Posted on July 05, 2015 at 14:30Hello everyone
I am using STM32F103RET and I try to use RTC
The problem is, when I try to use LSE as RTC clock source, the code is trapped in
''while (RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET) {}; ''
loop, it seems that LSE Crystal is not working. I have changed the crystal and even I replaced the crystal with a working digital clock crystal ( I took crystal out from the board ). There is no 32768Hz oscillation at crystal pins
Also, when I try to use LSI instead, RTC runs but after reset ( when battery is connected ) it seems that LSI is getting disabled, while backup registers work correctly
Can anyone share his experience with me...
This is my Code
int main(void)
{
...
RCC_Configuration(); // Clock config
...
RTC_init();
...
}
...
void RTC_init(void)
{
RTC_NVIC_Configuration();
RTC_Configuration();
}
...
void RTC_Configuration(void)
{
RCC_APB1PeriphClockCmd( RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE );// Enable PWR and BKP clocks
PWR_BackupAccessCmd ( ENABLE ); // Allow access to BKP Domain
if ( BKP_ReadBackupRegister(BKP_REG_SIGN) != 0xA5A5 )
{
/* Reset Backup Domain */
BKP_DeInit();
// RCC_LSICmd ( ENABLE ); // ????????????????????????????????????????????????????
// while( RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET ) {}; // Wait till LSI is ready
// RCC_RTCCLKConfig( RCC_RTCCLKSource_LSI ); // Select the RTC Clock Source
// RTC_WaitForLastTask(); // Wait until last write operation on RTC registers has finished
RCC_LSEConfig(RCC_LSE_ON); // Enable LSE ?????????????????????????????????????
while (RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET) {}; // Wait till LSE is ready
RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE); // Select LSE as RTC Clock Source
RTC_WaitForLastTask(); // Wait until last write operation on RTC registers has finished
// RCC_RTCCLKConfig(RCC_RTCCLKSource_HSE_Div128); // assuming HSE is turned on before, in RCC_init()
/* Enable RTC Clock */
RCC_RTCCLKCmd(ENABLE);
BKP_WriteBackupRegister( BKP_REG_SIGN, 0xA5A5 );
}
/* Wait for RTC registers synchronization */
RTC_WaitForSynchro();
/* Enable the RTC Second */
RTC_ITConfig(RTC_IT_SEC, ENABLE);
/* Wait until last write operation on RTC registers has finished */
RTC_WaitForLastTask();
...
}
#lmgtfy #stm32f10x
