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Erratic Task Scheduling

Posted by Engin AYDOGAN on June 25, 2008

I'm running a task that blinks a LED on the board periodically. But the LED blinks very erratically, without a consistent interval. From what I have noticed that it only blinks when there's some communication within ethernet port. Any ideas ?

Kind regards,


RE: Erratic Task Scheduling

Posted by Richard on June 25, 2008
There is very little information here on which a judgement can be made.

If you Ethernet port is causing interrupts from which a context switch is performed, then maybe the tick interrupt is not working and you are only getting scheduling when the Ethernet interrupt fires.

Alternatively, maybe the LED is being used by the Ethernet hardware and/or software to indicate traffic on the network.


RE: Erratic Task Scheduling

Posted by Engin AYDOGAN on June 25, 2008
Hi Richard,

I have also suspected what you said about interrupts but it turned out to be something else.

The data register I'm using to toggle the LED is also used by the ethernet controllers LEDs so it was altering the higher bits of the value unexpectedly. I've corrected the code and it works quite stable right now.

Thanks for FreeRTOS and your time :)

Kind regards,


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