Posted on July 26, 2017 at 20:10Hello !!
I use this family of MCUs some years..
I never faced any kind of problem with rtc
It keeps the time and calendal like the other 'modern and complexer' RTCs
The behaviour you described is from software provided to 'support' the rtc
Here are some fundamedal functions to work with . in C
keep in mind to full fill the structures with valid values before write the clock
write all theese code to a module xxx.c
#include 'stm32f1xx_hal.h'
#include <time.h>
//##############################################################################
extern void SystemClock_Config(void);
extern RTC_HandleTypeDef hrtc;
extern HAL_StatusTypeDef RTC_WriteTimeCounter(RTC_HandleTypeDef* hrtc, uint32_t TimeCounter);
//##############################################################################
void RTCSetAlarm(struct tm* cl)
{
uint32_t TimeCounter= mktime(cl);
//TimeCounter +=100;
while((hrtc.Instance->CRL & RTC_CRL_RTOFF) == (uint32_t)RESET);
/* Disable the write protection for RTC registers */
SET_BIT(hrtc.Instance->CRL, RTC_CRL_CNF);
/* Set RTC COUNTER MSB word */
WRITE_REG(hrtc.Instance->ALRH, (TimeCounter >> 16));
/* Set RTC COUNTER LSB word */
WRITE_REG(hrtc.Instance->ALRL, (TimeCounter & RTC_ALRL_RTC_ALR));
/* Enable the write protection for RTC registers */
CLEAR_BIT(hrtc.Instance->CRL, RTC_CRL_CNF);
/* Wait till RTC is in INIT state */
while((hrtc.Instance->CRL & RTC_CRL_RTOFF) == (uint32_t)RESET);
/* Clear flag alarm A */
hrtc.Instance->CRL &= ~(RTC_FLAG_ALRAF);
/* Configure the Alarm interrupt */
SET_BIT(hrtc.Instance->CRH, (RTC_IT_ALRA));
/* RTC Alarm Interrupt Configuration: EXTI configuration */
__HAL_RTC_ALARM_EXTI_ENABLE_IT();
__HAL_RTC_ALARM_EXTI_ENABLE_RISING_EDGE();
}
//##############################################################################
void RTCGetClock(struct tm** cl)
{
uint16_t high1 = 0, high2 = 0, low = 0;
uint32_t timecounter = 0;
high1 = READ_REG(hrtc.Instance->CNTH & RTC_CNTH_RTC_CNT);
again2:
low = READ_REG(hrtc.Instance->CNTL & RTC_CNTL_RTC_CNT);
high2 = READ_REG(hrtc.Instance->CNTH & RTC_CNTH_RTC_CNT);
if (high1 != high2)
{
high1=high2;//read again CNTL register then return the counter value
goto again2;
}
timecounter = (((uint32_t) high1 << 16 ) | low);
*cl= localtime(&timecounter);
}
//##############################################################################
void RTCSetClock(struct tm* cl)
{
uint32_t TimeCounter= mktime(cl);
while((hrtc.Instance->CRL & RTC_CRL_RTOFF) == (uint32_t)RESET);
hrtc.Init.AsynchPrediv = RTC_AUTO_1_SECOND;
hrtc.Init.OutPut = RTC_OUTPUTSOURCE_NONE;
HAL_RTC_Init(&hrtc);
__HAL_RTC_WRITEPROTECTION_DISABLE(&hrtc);
/* Set RTC COUNTER MSB word */
WRITE_REG(hrtc.Instance->CNTH, (TimeCounter >> 16));
/* Set RTC COUNTER LSB word */
WRITE_REG(hrtc.Instance->CNTL, (TimeCounter & RTC_CNTL_RTC_CNT));
/* Disable the write protection for RTC registers */
__HAL_RTC_WRITEPROTECTION_ENABLE(&hrtc);
/* Wait till RTC is in INIT state and if Time out is reached exit */
while((hrtc.Instance->CRL & RTC_CRL_RTOFF) == (uint32_t)RESET);
}
//##############################################################################
At HAL initialiation before use the above module, must do at least this:(at main function)
RTC_HandleTypeDef hrtc;//in global scope
The LSE must be running allready and the rtc must have as source LSE(vbat is connected)
hrtc.Instance = RTC;// it exists no need to initialise again
hrtc.State = HAL_RTC_STATE_READY;// and is counting
HAL_PWR_EnableBkUpAccess();// enable the clocks
__HAL_RCC_RTC_ENABLE();
__HAL_RCC_BKP_CLK_ENABLE();
make a try.
