About RTC in sleep mode

[j_m]

We are developing a device that periodically boots in Sleep mode using the STM32G04.
Set the WakeUpTime with HAL_RTCEx_SetWakeUpTimer_IT and enter Sleep with HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);.
If you make a program to Sleep for 10 minutes, the RTC time is the same before and after startup and the RTC is not counting during Sleep.
The time in Sleep is set to 10 minutes, but even if I do HAL_RTC_GetTime, the value is the same before Sleep and after Sleep.
Is it possible to make it so that the RTC is updated during Sleep?

[Stassen.C]

Hello J_m,

First of all I can see that you are entering stop mode rather than sleep mode with HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);

In this case I would like to know how you clocked your RTC please?

Regards,
Stassen 

[j_m]

Hello Stassen

I would like to use the STOP mode.
I want to see how much time has passed before entering STOP mode and after wake up.

[Stassen.C]

Hello J_m,

In this case i suggest you:
- clock your RTC with the LSE
- Before going into stop mode, read the RTC counter value
- Enter STOP mode
- Upon wakeup you read the RTC counter value

Note that in stop mode all clocks are switched off except the LSE/LSI.

Hope this helps.

Regards,
Stassen

[j_m]

Hello Stassen

Thanks.
Is the following code sufficient to set up the RTC to run on LSE?

void SystemClock_Config(void)

{

    RCC_OscInitTypeDef RCC_OscInitStruct = { 0 };

    RCC_ClkInitTypeDef RCC_ClkInitStruct = { 0 };

    /** Configure the main internal regulator output voltage

     */

    HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1);

    /** Configure LSE Drive Capability

     */

    HAL_PWR_EnableBkUpAccess();

    __HAL_RCC_LSEDRIVE_CONFIG(RCC_LSEDRIVE_LOW);

    /** Initializes the RCC Oscillators according to the specified parameters

     * in the RCC_OscInitTypeDef structure.

     */

    RCC_OscInitStruct.OscillatorType      = RCC_OSCILLATORTYPE_HSI | RCC_OSCILLATORTYPE_LSE;

    RCC_OscInitStruct.LSEState            = RCC_LSE_ON;

    RCC_OscInitStruct.HSIState            = RCC_HSI_ON;

    RCC_OscInitStruct.HSIDiv              = RCC_HSI_DIV1;

    RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;

    RCC_OscInitStruct.PLL.PLLState        = RCC_PLL_NONE;

    if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {

        Error_Handler();

    }

    /** Initializes the CPU, AHB and APB buses clocks

     */

    RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_SYSCLK

                                  | RCC_CLOCKTYPE_PCLK1;

    RCC_ClkInitStruct.SYSCLKSource   = RCC_SYSCLKSOURCE_HSI;

    RCC_ClkInitStruct.AHBCLKDivider  = RCC_SYSCLK_DIV1;

    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

    if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK) {

        Error_Handler();

    }

}

static 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 };

    /* 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;

    hrtc.Init.OutPutPullUp   = RTC_OUTPUT_PULLUP_NONE;

    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          = 0;

    sTime.Minutes        = 0;

    sTime.Seconds        = 0;

    sTime.SubSeconds     = 0;

    sTime.DayLightSaving = RTC_DAYLIGHTSAVING_NONE;

    sTime.StoreOperation = RTC_STOREOPERATION_RESET;

    if (HAL_RTC_SetTime(&hrtc, &sTime, RTC_FORMAT_BIN) != HAL_OK) {

        Error_Handler();

    }

    sDate.WeekDay = RTC_WEEKDAY_MONDAY;

    sDate.Month   = RTC_MONTH_JANUARY;

    sDate.Date    = 1;

    sDate.Year    = 0;

    if (HAL_RTC_SetDate(&hrtc, &sDate, RTC_FORMAT_BIN) != HAL_OK) {

        Error_Handler();

    }

    /** Enable the WakeUp

     */

    if (HAL_RTCEx_SetWakeUpTimer_IT(&hrtc, 0, RTC_WAKEUPCLOCK_CK_SPRE_16BITS) != HAL_OK) {

        Error_Handler();

    }

    /* USER CODE BEGIN RTC_Init 2 */

    /* USER CODE END RTC_Init 2 */

}

[Stassen.C]

J_m,

That should do it, just check that in the HAL_RTC_MspInit the clock selection is also LSE. 

Regards,
Stassen

[j_m]

Thank you very much.
I can confirm that the RTC is updated.