The Internet has made the world a global village. At the same time, various communication protocols adopted in automobiles have made cars more integrated and integrated. Under ideal conditions, various information is free to interact, arrive in real time and be accurate. In the process of transition from mechanized electrification to electronicization, several communication protocols have emerged for solving the problem of information interaction between electronic units for different requirements of specific applications. The most widely used CAN bus is in the leading automobile industry. In Europe and the United States, it has already been used on a large scale. In recent years, LIN bus and flexray bus have appeared one after another. Because of the easy implementation of LIN bus and low cost, and the application is not suitable for real-time requirements, so in recent years, It has also begun to be used on a large scale, and the Flexray bus is used in a high-speed car because of its high technical barriers and high implementation due to its high security and power system. In addition to this bus-type communication protocol, Bluetooth communication has also begun to be used in in-vehicle infotainment systems in recent years. This article refers to the address: http:// In the implementation of the communication protocol, the bottom layer of the industry chain is the chip manufacturers, which provide transceivers and controllers for various protocols. The agreement consistency is basically ignored. Another automotive electronic component supplier, automobile OEM And the vehicle network developers play different roles, the OEM defines the function, the network developer develops the application layer protocol of the bus, the component supplier is the implementation of the specific agreement and the realization of the function, the network developer and the component supplier Sometimes it can be combined into one, in fact, automotive electronics giants such as Siemens Bosch Delphi are such a role. In-vehicle network development is the development of an application layer protocol that is currently widely debated. It is undeniable that this is a very complicated problem. What are the key technologies, the principles of design protocols, the functional and real-time requirements to be considered, and so on. How to verify the simulation, these are systemic problems. The domestic start in this area is late, there are fewer professionals, you need to know the car, understand the communication, understand the electronic talents together, and definitely can not stay at the level of theoretical research. It must be developed in conjunction with the needs of the OEM. Of course, if it is only positioned in the role of the component supplier, there is no need to do this, because the design of large systems has always been from the overall architecture to the development of the corresponding component modules. Simple component suppliers do not have the awareness of the overall structure, nor do they have this driving force. Of course, this is only a statement. These four protocols, the author has a deep understanding of LIN bus and Bluetooth, have done actual development, CAN bus second, Flexray is only a little bit of water, but also intend to study it, then the following will share some superficial about LIN and Bluetooth Awareness. LIN bus is used in applications where CAN bus bandwidth is not required. Controls such as lamp, door, seat and wiper are its application fields. As the effective compensation of CAN network, the biggest advantage is the low cost, mainly because it is mainly Adopt UART data format, so no separate controller is needed, it can be implemented in software on UART, and it has a unique clock synchronization mechanism so that the slave node can save the external crystal oscillator and only use the internal crystal oscillator of the processor to meet the accuracy requirement. So, those low-speed control applications will adopt a LIN bus that costs significantly less than CAN. The LIN bus is a master-multi-slave structure, so the application layer protocol is mainly implemented on the master node. The development of the LIN network is also the development of the master node. How to develop the method is not repeated here. The application of Bluetooth was first introduced not to solve the wiring harness problem inside the car. Its application is limited to the infotainment system. Currently, mature applications only have hands-free and streaming music playback. I saw on the Internet that wireless communication such as Bluetooth can completely solve the wiring problem inside the car. As a Bluetooth technician, I can only be speechless: the typical dreamer's argument. First of all, the electromagnetic environment inside the car is not fully compatible with wired communication. Moreover, for wireless communication, the basis for reliable transmission of data is stable connection. The connection of bus-type wired communication will be broken unless there is a physical failure. On, the connection based on frequency hopping technology is not so stable, and according to the current Bluetooth protocol, the fastest time to establish a Bluetooth connection is 2.56 seconds (the paging cycle is 1.28 seconds, the detection of the master device is detected in the current window). Calling the request, giving a response in the next cycle, and then the master device gives a response and then establishes a connection in the next cycle, obviously the fastest time is 2.56 seconds), obviously the electronic control unit with more stringent real-time and stability requirements cannot Adopt Bluetooth technology. Pro Bass Speaker,Woofer Loudspeaker,Subwoofer Audio Speaker,5 Inch Woofer Speaker Guangzhou Yuehang Audio Technology Co., Ltd , https://www.yhspeakers.com