Is the problem caused because sAlarm.AlarmTime.Seconds is reset when shutdown ?
For test purposes, I am using the following settings:
- RTC Wakeup Timer set to 5 seconds
- RTC Alarm set to 30 seconds
The MCU runs for 10 seconds, then shuts down for 5 seconds using the functions:
- HAL_RTCEx_SetWakeUpTimer_IT(&hrtc, 5, RTC_WAKEUPCLOCK_CK_SPRE_16BITS);
- HAL_PWREx_EnterSHUTDOWNMode)
When the MCU wakes, sAlarm.AlarmTime.Seconds is zero, so I have to set it back to 0x30 (should it be 0x30 or decimal 30, I'm not sure because its BCD ?).
The diagram below explains what I think might be happening, it should fully shut down and not wake again when the alarm is reached (30 seconds). But maybe it doesn't because sAlarm.AlarmTime.Seconds is reset when shutdown. ?
The application is battery powered and once manually switched on, it is supposed to read a pressure sensor every few minutes then shutdown between each measurement.
After 12 hours of being switched on, it is supposed to permanently shutdown and not wake again until switched manually on again.
I am using shorter times for test purposed, the 5 second shutdown and wake for 10 seconds works.
But the permanent shutdown (set by sAlarm.AlarmTime) is not working.
I have either implemted this wrong or it is not possible ?
I only initialize the RTC once, because I check if the MCU was woken by the RTC as follows...
if (__HAL_PWR_GET_FLAG(PWR_FLAG_SB)) {
// Woke from standby
__HAL_PWR_CLEAR_FLAG(PWR_FLAG_SB);
}
else
{
MX_RTC_Init();
}
I set a breakpoint on the line MX_RTC_Init() and the breakpoint is only hit on the first startup. When the RTC wakes the MCU, the breakpoint is not hit.
The diagram below shows the behavior I expect...
The diagram below shows what is actually happening, with the following observations made...
- shutdownRun called at 25 seconds, but it does not shutdown and continues running
- shutdownFull is not called at 30 seconds (sAlarm.AlarmTime.Seconds was set to 0x30)
- sAlarm.AlarmTime.Seconds is reset when woken by the RTC
- is this not to be expected as when the MCU is shutdown all variables are lost, so how is this supposed to be handled ?
The diagram below shows the alarm works if I don't shutdown with RTC wake...
Below is the main code...
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_DMA_Init();
MX_DAC1_Init();
MX_TIM6_Init();
MX_SPI2_Init();
MX_LPUART1_UART_Init();
MX_SPI1_Init();
MX_I2C1_Init();
MX_USART3_UART_Init();
MX_ADC1_Init();
MX_TIM7_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
if (__HAL_PWR_GET_FLAG(PWR_FLAG_SB)) {
// Woke from shutdown
__HAL_PWR_CLEAR_FLAG(PWR_FLAG_SB);
}
else
{
MX_RTC_Init();
}
Enable_PC13_EXTI(); // enable power switch wake up
HAL_RTCEx_SetWakeUpTimer_IT(&hrtc, 5, RTC_WAKEUPCLOCK_CK_SPRE_16BITS); // enable RTC wake up
while (1) {
HAL_Delay(10000);
shutdownRun();
if (flgReqShudownFull){
shutdownFull();
}
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
Below is the RTC init function (only called once)...
static void MX_RTC_Init(void)
{
/* USER CODE BEGIN RTC_Init 0 */
/* USER CODE END RTC_Init 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 = 127;
hrtc.Init.SynchPrediv = 255;
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;
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;
sTime.Seconds = 0x0;
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_MONDAY;
sDate.Month = RTC_MONTH_JANUARY;
sDate.Date = 0x1;
sDate.Year = 0x0;
if (HAL_RTC_SetDate(&hrtc, &sDate, RTC_FORMAT_BCD) != HAL_OK)
{
Error_Handler();
}
/** Enable the Alarm A
*/
sAlarm.AlarmTime.Hours = 0x0;
sAlarm.AlarmTime.Minutes = 0x0;
sAlarm.AlarmTime.Seconds = 0x30;
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_ALL;
sAlarm.AlarmDateWeekDaySel = RTC_ALARMDATEWEEKDAYSEL_DATE;
sAlarm.AlarmDateWeekDay = 0x1;
sAlarm.Alarm = RTC_ALARM_A;
if (HAL_RTC_SetAlarm(&hrtc, &sAlarm, RTC_FORMAT_BCD) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN RTC_Init 2 */
/* USER CODE END RTC_Init 2 */
}
Below is the shutdownRun function...
void shutdownRun (void){
/* Disable all used wakeup sources*/
HAL_RTCEx_DeactivateWakeUpTimer(&hrtc);
HAL_RTCEx_SetWakeUpTimer_IT(&hrtc, 5, RTC_WAKEUPCLOCK_CK_SPRE_16BITS);
/* Clear all related wakeup flags */
__HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);
/* Enter the shutdown mode */
HAL_PWREx_EnterSHUTDOWNMode();
}
Below is the shutdownFull function...
void shutdownFull (void){
HAL_RTCEx_DeactivateWakeUpTimer(&hrtc); // disable RTC wakeup
Enable_PC13_Wakeup();
HAL_PWREx_EnterSHUTDOWNMode();
}
Below is the RTC alarm interrupt, I set a breakpoint here but it never hits...
void HAL_RTC_AlarmAEventCallback(RTC_HandleTypeDef *hrtc) {
flgReqShudownFull = 1;
}
