Hi, Victor,
I really appreciated the information you gave me. the more relative code may address the question:
rtc init in ./cubemx/Src/rtc.c
RTC_HandleTypeDef hrtc;
/* RTC init function */
void MX_RTC_Init(void)
{
/* USER CODE BEGIN RTC_Init 0 */
/* USER CODE END RTC_Init 0 */
RTC_TimeTypeDef sTime = {0};
RTC_DateTypeDef sDate = {0};
RTC_AlarmTypeDef sAlarm = {0};
/* USER CODE BEGIN RTC_Init 1 */
/* USER CODE END RTC_Init 1 */
/** Initialize RTC Only
*/
hrtc.Instance = RTC;
hrtc.Init.HourFormat = RTC_HOURFORMAT_24;
hrtc.Init.AsynchPrediv = RTC_PREDIV_A;
hrtc.Init.SynchPrediv = RTC_PREDIV_S;
hrtc.Init.OutPut = RTC_OUTPUT_DISABLE;
hrtc.Init.OutPutRemap = RTC_OUTPUT_REMAP_NONE;
hrtc.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
hrtc.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
hrtc.Init.OutPutPullUp = RTC_OUTPUT_PULLUP_NONE;
hrtc.Init.BinMode = RTC_BINARY_MIX;
hrtc.Init.BinMixBcdU = RTC_BINARY_MIX_BCDU_2;
if (HAL_RTC_Init(&hrtc) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN Check_RTC_BKUP */
/* USER CODE END Check_RTC_BKUP */
/** Initialize RTC and set the Time and Date
*/
sTime.Hours = 0x0;
sTime.Minutes = 0x0;
// when RTC work in mix mode, readout RTC value will less 1 second than correct value,
// see RM0461 page 906: "SS can be larger than PREDIV_S only after a shift operation.
// In that case, the correct time/date is one second less than as indicated by RTC_TR/RTC_DR."
sTime.Seconds = 0x2;
sTime.DayLightSaving = RTC_DAYLIGHTSAVING_NONE;
sTime.StoreOperation = RTC_STOREOPERATION_RESET;
if (HAL_RTC_SetTime(&hrtc, &sTime, RTC_FORMAT_BCD) != HAL_OK)
{
Error_Handler();
}
sDate.WeekDay = RTC_WEEKDAY_SATURDAY;
sDate.Month = RTC_MONTH_JANUARY;
sDate.Date = 0x1;
sDate.Year = 0x0;
if (HAL_RTC_SetDate(&hrtc, &sDate, RTC_FORMAT_BCD) != HAL_OK)
{
Error_Handler();
}
if (HAL_RTCEx_SetSSRU_IT(&hrtc) != HAL_OK)
{
Error_Handler();
}
/** Enable the Alarm A
*/
sAlarm.AlarmTime.Hours = 0x0;
sAlarm.AlarmTime.Minutes = 0x0;
sAlarm.AlarmTime.Seconds = 0x0;
sAlarm.AlarmTime.SubSeconds = 0x0;
sAlarm.AlarmTime.DayLightSaving = RTC_DAYLIGHTSAVING_NONE;
sAlarm.AlarmTime.StoreOperation = RTC_STOREOPERATION_RESET;
sAlarm.AlarmMask = RTC_ALARMMASK_NONE;
sAlarm.AlarmSubSecondMask = RTC_ALARMSUBSECONDMASK_SS14_10;
sAlarm.AlarmDateWeekDaySel = RTC_ALARMDATEWEEKDAYSEL_DATE;
sAlarm.AlarmDateWeekDay = 0x1;
sAlarm.Alarm = RTC_ALARM_A;
if (HAL_RTC_SetAlarm_IT(&hrtc, &sAlarm, RTC_FORMAT_BCD) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN RTC_Init 2 */
// lptimer_bkup_write_msbticks(RTC_TIMESTAMP_MSB_INIT_VAL);
// lptimer_bkup_write_second(RTC_INIT_SYSTIME_SECOND_COMPENSATION);
/* USER CODE END RTC_Init 2 */
}
void HAL_RTC_MspInit(RTC_HandleTypeDef* rtcHandle)
{
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
if(rtcHandle->Instance==RTC)
{
/* USER CODE BEGIN RTC_MspInit 0 */
HAL_NVIC_ClearPendingIRQ(TAMP_STAMP_LSECSS_SSRU_IRQn);
HAL_NVIC_ClearPendingIRQ(RTC_Alarm_IRQn);
/* USER CODE END RTC_MspInit 0 */
/** Initializes the peripherals clocks
*/
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RTC;
PeriphClkInitStruct.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
{
Error_Handler();
}
/* RTC clock enable */
__HAL_RCC_RTC_ENABLE();
__HAL_RCC_RTCAPB_CLK_ENABLE();
/* RTC interrupt Init */
HAL_NVIC_SetPriority(TAMP_STAMP_LSECSS_SSRU_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(TAMP_STAMP_LSECSS_SSRU_IRQn);
HAL_NVIC_SetPriority(RTC_Alarm_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(RTC_Alarm_IRQn);
/* USER CODE BEGIN RTC_MspInit 1 */
rt_kprintf("rtc init\n");
/* USER CODE END RTC_MspInit 1 */
}
}
rtc clock prescale define in main.h
#define RTC_N_PREDIV_S 10
#define RTC_PREDIV_A ((1<<(15-RTC_N_PREDIV_S))-1)
#define RTC_PREDIV_S ((1<<RTC_N_PREDIV_S)-1
convert between epoch and rtc; alarm setting code in drv_lptimer.h
static const uint8_t days_in_month[] = {0, 31, 28, 31, 30, 31, 30,
31, 31, 30, 31, 30, 31};
// NOTE: generated by chatgpt
static inline uint32_t is_leap_year(uint32_t year)
{
year += 2000;
return (year % 4 == 0 && year % 100 !=0) || year % 400 == 0;
}
static inline uint8_t month_days(uint32_t year, uint8_t month) {
if (month == 2 && is_leap_year(year)) {
return 29;
} else {
return days_in_month[month];
}
}
// TODO: execute time optimize
static void calendar_add(RTC_DateTypeDef *rtc_date, uint32_t days)
{
while (days > 0) {
uint8_t month_days_count = month_days(rtc_date->Year, rtc_date->Month);
if (days >= month_days_count - rtc_date->Date + 1U) {
days -= (month_days_count - rtc_date->Date + 1U);
rtc_date->Date = 1;
if (rtc_date->Month == 12) {
rtc_date->Year++;
rtc_date->Month = 1;
} else {
rtc_date->Month++;
}
} else {
rtc_date->Date += days;
days = 0;
}
}
}
static uint32_t calendar_diff(RTC_DateTypeDef *after, RTC_DateTypeDef *prev)
{
uint32_t prev_elapse_days = 0; // prev date elpase days in the year
uint32_t after_elapse_days = 0; // after date elpase days from the previous year
for (uint8_t i = 1; i < prev->Month; ++i) {
prev_elapse_days += days_in_month[i];
}
if (prev->Month > 2 && is_leap_year(prev->Year)) {
prev_elapse_days += 1;
}
prev_elapse_days += prev->Date;
for (uint8_t i = 1; i < after->Month; ++i) {
after_elapse_days += days_in_month[i];
}
if (after->Month > 2 && is_leap_year(after->Year)) {
prev_elapse_days += 1;
}
after_elapse_days += after->Date;
for (uint32_t year = prev->Year; year < after->Year; year++) {
after_elapse_days += is_leap_year(year) ? 366 : 365;
}
return after_elapse_days - prev_elapse_days;
}
static void second_add(RTC_TimeTypeDef * rtc_time, RTC_DateTypeDef * rtc_date, uint32_t seconds)
{
rtc_time->Seconds = rtc_time->Seconds + (seconds % 60U);
if (rtc_time->Seconds > 59U) {
rtc_time->Seconds = rtc_time->Seconds % 60;
rtc_time->Minutes = rtc_time->Minutes + 1;
}
rtc_time->Minutes = rtc_time->Minutes + (seconds / 60U % 60U);
if (rtc_time->Minutes > 59U) {
rtc_time->Minutes = rtc_time->Minutes % 60;
rtc_time->Hours = rtc_time->Hours + 1;
}
rtc_time->Hours = rtc_time->Hours + (seconds / 3600U % 24);
if (rtc_time->Hours > 23U) {
rtc_time->Hours = rtc_time->Hours % 24;
calendar_add(rtc_date, seconds / 3600U / 24U + 1U);
} else {
calendar_add(rtc_date, seconds / 3600U / 24U);
}
}
static uint32_t second_diff(RTC_DateTypeDef *after_date, RTC_TimeTypeDef *after_time,
RTC_DateTypeDef *prev_date, RTC_TimeTypeDef *prev_time)
{
uint32_t day_diff = calendar_diff(after_date, prev_date);
return day_diff * 3600 * 24 +
((int)(after_time->Hours) - (int)(prev_time->Hours)) * 3600 +
((int)(after_time->Minutes) - (int)(prev_time->Minutes)) * 60 +
(int)(after_time->Seconds) - (int)(prev_time->Seconds);
}
static void subsecond_add(RTC_TimeTypeDef * rtc_time, RTC_DateTypeDef * rtc_date, uint32_t ticks)
{
uint32_t alarm_subsec = ticks & RTC_PREDIV_S;
/* if underflowed, carry to second */
if (alarm_subsec > (rtc_time->SubSeconds & RTC_PREDIV_S)) {
second_add(rtc_time, rtc_date, ticks / (1 << RTC_N_PREDIV_S) + 1);
} else {
second_add(rtc_time, rtc_date, ticks / (1 << RTC_N_PREDIV_S));
}
rtc_time->SubSeconds -= alarm_subsec;
}
void lptimer_timestamp2localtime(const uint32_t timestamp, struct tm *localtime)
{
RTC_DateTypeDef rtc_date;
RTC_TimeTypeDef rtc_time;
rtc_date.Date = 1;
rtc_date.Month = 1;
rtc_date.Year = 0;
rtc_time.Seconds = 0;
rtc_time.Minutes = 0;
rtc_time.Hours = 0;
second_add(&rtc_time, &rtc_date, timestamp - SECOND_BETWEEN_1970_2000);
localtime->tm_sec = rtc_time.Seconds;
localtime->tm_min = rtc_time.Minutes;
localtime->tm_hour = rtc_time.Hours;
localtime->tm_mday = rtc_date.Date;
localtime->tm_mon = rtc_date.Month;
localtime->tm_year = rtc_date.Year + 100;
localtime->tm_isdst = -1;
}
uint32_t lptimer_localtime2timestamp(struct tm *localtime)
{
RTC_DateTypeDef prev_date;
RTC_TimeTypeDef prev_time;
RTC_DateTypeDef after_date;
RTC_TimeTypeDef after_time;
prev_date.Date = 1;
prev_date.Month = 1;
prev_date.Year = 0;
prev_time.Seconds = 0;
prev_time.Minutes = 0;
prev_time.Hours = 0;
after_time.Seconds = localtime->tm_sec;
after_time.Minutes = localtime->tm_min;
after_time.Hours = localtime->tm_hour;
after_date.Date = localtime->tm_mday;
after_date.Month = localtime->tm_mon;
after_date.Year = localtime->tm_year - 100;
return second_diff(&after_date, &after_time, &prev_date, &prev_time) + SECOND_BETWEEN_1970_2000;
}
void lptimer_set_timeout(uint32_t timeout)
{
RTC_TimeTypeDef rtcTime = {0};
RTC_DateTypeDef rtcDate = {0};
HAL_RTC_GetTime(&hrtc, &rtcTime, RTC_FORMAT_BIN);
HAL_RTC_GetDate(&hrtc, &rtcDate, RTC_FORMAT_BIN);
LOG_I("RTC: %u %u:%u:%u %u", rtcDate.Date, rtcTime.Hours, rtcTime.Minutes, rtcTime.Seconds, rtcTime.SubSeconds);
// when RTC work in mix mode, should need set RTC alarm add extra 1 second (equals RTC_PREDIV_S + 1
// tick), see RM0461 page 906: "SS can be larger than PREDIV_S only after a shift operation.
// In that case, the correct time/date is one second less than as indicated by RTC_TR/RTC_DR."
subsecond_add(&rtcTime, &rtcDate, timeout + RTC_PREDIV_S + 1);
/* USER CODE END TIMER_IF_StartTimer */
RTC_AlarmTypeDef sAlarm = {0};
/*Stop timer if one is already started*/
lptimer_stop();
/* starts timer*/
sAlarm.BinaryAutoClr = RTC_ALARMSUBSECONDBIN_AUTOCLR_NO;
sAlarm.AlarmMask = RTC_ALARMMASK_NONE;
sAlarm.AlarmSubSecondMask = RTC_ALARMSUBSECONDMASK_SS14_10;
sAlarm.AlarmTime = rtcTime;
sAlarm.AlarmDateWeekDay = rtcDate.Date;
sAlarm.AlarmDateWeekDaySel = RTC_ALARMDATEWEEKDAYSEL_DATE;
sAlarm.Alarm = RTC_ALARM_A;
if (HAL_RTC_SetAlarm_IT(&hrtc, &sAlarm, RTC_FORMAT_BIN) != HAL_OK)
{
Error_Handler();
}
// LOG_I("set next timeout: %u", timeout);
// LOG_I("ALARM: %u %u:%u:%u %u", rtcDate.Date, rtcTime.Hours, rtcTime.Minutes, rtcTime.Seconds, rtcTime.SubSeconds);
}
void lptimer_stop(void)
{
/* Clear RTC Alarm Flag */
__HAL_RTC_ALARM_CLEAR_FLAG(&hrtc, RTC_FLAG_ALRAF);
/* Disable the Alarm A interrupt */
HAL_RTC_DeactivateAlarm(&hrtc, RTC_ALARM_A);
/*overload RTC feature enable*/
hrtc.IsEnabled.RtcFeatures = UINT32_MAX;
}
