[原创] 【NUCLEO-L452RE测评】+RTC电子时钟

jinglixixi 2020-12-31 21:49 楼主

在STM32L452RE内部配置有RTC计时器，将它与OLED屏配合即可实现一个电子时钟。

实现图1所示效果的主程序为：

int main(void)
{
  HAL_Init();
  /* Configure the system clock to 80 MHz */
  SystemClock_Config();
  APP_OLED_Init();
  OLED_Init();
  OLED_Clear();
  OLED_ShowString(8,0,"STM32L452RE",16);
  OLED_ShowString(8,2,"OLED & RTC",16);
  OLED_ShowCHinese(80,0,0);
  OLED_ShowCHinese(96,0,1);
  OLED_ShowCHinese(112,0,2);
  /* Configure RTC prescaler and RTC data registers */
  RtcHandle.Instance = RTC;
  RtcHandle.Init.HourFormat = RTC_HOURFORMAT_24;
  RtcHandle.Init.AsynchPrediv = RTC_ASYNCH_PREDIV;
  RtcHandle.Init.SynchPrediv = RTC_SYNCH_PREDIV;
  RtcHandle.Init.OutPut = RTC_OUTPUT_DISABLE;
  RtcHandle.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
  RtcHandle.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
  if (HAL_RTC_Init(&RtcHandle) != HAL_OK)
  {
    /* Initialization Error */
    Error_Handler();
  }

  /*##-2- Check if Data stored in BackUp register1: No Need to reconfigure RTC#*/
  /* Read the Back Up Register 1 Data */
  if (HAL_RTCEx_BKUPRead(&RtcHandle, RTC_BKP_DR1) != 0x32F2)
  {
    /* Configure RTC Calendar */
    RTC_CalendarConfig();
  }

  /* Infinite loop */
  while (1)
  {

       RTC_CalendarShow(aShowTime, aShowDate);
       HAL_Delay(100);
  }
}

图1 RTC电子时钟

实现RTC显示的函数为：

static void RTC_CalendarShow(uint8_t *showtime, uint8_t *showdate)
{
  RTC_DateTypeDef sdatestructureget;
  RTC_TimeTypeDef stimestructureget;
  /* Get the RTC current Time */
  HAL_RTC_GetTime(&RtcHandle, &stimestructureget, RTC_FORMAT_BIN);
  /* Get the RTC current Date */
  HAL_RTC_GetDate(&RtcHandle, &sdatestructureget, RTC_FORMAT_BIN);
  /* Display time Format : hh:mm:ss */
  sprintf((char *)showtime, "%2d:%2d:%2d", stimestructureget.Hours, stimestructureget.Minutes, stimestructureget.Seconds);
  OLED_ShowString(26,6,showtime,16);
  /* Display date Format : mm-dd-yy */
  sprintf((char *)showdate, "%2d-%2d-%2d", 2000 + sdatestructureget.Year,sdatestructureget.Month, sdatestructureget.Date);
  OLED_ShowString(10,4,showdate,16);
}

调用的字符串显示函数为：

void OLED_ShowString(u8 x,u8 y,u8 *chr,u8 Char_Size)
{
    unsigned char j=0;
    while (chr[j]!='\0')
    {       
            OLED_ShowChar(x,y,chr[j],Char_Size);
            x+=8;
            if(x>120){x=0;y+=2;}
            j++;
    }
}

由于例程所设置的初始时间是2018年，故需要在函数 MX_RTC_Init()中进行修改，修改后的运行效果如图2所示。