1.. _modbus: 2 3Modbus 4###### 5 6Modbus is an industrial messaging protocol. The protocol is specified 7for different types of networks or buses. Zephyr OS implementation 8supports communication over serial line and may be used 9with different physical interfaces, like RS485 or RS232. 10TCP support is not implemented directly, but there are helper functions 11to realize TCP support according to the application's needs. 12 13Modbus communication is based on client/server model. 14Only one client may be present on the bus. Client can communicate with several 15server devices. Server devices themselves are passive and must not send 16requests or unsolicited responses. 17Services requested by the client are specified by function codes (FCxx), 18and can be found in the specification or documentation of the API below. 19 20Zephyr RTOS implementation supports both client and server roles. 21 22More information about Modbus and Modbus RTU can be found on the website 23`MODBUS Protocol Specifications`_. 24 25Samples 26******* 27 28* :zephyr:code-sample:`modbus-rtu-server` and :zephyr:code-sample:`modbus-rtu-client` samples give 29 the possibility to try out RTU server and RTU client implementation with an evaluation board. 30* :zephyr:code-sample:`modbus-tcp-server` sample is a simple Modbus TCP server. 31* :zephyr:code-sample:`modbus-gateway` sample shows how to build a TCP to serial line 32 gateway with Zephyr OS. 33 34API Reference 35************* 36 37.. doxygengroup:: modbus 38 39.. _`MODBUS Protocol Specifications`: https://www.modbus.org/specs.php 40
