Posted on October 05, 2013 at 17:36
Hi all,
I need a bit help, since I can't get the RTC based on LSI making a robust timer.
I try to generate an interrupt every 10 seconds.
Here the code that concerns the RTC :
void main(void)
{
EXTI_Configuration();
RTC_Configuration();
NVIC_Configuration();
RTC_SetAlarm(RTC_GetCounter()+ 1);
RTC_WaitForLastTask();
/* Start IT */
while(1)
{
PWR_EnterSTOPMode(PWR_Regulator_LowPower, PWR_STOPEntry_WFI);
}
}
void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
/* Configure the NVIC Preemption Priority Bits */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
NVIC_InitStructure.NVIC_IRQChannel = RTCAlarm_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
void EXTI_Configuration(void)
{
EXTI_InitTypeDef EXTI_InitStructure;
/* Configure EXTI Line17(RTC Alarm) to generate an interrupt on rising edge */
EXTI_ClearITPendingBit(EXTI_Line17);
EXTI_InitStructure.EXTI_Line = EXTI_Line17;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);
}
void RTC_Configuration(void)
{
/* Enable PWR and BKP clocks */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);
/* Allow access to BKP Domain */
PWR_BackupAccessCmd(ENABLE);
/* Reset Backup Domain */
BKP_DeInit();
/* 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);
/* Enable RTC Clock */
RCC_RTCCLKCmd(ENABLE);
/* Wait for RTC registers synchronization */
RTC_WaitForSynchro();
/* Set RTC prescaler: set RTC period to 1sec */
RTC_SetPrescaler(40000);
/* Wait until last write operation on RTC registers has finished */
RTC_WaitForLastTask();
/* Enable the RTC Alarm interrupt */
RTC_ITConfig(RTC_IT_ALR, ENABLE);
/* Wait until last write operation on RTC registers has finished */
RTC_WaitForLastTask();
}
void RTCAlarm_IRQHandler(void)
{
if(RTC_GetITStatus(RTC_IT_ALR) != RESET)
{
/* Clear RTC Alarm interrupt pending bit */
RTC_ClearITPendingBit(RTC_IT_ALR);
/* Wait until last write operation on RTC registers has finished */
RTC_WaitForLastTask();
/* Alarm in 3 second */
RTC_SetAlarm(RTC_GetCounter()+ 10);
if (GPIOB->ODR & LCD_BL)
{
GPIOB->BRR = LCD_BL;
}
else
{
GPIOB->BSRR = LCD_BL;
}
G_SEQ_Timestamp += 10;
/* Clear EXTI line17 pending bit */
EXTI_ClearITPendingBit(EXTI_Line17);
/* Check if the Wake-Up flag is set */
if(PWR_GetFlagStatus(PWR_FLAG_WU) != RESET)
{
/* Clear Wake Up flag */
PWR_ClearFlag(PWR_FLAG_WU);
}
}
}
Sometimes I get an IT every 10 seconds, sometimes every x minutes, sometimes ever seconds ... well, it's just not reliable.
Any help would be appreciated.
Best regards,
Vincent.
