STM32F4XX RTC calendar can not be configured

[sanmingx]

Posted on May 01, 2015 at 01:45

When system boots up, RTC is initialized and could be configured with success, but any calendar configuration afterward will always fail with ''  if (RTC_EnterInitMode() == ERROR)'' in RTC_SetTime() standard API.

When system boots up, below code is called //-------------------------------------------------------------------------------

void Rtc::open()

{  // Enable the Power Controller APB1  // interface clock  /* Enable PWR peripheral clock */   uint32_t status;  uint8_t stat = 1;

 RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE); /* Allow access to BKP Domain */ 

 PWR_BackupAccessCmd(ENABLE);

 status = RTC_ReadBackupRegister(RTC_BKP_DR19);

   // Power up and wait until LSI is ready  RCC_LSICmd(ENABLE);  while(RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET)  {  }

 // Select the RTC Clock Source

 RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI);

 // Enable the RTC Clock

 RCC_RTCCLKCmd(ENABLE);

 RTC_WaitForSynchro();

 //RTC_WriteBackupRegister(RTC_BKP_DR0, 0x32F2);

 RTC_WriteBackupRegister(RTC_BKP_DR19, 0x1234);

 RTC_WaitForSynchro();

 RTC_ClearITPendingBit(RTC_IT_WUT);

 EXTI_ClearITPendingBit(EXTI_Line22); } //------------------------------------ Configure calendar ---------------

void Rtc::write(TimeDateStruct idateTime)

{      RTC_SetTime(RTC_Format_BIN, &idateTime.time); } as you can see, RTC_SetTime is standard API from lib as below, it stops on line ''if (RTC_EnterInitMode() == ERROR)'' of ''INITF'' flag timeout. Please help this issue, thanks

ErrorStatus RTC_SetTime(uint32_t RTC_Format, RTC_TimeTypeDef* RTC_TimeStruct)

{   uint32_t tmpreg = 0;   ErrorStatus status = ERROR;       /* Check the parameters */   assert_param(IS_RTC_FORMAT(RTC_Format));     if (RTC_Format == RTC_Format_BIN)   {     if ((RTC->CR & RTC_CR_FMT) != (uint32_t)RESET)     {       assert_param(IS_RTC_HOUR12(RTC_TimeStruct->RTC_Hours));       assert_param(IS_RTC_H12(RTC_TimeStruct->RTC_H12));     }     else     {       RTC_TimeStruct->RTC_H12 = 0x00;       assert_param(IS_RTC_HOUR24(RTC_TimeStruct->RTC_Hours));     }     assert_param(IS_RTC_MINUTES(RTC_TimeStruct->RTC_Minutes));     assert_param(IS_RTC_SECONDS(RTC_TimeStruct->RTC_Seconds));   }   else   {     if ((RTC->CR & RTC_CR_FMT) != (uint32_t)RESET)     {       tmpreg = RTC_Bcd2ToByte(RTC_TimeStruct->RTC_Hours);       assert_param(IS_RTC_HOUR12(tmpreg));       assert_param(IS_RTC_H12(RTC_TimeStruct->RTC_H12));     }     else     {       RTC_TimeStruct->RTC_H12 = 0x00;       assert_param(IS_RTC_HOUR24(RTC_Bcd2ToByte(RTC_TimeStruct->RTC_Hours)));     }     assert_param(IS_RTC_MINUTES(RTC_Bcd2ToByte(RTC_TimeStruct->RTC_Minutes)));     assert_param(IS_RTC_SECONDS(RTC_Bcd2ToByte(RTC_TimeStruct->RTC_Seconds)));   }     /* Check the input parameters format */   if (RTC_Format != RTC_Format_BIN)   {     tmpreg = (((uint32_t)(RTC_TimeStruct->RTC_Hours) << 16) | \              ((uint32_t)(RTC_TimeStruct->RTC_Minutes) << 😎 | \              ((uint32_t)RTC_TimeStruct->RTC_Seconds) | \              ((uint32_t)(RTC_TimeStruct->RTC_H12) << 16));   }    else   {     tmpreg = (uint32_t)(((uint32_t)RTC_ByteToBcd2(RTC_TimeStruct->RTC_Hours) << 16) | \                    ((uint32_t)RTC_ByteToBcd2(RTC_TimeStruct->RTC_Minutes) << 😎 | \                    ((uint32_t)RTC_ByteToBcd2(RTC_TimeStruct->RTC_Seconds)) | \                    (((uint32_t)RTC_TimeStruct->RTC_H12) << 16));   } 

  /* Disable the write protection for RTC registers */

  RTC->WPR = 0xCA;   RTC->WPR = 0x53;

  /* Set Initialization mode */

  if (RTC_EnterInitMode() == ERROR)   {     status = ERROR;   }   else   {     /* Set the RTC_TR register */     RTC->TR = (uint32_t)(tmpreg & RTC_TR_RESERVED_MASK);

    /* Exit Initialization mode */

    RTC_ExitInitMode();

    /* If  RTC_CR_BYPSHAD bit = 0, wait for synchro else this check is not needed */

    if ((RTC->CR & RTC_CR_BYPSHAD) == RESET)     {     if(RTC_WaitForSynchro() == ERROR)     {       status = ERROR;     }     else     {       status = SUCCESS;     }   }     else     {       status = SUCCESS;     }   }   /* Enable the write protection for RTC registers */   RTC->WPR = 0xFF;       return status; }

[Tesla DeLorean]

Posted on May 01, 2015 at 03:22

Make sure you reset the RTC if it gets into an unknown state, and that clocks are enabled.

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[sanmingx]

Posted on May 05, 2015 at 20:48

Hello, Clivel

I did try to reset the RTC by calling ''RCC_BackupResetCmd(ENABLE); RCC_BackupResetCmd(DISABLE)'' followed when '' RTC_EnterInitMode() == ERROR'' occurred, it seemed not fix my issue at all. Is it the right way to reset RTC? the clock is sourced with LSI, with no external battery, the Vbatt is 3.3 V, I guess it is good.

[engenharia2]

Posted on January 14, 2016 at 15:12

Hi xiang.sanming, I have the same problem using the HAL Library. Do you got a solution to fix this problem? Thank you!

[Tesla DeLorean]

Posted on January 14, 2016 at 19:19

I'm not sure someone who participated for 2 posts, 8 months ago, using the SPL, is going to be at all useful with your HAL issues.

See if there is anything useful you can gleen from the cited thread.