FreeRTOS Mutex example ?

[antonius]

Posted on April 03, 2017 at 00:53

Everyone,

Does anyone know where I can find a simple example for FreeRTOS on Mutex ?

I want to do two task but the first task never finishes and jump already to the second one because of the systick,

how can I make the first one finish and do the second one with Mutex ?

Thanks for reading and advicing

#multitasking #rtos #stm32f1xx #mutex Note: this post was migrated and contained many threaded conversations, some content may be missing.

[Barry.Richard]

Posted on April 03, 2017 at 06:17

Try the

http://www.freertos.org/a00113.html

 or better still the

http://www.freertos.org/Documentation/RTOS_book.html

.

[antonius]

Posted on April 03, 2017 at 11:14

Thanks for the link, I appreciate that, can you tell me which directory containing an example for semaphore in FreeRTOS9 directory ? thanks

[Amel NASRI]

Posted on April 03, 2017 at 16:55

Hello

H.Rick

‌,

In all STM32Cube packages, you will find an example called ''FreeRTOS_Mutexes''.

Just search it in the package you are using.

You can getmore details about mutexes in the

http://www.st.com/content/ccc/resource/technical/document/user_manual/2d/60/ff/15/8c/c9/43/77/DM00105pdf/files/DM00105pdf/jcr:content/translations/en.DM00105pdf

''Developing Applications on STM32Cube with RTOS'', sub-section ''Mutexes example''.

If you are using an STM32F4, the example ''

FreeRTOS_Mutexes'' is available as application example for boards marked with ''x'' in this table (extracted from

http://www.st.com/content/ccc/resource/technical/document/application_note/ca/34/db/d3/71/50/44/9b/DM002135pdf/files/DM002135pdf/jcr:content/translations/en.DM002135pdf

:(

-Amel

[dechawat]

Posted on April 03, 2017 at 21:12

I think use semaphore instead of mutex is easier.

SemaphoreHandle_t Sem1, Sem2;

int main(void) {

      /* Create semaphore. */

      Sem1 = xSemaphoreCreateBinary();

      Sem2 = xSemaphoreCreateBinary();

      .... Create task and run scheduler.

}

void Task1(void *param) {

      /* Give once for first time. */       xSemaphoreGive(Sem1);

      while(1) {

/* Wait for Sem1 */

            if(xSemaphoreTake(Sem1, portMAX_DELAY) == pdTURE) {

                  /* Your first task code */

                  /* Wake

the

second task. */

                  xSemaphoreGive(Sem2);

            }

      }

}

void Task2(void *param) {

      while(1) {

            /* Wait for Sem2 */

            if(xSemaphoreTake(Sem2, portMAX_DELAY) == pdTURE) {

 /* Your second task code */

                  /* Wake

the

 first task. */

                  xSemaphoreGive(Sem1);

            }

      }

}

[antonius]

Posted on April 04, 2017 at 00:23

Thank you very much for the advice.

[antonius]

Posted on April 04, 2017 at 08:58

That's good idea to try, thanks

[antonius]

Posted on April 05, 2017 at 05:51

What should I add on task2 if task 2 time is much longer than task 1 ? and task 2 time is much longer than default systick ?

It seemed that it's doing task 1 but failed on task 2 then stop forever ?

thanks

[Barry.Richard]

Posted on April 05, 2017 at 06:04

Did you read the chapter on mutexes in the book I posted a link to in my first reply?  In particular read the part about using mutexes from tight loops.

[antonius]

Posted on April 05, 2017 at 07:20

This chapter : 7.3 Mutexes (and Binary Semaphores) ?

Which part exactly ? May be I missed it ?