/**
??******************************************************************************
??*?@file????system_stm32f4xx.c
??*?@author??MCD?Application?Team
??*?@version?V1.0.0
??*?@date????30-September-2011
??*?@brief???CMSIS?Cortex-M4?Device?Peripheral?Access?layer?System?Source?File.
??*??????????This?file?contains?the?system?clock?configuration?for?STM32F4xx?devices
??*??????????and?is?generated?by?the?clock?configuration?tool
??*??????????stm32f4xx_Clock_Configuration_V1.0.0.xls
??*?????????????
??*?1.??This?file?provides?two?functions?and?one?global?variable?to?be?called?from?
??*?????user?application:
??*??????-?SystemInit（）:?Setups?the?system?clock?（System?clock?source?PLL?Multiplier
??*??????????????????????and?Divider?factors?AHB/APBx?prescalers?and?Flash?settings）
??*??????????????????????depending?on?the?configuration?made?in?the?clock?xls?tool.?
??*??????????????????????This?function?is?called?at?startup?just?after?reset?and?
??*??????????????????????before?branch?to?main?program.?This?call?is?made?inside
??*??????????????????????the?“startup_stm32f4xx.s“?file.
??*
??*??????-?SystemCoreClock?variable:?Contains?the?core?clock?（HCLK）?it?can?be?used
??*??????????????????????????????????by?the?user?application?to?setup?the?SysTick?
??*??????????????????????????????????timer?or?configure?other?parameters.
??*?????????????????????????????????????
??*??????-?SystemCoreClockUpdate（）:?Updates?the?variable?SystemCoreClock?and?must
??*?????????????????????????????????be?called?whenever?the?core?clock?is?changed
??*?????????????????????????????????during?program?execution.
??*
??*?2.?After?each?device?reset?the?HSI?（16?MHz）?is?used?as?system?clock?source.
??*????Then?SystemInit（）?function?is?called?in?“startup_stm32f4xx.s“?file?to
??*????configure?the?system?clock?before?to?branch?to?main?program.
??*
??*?3.?If?the?system?clock?source?selected?by?user?fails?to?startup?the?SystemInit（）
??*????function?will?do?nothing?and?HSI?still?used?as?system?clock?source.?User?can?
??*????add?some?code?to?deal?with?this?issue?inside?the?SetSysClock（）?function.
??*
??*?4.?The?default?value?of?HSE?crystal?is?set?to?25MHz?refer?to?“HSE_VALUE“?define
??*????in?“stm32f4xx.h“?file.?When?HSE?is?used?as?system?clock?source?directly?or
??*????through?PLL?and?you?are?using?different?crystal?you?have?to?adapt?the?HSE
??*????value?to?your?own?configuration.
??*
??*?5.?This?file?configures?the?system?clock?as?follows:
??*=============================================================================
??*=============================================================================
??*????????Supported?STM32F4xx?device?revision????|?Rev?A
??*-----------------------------------------------------------------------------
??*????????System?Clock?source????????????????????|?PLL?（HSE）
??*-----------------------------------------------------------------------------
??*????????SYSCLK（Hz）?????????????????????????????|?168000000
??*-

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2015-03-16?20:42??ms5611\
?????目錄???????????0??2015-03-16?20:42??ms5611\Libraries\
?????目錄???????????0??2015-03-16?20:42??ms5611\Libraries\CMSIS\
?????文件???????51511??2014-10-29?18:18??ms5611\Libraries\CMSIS\CMSIS?END?USER?LICENCE?AGREEMENT.pdf
?????目錄???????????0??2015-03-16?20:42??ms5611\Libraries\CMSIS\DSP_Lib\
?????目錄???????????0??2015-03-16?20:42??ms5611\Libraries\CMSIS\DSP_Lib\Examples\
?????目錄???????????0??2015-03-16?20:42??ms5611\Libraries\CMSIS\DSP_Lib\Examples\Common\
?????目錄???????????0??2015-03-16?20:42??ms5611\Libraries\CMSIS\DSP_Lib\Examples\Common\Include\
?????文件????????1979??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\Common\Include\math_helper.h
?????目錄???????????0??2015-03-16?20:42??ms5611\Libraries\CMSIS\DSP_Lib\Examples\Common\Source\
?????文件????????9852??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\Common\Source\math_helper.c
?????目錄???????????0??2015-03-16?20:42??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\
?????目錄???????????0??2015-03-16?20:42??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\ARM\
?????文件?????????405??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\ARM\arm_class_marks_example.ini
?????文件????????8217??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\ARM\arm_cortexM0l_class_marks_example.uvopt
?????文件???????15090??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\ARM\arm_cortexM0l_class_marks_example.uvproj
?????文件????????8417??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\ARM\arm_cortexM3l_class_marks_example.uvopt
?????文件???????15082??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\ARM\arm_cortexM3l_class_marks_example.uvproj
?????文件????????8233??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\ARM\arm_cortexM4lf_class_marks_example.uvopt
?????文件???????15107??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\ARM\arm_cortexM4lf_class_marks_example.uvproj
?????文件????????4363??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\ARM\startup_ARMCM0.s
?????文件????????5000??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\ARM\startup_ARMCM3.s
?????文件????????5000??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\ARM\startup_ARMCM4.s
?????目錄???????????0??2015-03-16?20:42??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\GCC\
?????文件????????5804??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\GCC\ARMCMx.ld
?????文件?????????405??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\GCC\arm_class_marks_example.ini
?????文件????????7549??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\GCC\arm_cortexM0l_class_marks_example.uvopt
?????文件???????11862??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\GCC\arm_cortexM0l_class_marks_example.uvproj
?????文件????????7563??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\GCC\arm_cortexM3l_class_marks_example.uvopt
?????文件???????11854??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\GCC\arm_cortexM3l_class_marks_example.uvproj
?????文件????????7564??2014-10-29?18:18??ms5611\Libraries\CMSIS\DSP_Lib\Examples\arm_class_marks_example\GCC\arm_cortexM4lf_class_marks_example.uvopt
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