Receiving queue message but nobody sends

willywortel wrote on Tuesday, March 24, 2009:

I`m on pic32.

Have created a queue succesfully for RS485 task. No other task / file has the queue send function to this queue.

When using this:

        while( xQueueReceive( xRS485Queue, &Rs485msg, 1000 ) != pdPASS );
        // block as long as UART interrupt is still busy

After some amount of time (less then a minute) it manages to break the while loop.
I don’t get it. Anyone any suggestions where i should look? i`m sure nobody sends data to this queue

It doesnt happen when i use portMAX_DELAY, but from my insights it than only takes longer since
portMAX_DELAY = oxFFFF = 65535mS = ~ about an hour (when using 1000hz for os tick counter).
So i think when i use portMAX_DELAY it only takes longer when the loop breaks.

willywortel wrote on Tuesday, March 24, 2009:

Gets even more strange.

when using this test code:

        unsigned portLONG data = 0;
        while( data == 0 )
            data = xQueueReceive( xRS485Queue, &Rs485msg, 1000);

Then the code gets in the while(1) part. When checking the data variable with the REALICE debugger, the variable is 0.

Still, nobody sends data to the queue

davedoors wrote on Tuesday, March 24, 2009:

Which version of FreeRTOS are you using?

willywortel wrote on Tuesday, March 24, 2009:


rtel wrote on Tuesday, March 24, 2009:

I could not offer any explanation for that behaviour, it is not something I have seen or had reported before.

The queue receive implementation in V5.2.0 is different.  Try using that - it would be interesting to see if it made any difference.  V5.2.0 is completely backward compatible with V5.1.2.


willywortel wrote on Tuesday, March 24, 2009:

Very stupid fault. Someone else in my repro worked on the same code for the USB.

In his peace of code he was using a function that used this queue

Shame on me :blush:

Sorry for your time. Thanks for the reply’s!!