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AVR32 Semaphore Scheduler Problem

Posted by Markus Groh on September 25, 2010
Hi!

I'm relatively new to FreeRTOS. I'm using an Atmel AVR MCU (UC3A0512) on the EVK1100 Evaluation Board. Actually I'm making my first experiences in mutitasking. So I have a serious problem I'm not able to solve :(

I use an GPIO-Interrupt wich evokes an ISR. This ISR works fine (traced it via usart debugging messages). This ISR 'gives' an Semaphore (binary) with
xSemaphoreGiveFromISR(gpiointerrupt,&xHighPriorityTaskWoken);

This evokes a high priority task which blocks for this semaphore. I also traced this behavior via usart. This Semaphore was taken, code executes, task wants again take the semaphore....and then everything crashed. The MCU stops, no lower tasks resumed.
Has anybody a tip or a solution for my problem? Something I'm making wrong, but after a lot of tests I didn't find a solution and it irks me.

Thanks a lot!

RE: AVR32 Semaphore Scheduler Problem

Posted by Markus Groh on September 26, 2010
Ok, I solved my problem. It was an error in the function protoype of the ISR.

I simply forgot the compiler attribute for the AVR-port

__attribute__ ((naked))

Now, everything works fine.


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