RTC - Timestamp when the RTC's power supply is VBAT.

[romybompart]

Posted on December 03, 2013 at 17:51

Hi everyone,

I am trying to figure out how make work the RTC timestamp feature when this peripheral is supplied by VBAT and when a Tamper detection occurs. And be sure about my RTC configuration , because the RTC is not keeping the time or is not running,when the power supply is turned off. I read this: ''A tamper detection event resets all backup registers (RTC_BKPxR).'' (RM0090Reference manual, Page 791). Sowhen a TAMPER event occurs, all backup data registers are erased. In this case, I am using the backup data register 0 to write a 0x32F2, thus when I turn on the power supply this data should be there at the moment to read the register data to tell the program '' HEY!, you don't have to configure me again'', but if a TAMPER event occurs this register is erased. Maybe it is happening. Question : What do you recommend me to solve it? Note: I have measure the signal in osc32_in and osc32_out whe the power supply is turned off and there is a 678 Khz wave. So the VBAT is supplying the RTC peripheral. My code:

/* The code in my .h */
#ifndef __USER_STM32F4xx_RTC_H
#define __USER_STM32F4xx_RTC_H
/* Uncomment the corresponding line to select the RTC Clock source */
#define RTC_CLOCK_SOURCE_LSE // LSE used as RTC source clock */
//#define RTC_CLOCK_SOURCE_LSI */ // LSI used as RTC source clock. The RTC Clock
#include <stm32f4xx_rtc.h>
#include <stm32f4xx_pwr.h>
#include <stm32f4xx_exti.h>
#include <stdio.h>
#include ''Uart_Hardware.h''
#define ALREADY_CONFIG 0x32F2
extern
void
User_RTC_TAMP1_Init(
void
);
static
void
User_RTC_Config(
void
);
static
void
User_TAMPER_Config(
void
);
static
void
Time_Config_first_time(
void
);
extern
void
RTC_TimeShow(
void
);
extern
void
RTC_DateShow(
void
);
extern
void
Usart_Set_Calendar_RTC(
void
);
#endif
/* The code in my .c*/
#include ''User_stm32f4xx_RTC.h''
RTC_InitTypeDef RTC_InitStructure;
RTC_TimeTypeDef RTC_TimeStructure;
RTC_DateTypeDef RTC_DateStructure;
__IO uint32_t SynchPrediv =0, AsynchPrediv =0;
char
RTC_Buffer[50];
/**
* @brief Configure the RTC peripheral with the Tamper feature at the beginning of its use
* @param None
* @retval None
*/
void
User_RTC_TAMP1_Init(
void
)
{
/*Declaring variables for Interruption configuration*/
NVIC_InitTypeDef NVIC_InitStructure;
EXTI_InitTypeDef EXTI_InitStructure;
/* Enable the PWR clock */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);
/* Allow access to RTC */
PWR_BackupAccessCmd(ENABLE);
/* Configure one bit for preemption priority */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
/*Clearing the RTC_IT_TAMP1 Flag*/
RTC_ClearITPendingBit(RTC_IT_TAMP1);
/* Enable The external line21 interrupt */
EXTI_ClearITPendingBit(EXTI_Line21);
EXTI_InitStructure.EXTI_Line = EXTI_Line21; 
/*The line 21 is connected to RTC Tamper and Time Stamp events*/
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt; 
/*Although there is an specific handler for TAMP_STAMP */
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);
/* Enable TAMPER IRQChannel */
NVIC_InitStructure.NVIC_IRQChannel = TAMP_STAMP_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
if
(RTC_ReadBackupRegister(RTC_BKP_DR0) != ALREADY_CONFIG)
{ 
/*RTC Configuring for the first time*/
User_RTC_Config();
/* Setting and configuring the time*/
Time_Config_first_time();
/*TAMPER Configuration for the first time*/
User_TAMPER_Config();
/*Write to the first RTC Backup Data Register the user flag ALREADY_CONFIG*/
RTC_WriteBackupRegister(RTC_BKP_DR0, ALREADY_CONFIG);
}
else
{
/* Check if the Power On Reset flag is set */
if
(RCC_GetFlagStatus(RCC_FLAG_PORRST) != RESET)
{
Usart_Send(
''\r\n Ocurrio un Power On Reset ....\n\r''
,USARTPC);
}
/* Check if the Pin Reset flag is set */
if
(RCC_GetFlagStatus(RCC_FLAG_PINRST) != RESET)
{
Usart_Send(
''\r\n Ocurrio un Reset Externo ....\n\r''
,USARTPC);
}
Usart_Send(
''\n\r No se requiere configurar RTC....\n\r''
,USARTPC);
/* Enable the RTC Clock */
RCC_RTCCLKCmd(ENABLE);
/* Wait for RTC APB registers synchronisation */
RTC_WaitForSynchro();
} 
/*Disabling the RTC ALARM*/
RTC_AlarmCmd(RTC_Alarm_A, DISABLE);
}
/**
* @brief Configure the RTC peripheral by selecting the clock source.
* @param None
* @retval None
*/
void
User_RTC_Config(
void
)
{
// /* 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);
SynchPrediv = 0xFF;
AsynchPrediv = 0x7F;
#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);
SynchPrediv = 0xFF;
AsynchPrediv = 0x7F;
#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();
}
/**
* @brief Configuration of Tamper 
* @param None
* @retval None
*/
void
User_TAMPER_Config(
void
)
{
/* Disable the Tamper 1 detection */
RTC_TamperCmd(RTC_Tamper_1, DISABLE);
/* Clear Tamper 1 pin Event(TAMP1F) pending flag */
RTC_ClearFlag(RTC_FLAG_TAMP1F);
/*Selecting PC13 as a Tamper pin*/
RTC_TamperPinSelection(RTC_TamperPin_PC13);
/* Precharge time*/
RTC_TamperPinsPrechargeDuration(RTC_TamperPrechargeDuration_4RTCCLK);
/* Configure the Tamper 1 Trigger */
RTC_TamperTriggerConfig(RTC_Tamper_1, RTC_TamperTrigger_RisingEdge);
/* Enable the Tamper interrupt */
RTC_ITConfig(RTC_IT_TAMP, ENABLE);
/* Clear Tamper 1 pin interrupt pending bit */
RTC_ClearITPendingBit(RTC_IT_TAMP1);
/* Enable The TimeStamp */
RTC_TimeStampOnTamperDetectionCmd(ENABLE); 
/* Enable the Tamper 1 detection */
RTC_TamperCmd(RTC_Tamper_1, ENABLE);
}
/**
* @brief Time Configuration
* @param None
* @retval None
*/
void
Time_Config_first_time(
void
)
{
/* Set the Time */
RTC_TimeStructure.RTC_Hours = 9;
RTC_TimeStructure.RTC_Minutes = 30;
RTC_TimeStructure.RTC_Seconds = 0;
/* Set the Date */
RTC_DateStructure.RTC_Month = RTC_Month_September;
RTC_DateStructure.RTC_Date = 22; 
RTC_DateStructure.RTC_Year = 13; 
RTC_DateStructure.RTC_WeekDay = RTC_Weekday_Friday; 
/* Calendar Configuration */
RTC_InitStructure.RTC_AsynchPrediv = AsynchPrediv;
RTC_InitStructure.RTC_SynchPrediv = SynchPrediv;
RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_12;
RTC_Init(&RTC_InitStructure);
/* Check on RTC init */
if
(RTC_Init(&RTC_InitStructure) == ERROR){Usart_Send(
''\n\r/!\\***** Falla al inicializar el RTC ********/!\\ \n\r''
,USARTPC);}
/* Set Current Time and Date */
if
(RTC_SetTime(RTC_Format_BCD, &RTC_TimeStructure) == ERROR){Usart_Send(
''\n\r/!\\***** Falla al setear el tiempo del RTC ********/!\\ \n\r''
,USARTPC);} 
if
(RTC_SetDate(RTC_Format_BCD, &RTC_DateStructure) == ERROR){Usart_Send(
''\n\r/!\\***** Falla al setear la fecha del RTC ********/!\\ \n\r''
,USARTPC);}
}
/**
* @brief Display the current time on the Hyperterminal.
* @param None
* @retval None
*/
void
RTC_TimeShow(
void
)
{
/* Get the current Time */
RTC_GetTime(RTC_Format_BIN, &RTC_TimeStructure);
sprintf(RTC_Buffer,
''\n\r El tiempo actual es : %0.2d:%0.2d:%0.2d \n\r''
, RTC_TimeStructure.RTC_Hours, RTC_TimeStructure.RTC_Minutes, RTC_TimeStructure.RTC_Seconds);
Usart_Send(RTC_Buffer,USARTPC);
}
/**
* @brief Display the current date on the Hyperterminal.
* @param None
* @retval None
*/
void
RTC_DateShow()
{
/* Get the current Time */
RTC_GetDate(RTC_Format_BIN, &RTC_DateStructure);
sprintf(RTC_Buffer,
''\n\r La Fecha es : %0.2d-%0.2d-%0.2d \n\r''
, RTC_DateStructure.RTC_Date, RTC_DateStructure.RTC_Month, RTC_DateStructure.RTC_Year);
Usart_Send(RTC_Buffer,USARTPC);
}

#vbat #stm32 #rtc #timestamp