em_rtc.c

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/***************************************************************************/
#include "em_rtc.h"
#if defined(RTC_COUNT) && (RTC_COUNT > 0)

#include "em_assert.h"
#include "em_bus.h"

/***************************************************************************/
/***************************************************************************/
/*******************************************************************************
 *******************************   DEFINES   ***********************************
 ******************************************************************************/

#define RTC_COMP_REG_VALID(reg)    (((reg) <= 1))

/*******************************************************************************
 **************************   LOCAL FUNCTIONS   ********************************
 ******************************************************************************/

#if defined(_EFM32_GECKO_FAMILY)
/***************************************************************************/
__STATIC_INLINE void regSync(uint32_t mask)
{
  /* Avoid deadlock if modifying the same register twice when freeze mode is */
  /* activated. */
  if (RTC->FREEZE & RTC_FREEZE_REGFREEZE)
    return;

  /* Wait for any pending previous write operation to have been completed */
  /* in low frequency domain. This is only required for the Gecko Family */
  while (RTC->SYNCBUSY & mask)
    ;
}
#endif

/*******************************************************************************
 **************************   GLOBAL FUNCTIONS   *******************************
 ******************************************************************************/

/***************************************************************************/
uint32_t RTC_CompareGet(unsigned int comp)
{
  uint32_t ret;

  EFM_ASSERT(RTC_COMP_REG_VALID(comp));

  /* Initialize selected compare value */
  switch (comp)
  {
    case 0:
      ret = RTC->COMP0;
      break;

    case 1:
      ret = RTC->COMP1;
      break;

    default:
      /* Unknown compare register selected */
      ret = 0;
      break;
  }

  return ret;
}


/***************************************************************************/
void RTC_CompareSet(unsigned int comp, uint32_t value)
{
  volatile uint32_t *compReg;
#if defined(_EFM32_GECKO_FAMILY)
  uint32_t          syncbusy;
#endif

  EFM_ASSERT(RTC_COMP_REG_VALID(comp)
             && ((value & ~(_RTC_COMP0_COMP0_MASK
                            >> _RTC_COMP0_COMP0_SHIFT)) == 0));

  /* Initialize selected compare value */
  switch (comp)
  {
    case 0:
      compReg = &(RTC->COMP0);
#if defined(_EFM32_GECKO_FAMILY)
      syncbusy = RTC_SYNCBUSY_COMP0;
#endif
      break;

    case 1:
      compReg = &(RTC->COMP1);
#if defined(_EFM32_GECKO_FAMILY)
      syncbusy = RTC_SYNCBUSY_COMP1;
#endif
      break;

    default:
      /* Unknown compare register selected, abort */
      return;
  }
#if defined(_EFM32_GECKO_FAMILY)
  /* LF register about to be modified require sync. busy check */
  regSync(syncbusy);
#endif

  *compReg = value;
}


/***************************************************************************/
void RTC_Enable(bool enable)
{
#if defined(_EFM32_GECKO_FAMILY)
  /* LF register about to be modified require sync. busy check */
  regSync(RTC_SYNCBUSY_CTRL);
#endif

  BUS_RegBitWrite(&(RTC->CTRL), _RTC_CTRL_EN_SHIFT, enable);

#if defined(_EFM32_GECKO_FAMILY)
  /* Wait for CTRL to be updated before returning, because calling code may
     depend upon that the CTRL register is updated after this function has
     returned. */
  regSync(RTC_SYNCBUSY_CTRL);
#endif
}


/***************************************************************************/
void RTC_FreezeEnable(bool enable)
{
  if (enable)
  {
#if defined(_EFM32_GECKO_FAMILY)
    /* Wait for any ongoing LF synchronization to complete. This is just to */
    /* protect against the rare case when a user                            */
    /* - modifies a register requiring LF sync                              */
    /* - then enables freeze before LF sync completed                       */
    /* - then modifies the same register again                              */
    /* since modifying a register while it is in sync progress should be    */
    /* avoided.                                                             */
    while (RTC->SYNCBUSY)
      ;
#endif
    RTC->FREEZE = RTC_FREEZE_REGFREEZE;
  }
  else
  {
    RTC->FREEZE = 0;
  }
}


/***************************************************************************/
void RTC_Init(const RTC_Init_TypeDef *init)
{
  uint32_t tmp;

  if (init->enable)
  {
    tmp = RTC_CTRL_EN;
  }
  else
  {
    tmp = 0;
  }

  /* Configure DEBUGRUN flag, sets whether or not counter should be
   * updated when debugger is active */
  if (init->debugRun)
  {
    tmp |= RTC_CTRL_DEBUGRUN;
  }

  /* Configure COMP0TOP, this will use the COMP0 compare value as an
   * overflow value, instead of default 24-bit 0x00ffffff */
  if (init->comp0Top)
  {
    tmp |= RTC_CTRL_COMP0TOP;
  }

#if defined(_EFM32_GECKO_FAMILY)
  /* LF register about to be modified require sync. busy check */
  regSync(RTC_SYNCBUSY_CTRL);
#endif

  RTC->CTRL = tmp;
}



/***************************************************************************/
void RTC_Reset(void)
{
  /* Restore all essential RTC register to default config */
  RTC->FREEZE = _RTC_FREEZE_RESETVALUE;
  RTC->CTRL   = _RTC_CTRL_RESETVALUE;
  RTC->COMP0  = _RTC_COMP0_RESETVALUE;
  RTC->COMP1  = _RTC_COMP1_RESETVALUE;
  RTC->IEN    = _RTC_IEN_RESETVALUE;
  RTC->IFC    = _RTC_IFC_RESETVALUE;

#if defined(_EFM32_GECKO_FAMILY)
  /* Wait for CTRL, COMP0 and COMP1 to be updated before returning, because the
     calling code may depend upon that the register values are updated after
     this function has returned. */
  regSync(RTC_SYNCBUSY_CTRL | RTC_SYNCBUSY_COMP0 | RTC_SYNCBUSY_COMP1);
#endif
}



/***************************************************************************/
void RTC_CounterReset(void)
{
  /* A disable/enable sequnce will start the counter at zero */
  RTC_Enable(false);
  RTC_Enable(true);
}


#endif /* defined(RTC_COUNT) && (RTC_COUNT > 0) */