by the management unit 31 of node 51, with reference to the flowchart of the Fig. 3 described. Node processing can be started when the transceiver 32 of node 51 enters the transmit and receive allow state. The management unit 31 has a timer function for measuring time. During node processing, the management unit 31 measures a time since the last transmission of the communication request frame to the bus and a duration that indicates the time the receive allow state has been maintained since the transition to the receive allow state.

[0036] In node processing, which is in Fig. As shown in Figure 3, the management unit 31 maintains the transmit and receive permission state in S110. In S120, the management unit 31 determines whether the transceiver 32 meets a condition for transitioning to the receive permission state. The condition under which the transceiver 32 transitions to the receive permission state includes the elapse of a node transition time t1 or the receipt of a transition command frame. The node transition time t1 is counted from the time the communication request frame is sent by node 51 or another node to bus 5, 6, 7 connected to transceiver 32. The transition instruction framework represents the transition to the receive-allow state of transceiver 32. That is, the conditions under which node 51 transitions to the receive-allow state include a case where the transition is determined by node 51 and a case where the transition is instructed by another node.

[0037] If the condition for transitioning to the receive permission state is not met, the processing of management unit 31 reverts to operation in S110. If the condition for transitioning to the receive permission state is met, management unit 31 in S130 causes transceiver 32 to transition to the receive permission state.

[0038] Subsequently, in S140, the administrative unit 31 compares the duration of the receive permission state with the predetermined sleep time t2. If the duration of the receive permission state is shorter than the sleep time t2, the administrative unit 31 returns to operation in S130.

[0039] If the duration of the receive permission state is equal to or greater than the sleep time t2, the management unit 31 in S150 causes the transceiver 32 to transition from the receive permission state to the transmit and receive prohibition state. Once the operations described above are complete, node processing is terminated.

[0040] The control unit 11 of the switching device 10 executes the in Fig. 4 shows gateway processing. The controller 11 of the switching device 10 performs the gateway processing for the bus transceivers 16, 17, 18 when the bus transceivers 16, 17, 18 enter the transmit and receive permission state. The controller 11 has a timer function for measuring time. In gateway processing, the controller 11 measures the time since the last transmission of the communication request frame to the bus by the respective bus transceivers 16, 17, 18 and the duration, similar to node processing.

[0041] Gateway processing involves almost identical processing to node processing, but operation in S220 is performed instead of operation in S120 of node processing. In S220, controller 11 determines whether the bus transceivers 16, 17, 18 meet a condition for transitioning to the allow-to-receive state.

[0042] The condition under which bus transceivers 16, 17, 18 enter the receive-allow state differs from the condition under which transceiver 32 enters the receive-allow state. Specifically, the condition under which bus transceivers 16, 17, 18 enter the receive-allow state includes the elapse of a switching transition time t1 + α or the elapsed time of another node connected to bus 5, 6, 7. The switching transition time t1 + α is counted from the time the communication request frame is sent by bus transceivers 16, 17, 18. During the switching transition time t1 + α, a predetermined additional time α is added to the node transition time t1 described above.

[0043] That is, if the communication request framework is not sent, the controller 11 maintains the transmit and receive permission state for an additional time α longer than the node transition time t1, and then transitions to the receive permission state. The additional time α can be set to any value. In the present embodiment, the additional time α is set to a value greater than zero and equal to or less than the sleep time t2.

[0044] The additional time α can be set according to a transmit cycle, which specifies a cycle with which node 30 sends the data based on the transmit request. A lower or upper limit of the additional time α can be set based on a natural multiple of the transmit cycle. It is now assumed that the lower limit of the additional time α is set to a natural multiple of the transmit cycle. In this case, the switching device 10 can reliably receive the data sent by node 30 based on the transmit request during the additional time α.

[0045] In this configuration, once the switching transition time t1 + α has elapsed, the controller 11 causes the bus transceivers 16, 17, 18 to transition from the transmit-enabled state to the receive-enabled state. Once the sleep time t2 has elapsed after the node transition time t1 has passed, the controller 11 causes the bus transceivers 16, 17, 18 to transition to the transmit-and-receive-disabled state.

[0046] The condition under which the bus transceiver 16, 17, 18 enters the receive-allow state includes the reception of the transition command frame and the elapse of the additional time α since its reception. The transition command frame indicates that the transceiver 32 enters, or will enter, the receive-allow state. That is, even if the transition command frame is received, the switching device 10 does not immediately enter the receive-allow state, but rather enters it after the additional time α has elapsed.

[0047] That is, the condition under which the bus transceiver 16, 17, 18 enters the allow-to-receive state is set to the elapse of the time at which the additional time α is added to the condition of entering the allow-to-receive state for the node.

[0048] Once S220 has finished operating, operations in S130 and the other operations mentioned above will be executed. When operations in S150 have finished, gateway processing will also end.

[0049] An example of the operation of data transmission between a communication node A and a communication node B via the switching device 10 is given with reference to Fig. 5 described. Communication node A is one of nodes 30. Communication node B is another of nodes 30, connected to a different bus (5, 6, 7) than the bus of communication node A. It is assumed that communication node A sends a communication request frame requesting the transmission of some type of data to communication node B. In this case, communication node A first sends the communication request frame to switching device 10.

[0050] The switching device 10 sends the communication request frame to bus 5, 6, 7, which is connected to communication node B. In the state where no data transmission request is present at the switching device 10, the switching device 10 resets the switching transition time t1 + α, and clocking or counting of the switching transition time t1 + α is started when the communication request frame is received.

[0051] It is now assumed that the transmission request continues to be issued for a while after communication node A has initiated transmission of the communication request frame. In this case, communication node A starts a clocking or counting of the node transition time t1 after the transmission of the communication request has ended. That is, there may be a case in which the time at which switching device 10 starts a clocking or counting of the switching transition time t1 + α differs from the time at which communication node A starts a clocking or counting of the node transition time t1.

[0052] In this case, the switching device 10 may receive an event frame or similar from communication node A after the node transition time t1 has elapsed. In the present embodiment, the bus transceiver 16, 17, 18 of the switching device 10 maintains the transmit and receive permission state until the switching transition time t1 + α has elapsed. With this configuration, the bus transceiver 16, 17, 18 can maintain the transmit and receive permission state until the node transition time t1 has elapsed at communication node A. Even if a frame to be transmitted from communication node A is received after the node transition time t1 has elapsed, the switching device 10 can easily transmit the frame with this configuration. 1-3. Effects

[0053] According to the first embodiment described in detail above, the following effects can be achieved.

[0054] (1a) In the communication system 1 described above, the switching device 10 contains the bus transceivers 16, 17, 18 and the controller 11. The switching device 10 transmits the data between the buses. Each of the buses is connected to one or more nodes 30.

[0055] A special node, representing at least one of the 30 nodes, transitions between several states, including a transmit-enabled state and a transmit-incapable state. In the transmit-enabled state, the special node can send data. In the transmit-incapable state, the special node cannot send data. The special node transitions from the transmit-enabled state to the transmit-incapable state after the predetermined node transition time t1 has elapsed since the occurrence of the predetermined event.

[0056] The bus transceivers 16, 17, 18 are arranged in a one-to-one relationship with the buses. Each of the bus transceivers 16, 17, 18 performs sending and receiving data and transitions between several states, including the transmit-enabled state and the transmit-disabled state.

[0057] The controller 11 causes a special bus transceiver to transition from the transmit-enabled state to the transmit-disabled state when the switching transition time t1 + α has elapsed since the occurrence of the predetermined event. The switching transition time t1 + α is obtained by adding the node transition time t1 to the predetermined additional time α. The special bus transceiver represents one of the bus transceivers 16, 17, 18, which performs transmitting and receiving data over the bus connected to the special node.

[0058] The node transition time t1, during which the special node transitions from the transmit-enabled state to the transmit-incapable state, is set to be longer than the switching transition time t1 + α, during which the special bus transceiver 16, 17, 18 transitions from the transmit-enabled state to the transmit-incapable state. While the special node is in the transmit-enabled state, the switching device 10 described above can thus prevent the special bus transceiver 16, 17, 18 from transitioning to the transmit-incapable state. This configuration simplifies the structure of the communication system 1 and prevents the switching device 10 from being unable to transmit data due to the transmit-incapable state when the special bus transceiver 16, 17, 18 is transmitting data.

[0059] (1b) In the communication system 1 described above, all nodes 30 are arranged as special nodes. In the switching device 10, each bus transceiver 16, 17, 18 is arranged as a special bus transceiver. The controller 11 causes each of the special bus transceivers to transition from the transmit-enabled state to the transmit-disabled state.

[0060] In the switching device 10, each of the bus transceivers 16, 17, 18 is arranged as a special bus transceiver. The node transition time t1, during which the special node transitions from the transmit-enabled state to the transmit-incapable state, is set to be longer than the switching transition time t1 + α, during which the special bus transceiver 16, 17, 18 transitions from the transmit-enabled state to the transmit-incapable state. Thus, the configuration can prevent the respective bus transceivers 16, 17, 18 from transitioning to the transmit-incapable state when all nodes 30 are in the transmit-enabled state.

[0061] (1c) In the communication system 1 described above, the special node transitions between the states containing the receive-enabled state and the transmit-and-receive-disabled state, each provided as a transmit-disabled state. In the receive-enabled state, the special node cannot transmit data but can receive it. In the transmit-and-receive-disabled state, the special node cannot transmit or receive data. When the node transition time t1 has elapsed, the special node transitions from the transmit-enabled state to the receive-enabled state. When the predetermined sleep time t2 has elapsed after the node transition time t1 has elapsed, the special node transitions from the receive-enabled state to the transmit-and-receive-disabled state.In the switching device 10, the switching transition time t1 + α is set to be equal to or less than the sum of the node transition time t1 and the sleep time t2.

[0062] With this configuration, the switching device 10 can quickly transition from the transmit-enabled state to the transmit-disabled state after the special node has entered the transmit-and-receive-blocked state. Thus, the configuration can save energy and reliably transmit data.

[0063] (1d) In the communication system 1 described above, the respective bus transceivers 16, 17, 18 of the switching device 10 transition between the states containing the receive permission state and the transmit and receive prohibition state, each of which is provided as a transmit incapacity state.

[0064] The above-described switching device 10 can enter the transmit and receive prohibition state as a transmit incapacity state, so that the configuration can save energy.

[0065] (1e) In the communication system 1 described above, the controller 11 of the switching device 10 causes the special bus transceiver 16, 17, 18 to transition from the transmit state to the receive state when the switching transition time t1 + α has elapsed. When the sleep time t2 has elapsed after the node transition time t1 has elapsed, the controller 11 causes the bus transceiver 16, 17, 18 to transition from the receive state to the transmit and receive prohibition state.

[0066] The switching device 10 described above can cause the special bus transceiver to enter the transmit and receive prohibition state in conjunction with the transition of the special node to the transmit and receive prohibition state. 2. Other embodiments

[0067] Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications within the present invention are possible.

[0068] (2a) In the embodiment described above, each of the nodes 30 serves as a special node, but the present invention is not limited to this. For example, at least one of the nodes 30 can serve as a special node.

[0069] (2b) In the embodiment described above, all bus transceivers 16, 17, 18 are arranged as special bus transceivers, and the switching transition time t1 + α, which is the time for a transition from the transmit-enabled state to the transmit-incapable state, is set to be longer than the node transition time t1. The special bus transceiver can be defined as bus transceiver 16, 17, 18, which performs transmit and receive using the bus connected to the special bus. In this case, the switching transition time t1 + α, which is the time for a transition from the transmit-enabled state to the transmit-incapable state, can be set to be longer than the node transition time t1 only for the special bus transceiver.

[0070] (2c) Furthermore, in the embodiment described above, the node transition time t1 can take on any value. For example, the node transition time t1 can be 0. In this case, the reception of the communication request frame, the output of the transmit request, or the reception of the transition command from the outside can be determined as the occurrence of the event and can directly trigger the transition from the transmit-enabled state to the transmit-disabled state. Such a configuration is also included in the technical concept of the claims of the present invention.

[0071] (2d) Several functions of an element in the above embodiment can be achieved by several elements, or a function or element can be achieved by several elements. Furthermore, several functions of several elements can be achieved by one element, or a function achieved by several elements can be achieved by one element. Part of the configuration of the above embodiment can be omitted. At least part of the configuration of the above embodiment can be added to or replaced by another configuration of the above embodiment. All modes included in the technical concept of the claims correspond to embodiments of the present invention.

[0072] (2e) In addition to the communication system 1 described above, various features such as a device such as a switching device or a node forming the communication system 1, a program to cause the computer to act as the communication system 1, a non-volatile storage medium such as a semiconductor memory in which the program is stored, and a transmission method may be provided to realize the present invention. 3. Correspondence between the configuration of the present embodiments and the configuration of the present invention

[0073] In the configuration of the embodiments described above, the Bus-A transceiver 16, the Bus-B transceiver 17, and the Bus-C transceiver 18 correspond to a communication section of the present invention. Furthermore, the operations in S110, S220, S130, S140, and S150 in the processing performed by the controller 11 in the embodiment described above correspond to a state control section of the present invention.

Claims

[1] A switching device (10) configured to switch data between a plurality of buses, wherein one or more nodes (51, 52, 61, 62, 63, 71, 72, 73) are connected to the respective buses, wherein at least one of the nodes is defined as a special node, wherein the special node is configured to transition between a plurality of states including a transmission-enabled state and a transmission-disabled state, wherein transmission of the data is possible in the transmission-enabled state, wherein transmission of the data is not possible in the transmission-disabled state, and wherein the special node transitions from the transmission-enabled state to the transmission-disabled state when a predetermined node transition time has elapsed since an occurrence of a predetermined event, the switching device comprising: a plurality of communication sections (16, 17, 18) configured to transmit and receive the data and to transition between the states including the transmit-enabled state and the transmit-incapable state, the communication sections being connected to the buses in a one-to-one relationship; and a state control section (S110, S220, S130, S140, S150) configured to cause a specific communication section to transition from the transmission-enabled state to the transmission-incapable state when a switching transition time has elapsed since the occurrence of the predetermined event, wherein the specific communication section represents at least one of the communication sections to which at least one of the buses connected to the specific node is connected, and wherein the switching transition time is calculated by adding a predetermined additional time to the node transition time. [2] Switching device according to claim 1, wherein each of the nodes is arranged as a special node; each of the communication sections is arranged as the special communication section; and the state control section causes the special communication section to transition from the transmit-enabled state to the transmit-incapable state. [3] Switching device according to claim 1 or 2, wherein the special node transitions between the states including a reception permission state and a transmission and reception prohibition state, each provided as the transmission non-enablement state; sending the data is possible in the reception permission state and sending and receiving is not possible in the sending and receiving prohibition state; the specific node transitions from the transmit enable state to the receive allow state when the node transition time has elapsed; the special node transitions from the reception permission state to the transmission and reception prohibition state when a predetermined sleep time has elapsed since a lapse of the node transition time; and the switching transition time is equal to or less than a sum of the node transition time and the sleep time. [4] The switching device according to claim 3, wherein each of the communication sections transitions between the states including the reception permission state and the transmission and reception prohibition state, each provided as the transmission non-enabled state. [5] Switching device according to claim 4, wherein the state control section causes the specific node to transition from the transmission enable state to the reception allow state when the switching transition time has elapsed; and the state control section causes the specific node to transition from the reception permission state to the transmission and reception prohibition state when the sleep time has elapsed since the elapse of the node transition time.

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