system_efm32pg12b.c

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/***************************************************************************/
#include <stdint.h>
#include "em_device.h"

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

#define EFM32_LFRCO_FREQ  (32768UL)
#define EFM32_ULFRCO_FREQ (1000UL)

/*******************************************************************************
 **************************   LOCAL VARIABLES   ********************************
 ******************************************************************************/

/* System oscillator frequencies. These frequencies are normally constant */
/* for a target, but they are made configurable in order to allow run-time */
/* handling of different boards. The crystal oscillator clocks can be set */
/* compile time to a non-default value by defining respective EFM_nFXO_FREQ */
/* values according to board design. By defining the EFM_nFXO_FREQ to 0, */
/* one indicates that the oscillator is not present, in order to save some */
/* SW footprint. */

#ifndef EFM32_HFRCO_MAX_FREQ
#define EFM32_HFRCO_MAX_FREQ            (38000000UL)
#endif

#ifndef EFM32_HFXO_FREQ
#define EFM32_HFXO_FREQ                 (40000000UL)
#endif

#ifndef EFM32_HFRCO_STARTUP_FREQ
#define EFM32_HFRCO_STARTUP_FREQ        (19000000UL)
#endif


/* Do not define variable if HF crystal oscillator not present */
#if (EFM32_HFXO_FREQ > 0UL)

static uint32_t SystemHFXOClock = EFM32_HFXO_FREQ;
#endif

#ifndef EFM32_LFXO_FREQ
#define EFM32_LFXO_FREQ (EFM32_LFRCO_FREQ)
#endif
/* Do not define variable if LF crystal oscillator not present */
#if (EFM32_LFXO_FREQ > 0UL)

static uint32_t SystemLFXOClock = 32768UL;
#endif


/*******************************************************************************
 **************************   GLOBAL VARIABLES   *******************************
 ******************************************************************************/

uint32_t SystemCoreClock;


uint32_t SystemHfrcoFreq = EFM32_HFRCO_STARTUP_FREQ;


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

/***************************************************************************/
uint32_t SystemCoreClockGet(void)
{
  uint32_t ret;
  uint32_t presc;

  ret   = SystemHFClockGet();
  presc = (CMU->HFCOREPRESC & _CMU_HFCOREPRESC_PRESC_MASK) >>
          _CMU_HFCOREPRESC_PRESC_SHIFT;
  ret  /= (presc + 1);

  /* Keep CMSIS system clock variable up-to-date */
  SystemCoreClock = ret;

  return ret;
}


/***************************************************************************/
uint32_t SystemMaxCoreClockGet(void)
{
  return (EFM32_HFRCO_MAX_FREQ > EFM32_HFXO_FREQ ? \
          EFM32_HFRCO_MAX_FREQ : EFM32_HFXO_FREQ);
}


/***************************************************************************/
uint32_t SystemHFClockGet(void)
{
  uint32_t ret;

  switch (CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK)
  {
    case CMU_HFCLKSTATUS_SELECTED_LFXO:
#if (EFM32_LFXO_FREQ > 0)
      ret = SystemLFXOClock;
#else
      /* We should not get here, since core should not be clocked. May */
      /* be caused by a misconfiguration though. */
      ret = 0;
#endif
      break;

    case CMU_HFCLKSTATUS_SELECTED_LFRCO:
      ret = EFM32_LFRCO_FREQ;
      break;

    case CMU_HFCLKSTATUS_SELECTED_HFXO:
#if (EFM32_HFXO_FREQ > 0)
      ret = SystemHFXOClock;
#else
      /* We should not get here, since core should not be clocked. May */
      /* be caused by a misconfiguration though. */
      ret = 0;
#endif
      break;

    default: /* CMU_HFCLKSTATUS_SELECTED_HFRCO */
      ret = SystemHfrcoFreq;
      break;
  }

  return ret / (1U + ((CMU->HFPRESC & _CMU_HFPRESC_PRESC_MASK)
                      >> _CMU_HFPRESC_PRESC_SHIFT));
}


/**************************************************************************/
uint32_t SystemHFXOClockGet(void)
{
  /* External crystal oscillator present? */
#if (EFM32_HFXO_FREQ > 0)
  return SystemHFXOClock;
#else
  return 0;
#endif
}


/**************************************************************************/
void SystemHFXOClockSet(uint32_t freq)
{
  /* External crystal oscillator present? */
#if (EFM32_HFXO_FREQ > 0)
  SystemHFXOClock = freq;

  /* Update core clock frequency if HFXO is used to clock core */
  if ((CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK) == CMU_HFCLKSTATUS_SELECTED_HFXO)
  {
    /* The function will update the global variable */
    SystemCoreClockGet();
  }
#else
  (void)freq; /* Unused parameter */
#endif
}


/**************************************************************************/
void SystemInit(void)
{
#if (__FPU_PRESENT == 1) && (__FPU_USED == 1)
  /* Set floating point coprosessor access mode. */
  SCB->CPACR |= ((3UL << 10*2) |                    /* set CP10 Full Access */
                 (3UL << 11*2)  );                  /* set CP11 Full Access */
#endif
}


/**************************************************************************/
uint32_t SystemLFRCOClockGet(void)
{
  /* Currently we assume that this frequency is properly tuned during */
  /* manufacturing and is not changed after reset. If future requirements */
  /* for re-tuning by user, we can add support for that. */
  return EFM32_LFRCO_FREQ;
}


/**************************************************************************/
uint32_t SystemULFRCOClockGet(void)
{
  /* The ULFRCO frequency is not tuned, and can be very inaccurate */
  return EFM32_ULFRCO_FREQ;
}


/**************************************************************************/
uint32_t SystemLFXOClockGet(void)
{
  /* External crystal oscillator present? */
#if (EFM32_LFXO_FREQ > 0)
  return SystemLFXOClock;
#else
  return 0;
#endif
}


/**************************************************************************/
void SystemLFXOClockSet(uint32_t freq)
{
  /* External crystal oscillator present? */
#if (EFM32_LFXO_FREQ > 0)
  SystemLFXOClock = freq;

  /* Update core clock frequency if LFXO is used to clock core */
  if ((CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK) == CMU_HFCLKSTATUS_SELECTED_LFXO)
  {
    /* The function will update the global variable */
    SystemCoreClockGet();
  }
#else
  (void)freq; /* Unused parameter */
#endif
}