rt-thread-official/bsp/efm32/Libraries/Device/EnergyMicro/EFM32GG/Source/system_efm32gg.c

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/***************************************************************************//**
* @file
* @brief CMSIS Cortex-M3 System Layer for EFM32GG devices.
* @author Energy Micro AS
* @version 3.0.0
*******************************************************************************
* @section License
* <b>(C) Copyright 2012 Energy Micro AS, http://www.energymicro.com</b>
******************************************************************************
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*
* DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Energy Micro AS has no
* obligation to support this Software. Energy Micro AS is providing the
* Software "AS IS", with no express or implied warranties of any kind,
* including, but not limited to, any implied warranties of merchantability
* or fitness for any particular purpose or warranties against infringement
* of any proprietary rights of a third party.
*
* Energy Micro AS will not be liable for any consequential, incidental, or
* special damages, or any other relief, or for any claim by any third party,
* arising from your use of this Software.
*
******************************************************************************/
#include <stdint.h>
#include "efm32.h"
/*******************************************************************************
****************************** DEFINES ************************************
******************************************************************************/
/** LFRCO frequency, tuned to below frequency during manufacturing. */
#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 EFM32_nFXO_FREQ */
/* values according to board design. By defining the EFM32_nFXO_FREQ to 0, */
/* one indicates that the oscillator is not present, in order to save some */
/* SW footprint. */
#ifndef EFM32_HFXO_FREQ
#ifdef _EFM32_GIANT_FAMILY
#define EFM32_HFXO_FREQ (48000000UL)
#else
#define EFM32_HFXO_FREQ (32000000UL)
#endif
#endif
/* Do not define variable if HF crystal oscillator not present */
#if (EFM32_HFXO_FREQ > 0)
/** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
/** System HFXO clock. */
static uint32_t SystemHFXOClock = EFM32_HFXO_FREQ;
/** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
#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 > 0)
/** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
/** System LFXO clock. */
static uint32_t SystemLFXOClock = EFM32_LFXO_FREQ;
/** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
#endif
/*******************************************************************************
************************** GLOBAL VARIABLES *******************************
******************************************************************************/
/**
* @brief
* System System Clock Frequency (Core Clock).
*
* @details
* Required CMSIS global variable that must be kept up-to-date.
*/
uint32_t SystemCoreClock;
/*******************************************************************************
************************** GLOBAL FUNCTIONS *******************************
******************************************************************************/
/***************************************************************************//**
* @brief
* Get the current core clock frequency.
*
* @details
* Calculate and get the current core clock frequency based on the current
* configuration. Assuming that the SystemCoreClock global variable is
* maintained, the core clock frequency is stored in that variable as well.
* This function will however calculate the core clock based on actual HW
* configuration. It will also update the SystemCoreClock global variable.
*
* @note
* This is an EFM32 proprietary function, not part of the CMSIS definition.
*
* @return
* The current core clock frequency in Hz.
******************************************************************************/
uint32_t SystemCoreClockGet(void)
{
uint32_t ret;
ret = SystemHFClockGet();
#if defined (_EFM32_GIANT_FAMILY)
/* Leopard/Giant Gecko has an additional divider */
ret = ret / (1 + ((CMU->CTRL & _CMU_CTRL_HFCLKDIV_MASK)>>_CMU_CTRL_HFCLKDIV_SHIFT));
#endif
ret >>= (CMU->HFCORECLKDIV & _CMU_HFCORECLKDIV_HFCORECLKDIV_MASK) >>
_CMU_HFCORECLKDIV_HFCORECLKDIV_SHIFT;
/* Keep CMSIS variable up-to-date just in case */
SystemCoreClock = ret;
return ret;
}
/***************************************************************************//**
* @brief
* Get the current HFCLK frequency.
*
* @note
* This is an EFM32 proprietary function, not part of the CMSIS definition.
*
* @return
* The current HFCLK frequency in Hz.
******************************************************************************/
uint32_t SystemHFClockGet(void)
{
uint32_t ret;
switch (CMU->STATUS & (CMU_STATUS_HFRCOSEL | CMU_STATUS_HFXOSEL |
CMU_STATUS_LFRCOSEL | CMU_STATUS_LFXOSEL))
{
case CMU_STATUS_LFXOSEL:
#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_STATUS_LFRCOSEL:
ret = EFM32_LFRCO_FREQ;
break;
case CMU_STATUS_HFXOSEL:
#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_STATUS_HFRCOSEL */
switch (CMU->HFRCOCTRL & _CMU_HFRCOCTRL_BAND_MASK)
{
case CMU_HFRCOCTRL_BAND_28MHZ:
ret = 28000000;
break;
case CMU_HFRCOCTRL_BAND_21MHZ:
ret = 21000000;
break;
case CMU_HFRCOCTRL_BAND_14MHZ:
ret = 14000000;
break;
case CMU_HFRCOCTRL_BAND_11MHZ:
ret = 11000000;
break;
case CMU_HFRCOCTRL_BAND_7MHZ:
ret = 7000000;
break;
case CMU_HFRCOCTRL_BAND_1MHZ:
ret = 1000000;
break;
default:
ret = 0;
break;
}
break;
}
return ret;
}
/**************************************************************************//**
* @brief
* Get high frequency crystal oscillator clock frequency for target system.
*
* @note
* This is an EFM32 proprietary function, not part of the CMSIS definition.
*
* @return
* HFXO frequency in Hz.
*****************************************************************************/
uint32_t SystemHFXOClockGet(void)
{
/* External crystal oscillator present? */
#if (EFM32_HFXO_FREQ > 0)
return SystemHFXOClock;
#else
return 0;
#endif
}
/**************************************************************************//**
* @brief
* Set high frequency crystal oscillator clock frequency for target system.
*
* @note
* This function is mainly provided for being able to handle target systems
* with different HF crystal oscillator frequencies run-time. If used, it
* should probably only be used once during system startup.
*
* @note
* This is an EFM32 proprietary function, not part of the CMSIS definition.
*
* @param[in] freq
* HFXO frequency in Hz used for target.
*****************************************************************************/
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->STATUS & CMU_STATUS_HFXOSEL)
{
/* The function will update the global variable */
SystemCoreClockGet();
}
#else
(void)freq; /* Unused parameter */
#endif
}
/**************************************************************************//**
* @brief
* Initialize the system.
*
* @details
* Do required generic HW system init.
*
* @note
* This function is invoked during system init, before the main() routine
* and any data has been initialized. For this reason, it cannot do any
* initialization of variables etc.
*****************************************************************************/
void SystemInit(void)
{
}
/**************************************************************************//**
* @brief
* Get low frequency RC oscillator clock frequency for target system.
*
* @note
* This is an EFM32 proprietary function, not part of the CMSIS definition.
*
* @return
* LFRCO frequency in Hz.
*****************************************************************************/
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;
}
/**************************************************************************//**
* @brief
* Get ultra low frequency RC oscillator clock frequency for target system.
*
* @note
* This is an EFM32 proprietary function, not part of the CMSIS definition.
*
* @return
* ULFRCO frequency in Hz.
*****************************************************************************/
uint32_t SystemULFRCOClockGet(void)
{
/* The ULFRCO frequency is not tuned, and can be very inaccurate */
return EFM32_ULFRCO_FREQ;
}
/**************************************************************************//**
* @brief
* Get low frequency crystal oscillator clock frequency for target system.
*
* @note
* This is an EFM32 proprietary function, not part of the CMSIS definition.
*
* @return
* LFXO frequency in Hz.
*****************************************************************************/
uint32_t SystemLFXOClockGet(void)
{
/* External crystal oscillator present? */
#if (EFM32_LFXO_FREQ > 0)
return SystemLFXOClock;
#else
return 0;
#endif
}
/**************************************************************************//**
* @brief
* Set low frequency crystal oscillator clock frequency for target system.
*
* @note
* This function is mainly provided for being able to handle target systems
* with different HF crystal oscillator frequencies run-time. If used, it
* should probably only be used once during system startup.
*
* @note
* This is an EFM32 proprietary function, not part of the CMSIS definition.
*
* @param[in] freq
* LFXO frequency in Hz used for target.
*****************************************************************************/
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->STATUS & CMU_STATUS_LFXOSEL)
{
/* The function will update the global variable */
SystemCoreClockGet();
}
#else
(void)freq; /* Unused parameter */
#endif
}