23.2. modbus rtu slave

23.2.1. Overview

  • This project demonstrates the modbus rtu slave function

  • In this example project, one board serves as rtu master and the other board serves as rtu slave. The master sends a read holding register and waits for the slave to respond to the request data.

23.2.2. Note

  • When using uart for modbus communication and communicating with an rtu slave, you must reset the slave first and then the host.

23.2.3. Board Setting

  • Please refer to the description in the specific development board {ref}` pin description <board_resource>` section.

  • Connect the modbus uart pins of the two boards.

  • The two boards must be connected to the GND of both sides to share the ground to ensure signal transmission.

23.2.4. Running the example

  • Run slave first, then master

  • When the project runs correctly, the serial terminal will output the following information:

modbus rtu slave example
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8
parse ok, recv master msg len:8