/**

  ******************************************************************************

  * @file    RTC/RTC_LSI/main.c 

  * @author  MCD Application Team

  * @version V1.0.0

  * @date    18-May-2012

  * @brief   Main program body

  ******************************************************************************

  * @attention

  *

  * <h2><center>&copy; COPYRIGHT 2012 STMicroelectronics</center></h2>

  *

  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");

  * You may not use this file except in compliance with the License.

  * You may obtain a copy of the License at:

  *

  *        http://www.st.com/software_license_agreement_liberty_v2

  *

  * Unless required by applicable law or agreed to in writing, software 

  * distributed under the License is distributed on an "AS IS" BASIS, 

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  *

  ******************************************************************************

  */



/* Includes ------------------------------------------------------------------*/

#include "main.h"



/** @addtogroup STM32F0xx_StdPeriph_Examples

  * @{

  */



/** @addtogroup RTC_LSI

  * @{

  */



/* Private typedef -----------------------------------------------------------*/

/* Private define ------------------------------------------------------------*/

/* Private macro -------------------------------------------------------------*/

/* Private variables ---------------------------------------------------------*/

RTC_InitTypeDef   RTC_InitStructure;

__IO uint32_t LsiFreq = 0;

__IO uint32_t CaptureNumber = 0, PeriodValue = 0;



/* Private function prototypes -----------------------------------------------*/

void RTC_Config(void);

uint32_t GetLSIFrequency(void);



/* Private functions ---------------------------------------------------------*/



/**

  * @brief  Main program.

  * @param  None

  * @retval None

  */

int main(void)

{

  /*!< At this stage the microcontroller clock setting is already configured, 

       this is done through SystemInit() function which is called from startup

       file (startup_stm32f0xx.s) before to branch to application main.

       To reconfigure the default setting of SystemInit() function, refer to

       system_stm32f0xx.c file

     */ 



/* Initialize LEDs mounted on STM320518-EVAL board --------------------------*/

  STM_EVAL_LEDInit(LED1);

  STM_EVAL_LEDInit(LED2);

  STM_EVAL_PBInit(BUTTON_KEY, BUTTON_MODE_GPIO);

  

  /* RTC Configuration -------------------------------------------------------*/

  RTC_Config();



  /* Wait Until KEY BUTTON is pressed */

  while(STM_EVAL_PBGetState(BUTTON_KEY) != RESET)

  {

  }

  

  /* Get the LSI frequency:  TIM14 is used to measure the LSI frequency */

  LsiFreq = GetLSIFrequency();



  /* Turn on LED2 */

  STM_EVAL_LEDOn(LED2);



  /* Calendar Configuration */

  RTC_InitStructure.RTC_AsynchPrediv = 99;

  RTC_InitStructure.RTC_SynchPrediv	=  (LsiFreq/100) - 1;

  RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24;

  RTC_Init(&RTC_InitStructure);



  /* Infinite loop */

  while (1)

  {

  }

}



/**

  * @brief  Configure the RTC peripheral by selecting the clock source.

  * @param  None

  * @retval None

  */

void RTC_Config(void)

{

  RTC_TimeTypeDef RTC_TimeStructure;

  NVIC_InitTypeDef NVIC_InitStructure; 

  EXTI_InitTypeDef EXTI_InitStructure;

  RTC_AlarmTypeDef RTC_AlarmStructure;

  /* Enable the PWR clock */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

  

  /* Allow access to RTC */

  PWR_BackupAccessCmd(ENABLE);



/* 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);

   

  /* Enable the RTC Clock */

  RCC_RTCCLKCmd(ENABLE);



  /* Wait for RTC APB registers synchronisation */

  RTC_WaitForSynchro();



  /* Calendar Configuration */

  RTC_InitStructure.RTC_AsynchPrediv = 99;

  RTC_InitStructure.RTC_SynchPrediv	=  399; /* (40KHz / 100) - 1 = 399*/

  RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24;

  RTC_Init(&RTC_InitStructure);  



  /* EXTI configuration *******************************************************/

  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);

  

  /* Enable the RTC Wakeup Interrupt */

  NVIC_InitStructure.NVIC_IRQChannel = RTC_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPriority = 0;

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);

  

    /* Set the alarm X+5s */

  RTC_AlarmStructure.RTC_AlarmTime.RTC_H12     = RTC_H12_AM;

  RTC_AlarmStructure.RTC_AlarmTime.RTC_Hours   = 0x00;

  RTC_AlarmStructure.RTC_AlarmTime.RTC_Minutes = 0x00;

  RTC_AlarmStructure.RTC_AlarmTime.RTC_Seconds = 0x01;

  RTC_AlarmStructure.RTC_AlarmDateWeekDay = 0x31;

  RTC_AlarmStructure.RTC_AlarmDateWeekDaySel = RTC_AlarmDateWeekDaySel_Date;

  RTC_AlarmStructure.RTC_AlarmMask = RTC_AlarmMask_DateWeekDay;

  RTC_SetAlarm(RTC_Format_BCD, RTC_Alarm_A, &RTC_AlarmStructure);



  RTC_ITConfig(RTC_IT_ALRA, ENABLE);

    

  /* Enable the alarm */

  RTC_AlarmCmd(RTC_Alarm_A, ENABLE);

  

  /* Set the time to 00h 00mn 00s AM */

  RTC_TimeStructure.RTC_H12     = RTC_H12_AM;

  RTC_TimeStructure.RTC_Hours   = 0x00;

  RTC_TimeStructure.RTC_Minutes = 0x00;

  RTC_TimeStructure.RTC_Seconds = 0x00;  

  

  RTC_SetTime(RTC_Format_BCD, &RTC_TimeStructure);

}



/**

  * @brief  Configures TIM14 to measure the LSI oscillator frequency. 

  * @param  None

  * @retval LSI Frequency

  */

uint32_t GetLSIFrequency(void)

{

  NVIC_InitTypeDef   NVIC_InitStructure;

  TIM_ICInitTypeDef  TIM_ICInitStructure;

  RCC_ClocksTypeDef  RCC_ClockFreq;



  /* TIM14 configuration *******************************************************/ 

  /* Enable TIM14 clock */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM14, ENABLE);

  

  /* Reset TIM14 registers */

  TIM_DeInit(TIM14);



  /* Configure TIM14 prescaler */

  TIM_PrescalerConfig(TIM14, 0, TIM_PSCReloadMode_Immediate);



  /* Connect internally the TIM14_CH1 to the RTC clock output */

  TIM_RemapConfig(TIM14, TIM14_RTC_CLK);



  /* TIM14 configuration: Input Capture mode ---------------------

     The reference clock(LSE or external) is connected to TIM14 CH1

     The Rising edge is used as active edge,

     The TIM14 CCR1 is used to compute the frequency value 

  ------------------------------------------------------------ */

  TIM_ICInitStructure.TIM_Channel     = TIM_Channel_1;

  TIM_ICInitStructure.TIM_ICPolarity  = TIM_ICPolarity_Rising;

  TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;

  TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV8;

  TIM_ICInitStructure.TIM_ICFilter = 0x0;

  TIM_ICInit(TIM14, &TIM_ICInitStructure);



  /* Enable the TIM14 global Interrupt */

  NVIC_InitStructure.NVIC_IRQChannel = TIM14_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPriority = 0;

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);



  /* Enable TIM14 counter */

  TIM_Cmd(TIM14, ENABLE);



  /* Reset the flags */

  TIM14->SR = 0;

    

  /* Enable the CC1 Interrupt Request */  

  TIM_ITConfig(TIM14, TIM_IT_CC1, ENABLE);





  /* Wait until the TIM14 get 2 LSI edges (refer to TIM14_IRQHandler() in 

    stm32F0xx_it.c file) ******************************************************/

  while(CaptureNumber != 2)

  {

  }

  /* Deinitialize the TIM14 peripheral registers to their default reset values */

  TIM_DeInit(TIM14);





  /* Compute the LSI frequency, depending on TIM14 input clock frequency (PCLK1)*/

  /* Get SYSCLK, HCLK and PCLKx frequency */

  RCC_GetClocksFreq(&RCC_ClockFreq);

  

  /* PCLK1 prescaler equal to 1 => TIMCLK = PCLK1 */

  return ((RCC_ClockFreq.PCLK_Frequency / PeriodValue) * 8);

}



#ifdef  USE_FULL_ASSERT



/**

  * @brief  Reports the name of the source file and the source line number

  *         where the assert_param error has occurred.

  * @param  file: pointer to the source file name

  * @param  line: assert_param error line source number

  * @retval None

  */

void assert_failed(uint8_t* file, uint32_t line)

{ 

  /* User can add his own implementation to report the file name and line number,

     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */



  /* Infinite loop */

  while (1)

  {

  }

}

#endif



/**

  * @}

  */



/**

  * @}

  */



/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/