375 lines
12 KiB
C
375 lines
12 KiB
C
/***************************************************************************//**
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* @file
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* @brief CMSIS Cortex-M3 System Layer for EFM32G devices.
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* @author Energy Micro AS
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* @version 3.0.0
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*******************************************************************************
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* @section License
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* <b>(C) Copyright 2012 Energy Micro AS, http://www.energymicro.com</b>
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******************************************************************************
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*
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* DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Energy Micro AS has no
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* obligation to support this Software. Energy Micro AS is providing the
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* Software "AS IS", with no express or implied warranties of any kind,
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* including, but not limited to, any implied warranties of merchantability
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* or fitness for any particular purpose or warranties against infringement
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* of any proprietary rights of a third party.
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*
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* Energy Micro AS will not be liable for any consequential, incidental, or
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* special damages, or any other relief, or for any claim by any third party,
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* arising from your use of this Software.
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*
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******************************************************************************/
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#include <stdint.h>
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#include "efm32.h"
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/*******************************************************************************
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****************************** DEFINES ************************************
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******************************************************************************/
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/** LFRCO frequency, tuned to below frequency during manufacturing. */
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#define EFM32_LFRCO_FREQ (32768UL)
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#define EFM32_ULFRCO_FREQ (1000UL)
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/*******************************************************************************
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************************** LOCAL VARIABLES ********************************
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******************************************************************************/
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/* System oscillator frequencies. These frequencies are normally constant */
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/* for a target, but they are made configurable in order to allow run-time */
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/* handling of different boards. The crystal oscillator clocks can be set */
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/* compile time to a non-default value by defining respective EFM32_nFXO_FREQ */
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/* values according to board design. By defining the EFM32_nFXO_FREQ to 0, */
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/* one indicates that the oscillator is not present, in order to save some */
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/* SW footprint. */
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#ifndef EFM32_HFXO_FREQ
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#ifdef _EFM32_GIANT_FAMILY
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#define EFM32_HFXO_FREQ (48000000UL)
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#else
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#define EFM32_HFXO_FREQ (32000000UL)
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#endif
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#endif
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/* Do not define variable if HF crystal oscillator not present */
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#if (EFM32_HFXO_FREQ > 0)
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/** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
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/** System HFXO clock. */
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static uint32_t SystemHFXOClock = EFM32_HFXO_FREQ;
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/** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
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#endif
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#ifndef EFM32_LFXO_FREQ
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#define EFM32_LFXO_FREQ (EFM32_LFRCO_FREQ)
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#endif
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/* Do not define variable if LF crystal oscillator not present */
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#if (EFM32_LFXO_FREQ > 0)
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/** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
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/** System LFXO clock. */
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static uint32_t SystemLFXOClock = EFM32_LFXO_FREQ;
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/** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
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#endif
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/*******************************************************************************
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************************** GLOBAL VARIABLES *******************************
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******************************************************************************/
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/**
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* @brief
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* System System Clock Frequency (Core Clock).
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*
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* @details
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* Required CMSIS global variable that must be kept up-to-date.
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*/
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uint32_t SystemCoreClock;
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/*******************************************************************************
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************************** GLOBAL FUNCTIONS *******************************
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******************************************************************************/
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/***************************************************************************//**
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* @brief
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* Get the current core clock frequency.
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*
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* @details
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* Calculate and get the current core clock frequency based on the current
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* configuration. Assuming that the SystemCoreClock global variable is
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* maintained, the core clock frequency is stored in that variable as well.
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* This function will however calculate the core clock based on actual HW
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* configuration. It will also update the SystemCoreClock global variable.
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*
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* @note
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* This is an EFM32 proprietary function, not part of the CMSIS definition.
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*
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* @return
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* The current core clock frequency in Hz.
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******************************************************************************/
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uint32_t SystemCoreClockGet(void)
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{
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uint32_t ret;
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ret = SystemHFClockGet();
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#if defined (_EFM32_GIANT_FAMILY)
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/* Leopard/Giant Gecko has an additional divider */
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ret = ret / (1 + ((CMU->CTRL & _CMU_CTRL_HFCLKDIV_MASK)>>_CMU_CTRL_HFCLKDIV_SHIFT));
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#endif
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ret >>= (CMU->HFCORECLKDIV & _CMU_HFCORECLKDIV_HFCORECLKDIV_MASK) >>
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_CMU_HFCORECLKDIV_HFCORECLKDIV_SHIFT;
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/* Keep CMSIS variable up-to-date just in case */
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SystemCoreClock = ret;
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return ret;
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}
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/***************************************************************************//**
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* @brief
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* Get the current HFCLK frequency.
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*
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* @note
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* This is an EFM32 proprietary function, not part of the CMSIS definition.
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*
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* @return
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* The current HFCLK frequency in Hz.
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******************************************************************************/
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uint32_t SystemHFClockGet(void)
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{
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uint32_t ret;
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switch (CMU->STATUS & (CMU_STATUS_HFRCOSEL | CMU_STATUS_HFXOSEL |
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CMU_STATUS_LFRCOSEL | CMU_STATUS_LFXOSEL))
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{
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case CMU_STATUS_LFXOSEL:
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#if (EFM32_LFXO_FREQ > 0)
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ret = SystemLFXOClock;
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#else
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/* We should not get here, since core should not be clocked. May */
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/* be caused by a misconfiguration though. */
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ret = 0;
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#endif
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break;
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case CMU_STATUS_LFRCOSEL:
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ret = EFM32_LFRCO_FREQ;
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break;
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case CMU_STATUS_HFXOSEL:
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#if (EFM32_HFXO_FREQ > 0)
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ret = SystemHFXOClock;
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#else
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/* We should not get here, since core should not be clocked. May */
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/* be caused by a misconfiguration though. */
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ret = 0;
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#endif
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break;
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default: /* CMU_STATUS_HFRCOSEL */
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switch (CMU->HFRCOCTRL & _CMU_HFRCOCTRL_BAND_MASK)
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{
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case CMU_HFRCOCTRL_BAND_28MHZ:
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ret = 28000000;
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break;
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case CMU_HFRCOCTRL_BAND_21MHZ:
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ret = 21000000;
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break;
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case CMU_HFRCOCTRL_BAND_14MHZ:
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ret = 14000000;
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break;
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case CMU_HFRCOCTRL_BAND_11MHZ:
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ret = 11000000;
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break;
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case CMU_HFRCOCTRL_BAND_7MHZ:
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ret = 7000000;
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break;
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case CMU_HFRCOCTRL_BAND_1MHZ:
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ret = 1000000;
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break;
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default:
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ret = 0;
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break;
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}
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break;
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}
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return ret;
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}
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/**************************************************************************//**
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* @brief
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* Get high frequency crystal oscillator clock frequency for target system.
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*
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* @note
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* This is an EFM32 proprietary function, not part of the CMSIS definition.
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*
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* @return
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* HFXO frequency in Hz.
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*****************************************************************************/
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uint32_t SystemHFXOClockGet(void)
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{
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/* External crystal oscillator present? */
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#if (EFM32_HFXO_FREQ > 0)
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return SystemHFXOClock;
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#else
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return 0;
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#endif
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}
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/**************************************************************************//**
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* @brief
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* Set high frequency crystal oscillator clock frequency for target system.
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*
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* @note
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* This function is mainly provided for being able to handle target systems
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* with different HF crystal oscillator frequencies run-time. If used, it
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* should probably only be used once during system startup.
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*
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* @note
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* This is an EFM32 proprietary function, not part of the CMSIS definition.
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*
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* @param[in] freq
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* HFXO frequency in Hz used for target.
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*****************************************************************************/
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void SystemHFXOClockSet(uint32_t freq)
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{
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/* External crystal oscillator present? */
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#if (EFM32_HFXO_FREQ > 0)
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SystemHFXOClock = freq;
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/* Update core clock frequency if HFXO is used to clock core */
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if (CMU->STATUS & CMU_STATUS_HFXOSEL)
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{
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/* The function will update the global variable */
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SystemCoreClockGet();
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}
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#else
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(void)freq; /* Unused parameter */
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#endif
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}
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/**************************************************************************//**
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* @brief
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* Initialize the system.
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*
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* @details
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* Do required generic HW system init.
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*
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* @note
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* This function is invoked during system init, before the main() routine
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* and any data has been initialized. For this reason, it cannot do any
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* initialization of variables etc.
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*****************************************************************************/
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void SystemInit(void)
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{
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}
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/**************************************************************************//**
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* @brief
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* Get low frequency RC oscillator clock frequency for target system.
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*
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* @note
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* This is an EFM32 proprietary function, not part of the CMSIS definition.
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*
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* @return
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* LFRCO frequency in Hz.
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*****************************************************************************/
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uint32_t SystemLFRCOClockGet(void)
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{
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/* Currently we assume that this frequency is properly tuned during */
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/* manufacturing and is not changed after reset. If future requirements */
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/* for re-tuning by user, we can add support for that. */
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return EFM32_LFRCO_FREQ;
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}
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/**************************************************************************//**
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* @brief
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* Get ultra low frequency RC oscillator clock frequency for target system.
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*
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* @note
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* This is an EFM32 proprietary function, not part of the CMSIS definition.
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*
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* @return
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* ULFRCO frequency in Hz.
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*****************************************************************************/
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uint32_t SystemULFRCOClockGet(void)
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{
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/* The ULFRCO frequency is not tuned, and can be very inaccurate */
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return EFM32_ULFRCO_FREQ;
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}
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/**************************************************************************//**
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* @brief
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* Get low frequency crystal oscillator clock frequency for target system.
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*
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* @note
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* This is an EFM32 proprietary function, not part of the CMSIS definition.
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*
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* @return
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* LFXO frequency in Hz.
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*****************************************************************************/
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uint32_t SystemLFXOClockGet(void)
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{
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/* External crystal oscillator present? */
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#if (EFM32_LFXO_FREQ > 0)
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return SystemLFXOClock;
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#else
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return 0;
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#endif
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}
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/**************************************************************************//**
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* @brief
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* Set low frequency crystal oscillator clock frequency for target system.
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*
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* @note
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* This function is mainly provided for being able to handle target systems
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* with different HF crystal oscillator frequencies run-time. If used, it
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* should probably only be used once during system startup.
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*
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* @note
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* This is an EFM32 proprietary function, not part of the CMSIS definition.
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*
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* @param[in] freq
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* LFXO frequency in Hz used for target.
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*****************************************************************************/
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void SystemLFXOClockSet(uint32_t freq)
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{
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/* External crystal oscillator present? */
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#if (EFM32_LFXO_FREQ > 0)
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SystemLFXOClock = freq;
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/* Update core clock frequency if LFXO is used to clock core */
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if (CMU->STATUS & CMU_STATUS_LFXOSEL)
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{
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/* The function will update the global variable */
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SystemCoreClockGet();
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}
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#else
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(void)freq; /* Unused parameter */
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#endif
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}
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