How to keep date and time after shut down power in STM32F429iDisco?

[Linda]

Posted on June 10, 2015 at 23:34

Hi,

We want to add a cell battery to keep time and date. but in the schemaitcs, Pin 1 and Pin 6 in STM32F429iDisco for VBAT alredy connect to +3V.What we can do?Thanks a lot

[waclawek.jan]

Posted on June 11, 2015 at 16:20

See UM1670, 4.11.2 OSC 32 KHz clock supply, ''Oscillator on board (from X2 Crystal)''

JW

[Tesla DeLorean]

Posted on June 11, 2015 at 16:37

Yes, PC14/15, needs to be a 6pF crystal, check the BOM

ST commonly uses the EPSON 32.768KHz 6pF part (formerly JFVNY)

http://uk.mouser.com/ProductDetail/Epson-Timing/MC-306-327680K-E3ROHS/?qs=CU9taR8hkvbntLhqKVy/5g%3D%3D

You should review thoroughly the available documentation, or have your design engineer do so.6.8pF capacitors at C23,C240 Ohm resistors at R53, R54Open SB16,SB17

[Linda]

Posted on June 12, 2015 at 02:57

Dear Sir,

I have soldered those parts on the PCB, but no matter I open or close SB 16 and SB17, the time has not been updated.What is wrong? Do I need to do anything in coding/program? Why I need to open SB16/SB17, after open them, the crystal connects to no where.Thanks

[Tesla DeLorean]

Posted on June 12, 2015 at 05:13

Doesn't the SB just disconnect the STM32 from the pin header? This is done so the leads to the crystal a very short.

You should enable the LSE, and check that it starts and oscillates correctly.You would need to select it as a source for the RTC.You'd need to place the device in STANDBY, and make sure the code detects a reset out of standby, and not completely reinitialize the RTC. You could set the alarm to periodically exit standby, or use wakeup.

[Linda]

Posted on June 13, 2015 at 14:10

If I put the device on

  standby mode, the LCD is on, it take a lot of battery. how to shut of LCD?

Thanks

[Tesla DeLorean]

Posted on June 13, 2015 at 18:56

It's not designed to do that, you'd need to gate the primary supply at the regulator, probably.

It sounds like you need to design a custom board with the feature set you require.

[Linda]

Posted on June 14, 2015 at 15:09

I tried to put the device on STOP mode. But it can not wake up. Here is code I use:

int8_t RTC_Configuration(void){ RTC_Error = 0;  EXTI_InitTypeDef  EXTI_InitStructure;  NVIC_InitTypeDef  NVIC_InitStructure;   /* Enable the PWR clock */  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);  /* Allow access to RTC */  PWR_BackupAccessCmd(ENABLE);#if defined (RTC_CLOCK_SOURCE_LSI)  /* LSI used as RTC source clock*//* The RTC Clock may varies due to LSI frequency dispersion. */     /* Enable the LSI OSC */   RCC_LSICmd(ENABLE);  /* Wait till LSI is ready */    while(RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET)  {  }  /* Select the RTC Clock Source */  RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI);#elif defined (RTC_CLOCK_SOURCE_LSE) /* LSE used as RTC source clock */  /* Enable the LSE OSC */  RCC_LSEConfig(RCC_LSE_ON);  /* Wait till LSE is ready */    while(RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET)  {  }  /* Select the RTC Clock Source */  RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);#else  #error Please select the RTC Clock source inside the main.c file#endif /* RTC_CLOCK_SOURCE_LSI */  /* Enable the RTC Clock */  RCC_RTCCLKCmd(ENABLE);  /* Wait for RTC APB registers synchronisation */  RTC_WaitForSynchro();  /* RTC Wakeup Interrupt Generation: Clock Source: RTCCLK_Div16, Wakeup Time Base: ~4s     Wakeup Time Base = (16 / (LSE or LSI)) * WakeUpCounter  */  RTC_WakeUpClockConfig(RTC_WakeUpClock_RTCCLK_Div16);  RTC_SetWakeUpCounter(0x1FFF);  /* Enable the Wakeup Interrupt */  RTC_ITConfig(RTC_IT_WUT, ENABLE);  /* Connect EXTI_Line22 to the RTC Wakeup event */  EXTI_ClearITPendingBit(EXTI_Line22);  EXTI_InitStructure.EXTI_Line = EXTI_Line22;  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;  EXTI_InitStructure.EXTI_LineCmd = ENABLE;  EXTI_Init(&EXTI_InitStructure);   /* Enable the RTC Wakeup Interrupt */  NVIC_InitStructure.NVIC_IRQChannel = RTC_WKUP_IRQn;  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;  NVIC_Init(&NVIC_InitStructure);   /* Calendar Configuration with LSI supposed at 32KHz */  RTC_InitStructure.RTC_AsynchPrediv = 0x7F;  RTC_InitStructure.RTC_SynchPrediv =  0xFF; /* (32KHz / 128) - 1 = 0xFF*/  RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24;  RTC_Init(&RTC_InitStructure);    /* Get the LSI frequency:  TIM5 is used to measure the LSI frequency */  LsiFreq = GetLSIFrequency();  /* Adjust LSI Configuration */  RTC_InitStructure.RTC_AsynchPrediv = 0x7F;  RTC_InitStructure.RTC_SynchPrediv =  (LsiFreq/128) - 1;  RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24;  RTC_Init(&RTC_InitStructure);  return RTC_Error;}static void SYSCLKConfig_STOP(void){  /* After wake-up from STOP reconfigure the system clock */  /* Enable HSE */  RCC_HSEConfig(RCC_HSE_ON);  /* Wait till HSE is ready */  while (RCC_GetFlagStatus(RCC_FLAG_HSERDY) == RESET)  {  }    /* Enable PLL */  RCC_PLLCmd(ENABLE);   /* Wait till PLL is ready */  while (RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)  {  }    /* Select PLL as system clock source */  RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);  /* Wait till PLL is used as system clock source */  while (RCC_GetSYSCLKSource() != 0x08)  {  }}main {  STM_EVAL_PBInit(BUTTON_USER, BUTTON_MODE_EXTI);  while (1)  {    /* Insert 5 second delay */    GUI_Delay(5000);    /* Turn OFF LED4 */    STM_EVAL_LEDOff(LED4);    /* Enable Wakeup Counter */    RTC_WakeUpCmd(ENABLE);    /* Enter Stop Mode */    PWR_EnterSTOPMode(PWR_Regulator_LowPower, PWR_STOPEntry_WFI);     /* Disable Wakeup Counter */    RTC_WakeUpCmd(DISABLE);    /* Configures system clock after wake-up from STOP: enable HSE, PLL and select        PLL as system clock source (HSE and PLL are disabled in STOP mode) */    SYSCLKConfig_STOP();  }}

[Tesla DeLorean]

Posted on June 14, 2015 at 16:00

You might want to work on a more linear initialization sequence.

Measure the frequency after the LSI starts, then init the RTC (once), the init the WakeUp (after).

[Linda]

Posted on June 14, 2015 at 18:03

Check the LED3 and LED4, it seems wake up. just can not go back where it was. 

Then I tried add these code following, then it can not wake up.: JumpAddress = *(__IO uint32_t*) (0x08000000 + 4); Jump_To_Application = (pFunction) JumpAddress; __set_MSP(*(__IO uint32_t*) 0x08000000); Jump_To_Application();It becomce like that, then it can not wake up.static void SYSCLKConfig_STOP(void){  /* After wake-up from STOP reconfigure the system clock */  /* Enable HSE */  RCC_HSEConfig(RCC_HSE_ON);    /* Wait till HSE is ready */  while (RCC_GetFlagStatus(RCC_FLAG_HSERDY) == RESET)  {  }    /* Enable PLL */  RCC_PLLCmd(ENABLE);    /* Wait till PLL is ready */  while (RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)  {  }    /* Select PLL as system clock source */  RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);    /* Wait till PLL is used as system clock source */  while (RCC_GetSYSCLKSource() != 0x08)  {  } JumpAddress = *(__IO uint32_t*) (0x08000000 + 4); Jump_To_Application = (pFunction) JumpAddress; __set_MSP(*(__IO uint32_t*) 0x08000000); Jump_To_Application();};

[Linda]

Posted on August 20, 2015 at 17:26

Dear Sir,

I still can not make the LSE work, I can not detect any signal from the crystal. static void RTC_Config(void){  EXTI_InitTypeDef  EXTI_InitStructure;  NVIC_InitTypeDef  NVIC_InitStructure;   /* Enable the PWR clock */  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);  /* Allow access to RTC */  PWR_BackupAccessCmd(ENABLE);//#if defined (RTC_CLOCK_SOURCE_LSI)  /* LSI used as RTC source clock*////* The RTC Clock may varies due to LSI frequency dispersion. */   //  /* Enable the LSI OSC */ //  RCC_LSICmd(ENABLE); RCC_LSICmd(DISABLE);//  /* Wait till LSI is ready */  //  while(RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET)//  {//  }//  /* Select the RTC Clock Source *///  RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI);//  //#elif defined (RTC_CLOCK_SOURCE_LSE) /* LSE used as RTC source clock */  /* Enable the LSE OSC */  RCC_LSEConfig(RCC_LSE_ON);  /* Wait till LSE is ready */    while(RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET)  {  }  /* Select the RTC Clock Source */  RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);//#else////  #error Please select the RTC Clock source inside the main.c file//#endif /* RTC_CLOCK_SOURCE_LSI */    /* Enable the RTC Clock */  RCC_RTCCLKCmd(ENABLE);  /* Wait for RTC APB registers synchronisation */  RTC_WaitForSynchro();  /* RTC Wakeup Interrupt Generation: Clock Source: RTCCLK_Div16, Wakeup Time Base: ~4s     Wakeup Time Base = (16 / (LSE or LSI)) * WakeUpCounter  */  RTC_WakeUpClockConfig(RTC_WakeUpClock_RTCCLK_Div16);  RTC_SetWakeUpCounter(0x1FFF);  /* Enable the Wakeup Interrupt */  RTC_ITConfig(RTC_IT_WUT, ENABLE);  /* Connect EXTI_Line22 to the RTC Wakeup event */  EXTI_ClearITPendingBit(EXTI_Line22);  EXTI_InitStructure.EXTI_Line = EXTI_Line22;  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;  EXTI_InitStructure.EXTI_LineCmd = ENABLE;  EXTI_Init(&EXTI_InitStructure);    /* Enable the RTC Wakeup Interrupt */  NVIC_InitStructure.NVIC_IRQChannel = RTC_WKUP_IRQn;  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;  NVIC_Init(&NVIC_InitStructure);}