`modbus-server`

Run a Modbus client and a Modbus server in the same process over the RAW_ADU backend — the register model, with no UART, RS-485, or TCP wiring.

Source: examples/connectivity/modbus-server/.

What it does

Brings up one Zephyr Modbus client and one Zephyr Modbus server in a single process and exercises the register model — holding registers and coils — end to end. Because both ends are in-process over RAW_ADU, native_sim can build and run it without any physical bus.

:::note In-tree, not a third-party pin Modbus is the in-tree Zephyr subsystem. libraries: [modbus] is the ADR 0018 top-level form: the generator reads metadata/libraries/modbus.yaml and emits CONFIG_MODBUS=y. prj.conf keeps only the app-specific backend choice (RAW_ADU). :::

Moving to serial

For RTU or ASCII on real hardware, keep the server callbacks in src/main.c and replace the RAW_ADU setup with a UART-backed Modbus interface. The board devicetree must provide an enabled node with compatible zephyr,modbus-serial — Zephyr's CONFIG_MODBUS_SERIAL depends on that node plus a UART driver.

`board.yaml`

This is the odd one out of the library examples: it targets V2N on the E1M-X EVK, and its core is m33_sm rather than m55_hp.

libraries:
  - name: modbus

som:
  sku: E1M-V2N101

preset: e1m-x-evk

cores:
  m33_sm:
    os: zephyr
    app: ./src
    peripherals: []

diagnostics:
  log_level: info

Expected output

[modbus] RAW_ADU server example starting
[modbus] holding[0]=0x4d42
[modbus] coils[0..7]=0x01
[modbus] done

What it does​

Moving to serial​

board.yaml​

Expected output​

See also​

What it does

Moving to serial

`board.yaml`

Expected output

See also