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vSemaphoreCreateBinary

Posted by *anonymous on November 13, 2013

I have two Binary semaphores its not working simultaneously here if i comment vReadtask vCriticalTask will execute and if comment vCriticalTask , vReadtask will execute i cant use both simultaneously. What could be the reason? please help

vSemaphoreCreateBinary( xBinarySemaphore ); vSemaphoreCreateBinary( xReadSemaphore );

and two tasks

xTaskCreate( vReadTask, "Handler", MEDIUMSTACKSIZE, NULL, 11, &xReadHandler); xTaskCreate(vCriticalTask,"Critical", MEDIUMSTACKSIZE,NULL,12,&xCriticalHandle);

void vReadTask( void *pvParameters ) { for( ;; ) { xSemaphoreTake( xReadSemaphore, portMAX_DELAY );

     //read code
}

}

void vCriticalTask( void *pvParameters ) { for( ;; ) { xSemaphoreTake( xBinarySemaphore, portMAX_DELAY ); //critical code } }


vSemaphoreCreateBinary

Posted by richard_damon on November 13, 2013

Not seeing the SemaphoreGive code, the only problems that I can see is you might be running out of heap.

What exactly do you comment out to make one side to work.


vSemaphoreCreateBinary

Posted by *anonymous on November 13, 2013

I have many tasks in my program all others are work fine. The problem is in these two tasks, i can use either one of this task SemaphoreGive() using some other tasks, i comment the create task ////xTaskCreate( vReadTask, "Handler", MEDIUMSTACKSIZE, NULL, 11, &xReadHandler);

xTaskCreate(vCriticalTask,"Critical", MEDIUMSTACKSIZE,NULL,12,&xCriticalHandle);

this time CriticalTask will work

xTaskCreate( vReadTask, "Handler", MEDIUMSTACKSIZE, NULL, 11, &xReadHandler);

///xTaskCreate(vCriticalTask,"Critical",MEDIUMSTACKSIZE,NULL,12,&xCriticalHandle;

this time ReadTask will work.


vSemaphoreCreateBinary

Posted by *anonymous on November 13, 2013

Yes, the error was in my configTOTALHEAPSIZE i increased heap size problem solved. Thank you so much :-)


vSemaphoreCreateBinary

Posted by *anonymous on November 13, 2013

void vReadTask( void *pvParameters ) { for( ;; ) { xSemaphoreTake( xReadSemaphore, portMAX_DELAY ); //read code } }

Here the read code will execute first time (program starting) before giving a semaphore. why this happening? how to avoid this?


vSemaphoreCreateBinary

Posted by davedoors on November 13, 2013

Look at the vSemaphoreCreateBinary() definition in semphr.h. You will see it is given after it is created so the first take will pass. If you don't want that then take the semaphore straight after you have created it, before you use it in your task.


vSemaphoreCreateBinary

Posted by richardbarry on November 13, 2013

The head revision in SVN currently has a new xSemaphoreCreateBinary() function that works like all the other semaphore create function (a function that returns the semaphore) so the vSemaphoreCreateBinary() macro (note with a 'v' prefix) can be retired - although it will remain in the source code for backward compatibility. The 'x' version creates an empty semaphore, so a 'give' must be performed before a 'take' will pass.

Regards.


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