fsfw/doc/README-core.md

FSFW Core Modules

These 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

ObjectManager

• Must be created during program startup
• The component which handles all references. All SystemObjects register at this component.
• Any SystemObject needs to have a unique ObjectId. Those can be managed like objects::framework_objects.
• A reference to an object can be get by calling the following function. T must be the specific Interface you want to call. A nullptr check of the returning Pointer must be done. This function is based on Run-time type information.

	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->initialize() the produce function will be called and all SystemObjects 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