A rs485 bus communication method based on group call and time slot allocation

Abstract

The invention relates to a RS485 bus communication method based on group call and time slot allocation, which belongs to the field of communication technology, comprising: a master connects n slaves through an RS485 bus, the master and different slaves perform point-to-point polling to complete the initialization process, and the master performs the initialization according to The address of all the slaves received establishes an address link list; the master sends a group call command; the slave responds to the time slot allocation; the slave priority queue sends back; the slave normal queue sends back. The present invention directly utilizes the existing RS485 bus without any change in hardware, shortens the bus polling cycle by adopting group call and sequential response, and adopts a priority management mechanism to ensure priority transmission of important and urgent data.

Description

Technical field [0001] The present invention belongs to the field of communication technology, relates to an RS485 bus communication method based on group call and time slot allocation. Background [0002] With the development of technology and the improvement of living standards, more and more industrial control, medical, communications, consumer and other electronic products are becoming more and more intelligent, and embedded systems with microprocessors as the core have been increasingly widely used, and the management of these intelligent devices has also become a focus of embedded applications. When networking multiple embedded devices, because the RS485 bus has the unique advantages of master and slave networking: one master and multiple slaves, can drive up to 32 to 256 slave nodes; half-duplex communication, simple and convenient; differential transmission, high anti-interference, high speed, long distance; transmission lines are the fewest, only two lines, the lowest c...

AI Technical Summary

Problems solved by technology

Now the RS485 bus communication adopts the host to call the slave to answer, point-to-point polling one by one, causing the slave to have important and urgent information that cannot be quickly transmitted to the host

A feasible method is to add an additional input signal line to each device - chip select or arbitration signal line. The slave device obtains the priority through active application or preemption to realize fast transmission of its own information. The method is simple, but the signal line is added. , lost the versatility, lost the advantages of RS485

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