Debug module

The debug module intends to improve the overall debugging experience in the application. By default, it subscribes to all the events in the system and implements support for Memfault through the Memfault module integrated in nRF Connect SDK.


To enable the debug module, you must include the ../overlay-debug.conf overlay configuration file when building the application.


This section lists the various features supported by the module.


Memfault SDK provides the functionality to collect information from devices in the form of coredumps, error traces, metrics, logs and more. Information that is collected from the device can be sent to Memfault’s cloud solution for further analysis.

The debug module uses Memfault SDK to track nRF Connect SDK specific metrics such as LTE and stack metrics. In addition, the following types of custom Memfault metrics are defined and tracked when compiling in the debug module:

  • GpsTimeToFix - Time duration between the start of a GPS search and obtaining a fix.

  • GpsTimeoutSearchTime - Time duration between the start of a GPS search and a search timeout.

  • GpsSatellitesTracked - Number of satellites tracked during a GPS search window.

The debug module also implements Memfault SDK software watchdog, which is designed to trigger an assert before an actual watchdog timeout. This enables the application to be able to collect coredump data before a reboot occurs.

To enable Memfault, you must include the ../overlay-memfault.conf when building the application. To get started with Memfault, see Using Memfault SDK.

Configuration options

CONFIG_DEBUG_MODULE_MEMFAULT_USE_EXTERNAL_TRANSPORT - Configuration for transfer of Memfault data

This option, if enabled, makes the debug module trigger events carrying Memfault data. This data can be routed through an external transport to Memfault cloud, for example, through AWS IoT, Azure IoT Hub, or nRF Cloud.

CONFIG_DEBUG_MODULE_MEMFAULT_HEARTBEAT_INTERVAL_SEC - Configuration for |NCS| Memfault metrics tracking interval

This option sets the time interval for tracking nRF Connect SDK Memfault metrics.

CONFIG_DEBUG_MODULE_MEMFAULT_CHUNK_SIZE_MAX - Configuration for maximum size of transmitted packets.

This option sets the maximum size of packets transmitted over the configured custom transport.

Module configurations

To enable Memfault, you must set the following mandatory options:

To get detailed stack traces in coredumps sent to Memfault, you can increase the values for the following options:

For extended documentation regarding nRF Connect SDK Memfault integration, see Memfault module.

Module states

This module has no internal states.

Module events

The asset_tracker_v2/src/events/debug_module_event.h header file contains a list of various events emitted by the module.


This application uses the following nRF Connect SDK libraries and drivers:

API documentation

Header file: asset_tracker_v2/src/events/debug_module_event.h
Source files: asset_tracker_v2/src/events/debug_module_event.c
group debug_module_event

Debug module event.




enum debug_module_event_type



Event carrying memfault data that should be forwarded via the configured cloud backend to Memfault cloud. Only sent if CONFIG_DEBUG_MODULE_MEMFAULT_USE_EXTERNAL_TRANSPORT is enabled. Payload is of type debug_module_memfault_data.

enumerator DEBUG_EVT_ERROR

Event submitted by the debug module upon an irrecoverable error. The event includes a code indicating the cause of error.

struct debug_module_memfault_data
#include <debug_module_event.h>
struct debug_module_event
#include <debug_module_event.h>

Debug event.