/**
??******************************************************************************
??*?@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
-----------?---------??----------?-----??----

?????文件?????530693??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\CMSIS\ST\STM32F4xx\Include\stm32f4xx.h

?????文件???????2096??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\CMSIS\ST\STM32F4xx\Include\system_stm32f4xx.h

?????文件??????17824??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\CMSIS\ST\STM32F4xx\Release_Notes.html

?????文件??????29511??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\CMSIS\ST\STM32F4xx\Source\Templates\arm\startup_stm32f4xx.s

?????文件??????23970??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\CMSIS\ST\STM32F4xx\Source\Templates\gcc_ride7\startup_stm32f4xx.s

?????文件??????24546??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\CMSIS\ST\STM32F4xx\Source\Templates\iar\startup_stm32f4xx.s

?????文件??????21726??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\CMSIS\ST\STM32F4xx\Source\Templates\system_stm32f4xx.c

?????文件???????3672??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\CMSIS\ST\STM32F4xx\Source\Templates\TASKING\cstart_thumb2.asm

?????文件??????24040??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\CMSIS\ST\STM32F4xx\Source\Templates\TrueSTUDIO\startup_stm32f4xx.s

?????文件???????6792??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\misc.h

?????文件??????32417??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_adc.h

?????文件??????27186??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_can.h

?????文件???????2284??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_crc.h

?????文件??????12528??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_cryp.h

?????文件??????14814??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_dac.h

?????文件???????4164??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_dbgmcu.h

?????文件??????12845??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_dcmi.h

?????文件??????28750??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_dma.h

?????文件???????7880??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_exti.h

?????文件??????14463??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_flash.h

?????文件??????27044??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_fsmc.h

?????文件??????17569??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_gpio.h

?????文件???????8952??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_hash.h

?????文件??????31516??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_i2c.h

?????文件???????4191??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_iwdg.h

?????文件???????6022??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_pwr.h

?????文件??????24742??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_rcc.h

?????文件???????3826??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_rng.h

?????文件??????40414??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_rtc.h

?????文件??????22645??2011-10-28?10:31??STM32F4-Discovery_FW_V1.1.0\Libraries\STM32F4xx_StdPeriph_Driver\inc\stm32f4xx_sdio.h

............此處省略89個文件信息