JP2005086692A - Gateway apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gateway apparatus capable of starting an on-vehicle apparatus connected to a different network from a sleep state without causing a delay in message delivery. <P>SOLUTION: Units connected to different in-vehicle networks exchange message data and each unit reaches a sleep state in a standby state. The gateway apparatus 1 connects signal lines 51, 52 connected to CAN buses 7a, 7b of ordinary transfer paths by switches 4a, 4b in the sleep state and disconnects the signal lines 51, 52 by the switches 4a, 4b in a start state. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention connects a plurality of networks configured by in-vehicle devices in a vehicle, enables data transmission / reception, and is connected to different networks in a sleep state in order to save current consumption. Belongs to the technical field of in-vehicle gateway devices that start up without delay.

The conventional gateway apparatus determines the activation state by receiving the exchange of commands between the consumer LAN and the OEM-LAN in the vehicle by the I / O processor, and performs processing to absorb the difference in activation time (for example, (See Patent Document 1).
JP 2003-124966 A (page 2-4, full view)

  However, in the conventional gateway device, a message transmission delay occurs due to the sleep state.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a gateway device that can start an in-vehicle device connected to a different network without a message delay from a sleep state. It is in.

  In order to achieve the above object, according to the first aspect of the present invention, a plurality of in-vehicle networks are configured by connecting in-vehicle devices in a vehicle by different buses, and the plurality of in-vehicle networks use the same communication protocol, and the in-vehicle network The number of in-vehicle devices connected to the entire system is limited, and data is exchanged between in-vehicle devices connected to different in-vehicle networks. The gateway device is provided with sleep connection means for connecting different network buses in a sleep state separately from a normal transfer path, and the sleep connection means is brought into a non-connection state when the gateway device is activated. It is characterized by that.

  According to a second aspect of the present invention, in the gateway device according to the first aspect, a CPU that performs arithmetic control is configured to connect to a bus via a transceiver that performs transmission and reception, and the sleep connection unit includes the transceiver and the bus. The signal transmission path in the middle is connected by a switch, and the switch opens and closes the signal transmission path by a control signal from the CPU.

Therefore, in the invention according to claim 1, in the sleep state, the sleep connection means connects the buses of different networks through a different transfer path from the normal transfer path. The gateway device can send a specific signal that makes it possible to receive the wake-up signal even when the gateway device is in the sleep state, and each specified in-vehicle device and gateway device can be activated simultaneously and reliably by the wake-up signal. The message transfer delay of the gateway device can be made only to the gateway transfer time.
In addition, the processing load of the gateway device can be reduced by the sleep connection means.

  According to the second aspect of the present invention, a switch for switching between switches according to a control signal from the CPU connects the transceivers of different networks and the middle of the bus, and a way for starting each in-vehicle device without going through the CPU of the gateway device. It is possible to transmit / receive a specific signal for setting a standby state in which a wakeup signal can be received.

  Hereinafter, an embodiment for realizing the gateway device of the present invention will be described based on examples corresponding to the inventions according to claims 1 and 2.

(Example)
First, the configuration will be described.
FIG. 1 is a block diagram illustrating a gateway device according to an embodiment. FIG. 2 is a state transition diagram illustrating a state change of the gateway device according to the embodiment. FIG. 3 is a flowchart showing the flow of processing of the gateway device of the embodiment.

The gateway device 1 of the embodiment connects a network 9a configured by connecting a unit A81, a unit B82, etc. mounted in the vehicle to the CAN bus A7a, and a unit C83 mounted in the vehicle connected to the CAN bus B7b. And a network 9b configured as described above.
The network A9a and the network B9b use the same CAN (Controller Area Network) protocol as a communication protocol.

  The gateway device 1 mainly includes a CPU 2, transceivers 3a and 3b, switches 4a and 4b, signal lines 51 and 52, and signal lines 53 to 56 and 6.

  The CPU 2 performs a process of outputting data from the network A9a or the network B9b input via the transceivers 3a and 3b in synchronization with the network A9a or the network B9b serving as another network in a timely manner.

  The transceivers 3a and 3b are connected to the CAN bus A7a and the CAN bus B7b via signal lines 53 to 56, and as shown in FIG. 1, the potential difference between two lines of the CAN bus A7a or the CAN bus B7b, which is a twisted pair line, In other words, the dominant level and the recessive level are converted into bit signals and data is output to the CPU 2, and the data output by the CPU 2 is transmitted to the CAN bus A7a and the CAN bus B7b by a combination of the dominant level and the recessive level using a twisted pair line.

  The switches 4a and 4b (which constitute the sleep connection means together with the CPU 2 and the signal lines 51, 52 and 6) open and close the signal lines 51 and 52 according to the signal (Hi level or Lo level) from the CPU 2 by the signal line 6 ( Connect or disconnect).

[Switching process]
FIG. 3 is a flowchart showing the flow of switch switching processing executed by the CPU of the gateway device 1 of the embodiment. Each step will be described below.

  In step S1, it is determined whether the gateway device 1 is in a sleep state. If the gateway device 1 is in a sleep state, the process proceeds to step S2, and if it is in a normal operation state, the process proceeds to step S6.

  In step S2, it is determined whether or not there is an interrupt process based on a specific signal that makes a standby state capable of receiving a wake-up signal that activates a specific unit. If there is an interrupt process based on the specific signal, the process proceeds to step S3. If there is no interrupt processing due to, the process proceeds to step S7.

  In step S3, the output level from the CPU 2 to the switches 4a and 4b is set to Hi, and the switches 4a and 4b are switched so that the CAN bus A7a and the CAN bus B7b communicate with each other via the transceivers 3a and 3b of the gateway apparatus 1 and the CPU2. To do.

  In step S4, it is determined whether or not a wake-up signal has been received. If received, the process proceeds to step S5, and if not received, the process proceeds to step S7.

  In step S5, an application for performing normal gateway processing is started and the output level from the CPU 2 to the signal line is set to Hi.

  In step S6, it is determined whether or not a sleep signal is received. If received, the process proceeds to step S7, and if not received, the process proceeds to step S5.

  In step S7, the CPU 2 is set to the sleep state, the output level from the CPU 2 to the signal line is set to Lo, the switch is operated, and the signal line is set to the connected state.

[CPU state transition]
FIG. 2 is a state transition diagram showing how the state of the CPU 2 of the gateway device 1 changes.

  When the CPU 2 of the gateway device 1 is in the sleep state 101, the output of the CPU 2 is at the Lo level and is in the sleep state, so that the current consumption is kept low.

  In response to the sleep state 101, a specific signal serving as a request signal for starting a unit in a network different from the network in which the unit is provided is output from any vehicle-mounted unit, and the CPU 2 receives the specific signal as an interrupt process. Then, the CPU starts preparation state 102 from the sleep state 101.

  In the CPU activation preparation state 102, the output of the CPU becomes Hi level, and the CPU 2 measures the elapsed time in this state by counting by a timer. If the next wakeup signal cannot be obtained even when the elapsed time reaches a predetermined time, the CPU 2 times out and returns to the sleep state 101.

  When the CPU 2 receives a wake-up signal for a specific unit having a different network from the CPU activation preparation state 102, the CPU 2 activates the application and shifts to the normal activation state 103.

  When the CPU 2 receives a sleep signal with respect to the normal activation state 103 of the CPU, the CPU 2 is still in a state where the output is still at the Hi level and can immediately return to the normal activation state, and the state shifts to the sleep preparation state 104 where the CPU 2 can enter the sleep state. To do.

  When the CPU 2 enters the sleep preparation state 104, the elapsed time is measured, and if the wakeup signal is not received again within a predetermined time, the CPU 2 shifts to the sleep state 101.

[Message transmission delay]
Here, the message delay will be described.
As shown in FIG. 4, it is assumed that unit A, unit B, etc. are connected to the CAN bus A to form one network, and unit C, etc. are connected to the CAN bus B to form another network. In order to suppress current consumption during standby, each unit and the gateway device are set to a sleep state.
For example, when the unit A connected to the CAN bus A activates the unit B connected to the same CAN bus A, a specific signal specifying the unit B is first sent to the CAN bus A and the specific signal is received. The unit B starts the activation of each component so that the message can be transmitted and received. After that, the unit A sends a specific wakeup signal to the CAN bus A, and the unit B that receives this wakeup signal starts and Transition to the operating state.

Next, for example, when the unit A connected to the CAN bus A activates the unit C connected to the CAN bus B, a signal specifying the unit C is sent to the CAN bus A, but the gateway device operates. The specific signal is not transferred to the CAN bus B because it is not in a state. (In this state, the gateway device is first activated and then a specific signal is sent to a specific unit, but it takes a very long time.)
In order to activate unit C in this case, before unit C receives the wake-up signal transferred by the gateway device, a specific signal from the gateway device must flow through CAN bus B to be received by unit C.

  In this way, the control becomes complicated, and the gateway device is activated and the specific signal is transmitted from the gateway device by the specific signal from the unit A. Therefore, it takes time, and the wakeup signal from the unit A is received. There is a case where the time interval until the transmission is not sufficient and reception is not possible. For this reason, if the gateway device delays the transfer of the wake-up signal so that the unit C can reliably receive the specific signal and the wake-up signal, a message delay occurs.

[Message communication without delay]
<1> Sleep State When the unit A 81, unit B 82, unit C 83, etc. connected to the entire network including both networks and the gateway device 1 are in the sleep state and are saving power consumption The gateway device 1 sets the output to the signal line to the Lo level by the process of step S7. When the output to the signal line becomes Lo level, the switches 4a and 4b are closed (connected state). When the switches 4a and 4b are closed, the signal line 53 connected to the CAN bus A7a and the signal line 55 connected to the CAN bus B7b are connected by the signal line 52, and the signal connected to the CAN bus A7a. The signal line 56 connected to the line 54 and the CAN bus B7b is connected by the signal line 51 (the lower state in FIG. 2B). That is, in the sleep state, the CAN bus A7a and the CAN bus B7b are one continuous bus line electrically connected by the switches 4a and 4b and the signal lines 51 to 56, respectively. As a result, all the units that can wake up on the in-vehicle network are connected to the same bus line.

<2> Transition to the CPU startup preparation state When all the units including the gateway device 1 are in the sleep state, some trigger enters the unit A81 connected to the CAN bus A7a, and the unit A81 is connected to a different communication line. When the connected unit C83 has to be activated, the unit A81 sends a specific signal for identifying the unit C83 to be activated to the CAN bus A7a. When the CPU 2 of the gateway apparatus 1 receives the specific signal, the CPU 2 determines from the process of step S2 and shifts from the sleep state 101 to the CPU activation preparation state 102 by the process of step S3.

  In the CPU start-up state, when the next wake-up signal is received, the CPU waits in a state where it can be started, and the output from the CPU 2 to the signal line 6 is switched from Lo to Hi. Then, the switches 4a and 4b can switch the signal lines 51 and 52 from closed (connected state) to open (non-connected state), and transmit / receive message data from the network A9a to the network B9b via the transceivers 3a and 3b and the CPU 2. The connection, that is, the connection between the CAN bus A7a and the CAN bus B7b is cut off, resulting in two independent bus lines.

  Further, the specified unit C83 that has received the specific signal also enters a standby state in which it can be activated by the wakeup signal.

<3> Transition to the normal startup state When the wakeup signal is output to the unit C83 connected to the CAN bus B7b of the different network 9b in the CPU startup preparation state, the CPU 2 is already in the standby state. It starts and shifts to a normal start state (upper state in FIG. 2B), and a wakeup signal is transmitted to the specific unit C83. Since the specific unit C83 has already received the specific signal and is in a standby state, the specific unit C83 starts immediately without delay. Therefore, data transmitted from the different network A9a thereafter is transmitted as a message by the gateway device 1 without delay, and is received by the specified unit C83 without delay.
In other words, the communication delay at this time is only the delay that occurs when the gateway apparatus 1 transfers the same as in the normal state. As a result, the application of the specified unit C83 can perform processing without waiting for data. Alternatively, the latest data obtained by communication can be used without using previous or reference data.
From the viewpoint of the entire in-vehicle network, this means that normal message exchange can be performed without waiting for activation of a specific device.

[Reducing processing load]
No special processing is required for the CPU 2 for transmission / reception of a specific signal in the sleep state, and only the output Hi and Lo to the signal line 6 are switched in accordance with the state of the CPU itself. Therefore, such an effect is obtained in a state where the processing load on the CPU 2 is reduced.

[Maintaining high communication speed]
In this embodiment, the signal lines 51 and 52 are enabled by connecting the switches 4a and 4b, and when the CAN bus A7a and the CAN bus B7b are used as one bus, they are connected to the CAN bus A7a and the CAN bus B7b. A high communication speed is maintained by activating only 16 units or less of all units.

Next, the effect will be described.
In the gateway device of the embodiment, the effects listed below can be obtained.

(1) Units in the vehicle are connected by CAN bus A7a and CAN bus B7b to form a plurality of networks A9a and B9b. The plurality of networks A9a and network B9b are connected to the entire in-vehicle network using the same communication protocol. The gateway device 1 has a limit on the number of units to be exchanged, exchanges message data between units connected to different in-vehicle networks, and enters a sleep state together with each unit in a standby state. , The signal lines 51 and 52 connected to the CAN bus A7a and CAN bus B7b of the normal transfer path are connected by the switches 4a and 4b in the sleep state, and are not connected by the switches 4a and 4b at the start-up. In order to make each specified unit and the gateway device 1, Can be activated simultaneously and reliably by wakes up signal, the transfer delay of the message of the gateway device 1 can only be the gateway transfer time.
From the viewpoint of the in-vehicle network, the message exchange process can be performed without waiting for the activation of a specific unit, so that the entire in-vehicle network environment can be operated by performing mutual communication simultaneously.
Further, the processing load of the gateway device 1 can be reduced by the sleep connection means.

  (2) The CPU 2 that performs arithmetic control is configured to connect to the CAN bus A7a and the CAN bus B7b via the transceivers 3a and 3b that perform transmission and reception, and a signal line in the middle of the transceivers 3a and 3b and the CAN bus A7a and CAN bus B7b. 53 to 56 are connected by the switches 4a and 4b, and the switches 4a and 4b open and close (connect / disconnect) the signal lines 51 and 52 by a control signal from the CPU 2, so that the CPU 2 can control costs. By switching the switches 4a and 4b according to the control signal, the transceivers 3a and 3b of different networks are connected to each other in the middle of the CAN bus A7a and CAN bus B7b, and each vehicle-mounted device is activated without going through the CPU 2 of the gateway device 1. Send / receive a specific signal to enter standby mode to receive a wakeup signal for It can be.

  The gateway device of the present invention has been described based on the embodiments. However, the specific configuration is not limited to these embodiments, and departs from the gist of the invention according to each claim of the claims. Unless otherwise, design changes and additions are permitted.

  For example, in the embodiment, the switch for switching by the control signal of the CPU is shown as the sleep connection means. However, the switch may be switched by another circuit device.

It is a block diagram which shows the gateway apparatus of an Example. It is a state transition diagram which shows the state change of the gateway apparatus of an Example. It is a flowchart figure which shows the flow of a process of the gateway apparatus of an Example. It is a block diagram which shows the gateway apparatus of the conventional Example.

Explanation of symbols

1 Gateway device 2 CPU
3a transceiver 3b transceiver 4a switch 4b switch 51 signal line 52 signal line 53 signal line 54 signal line 55 signal line 56 signal line 6 signal line 7a CAN bus A
7b CAN bus B
81 Unit A
82 Unit B
83 Unit C
9a Network A
9b Network B

Claims (2)

Connect in-vehicle devices in the car with different buses to configure multiple in-car networks,
The plurality of in-vehicle networks are
Using the same communication protocol
There is a limit to the number of in-vehicle devices connected to the entire in-vehicle network,
While exchanging data between in-vehicle devices connected to different in-vehicle networks,
In the standby state, it goes to sleep with each in-vehicle device.
In the gateway device,
Provided with a sleep connection means to connect between different network buses in the sleep state separately from the normal transfer path,
The sleep connection means is disconnected when the gateway device is activated;
A gateway device characterized by that. The gateway device according to claim 1,
The CPU that performs arithmetic control is configured to connect to the bus via a transceiver that performs transmission and reception,
The sleep connection means
The transceiver and the signal transmission path in the middle of the bus are connected by a switch,
The switch opens and closes the signal transmission path with a control signal from the CPU.
A gateway device characterized by that.

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