Semi-asynchronous CAN bus control method based on single-bit synchronization and controller

Abstract

The invention discloses a semi-asynchronous CAN bus control method based on single-bit synchronization and a controller. The semi-asynchronous CAN bus control method based on single-bit synchronization comprises the following steps: generating a communication clock through a frequency division mode; enabling a communication clock to collect a start bit of a to-be-synchronized signal, wherein the start bit is a single-bit dominant signal; triggering a frequency divider to reset while a synchronizing signal is collected, so the initial phase of the communication clock is synchronized with the synchronizing signal. The asynchronous communication does not require a clock but requires a frequency, so that unequal-interval communication is realized, the communication efficiency is improved, the phase of the clock is flexibly changed on the basis of the synchronous communication by the semi-synchronous communication, and an unequal-interval communication function similar to the asynchronous communication is realized. Semi-asynchronous communication in the invention is based on asynchronous communication, and a synchronous clock is recovered from data so as to realize pseudo signal synchronization, that is, the error code problem in the asynchronous communication process is solved by the inaccurate synchronous clock.

Description

technical field [0001] The invention relates to the field of network communication, in particular to a semi-asynchronous CAN bus control method and controller based on single-bit synchronization. Background technique [0002] Controller Area Network (CAN or CAN bus for short) is a feature-rich vehicle bus standard. It is designed to allow microcontrollers and instruments on the network to communicate with each other without the need for a host. It is based on a messaging protocol and was originally designed to use multiplexed communication cables in vehicles to reduce copper wire usage, and has since been adopted by other industries as well. [0003] CAN is built on the Broadcast Communication Mechanism based on the information-oriented transmission protocol. According to the content of the information, it uses the message identifier (Message Identifier, each identifier is unique in the entire network) to define the content and the priority order of the message for deliver...

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Problems solved by technology

[0005] The CAN bus protocol itself is a highly stable asynchronous communication method. Since the CAN bus protocol is an asynchronous communication protocol, the error caused by the skew of the sampling point during the communication process is inevitable, that is, the sampling point is located near 90% or 10%. In the traditional CAN bus protocol, once the sampling point is skewed, an error occurs in the CRC check, and the node sending the data will resend the set of data to ensure the normal operation of the system, but the communication delay caused by the sending of the error code is still unacceptable. avoid

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