写一个stm32f103c8t6 用标准库函数实现rtc 实时时钟串口输出的代码

好的，以下是实现rtc实时时钟串口输出的代码：

#include "stm32f10x.h"
#include <stdio.h>

void USART1_Init(void) {
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE);

  GPIO_InitTypeDef GPIO_InitStruct;
  USART_InitTypeDef USART_InitStruct;

  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStruct);

  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_10;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStruct);

  USART_InitStruct.USART_BaudRate = 9600;
  USART_InitStruct.USART_WordLength = USART_WordLength_8b;
  USART_InitStruct.USART_StopBits = USART_StopBits_1;
  USART_InitStruct.USART_Parity = USART_Parity_No;
  USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStruct.USART_Mode = USART_Mode_Tx;

  USART_Init(USART1, &USART_InitStruct);
  USART_Cmd(USART1, ENABLE);
}

void RTC_Init(void) {
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);
  PWR_BackupAccessCmd(ENABLE);

  if ((RCC->BDCR & RCC_BDCR_RTCEN) != RCC_BDCR_RTCEN) {
    RCC_LSEConfig(RCC_LSE_ON);
    while (RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET) {
    }
    RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);

    RTC_InitTypeDef RTC_InitStruct;
    RTC_StructInit(&RTC_InitStruct);
    RTC_InitStruct.RTC_AsynchPrediv = 0x7F;
    RTC_InitStruct.RTC_SynchPrediv = 0xFF;
    RTC_InitStruct.RTC_HourFormat = RTC_HourFormat_24;
    RTC_Init(&RTC_InitStruct);
    RCC_RTCCLKCmd(ENABLE);
    RTC_WaitForSynchro();
  }
}

void RTC_SetDateTime(uint8_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t minute, uint8_t second) {
  RTC_TimeTypeDef RTC_TimeStruct;
  RTC_DateTypeDef RTC_DateStruct;

  RTC_TimeStruct.RTC_Hours = hour;
  RTC_TimeStruct.RTC_Minutes = minute;
  RTC_TimeStruct.RTC_Seconds = second;
  RTC_TimeStruct.RTC_H12 = RTC_H12_AM;

  RTC_DateStruct.RTC_Year = year;
  RTC_DateStruct.RTC_Month = month;
  RTC_DateStruct.RTC_Date = day;
  RTC_DateStruct.RTC_WeekDay = RTC_Weekday_Monday;

  RTC_SetTime(RTC_Format_BIN, &RTC_TimeStruct);
  RTC_SetDate(RTC_Format_BIN, &RTC_DateStruct);
}

void USART1_SendChar(char c) {
  while ((USART1->SR & USART_SR_TXE) == RESET) {
  }
  USART_SendData(USART1, c);
}

int USART1_SendString(const char* str, uint32_t timeout) {
  int i = 0;
  while (*str) {
    USART1_SendChar(*str++);
    i++;
    if (timeout != 0xFFFFFFFF) {
      uint32_t t = timeout;
      while ((USART1->SR & USART_SR_TXE) == RESET) {
        if ((t--) == 0) {
          return -1;
        }
      }
    }
  }
  return i;
}

int main(void) {
  USART1_Init();
  RTC_Init();
  RTC_SetDateTime(21, 6, 30, 12, 0, 0);

  char buf[32];
  while (1) {
    RTC_TimeTypeDef RTC_TimeStruct;
    RTC_DateTypeDef RTC_DateStruct;
    RTC_GetTime(RTC_Format_BIN, &RTC_TimeStruct);
    RTC_GetDate(RTC_Format_BIN, &RTC_DateStruct);
    sprintf(buf, "%04d-%02d-%02d %02d:%02d:%02d\r\n", RTC_DateStruct.RTC_Year, RTC_DateStruct.RTC_Month, RTC_DateStruct.RTC_Date, RTC_TimeStruct.RTC_Hours, RTC_TimeStruct.RTC_Minutes, RTC_TimeStruct.RTC_Seconds);
    USART1_SendString(buf, 1000000);
    for (int i = 0; i < 1000000; i++) {
      __NOP();
    }
  }
}