Address of the fuction pcName: given name to the task. The actual size of the stack depends on the micro controller. If the task does not have to be handled in the future, this can be leaved NULL. For example, if a task called vTaskDelay when the tick count was 10,, then it would immediately enter the Blocked state and remain in the Blocked state until the tick count reached 10, Any time that remains between vTaskDelay being called, and the next tick interrupt occurring, counts as one complete tick period. Therefore, the highest time resolution that can be achieved when specifying a delay period is, in the worst case, equal to one complete tick interrupt period.
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The same item will be returned the next time xQueueReceive or xQueuePeek is used to obtain an item from the same queue. The length of the buffer must be at least equal to the queue item size. The item size will have been set by the uxItemSize parameter of the call to xQueueCreate used to create the queue.
If a block time was specified xTicksToWait was not zero , then it is possible that the calling task was placed into the Blocked state, to wait for data to become available on the queue, but data was successfully read from the queue before the block time expired. If a block time was specified xTicksToWait was not zero then the calling task will have been placed into the Blocked state to wait for another task or interrupt to send data to the queue, but the block time expired before this happened.
Reads an item from a queue, but without removing the item from the queue. The queue handle will have been returned from the call to xQueueCreate used to create the queue. This will ensure that the interrupt returns directly to the highest priority Ready state task.
Notes Calling xQueueReceiveFromISR within an interrupt service routine can potentially cause a task that was blocked on a queue to leave the Blocked state. A context switch should be performed if such an unblocked task has a priority higher than or equal to the currently executing task the task that was interrupted.
The context switch will ensure that the interrupt returns directly to the highest priority Ready state task. It will instead just indicate whether or not a context switch is required. Therefore an interrupt that calls xQueueReceiveFromISR must not be allowed to execute prior to the scheduler being started.
Both send data to the back of a queue. The size of each item the queue can hold is set when the queue is created, and that many bytes will be copied from pvItemToQueue into the queue storage area. If a block time was specified xTicksToWait was not zero , then it is possible that the calling task was placed into the Blocked state, to wait for space to become available in the queue before the function returned, but data was successfully written to the queue before the block time expired.
If a block time was specified xTicksToWait was not zero then the calling task will have been placed into the Blocked state to wait for another task or interrupt to make room in the queue, but the specified block time expired before that happened.
Sender Receiver Sender task will continuously sending data to queue. Receiver task always waiting for queue. If that queue contains any data, receiver task read that data and prints in serial terminal.
Go through the below code. Then you will understand easily. This is only the main code. If you want to download the full project Please visit here.
FreeRTOS – LPC2148 Binary Semaphore
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