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Resuming task from interrupt delay problem

Posted by inimicus8 on September 21, 2015

Hi I have a problem that it takes a long time to resume a task when i call ”xTaskResumeFromISR” from within a interrupt. It takes at least 7ms from that I call ”xTaskResumeFromISR” to that the task starts executing. The delay time slowly increases to over 100ms. If i call vTaskResume from another task the task resumes immediately. I only have one interrupt on and only one other task that only contains a while loop and vTaskDelay(100/portTICKRATEMS);. (if I don’t have another task I can’t run the program for some reason)

program:

main: { xTaskCreate( taskB, ( signed char * ) "taskB", configMINIMALSTACKSIZE, NULL, 2, NULL );

xTaskCreate( CANControlTask, ( signed char * ) "CControl", configMINIMALSTACK_SIZE, NULL, 1, &canHandle );

// FreeRTOS start vTaskStartScheduler();

}

void CANControlTask( void* pdata ) { CANConfig(); while (1) {
CANReceiveRoutine(); vTaskSuspend( NULL ); // ulTaskNotifyTake( pdTRUE, (10000/portTICKRATEMS) ); } }

void CANRXInterrupt( void ) { BaseType_t xHigherPriorityTaskWoken = pdTRUE;

IO_OkStatusLedOn();
if (CAN_GetITStatus(CANx, CAN_IT_FMP0) != RESET)
{
    .......................................

	xTaskResumeFromISR( canHandle );
	//  vTaskNotifyGiveFromISR( canHandle , &xHigherPriorityTaskWoken );
	 CAN_ClearITPendingBit(CANx, CAN_IT_FMP0);
}

}

Does anyone know why this happens and how to fix it? Same thing happens when I use “ulTaskNotifyTake” and “vTaskNotifyGiveFromISR” When I run my program In CoOS I don’t get this problem.

Info about platform: MCU: stm32f407: IDE: coocox 2.0.3. toolchain: gcc 4.8 2004. RTOS: FreeRTOS V8.2.2


Resuming task from interrupt delay problem

Posted by rtel on September 21, 2015

Please read the documentation for the xTaskResumeFromISR() as it tells you two things:

1) Don't use the function to synchornise a task with an interrupt - it is dangerous and can lead to missed interrupts as it does not latch interrupts (like a semphore or task notification would). That might be what your problem is.

2) Use the function's return value to know if a context switch is required:

xYieldRequired = xTaskResumeFromISR( handle );
portYIELDFROMISR( xYieldRequired );


Resuming task from interrupt delay problem

Posted by inimicus8 on September 21, 2015

Yep that fixed it!!

I had totally missed that the “portYIELDFROMISR” function existed. Thank you very much for a fast reply :)


Resuming task from interrupt delay problem

Posted by alainm3 on September 21, 2015

Buy the book, it will save you days of fiddling around !!!

Alain

Em 21-09-2015 09:50, Jimmie Hansson escreveu: > > Yep that fixed it!! > > I had totally missed that the “portYIELDFROMISR” function existed. > Thank you very much for a fast reply > :) > > ------------------------------------------------------------------------ > > Resuming task from interrupt delay problem > https://sourceforge.net/p/freertos/discussion/382005/thread/842d6424/?limit=250#941c > > ------------------------------------------------------------------------ > > Sent from sourceforge.net because you indicated interest in > https://sourceforge.net/p/freertos/discussion/382005/ > > To unsubscribe from further messages, please visit > https://sourceforge.net/auth/subscriptions/ >


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