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xQueueSendToBack hang

Posted by uCXpresso on April 17, 2013
Dear FreeRTOS sirs,

I got a problem as below:
A task will be blocked when call the xQueyeSendToBack in queue is full, even the queue become to empty.

1. FreeRTOS v7.4.0
2. Queue length = 1 (unit)

RE: xQueueSendToBack hang

Posted by Richard on April 17, 2013
Which CPU are you using?
Which FreeRTOS version are you using?
Do you have a basic FreeRTOS application running.
Does the queue ever work or do you always have this problem?
What is posting to the queue?
How is the queue created?



RE: xQueueSendToBack hang

Posted by uCXpresso on April 17, 2013
Dear Sir,

1. CPU: LPC1768
2. FreeRTOS Version: v7.4.0
3. I have 3 tasks ruing , a Task in to blocked when query is full with xTicksToWait=portMAX_DELAY, even the queue become to empty by other task.
4. I post an integer data pointer to the queue (size=4), queue length = 1
5. queue create by xQueueCreate

If parameter xTicksToWait is 100, all task are work fine.

RE: xQueueSendToBack hang

Posted by Richard on April 18, 2013
Have you ensured all the points listed on the following two pages have been followed? As you are using a Cortex-M the second page is important if you are sending to the queue from an ISR.


If the information on those pages does not help then please post your queue create, send and receive code.


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