JP2005159568A - Gateway apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gateway apparatus capable of surely transmitting data with ID of higher priority when a transmission timing is delayed due to a transmission error or the like in communication carried out between different in-vehicle networks via the gateway apparatus. <P>SOLUTION: The gateway apparatus 1 for interconnecting differently formed networks A, B, temporarily storing and converting data received from one of the networks, and transmitting the resulting data to the other network so that on-vehicle apparatuses connected to the different networks make data communication with each other, is provided with a RAM 24 for storing priorities of ID codes denoting a transmission destination included in the data subjected to relay transmission, and a CPU 2 carries out priority discrimination processing for discriminating transmission priority on the basis of the priority of the ID code stored in the RAM 24 when there are a plurality of data to be transmitted next after the end of data transmission. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention belongs to the technical field of gateway devices that perform communication of devices belonging to different networks, and is particularly useful for enabling communication between different communication networks between in-vehicle devices.

Conventionally, in communication between devices connected to a CAN network, if a state in which transmission cannot be performed due to a transmission error continues, data to be transmitted is accumulated (for example, see Patent Document 1).
In order to connect such networks in the vehicle, the conventional gateway apparatus includes a CPU as a means for converting a protocol, and one device connected to the network on the transmission side. Therefore, it is equipped with a data buffer for temporarily storing received data and data to be transmitted, so that in-vehicle devices connected to the network can exchange data with in-vehicle devices in different networks in the vehicle. (For example, refer to Patent Document 2).
JP 2003-115852 A (page 2-7, full view) Japanese Patent Laying-Open No. 2002-243591 (page 2-10, full view)

  However, in the conventional gateway device, when transmission errors continue, scheduled data is accumulated, and when transmission is possible, data with high priority is also waited for transmission.

  The present invention has been made paying attention to the above-mentioned problems. The purpose of the present invention is that when communication performed via a gateway device between different in-vehicle networks is delayed due to a transmission error or the like, priority is given. It is an object of the present invention to provide a gateway device that can reliably transmit from a higher-rank ID.

  In order to achieve the above object, in the present invention, a plurality of in-vehicle networks are formed by in-vehicle devices in a vehicle, the different networks formed are connected, and data received from the network is temporarily stored and converted to be separated. In the gateway device that exchanges data between in-vehicle devices connected to different networks, the priority order of ID codes indicating the transmission destinations included in the data to be relayed is stored in advance. Priority ID storage means is provided, and when there is a plurality of data to be transmitted next after completion of data transmission, priority order determination means for determining the priority of transmission from the priority order of the ID code of the priority ID storage means It is provided.

  Therefore, in the present invention, communication performed via the gateway device between different in-vehicle networks can be reliably transmitted from an ID having a high priority when the transmission timing is delayed due to a transmission error or the like.

  Hereinafter, an embodiment for realizing the gateway device of the present invention will be described based on Example 1 corresponding to the first and second aspects of the invention.

First, the configuration will be described.
FIG. 1 is an explanatory diagram illustrating a configuration of a CAN system using the gateway device according to the first embodiment. FIG. 2 is a block diagram of the gateway device according to the first embodiment. FIG. 3 is an explanatory diagram of a CAN communication processing unit and a RAM portion of the CPU of the gateway device according to the first embodiment. FIG. 4 is an explanatory diagram comparing the relationship between the reception data and transmission data of the gateway device according to the first embodiment with the prior art. FIG. 5 is an explanatory diagram illustrating a data structure for temporarily storing transmission data of the gateway device according to the first embodiment. FIG. 6 is a flowchart illustrating the flow of reception processing of the gateway device according to the first embodiment. FIG. 7 is a flowchart illustrating a flow of transmission processing of the gateway device according to the first embodiment. FIG. 8 is a flowchart showing the flow of processing for sorting the transmission data of the gateway device according to the first embodiment in the priority order. FIG. 9 is a flowchart showing the flow of conventional reception processing. FIG. 10 is a flowchart showing the flow of conventional transmission processing.
The gateway device 1 according to the first embodiment is configured by connecting the in-vehicle devices A2 to A6 in the vehicle to the bus communication line A1 and the in-vehicle devices B2 to B6 to the bus communication line B1. To be connected to the network B to be connected.

  As shown in FIG. 2, the gateway device 1 mainly includes a CPU 2 (corresponding to priority order determination means), 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 termination resistors 7a and 7b, and are connected to the CPU 2, and the data received from the communication lines A1 and B1 each consisting of two lines are connected to the CPU 2. The data received from the communication lines A1 and B1 each composed of two lines is converted into a signal that can be input by the CPU 2 and output to the CPU 2, and the signal output from the CPU 2 is each composed of the communication line A1 composed of two lines. , B1 can be sent (communication signal according to the CAN protocol) and transmitted to the communication lines A1, B1.

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 in the CPU 2 for communication.

The EEPROM 6 registers and saves message IDs 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. In addition, the stored contents are deleted in response to a command from the CPU 2. Note that the number of message IDs is limited.
The CPU 2 is provided with communication units 21a and 21b (corresponding to a CAN communication processing unit) that perform transmission and reception for CAN communication with the transceivers 3a and 3b. Of these, the communication unit 21a will be described. The protocol core unit 211a that converts data into the CAN communication protocol, the access control unit 212a that controls access to the communication line, and the message box that temporarily stores data to be transmitted and received 213a.
The CPU 2 is provided with a ROM 23 and a RAM 24 (corresponding to priority ID storage means).

The watchdog timer unit 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 saves the data received by the communication units 21a and 21b as a FIFO data structure 231 by converting the protocol into data for transmission as necessary.

Here, the data received by the CPU 2 of the gateway device 1 and the data storage structure (FIFO data structure 231) when temporarily stored in the RAM 24 will be described.
Data received by CAN communication has a structure in which an ID indicating a transmission destination and data are combined as shown in FIG.
The storage structure of the received data in the RAM 24 includes, in addition to the received data, an address indicating a storage location, a save pointer S_Po which is a pointer indicating the address where the received data is saved, and a transmit pointer which is a pointer indicating the address of the data to be transmitted. T_Po and sort pointer So_Po, which is a temporary pointer used for ID priority determination, are configured. In addition, this data storage structure is used to input and output data using a FIFO (first in first out) method.

  Next, the operation will be described.

[Receive process flow]
FIG. 6 is a flowchart showing the flow of reception processing executed by the CPU 2 of the gateway apparatus 1 according to the first embodiment. Each step will be described below.

  In step S11, an interruption is performed when data is received.

  In step S12, the ID of the received data is read.

  In step S13, it is determined whether or not the transmission destination indicated by the ID is a transmission destination for performing gateway processing. If it is determined that the transmission destination is an ID for performing gateway processing, the process proceeds to step S14, where it is determined that the gateway processing is not performed. If so, the process proceeds to step S21.

  In step S14, the save pointer S_Po is read from the RAM 24 that stores the received data.

  In step S15, the ID is stored at the address corresponding to the read save pointer S_Po.

  In step S16, the data portion of the received data is read.

  In step S17, the read data portion is stored at an address corresponding to the save pointer S_Po.

  In step S18, the save pointer S_Po is incremented.

  In step S19, it is determined whether or not the save pointer S_Po has reached the end of the data structure.

  In step S20, the data content of the save pointer S_Po is reset.

  In step S21, the interrupt flag is cleared.

  In step S22, the interrupt process is returned.

[Transmission process flow]
FIG. 7 is a flowchart showing a flow of transmission processing executed by the CPU 2 of the gateway device 1 according to the first embodiment. Each step will be described below.

  In step S31, transmission processing is started.

  In step S32, it is determined whether or not the transmission process is completed. If the transmission is completed, the process proceeds to step S33. If the transmission is not completed, the process proceeds to step S40.

  In step S33, it is determined whether or not the data is accommodated in the temporary storage data structure of the RAM 24 by the FIFO method. If the data is accommodated, the process proceeds to step S34, and if the data is not accommodated, the process proceeds to step S43. Transition.

  In step S34, it is determined whether or not there are a plurality of frames of data stored in the data structure of the RAM 24. If there are a plurality of frames, the process proceeds to step S35, and if there are not, the process proceeds to step S36.

  In step S35, priority order processing based on the data ID is performed.

  In step S36, transmission data is set.

  In step S37, a transmission request is set.

  In step S38, 10 is added to the transmit pointer T_Po indicating the address of the data to be transmitted, and an offset is made to indicate the next data to be transmitted.

  In step S39, a transmission timer is set and counted up.

  In step S40, it is determined whether or not the transmission timer to be counted up is timed up. If the time is up, the process proceeds to step S41. If the time is not up, the process proceeds to step S43.

  In step S41, the transmission request is reset.

  In step S42, the timer is cleared.

  In step S43, the process ends.

[Data ID priority processing]
FIG. 8 is a flowchart showing the flow of the data ID process in step S35 in the transmission process executed by the CPU 2 of the gateway apparatus 1 according to the first embodiment. Each step will be described below.

  In step S351, priority processing based on ID is started.

  In step S352, | S_Po-T_Po | / 10 (where 10 is an address step value) is calculated to calculate the number of untransmitted IDs to obtain a COUNT value.

  In step S353, T_Po + 10 (address offset) is calculated and set to So_Po.

  In step S354, a process of setting T_Po to T_PoTMP is performed.

  In step S355, it is determined whether or not the data ID of the address indicated by T_PoTMP has a higher priority than the data ID of the address indicated by So_Po. If it is determined that the priority is higher, the process proceeds to step S357. If it is determined that the value is low, the process proceeds to step S356.

  In step S356, high priority data indicated by So_Po is transferred to the address indicated by T_PoTMP.

  In step S357, an update process is performed in which So_Po + 10 (address offset) is set to So_Po.

  In step S358, the COUNT value is decremented.

  In step S359, it is determined whether or not the COUNT value (the number of untransmitted IDs) has become 0. If 0, the process proceeds to step S360. If not, the process proceeds to step S355.

  In step S360, the data remaining in T_PoTMP as the highest priority ID is set as transmission data.

  In step S361, it is determined whether T_Po indicating the data to be transmitted and T_PoTMP set as data having high ID priority indicate different data. If different data are indicated, the process proceeds to step S362, and the same data is transferred. If it is shown, the process proceeds to step S363.

  In step S362, the data to be transmitted indicated by T_Po is set to the next highest priority as indicated by T_PoTMP.

  In step S363, T_Po is updated by performing T_Po + 10 (address offset) to be T_Po.

  In step S364, the transmission process ends.

[Gateway communication]
<1> When the transmitted data is single In the first embodiment, for example, when communication is performed from the network A to the network B, the data is transmitted to the gateway device 1 that is one node of the network A. .
The data sent to the gateway device 1 is converted from a communication signal on the CAN bus to a signal that can be handled by the CPU 2 via the terminating resistor 7a and the transceiver 3a connected to the communication line A1 of the network A, and sent to the communication unit 21a. It is done.

Data received by the communication unit 21a is temporarily stored in the message box 213a.
Thereafter, the transmission data converted by the CPU 2 is temporarily stored in the FIFO data structure 231 of the RAM 24 by the interrupt processing of steps S11 to S22 shown in FIG.
If the data to be transmitted is singular, the process proceeds to step S36 without passing through step S35 (steps S351 to S364 shown in FIG. 8) by the determination process in step S34, and the message box 213b of the communication unit 21b from the RAM 24. The data is transmitted from the CPU 2 by the access control unit 212b and the protocol core unit 211b according to the CAN protocol and communication processing, and transmitted to the communication line B1 of the network B via the transceiver 3b and the termination resistor 7b.

<2> When there are a plurality of data to be transmitted When there are a plurality of data to be transmitted, the data to be transmitted is temporarily stored in the FIFO data structure of the RAM 24 as shown in FIG.
In this data transmission process, if it is determined that there is a plurality of data to be transmitted after the transmission is completed, the transmission to be output first-out in the data structure in step S35, that is, the ID priority process shown in FIG. The priority of IDs for data between T_Po indicating the address of the data to be stored and S_Po indicating the address indicating the address to be saved is sequentially compared so that T_PoTMP indicates the address of the data with the highest priority ( Steps S352 to S359).

After this process, the data indicated by T_PoTMP is transferred to the message box as transmission data in the process of step S360 so as to be transmitted.
At this time, when the data to be transmitted by T_Po is different from the data indicated by T_PoTMP, the data indicated by T_Po is transferred to the address indicated by T_PoTMP (steps S361 to S364).
In this way, the data to be transmitted is always data with a high priority based on the ID even when a plurality of data to be transmitted are accumulated.
Therefore, actually, even when the transmission timing is delayed due to a transmission error or the like, transmission is performed from an ID having a high priority.

Moreover, it demonstrates compared with a prior art using FIG. In the prior art, when a plurality of data is received as shown in FIG. 4B, the received data are transmitted in the order of reception according to the FIFO (first in first out) system.
In the first embodiment, as shown in FIG. 4A, when a plurality of data is received, the data is transmitted according to the priority by the ID in the received data.

  Further, in this way, in the FIFO data structure 231, the priority of the data to be transmitted is determined, and the highest priority data is sent to the message boxes 213a and 213b. Only one transmission data is arranged in the boxes 213a and 213b. For this reason, the rest of the message boxes 213a and 213b are allotted for received data. Therefore, more message data can be received.

  Next, the effect will be described.

  In the gateway device of the first embodiment, the effects listed below can be obtained.

(1) A plurality of in-vehicle networks A and B are formed by in-vehicle devices in the vehicle, the different networks A and B are connected, and data received from the network is temporarily stored and converted to another network. In the gateway device 1 for exchanging data between in-vehicle devices connected to different networks, the priority order of ID codes indicating the destinations included in the data to be relayed is stored in advance. A RAM 24 is provided, and after the data transmission is completed, if there is a plurality of data to be transmitted next, the CPU 2 performs priority order judgment processing for judging the transmission priority order from the priority order of the ID code of the RAM 24. Can be transmitted from data with high priority.
This means that the communication in the in-vehicle device is sent in the order of importance of the data necessary for control of each device, so that no major troubles can occur when a transmission error occurs, and the driver This makes it possible to create a network of in-vehicle devices that accurately transmits information that can be easily felt by the driver to the information obtained from the in-vehicle devices without delay or interruption.

  (2) The networks A and B formed in the vehicle use the CAN protocol, and the CPU 2 that at least converts the data to be relayed is provided, and the communication units 21a and 21b that perform processing in accordance with the CAN protocol are connected to the CPU 2. The message boxes 213a and 213b for temporarily storing received data and a plurality of data to be transmitted are provided in the communication units 21a and 21b, the RAM 24 is provided in the CPU 2, and the RAM 24 and the message boxes 213a and 213b are connected to the communication line. The data to be transmitted is temporarily stored in the RAM 24 by connecting with A1 and B1, and the data in the RAM 24 is rearranged by the processing of the CPU 2, and only the transmission data with the highest priority is sent to the message boxes 213a and 213b. Because of this, it is possible to send data with high priority in the event of a transmission error. The assignment of the message box can be one, it is possible to assign other message boxes for reception. Therefore, more message data can be received, and communication between networks in the vehicle can be performed with a higher degree of freedom.

  As mentioned above, although the gateway apparatus of this invention has been demonstrated based on Example 1, it is not restricted to these Examples about concrete structure, The summary of the invention which concerns on each claim of a claim Unless it deviates, design changes and additions are allowed.

  For example, in the first embodiment, the data to be transmitted is temporarily stored in the RAM which is the internal storage device of the CPU, but the data to be transmitted is temporarily stored in the external storage device of the CPU. May be.

It is explanatory drawing which shows the structure of the CAN system using the gateway apparatus of Example 1. FIG. It is a block diagram of the gateway apparatus of Example 1. 3 is an explanatory diagram of a CAN communication processing unit and a RAM portion of the CPU of the gateway device of Embodiment 1. FIG. It is explanatory drawing which compared the relationship between the reception data of the gateway apparatus of Example 1, and transmission data with the past. It is explanatory drawing which shows the data structure of temporarily storing the transmission data of the gateway apparatus of Example 1. FIG. It is a flowchart figure which shows the flow of the reception process of the gateway apparatus of Example 1. FIG. It is a flowchart figure which shows the flow of the transmission process of the gateway apparatus of Example 1. FIG. It is a flowchart figure which shows the flow of a process which sorts the transmission data of the gateway apparatus of Example 1 into a priority. It is a flowchart figure which shows the flow of the conventional reception process. It is a flowchart figure which shows the flow of the conventional transmission process.

Explanation of symbols

1 Gateway device 2 CPU
21a Communication part 21b Communication part 22 Watchdog timer part 23 ROM
231 FIFO data structure 24 RAM
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 in-vehicle equipment A3 in-vehicle equipment A4 in-vehicle equipment A5 in-vehicle equipment A6 in-vehicle equipment B1 communication line B2 in-vehicle equipment B3 in-vehicle equipment B4 in-vehicle equipment B5 in-vehicle equipment B6 in-vehicle equipment

Claims (2)

Forming multiple in-car networks with in-car devices in the car,
Connect between the different networks formed,
Temporarily save and convert data received from the network and send it to another network,
Exchange data between in-vehicle devices connected to different networks,
In the gateway device,
Provide priority ID storage means for storing in advance the priority order of ID codes indicating the destination included in the data to be relayed,
A gateway device comprising priority order judging means for judging the priority order of transmission from the priority order of ID codes of the priority ID storage means when there is a plurality of data to be transmitted next after data transmission is completed . The gateway device according to claim 1,
The network formed in the vehicle uses the CAN protocol,
Provide at least a CPU to convert relayed data,
A CAN communication processing unit that performs processing according to the CAN protocol is provided in the CPU,
A message box that temporarily stores received data and data to be transmitted is provided in the CAN communication processing unit,
RAM is provided in the CPU as the priority ID storage means,
The RAM and the message box are connected by a bus,
A plurality of data to be transmitted are temporarily stored in the RAM, and the priority order judging means rearranges the data in the RAM so that only the transmission data with the highest priority is sent to the message box. A gateway device characterized by that.

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