CN114915515B

CN114915515B - CAN communication method and system based on SOC

Info

Publication number: CN114915515B
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: 2024-01-26
Anticipated expiration: 2042-05-04
Also published as: CN114915515A

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, poor in portability and low in software development efficiency of a vehicle controller due to dependence on specific SOC chip types. The method comprises the following steps: step S1, after a communication process is started, reading CAN communication configuration files, and initializing a periodic scheduling framework according to the configuration files; step S2, running an application process, and sequentially establishing IPC interactive links according to a 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 the step S2; and S4, synchronously transmitting CAN data according to the scheduling time sequence of each period of threads.

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, the function of software in an automobile is more and more important and the function of the automobile is more and more complex, the core control is changed from a traditional MCU into an SOC chip with high calculation power, and the demand of the CAN bus for application on a real-time core and a calculation core of the SOC chip is gradually increased along with the higher integration level of the SOC chip from the safety and real-time performance of the CAN bus although the application of high-speed Ethernet communication in the automobile is more and more extensive. On the existing MCU controller, the CAN communication protocol stack is developed and configured based on the standard AUTOSAR international specification, but on the SOC, the operating system based on Linux and the like does not have the standard CAN protocol stack software design specification facing the vehicle communication requirement.

CAN is an abbreviation of Controller Area Network, which indicates a controller area network, and CAN communication protocol was developed by german bosch in 1986, mainly for automotive-oriented communication systems, which are now serial communication protocols internationally standardized by ISO. In the development process of the vehicle electronic controller, because of the increase and decrease of multiple functions and the forwarding of signals, the design requirement for changing the CAN communication protocol is often met, and the same controller in the same vehicle type has some differences in the communication requirement.

The existing AUTOSAR specification is a development specification of basic software for a vehicle aiming at an MCU controller, and the original purpose of the development is to solve the complex diversity of the current automobile electronic and electric architecture and unify the standard of the automobile electronic and electric architecture. The modules such as CanIf, canTP, com related to communication in the standard have detailed hierarchical designs and interfaces and functional descriptions. The standard is currently widely used in MCU type controllers for production.

However, the existing MCU type controller has the following defects: due to the fact that the specific SOC chip type is depended on, the modularization degree is low, portability is poor, and the development efficiency of software of the vehicle controller is low.

In summary, the existing communication device depends on a specific SOC chip type, so that the modularization degree is low, portability is poor, and the software development efficiency of the vehicle controller is low.

Disclosure of Invention

The invention solves the problems of low modularization degree, poor portability and low software development efficiency of the vehicle controller of the existing communication method because of depending on the specific SOC chip type.

The invention relates to a CAN communication method based on SOC, which comprises the following steps:

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

step S2, running an application process, and sequentially establishing IPC interactive links according to a 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 the step S2;

and S4, synchronously transmitting CAN data according to the scheduling time sequence of each period of threads.

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

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 enabling bit length is 1, and the CAN continuous frame counting mark enabling bit length is 1.

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

the early stage is stored in a file form, when the CAN communication configuration file is read, the message during debugging CAN be flexibly modified, and the global variable in the C file is directly declared in the later stage so as to improve the starting time of the process.

Further, in one embodiment of the present invention, in the step S1, the period scheduling framework includes a kernel driving 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 the kernel driving system.

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

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

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

the interrupt module is used for responding to an external request to the controller.

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

the data receiving module is used for acquiring data in all the periods 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, respectively interacting the data with each application process in an IPC communication mode, and sending the data to the data sending module;

the data transmitting module is used for finishing the applied data and transmitting the data according to the required period and sequence.

Further, in an embodiment of the present invention, in the step S2, the application process includes 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 synchronizing the data which need to be updated in the period of the application process;

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

Further, in one 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, the application thread A2 and the application thread A3 are used for software business.

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

the application thread B1 and the 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 frame according to the configuration file;

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

the data module is used for judging whether all application processes with communication requirements complete data interaction, if so, executing the next module, and if not, returning and executing the link module;

and the sending module synchronously sends CAN data according to the scheduling time sequence of each period thread.

The invention solves the problems of low modularization degree, poor portability and low software development efficiency of the vehicle controller of the existing communication method because of depending on the specific SOC chip type. The method has the specific beneficial effects that:

1. the CAN communication method based on the SOC is independent of specific SOC chip types, high in modularization degree and good in portability, and CAN improve the software development efficiency of the vehicle controller.

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

3. The CAN communication method based on the SOC is suitable for the Linux and all operating systems of POSIX interfaces, and the layered software architecture of the CAN communication method is high in portability, so that the CAN communication method 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 invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

fig. 1 is a profile format diagram of an embodiment.

Fig. 2 is a diagram of a CAN communication system periodic schedule framework according to an embodiment.

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

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

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

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

In this embodiment, in step S1, the format of the configuration file is:

In this embodiment, the configuration file is:

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

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

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

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

In this embodiment, in the 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 present embodiment provides a CAN communication system based on SOC, including:

The embodiment provides a practical embodiment based on the CAN communication method based on the SOC and combined with a specific object:

the design of a CAN communication system period scheduling framework is shown in fig. 2, the whole CAN communication system consists of a kernel driving part and a CAN communication process, the example 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. In the figure, the communication thread with the period of 10ms is formed by 3 modules, and each module is realized by a function and comprises a data receiving module, a data transmission module and a data sending module. The data receiving module obtains the data in all the periods from the bus and then gives the data to the data transmission module, and the data received in the data transmission module are classified according to the message number of the CAN message and respectively interact with each application process in a mode of IPC communication. And the transmission module is used for placing the data summarized by interaction into the transmission module and then uniformly transmitting synchronous data. The kernel driving 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 for the controller. And the synchronous sending and receiving functions of single-frame CAN message data are realized in the CAN drive.

the working flow of the CAN communication system is shown in figure 3, after the communication process is started, a CAN communication configuration file is read, and the configuration file is stored in a file form in the early stage, so that the purpose of flexibly modifying a message during debugging is achieved, and global variables in a C file in the later stage are directly declared to improve the starting time of the process. The configuration file format is shown in fig. 1.

The message number is an internal message number, and the message numbers are sequentially arranged in all the received and transmitted messages of the controller and are used for identifying and extracting other information in each CAN message structure body. And the application module numbers correspond to all business processes and threads in the business processes. The IPC link is established by mutually identifying the CAN communication process and the service process. The CAN check is an enable bit and the CAN consecutive frame count is an enable bit indicating whether the message has checksum and consecutive count functions. If so, in the message sending function, performing checksum calculation on the data of other 7 bytes of the message, and sending the data after filling the checksum. The CAN continuous frame count is filled in the sequence number starting from 0 in the transmission message. The positions of the two bits are based on the initial settings of the CAN protocol, and the default checksum and consecutive count bits are consistent across all transmitted and received messages.

In the initialization process, the information in the configuration file is required to be copied into a global structure body in the communication module respectively in a manner of CAN message identifier, period, message length, checksum enabling bit and continuous counting enabling bit, and is sequenced according to message sequence numbers in the structure body. After all the message information is obtained, creating communication threads with the same message period in the communication process, and starting the communication scheduling framework. And then each business process is operated, IPC communication links are sequentially established with the business processes, and data needing to be sent and received in the period are synchronized through a mutual exclusion locking mechanism. After each communication thread completes interaction with each service thread, 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 50ms period thread, the meeting is more periodic in the profile to build its own internal CAN message list, with the relevant message information all in the local fabric variables. 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 finished with the business process A, the data which is just received is sent to the business process according to the message number, and the business process is synchronized to return the data which needs to be updated in the period. After the business process A completes data interaction with the communication, the communication process can continue to conduct data interaction with the business process B according to the configuration information. And after all service processes complete data interaction, completing packet processing of data transmission in the period in a communication thread, and finally transmitting based on a Socket CAN and CAN drive synchronization according to an internal CAN message number list.

The method, the system, the equipment and the medium for extracting news webpage information based on multidimensional text features are described in detail, and specific examples are applied to illustrate the principle and the implementation of the invention, and the description of the examples is only used for helping to understand the method and the core idea of the invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.

Claims

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

step S4, CAN data is synchronously transmitted according to the scheduling time sequence of each period thread;

the whole CAN communication system consists of a kernel driving part and a CAN communication process, threads of each communication message period are respectively established in the CAN communication process, the period is defined according to the communication requirement of each service, 3 modules are arranged in the CAN communication system, each module is realized by a function and comprises a data receiving module, a data transmission module and a data sending module, the data receiving module obtains data in all the periods from a bus and then sends the data to the data transmission module, the received data is classified according to the message number of the CAN message in the module, the data is interacted with each application process in an IPC communication mode, and the transmission module places the data which are summarized in interaction into the sending module and then performs synchronous data sending uniformly.

2. The SOC-based CAN communication method of claim 1, wherein in the step S1, the format of the configuration file is:

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

4. The SOC-based CAN communication method of claim 1, wherein in the step S1, the periodic scheduling framework includes a kernel driving system and a CAN communication process system;

5. The SOC-based CAN communication method of claim 4, wherein 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 exchanging data between any two processes;

6. The SOC-based CAN communication method of claim 1, wherein in the step S2, the application process includes an application process a and an application process B;

7. The SOC-based CAN communication method of claim 6, wherein the application process a includes an application thread A1, an application thread A2, and an application thread A3;

8. The SOC-based CAN communication method of claim 6 wherein the application process B includes an application thread B1 and an application thread B2;

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

the sending module synchronously sends CAN data according to the scheduling time sequence of each period thread;