Making Serial Port Drivers User-Configurable

This topic explains how to set up a serial driver so that it can be end-user configured (via parameters) to run on any of a flight controller board's configurable serial ports.

Preconditions

The driver is assumed to already exist, and be started in the shell using the command syntax:

<driver_name> start -d <serial_port> [-b <baudrate> | -b p:<param_name>]

where,

• -d: serial port name.
• -b: Baud rate (optional) if the driver supports multiple baud rates. If supported, the driver must allow you to specify the rate as both a bare baudrate and as a parameter name in the form -b p:<param_name> (which can be parsed with px4_get_parameter_value()).

  TIP

  See the gps driver for an example.

Making the Driver Configurable

To make driver configurable:

1. Create a YAML module configuration file:

   • Add a new file in the driver's source directory named module.yaml

   • Insert the following text and adjust as needed:

     module_name: uLanding Radar
     serial_config:
         - command: ulanding_radar start -d ${SERIAL_DEV} -b p:${BAUD_PARAM}
           port_config_param:
             name: SENS_ULAND_CFG
             group: Sensors

     INFO

     The full documentation of the module configuration file can be found in the validation/module_schema.yaml file. This is also used to validate all configuration files in CI.

2. Add the module configuration to the CMakeLists.txt file for the driver module:

   px4_add_module(
   	MODULE drivers__ulanding
   	MAIN ulanding_radar
   	SRCS
   		ulanding.cpp
   	MODULE_CONFIG
   		module.yaml
   	)