Device description module
The device description module defines custom GATT Service, which contains:
Information about whether the peripheral supports the Low Latency Packet Mode (LLPM)
Hardware ID (HW ID) of the peripheral
To support the LLPM, the peripheral must use the SoftDevice Link Layer.
This means that you must enable both the CONFIG_BT_LL_SOFTDEVICE and the CONFIG_CAF_BLE_USE_LLPM Kconfig options.
The Service is mandatory for all nRF Desktop peripherals that connect to the nRF Desktop centrals.
Module events
The dev_descr module does not submit any event nor subscribe for any event.
Configuration
The module uses Zephyr’s Hardware Information to obtain the hardware ID.
Enable the required driver using CONFIG_HWINFO.
The module is enabled by default for all nRF Desktop peripheral devices.
The dev_descr.h file contains the UUIDs used by the custom GATT Service.
The file is located in the configuration/common directory.
The UUIDs must be the same for all devices to ensure that the central is able to read the provided information.
Implementation details
The module uses BT_GATT_SERVICE_DEFINE to define the custom GATT Service.
More detailed information regarding GATT is available in Zephyr’s Generic Attribute Profile (GATT) documentation.