所使用庫：
使用STDPeriPh_Driver lib
目的：
將外部晶振8MHz改爲16MHz。
過程：
1 stm32f10x.h 中找HSE_VALUE
/**
* @brief In the following line adjust the value of External High Speed oscillator (HSE)
used in your application
Tip: To avoid modifying this file each time you need to use different HSE, you
can define the HSE value in your toolchain compiler preprocessor.
*/
#if !defined HSE_VALUE
#ifdef STM32F10X_CL
#define HSE_VALUE ((uint32_t)25000000) /*!< Value of the External oscillator in Hz */
#else
#define HSE_VALUE ((uint32_t)8000000) /*!< Value of the External oscillator in Hz */
#endif /* STM32F10X_CL */
#endif /* HSE_VALUE */
#define HSE_VALUE ((uint32_t)8000000) /*!< Value of the External oscillator in Hz */
更改為:
#define HSE_VALUE ((uint32_t)16000000) /*!< Value of the External oscillator in Hz */
2 system_stm32f10x.c 更改 配置 static void SetSysClockTo72(void)：
RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMULL9);
更改为：
RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLXTPRE_HSE_Div2 | RCC_CFGR_PLLMULL9);
RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE |
RCC_CFGR_PLLMULL));
// 8MHz HSE OSC; RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMULL9);
// 16MHz HSE OSC;
RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLXTPRE_HSE_Div2 | RCC_CFGR_PLLMULL9);
Others
void SystemInit (void)
>> SetSysClock();
>>SetSysClockTo72();
RTC CLK use LSI 40KHz
/*******************************************************************************
* Function Name : NVIC_Configuration
* Description : Configures the RTC.
* Input : None
* Output : None
* Return : None
* Attention : None
*******************************************************************************/
static void RTC_Configuration(void)
{
/* Enable PWR and BKP clocks */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);
/* Allow access to BKP Domain */
PWR_BackupAccessCmd(ENABLE);
/* Reset Backup Domain */
BKP_DeInit();
/* Enable LSE */
RCC_LSEConfig(RCC_LSE_ON);
/* Wait till LSE is ready */
while (RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET)
{}
/* Select LSE as RTC Clock Source */
RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);
/* Enable RTC Clock */
RCC_RTCCLKCmd(ENABLE);
/* Wait for RTC registers synchronization */
RTC_WaitForSynchro();
/* Wait until last write operation on RTC registers has finished */
RTC_WaitForLastTask();
/* Enable the RTC Second */
RTC_ITConfig(RTC_IT_SEC, ENABLE);
/* Wait until last write operation on RTC registers has finished */
RTC_WaitForLastTask();
/* Set RTC prescaler: set RTC period to 1sec */
RTC_SetPrescaler(32767); /* RTC period = RTCCLK/RTC_PR = (32.768 KHz)/(32767+1) */
/* Wait until last write operation on RTC registers has finished */
RTC_WaitForLastTask();
}
改为：
static void RTC_Configuration(void)
{
/* Enable PWR and BKP clocks */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);
/* Allow access to BKP Domain */
PWR_BackupAccessCmd(ENABLE);
/* Reset Backup Domain */
BKP_DeInit();
/* Enable LSE */
//liushi RCC_LSEConfig(RCC_LSE_ON);
/* Wait till LSE is ready */
//liushi while (RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET)
{}
/* Select LSE as RTC Clock Source */
//liushi RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);
RCC_LSICmd(ENABLE); //liushi add
/* Wait till LSI is ready */
while (RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET) //liushi add
{}
RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI); //liushi add
/* Enable RTC Clock */
RCC_RTCCLKCmd(ENABLE);
/* Wait for RTC registers synchronization */
RTC_WaitForSynchro();
/* Wait until last write operation on RTC registers has finished */
RTC_WaitForLastTask();
/* Enable the RTC Second */
RTC_ITConfig(RTC_IT_SEC, ENABLE);
/* Wait until last write operation on RTC registers has finished */
RTC_WaitForLastTask();
/* Set RTC prescaler: set RTC period to 1sec */
RTC_SetPrescaler(32767); /* RTC period = RTCCLK/RTC_PR = (32.768 KHz)/(32767+1) */
/* Wait until last write operation on RTC registers has finished */
RTC_WaitForLastTask();
}
