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xEventGroupClearBitsFromISR()
[Event Group API]



event_groups.h

 BaseType_t xEventGroupClearBitsFromISR(
                                EventGroupHandle_t xEventGroup,
                                const EventBits_t uxBitsToClear );

A version of xEventGroupClearBits() that can be called from an interrupt. The clear operation is deferred to the RTOS daemon task - which is also known as the timer service task. The priority of the daemon task is set by the configTIMER_TASK_PRIORITY setting in FreeRTOSConfig.h.

The RTOS source file FreeRTOS/source/event_groups.c must be included in the build for the xEventGroupClearBitsFromISR() function to be available.

Parameters:
xEventGroup   The event group in which the bits are to be cleared. The event group must have previously been created using a call to xEventGroupCreate().
uxBitsToClear   A bitwise value that indicates the bit or bits to clear in the event group. For example set uxBitsToClear to 0x08 to clear just bit 3. Set uxBitsToClear to 0x09 to clear bit 3 and bit 0.
Returns:
The value of the event group before the specified bits were cleared.
Example usage:
#define BIT_0	( 1 << 0 )
#define BIT_4	( 1 << 4 )

/* This code assumes the event group referenced by the
xEventGroup variable has already been created using a call to
xEventGroupCreate(). */
void anInterruptHandler( void )
{
BaseType_t xSuccess;

  /* Clear bit 0 and bit 4 in xEventGroup. */
  xSuccess = xEventGroupClearBitsFromISR(
                                xEventGroup, /* The event group being updated. */
                                BIT_0 | BIT_4 );/* The bits being cleared. */

  if( xSuccess == pdPASS )
  {
      /* The command was sent to the daemon task. */
  }
  else
  {
      /* The clear bits command was not sent to the daemon task. */
  }
}






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