The application module controls key mechanisms in the Asset Tracker v2. It decides when to sample data, what types of data to sample, and has explicit control over some aspects of the application.
This section documents the features implemented by the module.
Depending on the application’s Real-time configurations, the application module sends periodic sample requests to other modules in the system.
The sample requests are of type
APP_EVT_DATA_GET and contains a list of Data types that must be sampled by the corresponding module.
Each module handles the sample requests individually and if a module finds its corresponding data type in the list, it starts sampling for that particular data type.
For instance, if the GNSS module finds the
APP_DATA_GNSS data type, it starts searching for a GNSS fix.
Some modules even support multiple data types, such as the Modem module, which supports
In addition to the sample list, the module also includes a sample timeout in the
This timeout sets how much time each module has to sample data before the Data module sends what is available.
Sample requests are sent either periodically or upon detection of movement. The timeouts and modes that have an impact on the frequency of sample requests are documented in Real-time configurations.
The application module is the system’s initial point of entry and the source file of the module is
When the application boots, the module initializes the Application Event Manager and sends out the initial event
APP_EVT_START that starts the rest of the modules in the application.
It also initializes the Common Application Framework overview by calling the
module_set_state() API with the
This option is used to include GNSS in the initial sample request sent from the module.
If this option is enabled, the application module waits for a configured number of seconds set by
CONFIG_APP_REQUEST_GNSS_WAIT_FOR_AGPS_THRESHOLD_SECbefore requesting GNSS data, unless A-GPS data has been processed.
Number of seconds that the application module waits for A-GPS data to be processed before requesting GNSS data. If set to
-1, the application module waits until A-GPS data has been processed.
Include LTE neighbor cell measurement data in regular sampling requests. The data will be encoded together with the other sampled data and sent to cloud, where it can be used to determine the device’s location.
The application module has an internal state machine with the following states:
STATE_INIT- The initial state of the module.
STATE_RUNNING- The module has receieved its initial configuration from the data module and has started the appropriate timers.
SUB_STATE_ACTIVE_MODE- The application is in the active mode. In this state, the module sends out sample requests periodically.
SUB_STATE_PASSIVE_MODE- The application is in the passive mode. In this state, the module sends out a sample request upon movement.
STATE_SHUTDOWN- The module has been shut down after receiving a request from the utility module.
asset_tracker_v2/src/events/app_module_event.h header file contains a list of events sent by the module.
This module uses the following nRF Connect SDK libraries and drivers:
- group app_module_event
Application module event.
Event types submitted by Application module.
Signal that the application has done necessary setup, and now started.
Connect to LTE network.
Disconnect from LTE network.
Signal other modules to start sampling and report the data when it’s ready. The event must also contain a list with requested data types, app_module_data_type.
Create a list with all available sensor types in the system and distribute it as a APP_EVT_DATA_GET event.
Request latest configuration from the cloud.
Application module is waiting for movement to trigger the next sample request. This event is used to signal the sensor module to enable activity detection.
Application module does not depend on activity detection. This event is used to signal the sensor module to disable activity detection.
The application module needs A-GPS to be processed before it requests GNSS.
The application module has performed all procedures to prepare for a shutdown of the system.
An irrecoverable error has occurred in the application module. Error details are attached in the event structure.
- enumerator APP_EVT_START
Data types that the application module requests samples for in app_module_event_type APP_EVT_DATA_GET.
- enumerator APP_DATA_ENVIRONMENTAL
- #include <app_module_event.h>
Application module event.
- enum app_module_event_type