Heqian Technology: Provides a communication bridge between in-vehicle Ethernet and CAN for intelligent connected vehicles

In recent years, with the continuous development of automotive electronic equipment, automotive technological innovation with intelligence and networking as important features has brought major changes to the automotive industry. People have different functional requirements for smart cars, such as ADAS assisted driving, autonomous driving, in-vehicle entertainment, and body monitoring, which prompts car manufacturers to deploy a large number of ECUs in the car to implement complex functions to meet user needs, and a large number of ECUs The use of CAN bus requires high-speed, high-bandwidth, and low-latency vehicle network communication, but the traditional CAN bus cannot meet the high-speed, high-bandwidth, and low-latency requirements. Therefore, in order to meet the development of intelligence and networking, on the basis of traditional Ethernet, IEEE proposed an automotive Ethernet with high-speed, high-bandwidth, and low-latency transmission characteristics, prompting future automotive networks to transform from existing CAN to communication The basic network gradually transitions to a communication network with vehicle Ethernet as the backbone network. Therefore, a large number of outstanding companies at home and abroad are engaged in the research and development of automotive Ethernet technology. For example, in China, companies represented by Heqian Technology are focusing on the research and development of automotive Ethernet technology and accelerating the production of products based on the automotive Ethernet bus. production process.

Will the CAN bus be completely replaced by the automotive Ethernet bus?

CAN is an ISO internationally standardized serial communication protocol. It is a serial communication network that effectively supports distributed control or real-time control. Compared with other communication buses, the technical characteristics of CAN make it particularly effective in the automotive environment, see Table 1, for example: first of all, its high tolerance to noise, and supported by the physical layer and protocol of CAN, CAN supports native Multicast and broadcast, provides built-in frame prioritization, 100% distributed operation, and easily supports long single buses of tens of feet.

Compared with CAN, automotive Ethernet has high-speed transmission, can support a transmission rate of 10 G/s through optical fiber transmission, supports QoS and TSN, allows real-time deterministic communication, supports multiple different protocols, and supports service-oriented SOA communication. And scalable. Obviously, automotive Ethernet and CAN have different advantages in different application scenarios. At the current stage, in order to adapt to the functional requirements of intelligent and connected automobiles, the E/E architecture of automobiles has transitioned from traditional distributed to region-oriented E/E architecture. For example, the region includes: intelligent driving domain, cockpit domain, body domain, etc. Based on the regional E/E architecture, in the backbone network, high-bandwidth vehicle Ethernet is used to communicate and connect to the corresponding domain controller or regional gateway. Under the regional gateway or domain controller, it can communicate through a variety of different buses CAN, LIN, branch Onboard Ethernet connects the corresponding sensors and actuators. Therefore, the implementation of E/E architecture requires a combination of CAN and automotive Ethernet. In addition, CAN is still more cost-effective for many traditional automotive network use cases. To sum up, in the future for a long period of time, automotive Ethernet and CAN will not replace each other, but will coexist with each other. In a vehicle network where CAN and vehicle Ethernet coexist, there must be a need for mutual communication between CAN ECU and vehicle Ethernet ECU. However, there is currently no solution in the standard for mutual conversion of data packets between CAN ECU and vehicle Ethernet ECU.

How to realize mutual conversion between SOME/IP data of automotive Ethernet and data of CAN protocol?

Since the CAN bus and the vehicle Ethernet bus will coexist in the vehicle network for a long time, it is necessary to build a communication bridge between the CAN ECU and the vehicle Ethernet ECU to ensure the normal communication of the vehicle network. In order to find a solution, we searched in the authoritative patent database and found that Shanghai Heqian Electronic Technology Co., Ltd. (HingeTech) had earlier proposed a conversion scheme for CAN data packets and vehicle Ethernet data packets (the authorization announcement number is: CN111130676 B), its transformation method is as follows:

Figure 1 Schematic diagram of SOME/IP data conversion between CAN data and automotive Ethernet

Referring to Figure 1 and Table 2, by setting up a microprocessor controller (MCU), a CAN interface and a vehicle-mounted Ethernet interface are set at both ends of the microprocessor controller. The microprocessor controller is responsible for processing CAN data packets and vehicle-mounted Ethernet data packets. Parse and encapsulate into corresponding CAN data packets or vehicle Ethernet data packets according to requirements; the microprocessor controller includes a SOME/IP transmission module, a CAN transmission module, and a mapping table processing module. The mapping table processing module connects the SOME/IP transmission module and CAN The transmission module is used to decode the mutual conversion between SOME/IP protocol signals and CAN protocol signals; the mapping table processing module includes CAN address identification code (CAN ID) and SOME/IP Message address identification code (Message ID). ) corresponding mapping table; the mapping table also includes SOME/IP information address identification code and transmission terminal address, service port number and other information.

The core method of converting vehicle Ethernet SOME/IP data packets into CAN data packets includes: the SOME/IP transmission module unpacks according to the SOME/IP protocol. The unpacking process includes parsing and separating the received SOME/IP protocol signals. Output the message address identification code (Message ID) and payload signal; then call the mapping table processing module to parse out the CAN ID corresponding to the Message ID; the CAN transmission module encapsulates the CAN ID and payload signal according to the CAN standard protocol and transmits it through the CAN interface to the CAN bus.

The core steps of converting CAN format data packets into automotive Ethernet SOME/IP data packets include: The CAN transmission module unpacks according to the CAN protocol. The unpacking process includes parsing and separating the received signals transmitted according to the CAN protocol. CAN address identification code (CAN ID) and payload signal, and then call the mapping table processing module to parse out the Message ID used in conjunction with the CAN ID. Through the Message ID, the SOME/IP transmission module captures the Message ID and the corresponding protocol type, port and The IP address and payload signal are encapsulated according to the format of the SOME/IP protocol and sent to the vehicle Ethernet bus through the vehicle Ethernet interface. The load signal is forwarded through the built-in lookup mapping table, thus connecting the vehicle Ethernet network and the CAN network, and at the same time interconnecting the vehicle Ethernet network nodes and CAN network nodes through the device.

It can be seen that Heqian Technology provides the technology for mutual conversion of vehicle Ethernet data and CAN data, enabling normal communication between CAN ECU and vehicle Ethernet ECU in the region-oriented E/E architecture. In addition, the biggest difference between SOME/IP communication and CAN communication of automotive Ethernet is that SOME/IP communication is service-oriented, while CAN communication is signal-oriented. Service-oriented communication can greatly reduce network load and improve communication efficiency. Therefore, the car's Adaptive AUTOSAR uses SOME/IP as the SOA software architecture of the communication middleware. In the research work of automotive Ethernet, Heqian Technology has successfully mass-produced SOME/IP protocol stack and automated Hinge-Matrix SOA for SOME/IP communication for domain controllers, smart cockpits, instruments, ADAS assisted driving, autonomous driving and other applications. Tool. as shown in picture 2. The SOME/IP protocol stack provided by Heqian Technology supports multiple functions, such as: supporting SOME/IP-SD, SOME/IP, serialization and deserialization, Event, Field; high performance: CPU load <2% , request & response are less than 1ms; with high stability.

Figure 2 Heqian Technology SOME/IP protocol stack and automated SOA tools

In view of the current complexity of SOA-oriented service API development, Heqian Technology proposed Hinge-Matrix SOA Tool, which can quickly customize and generate service-based APIs according to scenarios. Hinge-Matrix SOA Tool, based on configuration files in multiple different formats, such as Excel format files, automatically generates service codes by importing Excel format configuration files into Hinge-Matrix SOA Tool, and imports the generated service codes into the SOME/IP protocol stack , quickly complete the development of Autosar API/Service API, greatly shortening the software development cycle.

To sum up, for a long period of time in the future, vehicle-mounted Ethernet and CAN networks will coexist in the vehicle network due to their different advantages. Heqian Technology provides mutual conversion of vehicle-mounted Ethernet SOME/IP data and CAN data. The method solves the mutual communication between the ECU of the vehicle Ethernet interface and the ECU of the CAN interface in the vehicle network, laying a solid foundation for the application of region-oriented E/E architecture, and also provides the corresponding SOME/IP protocol stack and SOA fast code Generate tools to accelerate the development of intelligent and connected cars from many aspects.