#include "stm32f10x.h"

USART_InitTypeDef USART_InitStructure;
uint8_t Data;
uint8_t flag;
uint8_t h = 0;
uint8_t m = 0;
uint8_t s = 0;
uint8_t clock[10];

NVIC_InitTypeDef   NVIC_InitStructure;

RCC_ClocksTypeDef RCC_Clocks;
__IO uint32_t PeriodValue = 0,  LsiFreq = 0;
__IO uint32_t OperationComplete = 0;

void NVIC_Configuration(void);
void RCC_Configuration(void);
void RTC_Configuration(void);
void GPIO_Configuration(void);
void USART_Configuration(void);


int main(void)
{
	RCC_Configuration();
	RTC_Configuration();
	NVIC_Configuration();
	GPIO_Configuration();
	USART_Configuration();

	while (1)
  {
		// while(USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == RESET){}
		// Data = USART_ReceiveData(USART2);

		if (flag) {
			int i;
			for(i=0; i<10; i++) {
				while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET){}

				USART_SendData(USART2, clock[i]);
			}
			flag = 0;
		}

  }
}


void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;


  /* Enable the USART2 Pins Software Remapping */
  GPIO_PinRemapConfig(GPIO_Remap_USART2, ENABLE);

  /* Configure USARTy Rx as input floating */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOD, &GPIO_InitStructure);

  /* Configure USARTy Tx as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOD, &GPIO_InitStructure);

}

void RCC_Configuration(void)
{
  /* Enable GPIO clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD | RCC_APB2Periph_AFIO, ENABLE);

  /* Enable USARTy Clock */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

}

void RTC_IRQHandler(void)
{
  if (RTC_GetITStatus(RTC_IT_SEC) != RESET)
  {
		RTC_ClearITPendingBit(RTC_FLAG_SEC);

		s+=1;
		if (s == 60) {
			s = 0;
			if(m < 59) {
				m+=1;
			} else {
				m = 0;
				if(h < 23) {
				h+=1;
				} else {
					 h =0;
				}
			}
		}
		clock[0] = h/10 + '0';
		clock[1] = h%10 + '0';
		clock[2] = ':';
		clock[3] = m/10 + '0';
		clock[4] = m%10 + '0';
		clock[5] = ':';
		clock[6] = s/10 + '0';
		clock[7] = s%10 + '0';
		clock[8] = 0x0D;
		clock[9] = 0x0A;
		flag++;
	}
}

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_LSEConfig(RCC_LSE_ON);
  /* Wait till LSI is ready */
  while (RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET)
  {}
  /* Select the RTC Clock Source */
  RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);

  /* Enable RTC Clock */
  RCC_RTCCLKCmd(ENABLE);

  /* Wait for RTC registers synchronization */
  RTC_WaitForSynchro();

  /* Wait until last write operation on RTC registers has finished */
  RTC_WaitForLastTask();

  /* Enable the RTC Second */
  RTC_ITConfig(RTC_IT_SEC, ENABLE);

  /* Wait until last write operation on RTC registers has finished */
  RTC_WaitForLastTask();

  /* Set RTC prescaler: set RTC period to 1sec */
  RTC_SetPrescaler(32768);

  /* Wait until last write operation on RTC registers has finished */
  RTC_WaitForLastTask();
}

void USART_Configuration(void)
{
	USART_InitStructure.USART_BaudRate = 9600;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  USART_Init(USART2, &USART_InitStructure);
	/* Enable the USARTy */
  USART_Cmd(USART2, ENABLE);
}

void NVIC_Configuration(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;

  /* Configure one bit for preemption priority */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

  /* Enable the RTC Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = RTC_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}