void RCC_DeInit(void)
{
/*Set HSION bit，內部高速時鍾使能HSI振盪器打開*/
RCC->CR |=(uint32_t)0x00000001;
/*Reset CFGR register,
31:30--00：選擇系統時鍾 (SYSCLK) 輸出到 MCO2 引腳
27:29--0xx:MCO2 預分頻器 (MCO2 prescaler)無分頻
24:26--0xx:MCO1 預分頻器 (MCO1 prescaler)無分頻
23--0：PLLI2S 時鍾用作 I2S 時鍾源
22:21--00：選擇 HSI 時鍾輸出到 MCO1 引腳
20:16--00000：無時鍾，適用於 RTC 時鍾的 HSE 分頻系數
15:13--0xx：AHB 時鍾不分頻
12:10--0xx：AHB 時鍾不分頻
9:8 保留，必須保持復位值
7:4--AHB 預分頻器 (AHB prescaler)，0xxx：系統時鍾不分頻
3:2 --SWS：系統時鍾切換狀態 (System clock switch status)，00：HSI 振盪器用作系統時鍾
1:0-- SW：系統時鍾切換 (System clock switch)，00：選擇 HSI 振盪器作為系統時鍾*/
RCC->CFGR = 0x00000000;
/* Reset HSEON, CSSON, PLLON, PLLI2S and PLLSAI(STM32F42xxx/43xxx/446xx/469xx/479xx devices) bits
HSEON：0：HSE 振盪器關閉，HSE 時鍾使能 (HSE clock enable)
CSSON：時鍾安全系統使能 (Clock security system enable)，0：時鍾安全系統關閉（時鍾監測器關閉）
PLLON：主 PLL (PLL) 使能 (Main PLL (PLL) enable)，0：PLL 關閉
PLLI2S：PLLI2S 使能 (PLLI2S enable)，0：PLLI2S 關閉
PLLSAI：無*/
RCC->CR &= (uint32_t)0xEAF6FFFF;
/* Reset PLLCFGR register */ RCC->PLLCFGR = 0x24003010;
#if defined(STM32F40_41xxx) || defined(STM32F427_437xx) || defined(STM32F429_439xx) || defined(STM32F401xx) || defined(STM32F411xE) || defined(STM32F446xx) || defined(STM32F469_479xx) /* Reset PLLI2SCFGR register */
RCC->PLLI2SCFGR = 0x20003000;
#endif /* STM32F40_41xxx || STM32F427_437xx || STM32F429_439xx || STM32F401xx || STM32F411xE || STM32F446xx || STM32F469_479xx */
#if defined(STM32F40_41xxx) || defined(STM32F427_437xx) || defined(STM32F429_439xx) || defined(STM32F446xx) || defined(STM32F469_479xx) /* Reset PLLSAICFGR register, only available for STM32F42xxx/43xxx/446xx/469xx/479xx devices */
RCC->PLLSAICFGR = 0x24003000;
#endif /* STM32F40_41xxx || STM32F427_437xx || STM32F429_439xx || STM32F446xx || STM32F469_479xx */
/* Reset HSEBYP bit */
RCC->CR &= (uint32_t)0xFFFBFFFF;
/* Disable all interrupts */
RCC->CIR = 0x00000000;
/* Disable Timers clock prescalers selection, only available for STM32F42/43xxx devices */ RCC->DCKCFGR = 0x00000000;
#if defined(STM32F410xx)
/* Disable LPTIM and FMPI2C clock prescalers selection, only available for STM32F410xx devices */
RCC->DCKCFGR2 = 0x00000000;
#endif /* STM32F410xx */ }
}