求助：STM32F103VC VBAT由3V电池直接供电，VDD掉电后32.768晶体停止振荡

Koowana · 发表于 2018-7-31 20:45:09

从示波器的测量来看，VDD3.3V电源一掉，则立刻停振。同时Backup中保存的内容也不存在了。
求各路朋友施加援手！！！

Koowana · 发表于 2018-7-31 21:20:28

u8 RTC_Init(void)
{
u8 temp=0;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);

PWR_BackupAccessCmd(ENABLE); //change to the function list below???
if (BKP_ReadBackupRegister(BKP_DR1) != 0x0505)
{

//RCC_BackupAccessCmd(ENABLE);

BKP_DeInit();
RCC_LSEConfig(RCC_LSE_ON);

while (RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET)
{
temp++;
Delay_mS(10);
if(temp>=250)
{
return 1;
}
}

RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);

RCC_RTCCLKCmd(ENABLE);
// RTC_WaitForLastTask();
RTC_WaitForSynchro();

RTC_WaitForLastTask();
RTC_ITConfig(RTC_IT_SEC, ENABLE);

RTC_EnterConfigMode();

RTC_WaitForLastTask();
RTC_SetPrescaler(32767);

RTC_WaitForLastTask();
RTC_Set(2017,12,30,07,58,00);

RTC_ExitConfigMode();

BKP_WriteBackupRegister(BKP_DR1, 0X0505);

}

else//??????
{
RTC_WaitForSynchro();
RTC_ITConfig(RTC_IT_SEC, ENABLE);
RTC_WaitForLastTask();
}

Koowana · 发表于 2018-7-31 21:21:18

void PVD_Init(void)
{
NVIC_InitTypeDef NVIC_InitStruct;
EXTI_InitTypeDef EXTI_InitStructure;

NVIC_InitStruct.NVIC_IRQChannel = PVD_IRQn;
NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStruct.NVIC_IRQChannelSubPriority = 2;
NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStruct);//enable interrupt

PWR_PVDLevelConfig(PWR_PVDLevel_2V9);
PWR_PVDCmd(ENABLE);

RCC_APB1PeriphClockCmd( RCC_APB1Periph_PWR, ENABLE); //_PWR, ENABLE); // ??????
}