Controller area network (CAN) bus data transceiver

Abstract

The invention provides a controller area network (CAN) bus data transceiver which comprises a microcontroller, a low-speed / fault-tolerant CAN transceiver, a high-speed transceiver, a switching circuit and a CAN type judgment circuit. When connection of the switching circuit and an exterior CAN bus is cut off, the CAN type judgment circuit judges current connected exterior CAN bus type of the data transceiver according to difference of voltage of a CAN high-speed wire and voltage of a CAN low-speed wire, and then sends the judgment result to the microcontroller. The microcontroller sends a switching signal of the CAN transceiver to the switching circuit and controls the connection state of the switching circuit, the low-speed / fault-tolerant CAN transceiver and the high-speed CAN transceiver. A connected signal of the CAN transceiver is sent to the switching circuit, building of connection of the switching circuit and the exterior CAN bus is controlled, and communication between the CAN transceiver and the exterior CAN bus is achieved.

Description

technical field [0001] The invention relates to the technical field of CAN bus communication in an automobile bus network, and more specifically relates to a CAN bus data transceiver device. Background technique [0002] CAN (Controller Area Network, Controller Area Network) bus is a standard bus for automotive computer control systems and embedded industrial control LANs. It is an ISO international standardized serial communication protocol. Among different types of CAN buses, high-speed CAN and low-speed / fault-tolerant CAN are the most widely used. Among them, high-speed CAN and low-speed / fault-tolerant CAN use two signal lines, CAN_H (CAN high line of external CAN bus) and CAN_L (CAN low line of external CAN bus). According to the CAN physical layer standard, the difference between high-speed CAN and low-speed / fault-tolerant CAN is that the bus voltages of the CAN_H line and the CAN_L line are different when they are in the dominant state, stealth state, and sleep state....

AI Technical Summary

Problems solved by technology

[0004] However, because the high-speed CAN transceiver and the low-speed / fault-tolerant CAN transceiver are basically the same in appearance, it is easy for the user to choose the wrong transceiver, and connect the high-speed CAN transceiver to the low-speed / fault-tolerant CAN bus by mistake, or vice versa. Low-speed / fault-tolerant CAN transceiver connected to high-speed CAN bus

This will not only cause the device not to work normally, but also affect the signal on the CAN bus, which will interfere with the communication on the CAN bus. In severe cases, it may cause misoperation of other devices connected to the CAN bus and cause danger.

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