[RTOS Support] FreeRTOS 8.0.0 RC2 - Event Groups question

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FreeRTOS 8.0.0 RC2 - Event Groups question

Posted by hermarcel on January 7, 2014

I am wondering if the new Event Groups facility can provide me with some specific functionality for which I am currently working on my own event handling based on message queues. Reading the documentation I am not sure and to prevent me from creating a solution for which FreeRTOS already has an answer, I created this topic.

One of the key features of my system is the ability to unblock several tasks when a single event occurs. Tasks can (de-)register themselves to the notification list of an event (after the event itself has been created).

Is this possible with the new Event Groups facility? Out of the box? With minor changes?

Thanks!

FreeRTOS 8.0.0 RC2 - Event Groups question

Posted by rtel on January 7, 2014

Yes, when an event occurs, all the tasks waiting on that event are unblocked.

Tasks wait on one or more bits within an event group in exactly the same way they would wait on a queue. However, if there are multiple tasks blocked to wait for a message arriving in a queue then only one task (the highest priority one) is unblocked when a message is available. Whereas if there are multiple tasks blocked to wait for the same bit (or set of bits) in an event group then all of the tasks are unblocked when that bit (or set of bits) are set.

Regards.