CN114915515A

CN114915515A - CAN communication method and system based on SOC

Info

Publication number: CN114915515A
Application number: CN202210477319.8A
Authority: CN
Inventors: 李岩; 刘奇; 王宏民; 孟祥泰
Original assignee: FAW Group Corp
Current assignee: FAW Group Corp
Priority date: 2022-05-04
Filing date: 2022-05-04
Publication date: 2022-08-16
Anticipated expiration: 2042-05-04
Also published as: CN114915515B

Abstract

A CAN communication method and system based on SOC belongs to the technical field of CAN communication and solves the problems that an existing communication device is low in modularization degree and poor in transportability and development efficiency of automobile controller software is low due to the fact that the existing communication device depends on specific SOC chip types. The method comprises the following steps: step S1, after the communication process is started, reading a CAN communication configuration file, and initializing a periodic scheduling framework according to the configuration file; step S2, running the application process, and sequentially establishing IPC interactive links according to the periodic scheduling framework; step S3, judging whether all application processes with communication requirements complete data interaction, if so, executing the next step, and if not, returning to and executing step S2; step S4, the CAN data is synchronously transmitted according to the scheduling timing of each cycle thread.

Description

CAN communication method and system based on SOC

Technical Field

The invention relates to the technical field of CAN communication, in particular to a CAN communication method and system based on SOC.

Background

With the development of automobile electronic technology and different scenes of intelligent networking service, the function of software in an automobile is more and more important, and meanwhile, the function of the automobile is more and more complex, the core control is changed from the traditional MCU into an SOC chip with high computing power, although the application of high-speed Ethernet communication in the automobile is more and more extensive, the CAN bus is sent from the safety and the real-time performance of the automobile, the CAN bus also occupies a place, and the requirement of applying the CAN bus on a real-time core and a computing core on the SOC is gradually increased along with the higher integration level of the SOC chip. On the existing MCU controller, a CAN communication protocol stack is developed and configured based on a standard AUTOSAR international specification, but on the SOC, a standard CAN protocol stack software design specification facing vehicle communication requirements does not exist based on operating systems such as Linux and the like.

CAN is an abbreviation of Controller Area Network, which means Controller Area Network, and CAN communication protocol developed by german bosch company in 1986, mainly for automobile communication system, and is now a serial communication protocol internationally standardized by ISO. In the development process of the electronic controller for the vehicle, because the increase and decrease of various functions and the signal forwarding are involved, the design requirement of changing the CAN communication protocol is often met, and the same controller in the same series of vehicle models has some differences in communication requirements.

The existing AUTOSAR specification is a basic software development specification for an MCU controller, and the initial purpose of the development specification is to solve the complex and diversified current automobile electronic and electrical architecture and unify the automobile electronic and electrical architecture standard. Modules in the standard, such as Canif, CanTP and Com, related to communication are in detailed layered design and interface and function description. The standard is widely applied to MCU type controllers of output at present.

However, the existing MCU type controller has the following defects: the method depends on specific SOC chip types, so that the modularization degree is low, the transportability is poor, and the development efficiency of the software of the vehicle controller is low.

In summary, the existing communication device depends on a specific SOC chip type, so that the degree of modularization is low, the transportability is not good, and the development efficiency of the software of the vehicle controller is low.

Disclosure of Invention

The invention solves the problems that the existing communication method depends on the specific SOC chip type, the modularization degree is low, the transportability is not good, and the development efficiency of the software of the vehicle controller is low.

The CAN communication method based on SOC comprises the following steps:

step S1, after the communication process is started, reading a CAN communication configuration file, and initializing a periodic scheduling framework according to the configuration file;

step S2, running the application process, and sequentially establishing IPC interactive links according to the periodic scheduling framework;

step S3, judging whether all application processes with communication requirements complete data interaction, if so, executing the next step, and if not, returning to and executing step S2;

step S4, the CAN data is synchronously transmitted according to the scheduling timing of each cycle thread.

Further, in an embodiment of the present invention, in the step S1, the format of the configuration file is:

the length of a CAN message number is 4, the length of an application module number is 2, the length of a CAN ID is 4, the length of a CAN message type is 1, the length of a CAN message period is 2, the length of a receiving/sending is 1, the length of the CAN message length is 1, the length of an initial value of CAN message data is 32, the length of a CAN verification enable bit is 1, and the length of a CAN continuous frame counting mark enable bit is 1.

Further, in an embodiment of the present invention, the configuration file is:

the early stage is stored in a file form, when a CAN communication configuration file is read, messages during debugging CAN be flexibly modified, and the later stage is also directly declared on the global variables in the C file, so that the starting time of the process is prolonged.

Further, in an embodiment of the present invention, in the step S1, the periodic scheduling framework includes a kernel driver system and a CAN communication process system;

the kernel driving system is used for providing basic scheduling and peripheral driving of the controller;

the CAN communication process system is used for calling a kernel driving system.

Further, in an embodiment of the present invention, the kernel driver system includes a file system, a CAN peripheral driver, an IPC driver, and an interrupt module;

the file system is used for controlling data storage in software and code CAN peripheral drivers;

the IPC driver is used for data exchange between any two processes;

the interrupt module is used for responding to a request given to the controller from the outside.

Further, in an embodiment of the present invention, the CAN communication process system includes a data receiving module, a data transmitting module and a data sending module;

the data receiving module is used for acquiring all data in the period from the bus and sending the data to the data transmission module;

the data transmission module is used for classifying the received data according to the message number of the CAN message, then respectively interacting the data with each application process in an IPC communication mode, and sending the data to the data sending module;

the data sending module is used for arranging the applied data and sending out the data according to the required period and sequence.

Further, in an embodiment of the present invention, in the step S2, the application processes include an application process a and an application process B;

the application process A is used for being in communication link with the IPC, sending the received data to the application process according to the message number, and synchronously returning the data which needs to be updated in the period by the application process;

and the application process B is used for carrying out data interaction with the communication process.

Further, in an embodiment of the present invention, the application process a includes an application thread a1, an application thread a2, and an application thread A3;

the application thread A1, application thread A2, and application thread A3 are for software traffic.

Further, in an embodiment of the present invention, the application process B includes an application thread B1 and an application thread B2;

the application thread B1 and application thread B2 are used for software business.

The invention relates to a CAN communication system based on SOC, which comprises:

the scheduling module reads the CAN communication configuration file after the communication process is started, and initializes a periodic scheduling framework according to the configuration file;

the link module runs the application process and sequentially establishes IPC interactive links according to a periodic scheduling framework;

the data module judges whether all the application processes with communication requirements complete data interaction, if so, executes the next module, and if not, returns to and executes the link module;

and the sending module is used for synchronously sending the CAN data according to the scheduling time sequence of each periodic thread.

The invention solves the problems that the existing communication method depends on the specific SOC chip type, the modularization degree is low, the transportability is not good, and the development efficiency of the software of the vehicle controller is low. The concrete beneficial effects include:

1. the SOC-based CAN communication method does not depend on specific SOC chip types, is high in modularization degree and good in transportability, and CAN improve the development efficiency of controller software for vehicles.

2. The CAN communication method based on SOC CAN not only realize the sending and receiving of a plurality of CAN messages through configuration, but also flexibly change the message ID, the sending length and the period of the message in a mode of reading a configuration file.

3. The SOC-based CAN communication method is suitable for operating systems of Linux and all POSIX interfaces, the layered software architecture of the SOC-based CAN communication method enables the SOC to have high portability on the whole, and the SOC CAN be deployed on different SOC chips and different cores on the same SOC chip.

Drawings

The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a configuration file format diagram according to an embodiment.

Fig. 2 is a frame diagram of a periodic scheduling of a CAN communication system according to an embodiment.

Fig. 3 is a flowchart illustrating the operation of the CAN communication system according to the embodiment.

Fig. 4 is a diagram of a data synchronization process of the CAN communication system according to the embodiment.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The SOC-based CAN communication method according to the present embodiment includes the following steps:

in step S4, CAN data is transmitted synchronously at the scheduling timing of each periodic thread.

In this embodiment, in step S1, the configuration file has a format that:

In this embodiment, the configuration file is:

In this embodiment, in step S1, the periodic scheduling framework includes a kernel driver system and a CAN communication process system;

In this embodiment, the kernel driver system includes a file system, a CAN peripheral driver, an IPC driver, and an interrupt module;

the IPC driver is used for data exchange between any two processes;

In this embodiment, the CAN communication process system includes a data receiving module, a data transmission module, and a data sending module;

In this embodiment, in step S2, the application process includes an application process a and an application process B;

In this embodiment, the application process a includes an application thread a1, an application thread a2, and an application thread A3;

In this embodiment, the application process B includes an application thread B1 and an application thread B2;

The system for CAN communication based on SOC according to the present embodiment includes:

the link module runs the application process and sequentially establishes IPC interactive links according to the periodic scheduling framework;

and the sending module is used for synchronously sending the CAN data according to the scheduling time sequence of each cycle thread.

The present embodiment is based on the SOC-based CAN communication method according to the present invention, and provides an actual embodiment in combination with specific objects:

the CAN communication system period scheduling framework is designed, as shown in fig. 2, the whole CAN communication system consists of a kernel driving part and a CAN communication process, the embodiment of the scheme is developed by adopting a Linux operating system, threads of each communication message period are respectively established in the CAN communication process, and the period is defined according to the communication requirements of each service. For example, a communication thread with a period of 10ms in the figure is internally provided with 3 modules, and each module is realized by one function and comprises a data receiving module, a data transmitting module and a data sending module. The data receiving module obtains all data in the period from the bus, then sends the data to the data transmission module, classifies the received data according to the message number of the CAN message in the module, and then interacts data with each application process in an IPC communication mode. The transmission module puts the interactive summarized data into the sending module, and then the synchronous data sending is carried out uniformly. The kernel driver part comprises a file system, a CAN peripheral driver, an IPC driver and an interrupt module and is used for providing basic scheduling and peripheral driver of the controller. The synchronous sending and receiving functions of single-frame CAN message data are realized in the CAN driver.

as shown in fig. 3, after a communication process is started, a CAN communication configuration file is read, and the configuration file is stored in a file form at an earlier stage, so that a message during debugging is flexibly modified, and a global variable in a C file is directly declared at a later stage, so that the starting time of the process is prolonged. The configuration file format is shown in fig. 1.

The message serial number is an internal message serial number, and the message serial number is sequentially arranged in all messages received and sent by the controller and used for identifying and extracting other information in each CAN message structure body. The application module number corresponds to all the business processes and threads in the business process. The method is used for mutual identification of the CAN communication process and the service process and establishing IPC link. The CAN check is an energy bit, and the CAN continuous frame counting is an energy bit which indicates whether the message has the functions of check sum and continuous counting. If yes, in the message sending function, the data of other 7 bytes of the message is checked and calculated, and the check sum is filled and sent out. The CAN consecutive frame count is filled in the sent message according to the sequence number starting from 0. The position of the two bits is based on the initial setting of the CAN protocol, and the default checksum and the continuous counting bits are consistent in all the sending and receiving messages.

In the initialization process, the information in the configuration file needs to be copied to a global structure body in the communication module respectively according to the modes of a CAN message identifier, a period, a message length, a check sum enable bit and a continuous counting enable bit, and the information is sorted according to the message sequence number in the middle sequence of the structure body. And after all message information is acquired, establishing a communication thread with the same message period in a communication process until the communication scheduling framework is started. Then, each service process is operated, IPC communication links are sequentially established with the service processes, and data needing to be sent and received in the period are synchronized through a mutual exclusion lock mechanism. After each communication thread finishes the interaction with each service thread, the data in the period is synchronously sent to the CAN bus.

as shown in fig. 4, which depicts a typical data synchronization practice, in a thread with a period of 50ms, a period in a conference profile establishes a self-performed internal CAN message list, and related message information is stored in a local structure variable. And the CAN receiving module is used for receiving the message data from the bus according to the matching of the corresponding message number and the application module number. In the transmission module, the IPC communication link is firstly completed with the service process A, the data received just now is sent to the service process according to the message number, and the service process is synchronized to return the data which needs to be updated in the period. And after the business process A completes data interaction with the communication, the communication process can continue to perform data interaction with the business process B according to the configuration information. And after all the service processes complete data interaction, completing packet processing of sending data in a cost cycle in a communication thread, and finally synchronously sending the data based on the Socket CAN and the CAN drive according to an internal CAN message number list.

The method, the system, the equipment and the medium for extracting the news webpage information based on the multi-dimensional text features are introduced in detail, specific examples are applied in the method for explaining the principle and the implementation mode of the invention, and the description of the embodiments is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A CAN communication method based on SOC is characterized by comprising the following steps:

2. The CAN communication method on an SOC according to claim 1, wherein in step S1, the configuration file has a format of:

the CAN message number length is 4, the application module number length is 2, the CAN ID length is 4, the CAN message type length is 1, the CAN message period length is 2, the receiving/transmitting length is 1, the CAN message data initial value length is 32, the CAN check enable bit length is 1, and the CAN continuous frame counting mark enable bit length is 1.

3. The CAN communication method based on SOC of claim 2, wherein the configuration file is:

4. The CAN communication method on a SOC according to claim 1, wherein in step S1, the periodic scheduling framework includes a kernel driver system and a CAN communication process system;

5. The CAN communication method based on SOC of claim 4, wherein the kernel driver system comprises a file system, a CAN peripheral driver, an IPC driver and an interrupt module;

the IPC driver is used for data exchange between any two processes;

6. The CAN communication method based on SOC of claim 4, wherein the CAN communication process system comprises a data receiving module, a data transmitting module and a data transmitting module;

7. The CAN communication method based on SOC of claim 1, wherein in the step S2, the application processes include application process A and application process B;

the application process A is used for being in communication link with the IPC, sending the received data to the application process according to the message number, and synchronously returning the data needing to be updated in the period by the application process;

8. The CAN communication method based on SOC of claim 7, wherein the application process A comprises application thread A1, application thread A2 and application thread A3;

9. The CAN communication method based on SOC of claim 7, wherein the application process B comprises application thread B1 and application thread B2;

10. A SOC-based CAN communication system, the system comprising: