Freertos and HAL external interrupts

[rolly loysney]

Posted on November 09, 2017 at 15:39

Hello,

I'm using stm32l496.

i'm trying to control LEDs with pwm through freeRTOS and using external Interrupts (gpio buttons)

i have some questions :

  i have some tasks looping while(1) to detect my input GPIO  and launch PWM timer :

void TASK(void)

{

while(1)

{

        if(HAL_GPIO_ReadPin(GPIOD, GPIO_PIN_1) == GPIO_PIN_SET)

         {

            HAL_TIM_PWM_Start(&htim16, TIM_CHANNEL_1);

            while(HAL_GPIO_ReadPin(GPIOD, GPIO_PIN_1) == GPIO_PIN_SET) 

               {

                  __HAL_TIM_SET_COMPARE(&htim16, TIM_CHANNEL_1, 2000);

                  osDelay(200);;

                  __HAL_TIM_SET_COMPARE(&htim16, TIM_CHANNEL_1, 0);

                  osDelay(200);

}

}

}

i'm using 10 tasks like this to activate leds on demand.

Sometimes, the PWM led doesn't start though.

i guess there is better way using External Interrupts right ?

When i use external input EXTI0_IRQHandler() to do same task

it crashes freertos.

when i use the

EXTI0_IRQHandler()

without freertos activated, in another project, it works.

How to correctly use external interrupts with freertos ? or correctly launch my timers within tasks ?

I guess my program is too much time consuming and it lags...

Thank you

#gpio-interrupt #pwm #freertos+hal

[Zt Liu]

Posted on November 10, 2017 at 05:14

Hi, rolly!

You should use TaskNotification

()

or TaskNotificationFromISR(), in the terminology of freeRTOS. (or osSignalSet if you use CMSIS OS API).

Please have a look at following document.

http://www.freertos.org/Documentation/161204_Mastering_the_FreeRTOS_Real_Time_Kernel-A_Hands-On_Tutorial_Guide.pdf

 ,Chapter 9.

Also, if you are porting freeRTOS to CMSIS-OS, you may also take a look at some ST-Examples like

'Your Cube Folders'\STM32Cube_FW_L4_V1.8.0\Projects\STM32L496ZG-Nucleo\Applications\FreeRTOS\FreeRTOS_SignalFromISR

Signals or TaskNotify is the most efficient way to trigger a task, without the need of an intermediate communication object!

Good Luck!

.Zt

[rolly loysney]

Posted on November 10, 2017 at 10:50

Thank you ZhiTai !

I've check that Application folder.

actually i'm starting my task like this :

xTaskCreate(

TASK

, 'IRQPwmLedShow1', configMINIMAL_STACK_SIZE, //AR_GAUCHE

NULL, tskIDLE_PRIORITY + 1, &xLedIRQPwmHandler1);

....

while(1)

{

vTaskResume(xLedPwmHandler1);

...

}

When you mention 'TaskNotification()

 

or TaskNotificationFromISR()' 

you mean    xTaskNotifyGive() xTaskNotify()  and  vTaskNotifyGiveFromISR()  ?

External hardware interrupt (

EXTI0_IRQHandler) is same as software ISR ? 

I just want to start a task when i push a button.

Thank you for your help

[Zt Liu]

Posted on November 11, 2017 at 02:40

Suppose you port your freeRTOS successfully.

Try the following codes, pretty mush the same as the example in chapter 9 of the ref book I gave you.

 /* The tasks to be created. */

static void vHandlerTask( void *pvParameters );

/* Stores the handle of the task to which interrupt processing is deferred. */

static TaskHandle_t xTaskHandler = NULL;

int main(void)

{   

   /*your initialization codes*/

   /* Create the 'handler' task, which is the task to which interrupt

   processing is deferred, and so is the task that will be synchronized

   with the interrupt.*/

   xTaskCreate( vHandlerTask, 'Handler', 128, NULL, 3, &xTaskHandler );

   /* Start the scheduler so the created tasks start executing. */

   vTaskStartScheduler();

}

static void vHandlerTask( void *pvParameters )

{

   uint32_t ulNotifyValue;

   for(;;)

   {

       /* Wait to receive a notification sent directly to this task from the interrupt handler. */

      ulNotifyValue = ulTaskNotifyTake(pdTRUE, 0xFFFFFFFF);

      if(ulNotifyValue != 0)

      {

         /*Your task job here*/

         BSP_LED_Toggle(LED1);

      }

   }

}

/*Your general GPIO_EXTI Callbacks here*/

void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)

{

   /* The xHigherPriorityTaskWoken parameter must be initialized to pdFALSE */  

   BaseType_t xHigherPriorityTaskWoken;

   xHigherPriorityTaskWoken = pdFALSE;

   

   /* your user button callback here*/

   if(GPIO_Pin == USER_BTN_PIN)

   {

      /* Send the notification directly to the task handler*/

      vTaskNotifyGiveFromISR( xTaskHandler, &xHigherPriorityTaskWoken );

      /*If xHigherPriorityTaskWoken was set to pdTRUE inside vTaskNotifyGiveFromISR()

        then calling portYIELD_FROM_ISR() will request a context switch. */

      portYIELD_FROM_ISR( xHigherPriorityTaskWoken );

   }   

}

It works in my Discovery F412.

You may also use oscilloscope to check the time between the button push and the trigger of your task.

Good Luck, rolly!

.Zt

[ranran]

Hello,

I have the same issue, and I tried the above suggestion, but nothing change.

I am not sure why freeRTOS fail to receive interrupt(?).

Any ideas ?

Ran