【NUCLEO-L452RE测评】+RTC电子时钟
<div class='showpostmsg'><p>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。</p><p>实现图1所示效果的主程序为：</p>
<pre>
<code class="language-cpp">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);
}
}</code></pre>
<p style="text-align:justify"> </p>
<p style="text-align:justify"></p>
<p>图1 RTC电子时钟</p>
<p> </p>
<p>实现RTC显示的函数为：</p>
<pre>
<code class="language-cpp">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);
}</code></pre>
<p align="left" style="text-align:left"> </p>
<p>调用的字符串显示函数为：</p>
<pre>
<code class="language-cpp">void OLED_ShowString(u8 x,u8 y,u8 *chr,u8 Char_Size)
{
unsigned char j=0;
while (chr!='\0')
{
OLED_ShowChar(x,y,chr,Char_Size);
x+=8;
if(x>120){x=0;y+=2;}
j++;
}
}</code></pre>
<p>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。</p>
<p style="text-align:justify"></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">图</span>2 <span style="font-family:宋体">校时后的显示效果</span></span></span></p>
<p style="text-align:justify"> </p>
<p>有人可能会问RTC具备万年历的功能吗？</p>
<p>那我们就用实时来说话吧，首先它可以区分大小月，见图3和图4所示。</p>
<p style="text-align:justify"></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">图</span>3 11<span style="font-family:宋体">月末</span></span></span></p>
<p style="text-align:justify"></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">图</span>4 12<span style="font-family:宋体">月初</span></span></span></p>
<p style="text-align:justify"> </p>
<p>再看闰年处理，2020年是闰年，图5和图6就能说明问题。</p>
<p style="text-align:justify"></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">图</span>5 <span style="font-family:宋体">二月末</span></span></span></p>
<p style="text-align:justify"></p>
<p style="text-align:justify"><span style="font-size:10.5pt"><span style="font-family:Calibri,sans-serif"><span style="font-family:宋体">图</span>6 <span style="background:white"><span style="font-family:宋体"><span style="color:#444444">闰年调整</span></span></span></span></span></p>
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