JP2005079888A - Gateway apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gateway apparatus for performing transmission after a prescribed time elapses even when transmission errors continuously occur and efficiently performing transmission. <P>SOLUTION: The apparatus includes a watch dot timer logic 22 for measuring a passage time from a data transmission start. After a prescribed passage time, data transmission is stopped and also data of RAM 24 to be transmitted is abandoned by a CPU 2. When transmission is stopped by the CPU 2, the CPU 2 transmits data which is received during measurement by the watch dog timer logic 22. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention belongs to the technical field of an in-vehicle gateway device that can be promptly restored after an error and can perform transmission efficiently.

A conventional gateway device includes a CPU as means for converting a protocol in order to connect networks in a vehicle using different protocols, and temporarily stores received data and data to be transmitted. The in-vehicle device connected to the network can exchange data with in-vehicle devices in different networks in the vehicle (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2002-243591 (page 2-10, full view)

  However, in the conventional gateway device, when the received data is converted into a protocol and data is transmitted, if the transmission cannot be performed due to a transmission error or the like, the received data accumulates and overflows. There was a risk of the network becoming congested.

  The present invention has been made paying attention to the above-mentioned problems, and the purpose of the present invention is to perform transmission efficiently after a predetermined time even if transmission errors occur continuously. It is to provide a gateway device.

  In order to achieve the above object, according to the first aspect of the present invention, the data received from the network is temporarily stored by connecting the different networks to which the in-vehicle device in the vehicle is connected. In the gateway device that transmits data to another network and exchanges data between in-vehicle devices connected to different networks, the gateway device includes time measuring means for measuring an elapsed time from the start of data transmission, Transmission stop processing means for canceling data transmission and discarding the data stored in the information storage means after the elapse of time, and when the transmission is stopped by the transmission stop processing means, the time measuring means is measuring And a transmission resumption processing means for transmitting the received data.

  According to a second aspect of the present invention, in the gateway device according to the first aspect, the transmission restart processing means transmits the data according to a predetermined priority when there are a plurality of data received during the time measurement. It is characterized by.

  Therefore, according to the first aspect of the present invention, when the elapsed time measured by the time measuring means elapses due to continuous transmission errors, the transmission is canceled by the transmission stop processing means, and the transmission data of the information storage means is Discarded. For this reason, the information storage means does not overflow due to accumulation of transmission data. In this way, when the transmission cancellation processing unit performs the transmission cancellation process, the transmission resumption processing unit transmits the data received during the time measurement. Therefore, when transmission errors continue, transmission can be resumed when a predetermined time elapses, and troubles caused by interruption of data exchange in the vehicle for a long time can be prevented.

  According to the second aspect of the present invention, when there is a plurality of data received during time measurement when the transmission stop processing unit performs the transmission stop processing and transmission is restarted by the transmission restart processing unit, a predetermined value is given. Since the data is transmitted according to the priority order, the more important information is transmitted with higher certainty. Therefore, efficient transmission can be performed even when a heavy load on the communication bus occurs.

  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 schematic diagram of a vehicle system using the gateway device of the embodiment. FIG. 2 is a block diagram of the gateway device of the embodiment.
The gateway device 1 of the embodiment communicates a network A configured by connecting an automatic transmission device A2 and an engine control device A3 in a vehicle with a communication line A1, and a body control device B2 and an air conditioner device B3 in the vehicle. It is provided so as to connect to the network B configured by connecting with the line B1.

  The gateway device 1 mainly includes a CPU (corresponding to transmission stop processing means and transmission resumption processing means) 2, transceivers 3a and 3b, a power supply circuit 4, an oscillator 5, an EEPROM 6, and termination resistors 7a and 7b.

  The transceivers 3a and 3b are connected to the communication lines A1 and B1 via the terminating resistors 7a and 7b, and are connected to the CPU 2. The CPU 2 receives data received from the communication lines A1 and B1 each consisting of two lines. A signal that can be input is output to the CPU 2, and the signal output from the CPU 2 is transmitted to the communication lines A 1 and B 1 as a signal that can flow through the communication lines A 1 and B 1 each consisting of two lines.

  The power supply circuit 4 supplies power to the CPU 2 and peripheral circuits.

  The oscillator 5 outputs to the CPU 2 an oscillation signal used for synchronization processing and signal generation with the CPU 2 for communication.

  The EEPROM 6 stores messages to be output to the networks A and B, and outputs message data to the CPU 2 in response to a command from the CPU 2. Further, the stored contents are erased in response to a command from the CPU 2. Note that the number of messages is limited.

  The CPU 2 is provided with communication logics 21 a and 21 b, a watchdog timer logic 22 and a timer logic 25 that are executed by an arithmetic processing unit (not shown), and a ROM 23 and a RAM (corresponding to information storage means) 24. Yes.

  The watchdog timer logic 22 monitors whether or not an abnormality has occurred in the processing executed by the CPU 2, for example, by detecting a flag at the end of the routine to be executed.

  The ROM 23 stores contents and data of processing performed by the CPU 2.

The RAM 24 temporarily stores the data received by the communication logics 21a and 21b and converted into protocol data as necessary.
A timer logic 25 (corresponding to a time measuring means) performs processing for measuring the time to be executed by the CPU 2.

  Next, the operation will be described.

[Transmission process]
FIG. 3 is a flowchart showing a flow of transmission processing executed by the CPU 2.

  In step S101, it is determined whether there is received data. If there is received data, the process proceeds to step S102, and if there is no received data, the process ends.

  In step S102, it is determined whether or not the previous transmission has timed up, that is, whether or not the elapsed time has elapsed without completing the transmission. If the time has elapsed, the process proceeds to step S103 and the time is up. If not, the process proceeds to step S105.

In step S103, it is determined whether or not there is a plurality of frames of data already received. If there are a plurality of frames, the process proceeds to step S104, and if there are not, the process proceeds to step S105.
Here, communication data in the network represents one piece of data as a frame. That is, a plurality of frames means communication data from a plurality of devices or a plurality of times of communication data.

  In step S104, the already received data is sorted by priority.

  In step S105, it is determined whether or not transmission has been completed without a communication error. If transmission has been completed, the process proceeds to step S106, and if transmission has not been completed, the process proceeds to step S109.

  In step S106, the next transmission data is set.

  In step S107, a request is made to transmit the next set transmission data.

  In step S108, a transmission timer is started.

  In step S109, it is determined whether or not the elapsed time being measured has expired. If the elapsed time has elapsed, the process proceeds to step S110, and if the time has not expired, the process ends.

  In step S110, the transmission data to be transmitted is discarded.

  In step S111, it is assumed that the transmission is stopped and the transmission is completed.

[Receive processing]
FIG. 4 is a flowchart showing a flow of processing included in the reception processing executed by the CPU 2.

  In step S201, reception interruption processing is performed when reception is performed.

  In step S202, received data is read.

  In step S203, the received data is temporarily stored.

  In step S204, the reception interrupt flag is cleared.

In step S205, a reception flag is set.
[Gateway action]
In the gateway device 1 of the embodiment, when the engine control device A3 and the automatic transmission device A2 transmit data used in different networks B, the processing of the communication logic 21a is performed via the terminating resistor 7a and the transceiver 3a connected to the communication line A1. Is input to the CPU 2.
In the CPU 2, when the communication protocols of the network A and the network B are different, the protocol is converted and the data is temporarily stored in the RAM 24, and the data is transferred from the CPU 2 to the transceiver 3b by the communication logic 21b at a predetermined timing. And output to the communication line B1 via the termination resistor 7b. The data output to the communication line B1 is received by the body control device B2 and the air conditioner device B3 of the network B as necessary.

Further, when the body control device B2 and the air conditioner device B3 of the network B transmit data, they are input to the communication logic 21b of the CPU 2 via the terminating resistor 7b and the transceiver 3b connected to the communication line B1.
In the case where the communication protocols of the network A and the network B are different, the CPU 2 converts the protocol and temporarily stores the data in the RAM 24, and outputs the data from the communication logic 21a to the transceiver 3a at a predetermined timing. And output to the communication line A1 via the terminating resistor 7a. The data output to the communication line A1 is received by the automatic transmission device A2 and the engine control device A3 of the network A as necessary.

[Response to transmission errors]
<1> When normal When data is received after data is received from one network and data is normally transmitted to the other network, it is determined that there is received data in the process of step S101. Is done. In this case, since the previous received data has been successfully converted into a protocol and transmission has been completed, it is determined in step S105 that the transmission has been completed, and the received data is converted into a protocol and transmitted by the processing in steps S106 to S108. At the same time, the elapsed time is measured by the timer logic 25. If it is normal, transmission will be completed before the elapsed time has elapsed.

<2> When a transmission error occurs and the next data to be transmitted has been received. Until then, data was transmitted normally. When the next data to be transmitted was received, there was an error in the transmission of the previous data. In this case, the elapsed time from the previous transmission is measured, but the time is not up. Therefore, it is determined that the transmission is not completed in the processing from step S102 to step S105, it is determined that the time is not up in the processing in step S109, and the processing ends.

<3> When a predetermined time has elapsed after a transmission error (single received data)
When a transmission error occurs and a predetermined time elapses (time up), the determination processing in step S109 discards the data to be transmitted temporarily stored in the RAM 24 in the processing in steps S110 and S111, and stops transmission. Assume that transmission is complete. As a result, the received data is transmitted by the processing in steps S106 to S108. Therefore, when a transmission error occurs and a predetermined time elapses, transmission is resumed.

<4> When a predetermined time has elapsed after a transmission error (multiple received data)
When a transmission error occurs and a predetermined time has elapsed (time up), when there are a plurality of received data, this is determined in the process of step S103, and is sorted according to the priority in the process of step S104. After the transmission data is discarded, transmission is performed according to the priority order.
Therefore, when a predetermined time elapses when a transmission error occurs, not only the transmission is resumed, but also at that time, the transmission is performed according to the priority order so that efficient transmission is performed.

  Next, the effect will be described.

  In the gateway device of the present embodiment, the following effects can be obtained.

  (1) By connecting between different networks A and B to which in-vehicle devices in the vehicle are connected, the data received from the network is transmitted to another network via the RAM 24 that temporarily stores the information. The gateway device 1 that exchanges data between in-vehicle devices connected to the network includes a timer logic 25 that measures an elapsed time from the start of data transmission, and stops data transmission after a predetermined elapsed time. The CPU 2 discards the data in the RAM 24 to be transmitted together, and when the CPU 2 stops the transmission, the data received during the measurement by the timer logic 25 is transmitted by the CPU 2. , Transmission can be resumed after a predetermined time, and data exchange in the vehicle is long Possible so as not to cause trouble due to be shut off during.

The above is particularly effective when using CAN (Controller Area Network) as the in-vehicle network protocol. Since the CAN uses the CSMA / CA method (or CSMA / CD method) as an access method to the bus used as the communication line, when transmission occurs, transmission data causes a transmission error due to collision (collision) on the bus. The transmission data is accumulated and retransmitted. At that time, the transmission priority is determined by the data ID.
If a gateway device is connected to this CAN network, the gateway device also becomes a single device connected to the network, so that data is likely to accumulate in the event of a transmission error. Further, since a lot of data is sent to the gateway device, it is easier to accumulate data. However, since information sent via the gateway device is important for the vehicle, there is a high need for avoiding a network congestion state. Therefore, in a vehicle using a CAN network, when transmission errors continue, transmission can be resumed when a predetermined time elapses, and data exchange in the vehicle can be prevented from being interrupted for a long time. This will improve reliability and safety.

  (2) Since the CPU 2 transmits data according to a predetermined priority when there are a plurality of data received during time measurement, efficient transmission is possible even if a heavy load on the communication bus occurs. it can.

This is also particularly effective when using CAN (Controller Area Network) as an in-vehicle network protocol. Since the CAN uses the CSMA / CA method (or CSMA / CD method) as described above, if a transmission error occurs, the priority of retransmission is determined by the data ID.
Therefore, if the data of different networks sent via the gateway device is also sent in the priority order by ID, very efficient communication will be performed even if a situation such as a heavy load on the communication bus occurs, Since important data can be transmitted and received more reliably in the CAN network, reliability and safety are improved in a vehicle using the CAN network.

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 RAM inside the CPU is used as the information storage unit, but an external storage device or the like may be used.
In the embodiment, the timer logic is used as the time measuring means. However, the oscillation signal of the oscillator may be used, or a timer circuit may be provided outside the CPU.
In the embodiment, the processing executed by the CPU is used as the transmission cancellation processing means and the transmission resumption processing means, but a circuit or the like may be provided separately.

It is a system schematic diagram of a vehicle using a gateway device of an example. It is a block diagram of the gateway apparatus of an Example. It is a flowchart which shows the flow of the transmission process performed with CPU. It is a flowchart which shows the flow of the process included in the reception process performed with CPU.

Explanation of symbols

1 Gateway device 2 CPU
21a Communication logic 21b Communication logic 22 Watchdog timer logic 23 ROM
24 RAM
25 Timer Logic 3a Transceiver 3b Transceiver 4 Power Supply Circuit 5 Oscillator 6 EEPROM
7a Terminating resistor 7b Terminating resistor A Network A
B Network B
A1 communication line A2 automatic transmission A3 engine control device B1 communication line B2 body control device B3 air conditioner device

Claims (2)

Connect different networks to which in-vehicle devices in the car are connected,
The data received from the network is sent to another network via an information storage means that temporarily stores the information,
Exchange data between in-vehicle devices connected to different networks,
In the gateway device,
It has time measuring means to measure the elapsed time from the start of data transmission,
Transmission stop processing means for canceling data transmission after a predetermined elapsed time and discarding the data of the information storage means to be transmitted,
When transmission is stopped by the transmission stop processing means, the transmission restart processing means for transmitting the data received during the measurement by the time measuring means,
A gateway device characterized by that. The gateway device according to claim 1,
The transmission resumption processing means includes
If there are multiple data received during time measurement, send the data according to a predetermined priority,
A gateway device characterized by that.

Images