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mbmail4
mbmail4
Associate III
August 27, 2016
Question

R/W to RTC backup registers

  • August 27, 2016
  • 2 replies
  • 1770 views
Posted on August 27, 2016 at 04:39

Hi.

I’m using an RTC example program from the CUBE F3

(STM32F3Nucleo)

download, and it work ok, except I cannot read or write to the RTC backup registers.

The example configures RTC as follows:

__HAL_RCC_PWR_CLK_ENABLE();

HAL_PWR_EnableBkUpAccess();

__HAL_RCC_RTC_ENABLE();

When I try to read and write to the backup registers, I cannot read back what I have previously written.

HAL_RTCEx_BKUPWrite(&RtcHandle, RTC_BKP_DR1, 0x32F2);

HAL_RTCEx_BKUPRead(&RtcHandle, RTC_BKP_DR1);

Even if I precede the read and or write with:

__HAL_RCC_PWR_CLK_ENABLE();

HAL_PWR_EnableBkUpAccess();

Any ideas?

Martin.

    This topic has been closed for replies.

    2 replies

    sunny
    sunny
    Associate III
    August 29, 2016
    Posted on August 29, 2016 at 05:49

    Hi,

    This might be happening because your RTC Oscillator Type and RTC Peripheral Clock might not be configured.

    Try to call the HAL_RTC_MspInit() and then perform RTC Read/Write.

    This should take care.

    Regards,

    Sunny

    mbmail4
    mbmail4Author
    Associate III
    September 6, 2016
    Posted on September 06, 2016 at 02:52

    Hi Sunny.

    I'm using the Nucleo board, and so far I cant seem to get the external 32khz clock to work. Most of the code I'm using has come from CUBE.

    I changed to external clock as below, but it wont start.  

    PeriphClkInit.

    RTCClockSelection

    = RCC_RTCCLKSOURCE_LSE;

    All my work so far has been with clock source set to RCC_RTCCLKSOURCE_LSI at 40khz.

    Within the RTC_MspInit() function I call:

    __HAL_RCC_PWR_CLK_ENABLE();

    HAL_PWR_EnableBkUpAccess();

    __HAL_RCC_RTC_ENABLE();

    and my sys clock config function is below: Sorry for the edits, blame ST.

    void

    SystemClock_Config(

    void

    )

    {

    RCC_OscInitTypeDef

    RCC_OscInitStruct;

    RCC_ClkInitTypeDef

    RCC_ClkInitStruct;

    RCC_PeriphCLKInitTypeDef

    PeriphClkInit;

    RCC_OscInitStruct.

    OscillatorType

    = RCC_OSCILLATORTYPE_LSI|RCC_OSCILLATORTYPE_HSE;

    RCC_OscInitStruct.

    HSEState

    = RCC_HSE_BYPASS;

    RCC_OscInitStruct.

    LSIState

    = RCC_LSI_ON;

    RCC_OscInitStruct.

    PLL

    .

    PLLState

    = RCC_PLL_ON;

    RCC_OscInitStruct.

    PLL

    .

    PLLSource

    = RCC_PLLSOURCE_HSE;

    RCC_OscInitStruct.

    PLL

    .

    PLLMUL

    = RCC_PLL_MUL9;

    RCC_OscInitStruct.

    PLL

    .

    PREDIV

    = RCC_PREDIV_DIV1;

    if

    (HAL_RCC_OscConfig(&RCC_OscInitStruct) !=

    HAL_OK

    )

    {

    Error_Handler();

    }

    RCC_ClkInitStruct.

    ClockType

    = RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_SYSCLK |

    RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2;

    RCC_ClkInitStruct.

    SYSCLKSource

    = RCC_SYSCLKSOURCE_PLLCLK;

    RCC_ClkInitStruct.

    AHBCLKDivider

    = RCC_SYSCLK_DIV1;

    RCC_ClkInitStruct.

    APB1CLKDivider

    = RCC_HCLK_DIV2;

    RCC_ClkInitStruct.

    APB2CLKDivider

    = RCC_HCLK_DIV1;

    if

    (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) !=

    HAL_OK

    )

    {

    Error_Handler();

    }

    PeriphClkInit.

    PeriphClockSelection

    = RCC_PERIPHCLK_USB | RCC_PERIPHCLK_USART1 |

    RCC_PERIPHCLK_USART2 | RCC_PERIPHCLK_USART3 |

    RCC_PERIPHCLK_RTC;

    PeriphClkInit.

    Usart1ClockSelection

    = RCC_USART1CLKSOURCE_PCLK2;

    PeriphClkInit.

    Usart2ClockSelection

    = RCC_USART2CLKSOURCE_PCLK1;

    PeriphClkInit.

    Usart3ClockSelection

    = RCC_USART3CLKSOURCE_PCLK1;

    PeriphClkInit.

    RTCClockSelection

    = RCC_RTCCLKSOURCE_LSI;

    PeriphClkInit.

    USBClockSelection

    = RCC_USBCLKSOURCE_PLL_DIV1_5;

    if

    (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) !=

    HAL_OK

    )

    {

    Error_Handler();

    }

    HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq() / 1000);

    HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);

    /* SysTick_IRQn interrupt configuration */

    HAL_NVIC_SetPriority(

    SysTick_IRQn

    , 0, 0);

    }

    static

    void

    MX_RTC_Init(

    void

    )

    {

    RTC_TimeTypeDef

    sTime;

    RTC_DateTypeDef

    sDate;

    RTC_AlarmTypeDef

    sAlarm;

    RTC_TamperTypeDef

    sTamper;

    /**Initialize RTC and set the Time and Date

    */

    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

    .

    OutPutPolarity

    = RTC_OUTPUT_POLARITY_HIGH;

    hrtc.

    Init

    .

    OutPutType

    = RTC_OUTPUT_TYPE_OPENDRAIN;

    if

    (HAL_RTC_Init(&hrtc) !=

    HAL_OK

    )

    {

    Error_Handler();

    }

    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

    = 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_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();

    }

    /**Enable the Alarm B

    */

    sAlarm.

    AlarmDateWeekDay

    = 0x1;

    sAlarm.

    Alarm

    = RTC_ALARM_B;

    if

    (HAL_RTC_SetAlarm(&hrtc, &sAlarm, RTC_FORMAT_BCD) !=

    HAL_OK

    )

    {

    Error_Handler();

    }

    /**Enable the WakeUp

    */

    if

    (HAL_RTCEx_SetWakeUpTimer(&hrtc, 0, RTC_WAKEUPCLOCK_RTCCLK_DIV16) !=

    HAL_OK

    )

    {

    Error_Handler();

    }

    /**Enable the RTC Tamper 2

    */

    sTamper.

    Tamper

    = RTC_TAMPER_2;

    sTamper.

    Trigger

    = RTC_TAMPERTRIGGER_RISINGEDGE;

    sTamper.

    Filter

    = RTC_TAMPERFILTER_DISABLE;

    sTamper.

    SamplingFrequency

    = RTC_TAMPERSAMPLINGFREQ_RTCCLK_DIV32768;

    sTamper.

    PrechargeDuration

    = RTC_TAMPERPRECHARGEDURATION_1RTCCLK;

    sTamper.

    TamperPullUp

    = RTC_TAMPER_PULLUP_ENABLE;

    sTamper.

    TimeStampOnTamperDetection

    = RTC_TIMESTAMPONTAMPERDETECTION_ENABLE;

    if

    (HAL_RTCEx_SetTamper(&hrtc, &sTamper) !=

    HAL_OK

    )

    {

    Error_Handler();

    }

    }

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