fsfw/docs/core.rst

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.. _core:
Core Modules
=============
The core modules provide the most important functionalities of the Flight Software Framework.
Clock
------
- This is a class of static functions that can be used at anytime
- Leap Seconds must be set if any time conversions from UTC to other times is used
Object Manager
---------------
- Must be created during program startup
- The component which handles all references. All :cpp:class:`SystemObject`\s register at this
component.
- All :cpp:class:`SystemObject`\s needs to have a unique Object ID. Those can be managed like
framework objects.
- A reference to an object can be retrieved by calling the ``get`` function of
:cpp:class:`ObjectManagerIF`. The target type must be specified as a template argument.
A ``nullptr`` check of the returning pointer must be done. This function is based on
run-time type information.
.. code-block:: cpp
template <typename T> T* ObjectManagerIF::get(object_id_t id);
- A typical way to create all objects on startup is a handing a static produce function to the
ObjectManager on creation. By calling ``ObjectManager::instance()->initialize(produceFunc)`` the
produce function will be called and all :cpp:class:`SystemObject`\s will be initialized
afterwards.
Event Manager
---------------
- Component which allows routing of events
- Other objects can subscribe to specific events, ranges of events or all events of an object.
- Subscriptions can be done during runtime but should be done during initialization
- Amounts of allowed subscriptions can be configured in ``FSFWConfig.h``
Health Table
---------------
- A component which holds every health state
- Provides a thread safe way to access all health states without the need of message exchanges
Stores
--------------
- The message based communication can only exchange a few bytes of information inside the message
itself. Therefore, additional information can be exchanged with Stores. With this, only the
store address must be exchanged in the message.
- Internally, the FSFW uses an IPC Store to exchange data between processes. For incoming TCs a TC
Store is used. For outgoing TM a TM store is used.
- All of them should use the Thread Safe Class storagemanager/PoolManager
Tasks
---------
There are two different types of tasks:
- The PeriodicTask just executes objects that are of type ExecutableObjectIF in the order of the
insertion to the Tasks.
- FixedTimeslotTask executes a list of calls in the order of the given list. This is intended for
DeviceHandlers, where polling should be in a defined order. An example can be found in
``defaultcfg/fsfwconfig/pollingSequence`` folder