[Basic application of CAN bus in the automotive industry]

How Can Can Work in the Automotive Industry

CAN (Controller Area Network, Controller Area Network) is a communication protocol widely used in the automotive industry. It is used to connect various electronic devices in vehicles, such as engine control modules, braking systems, air conditioning systems, airbags , door controller, etc.

The CAN protocol has the advantages of high reliability, high-speed transmission, and low cost. It can transmit information between automotive electronic devices, so that various electronic devices can coordinate with each other, thereby improving the reliability and efficiency of the entire automotive system.

In the automotive industry, the CAN protocol is widely used in the following areas:

1. Automobile control system:
   CAN protocol is used to connect various control modules in the automobile, such as engine control module, transmission control module, brake system control module, etc., to realize information exchange and coordination among these modules.

   • Engine control system: CAN bus is used to connect engine control modules, sensors and other equipment to realize engine control, fuel injection, ignition control and other functions. Through the CAN bus, high-speed and reliable information exchange can be realized between various devices, improving engine performance and fuel efficiency.
   • Braking system: CAN bus is used to connect braking system control modules, wheel speed sensors and other equipment to realize functions such as braking control and braking force distribution. Through the CAN bus, real-time and accurate information exchange can be realized among various devices of the braking system, which improves the braking efficiency and safety of the vehicle.
   • Air-conditioning system: CAN bus is used to connect air-conditioning control modules, temperature sensors and other equipment to realize functions such as air-conditioning control and temperature adjustment. Through the CAN bus, fast and accurate information exchange can be realized between various devices of the air conditioning system, improving the comfort in the car and the driving experience of the driver.

2. Automotive diagnostic system:
   CAN protocol can be used to connect automotive diagnostic instruments and various control modules in the car to achieve detection and troubleshooting of automotive electronic systems.

3. Car entertainment system:
   CAN protocol can be used to connect audio, video, navigation and other equipment in the car to realize the transmission and control of multimedia information.

4. Automobile safety system:
   The CAN protocol can be used to connect the safety airbags, anti-theft systems and other equipment in the automobile to realize the safety protection of the vehicle.

   • Airbag system: CAN bus is used to connect the airbag control module, collision sensor and other equipment to realize the control and trigger of the airbag. Through the CAN bus, fast and reliable information exchange can be realized between various devices of the airbag system, which improves the safety of the vehicle and the safety of the driver.

CAN bus is widely used in the automotive industry, which can realize high-speed and reliable information exchange between various devices, and improve the performance, safety and driving comfort of the whole vehicle.

Implementation of CAN protocol in code

The implementation of the CAN protocol usually needs to use the CAN controller chip and the corresponding software library to complete. Here are some commonly used CAN controller chips and software libraries:

CAN controller chip: Common CAN controller chips include Microchip MCP2515, NXP SJA1000, TI MCP2510, etc. These chips are usually connected with the main control chip through SPI or I2C interface to realize the control and communication of CAN bus.

Software library: Common CAN software libraries include STMCube HAL library of ST Company, MPLAB Harmony library of Microchip Company, LPCOpen library of NXP Company, etc. These software libraries provide the underlying driver program and high-level application program interface for CAN bus communication, which simplifies the development process of CAN bus.

The following is a CAN communication code example using the NXP software library, taking the LPCOpen library as an example:

/* 初始化CAN总线 */
CAN_Init(LPC_CAN1, 125000);
CAN_SetAFMode(LPC_CANAF, CAN_AF_OFF);
CAN_SetTxRqst(LPC_CAN1, CAN_MSG_TYPE, CAN_TXRQST_NEW);
CAN_SetupAcceptFilter(LPC_CANAF, 1, CAN_STD_ID, 0x123, CAN_RX_EN);
CAN_SetAFMode(LPC_CANAF, CAN_AF_ON);

/* 发送CAN数据 */
CAN_MSG_OBJ msg;
msg.msgobj = 1;
msg.mode_id = 0x123;
msg.dlc = 8;
msg.data[0] = 0x01;
msg.data[1] = 0x02;
msg.data[2] = 0x03;
msg.data[3] = 0x04;
msg.data[4] = 0x05;
msg.data[5] = 0x06;
msg.data[6] = 0x07;
msg.data[7] = 0x08;
CAN_SendMsg(LPC_CAN1, &msg);

/* 接收CAN数据 */
CAN_MSG_OBJ rxmsg;
if (CAN_Receive(LPC_CAN1, 1, &rxmsg) == CAN_OK)
{
    
    
    // 处理接收到的CAN数据
}