Posted on March 30, 2014 at 19:33 Dear community,
Knowing that the RTC manual stated that the LSI is not suitable for the RTC, I am trying to use the HSE clock source for the RTC.
I initialized the clock and RTC but the i was unable to read the time. Can you please help?
I initialized the clock as follows:
RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);
PWR_BackupAccessCmd(ENABLE);
RCC_HSEConfig( RCC_HSE_ON );
while(RCC_GetFlagStatus(RCC_FLAG_HSERDY) == RESET) {}
RCC_RTCCLKConfig(RCC_RTCCLKSource_HSE_Div8);
RCC_RTCCLKCmd(ENABLE);
RTC_WaitForSynchro();
RTC_InitStructure.RTC_AsynchPrediv = 0x7C;
RTC_InitStructure.RTC_SynchPrediv = 0x1F3F;
RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24;
RTC_Init(&RTC_InitStructure);
RTC_TimeStructure.RTC_H12 = RTC_H12_AM;
RTC_TimeStructure.RTC_Hours = 1;
RTC_TimeStructure.RTC_Minutes = 0;
RTC_TimeStructure.RTC_Seconds = 0;
RTC_SetTime(RTC_Format_BCD, &RTC_TimeStructure);
In order to read the clock i am using the following:
RTC_GetTime(RTC_Format_BCD, &RTC_TimeStructure);
uwMin = RTC_TimeStructure.RTC_Minutes;
uwSecond = RTC_TimeStructure.RTC_Seconds;
uwSecond_h = (((uint8_t)(RTC_TimeStructure.RTC_Seconds & 0xF0) >> 0x04)+ 0x30);
uwSecond_l = (((uint8_t)(RTC_TimeStructure.RTC_Seconds & 0x0F)) + 0x30);
uwSecondfraction = 1000 - ((uint32_t)((uint32_t)RTC_GetSubSecond() * 1000) / (uint32_t)0x3FF);
Unfortunately all the variables (uwMin, uwSecond, uwSecond_h, uwSecond_l, uwSecondfraction) has 0 as value.
Thank you in advance for the help.
Best regards,
Marc
#stm32f407discovery-rcc-hse-rtc
