#include<STM32RTC.h>/* Get the rtc object*/STM32RTC& rtc = STM32RTC::getInstance();/* Change these values to set the current initial time   format: date: "Dec 31 2017" and time: "23:59:56"   by default use built date and time*/staticconstchar* mydate = __DATE__;staticconstchar* mytime = __TIME__;//static const char* mydate = "Dec 31 2017";//static const char* mytime = "23:59:56";static byte seconds =0;static byte minutes =0;static byte hours =0;staticuint32_t subSeconds =0;static byte weekDay =1;static byte day =0;static byte month =0;static byte year =0;static STM32RTC::Hour_Format hourFormat = STM32RTC::HOUR_24;static STM32RTC::AM_PM period = STM32RTC::AM;staticuint8_tconv2d(constchar* p) {uint8_t v =0;if ('0' <= *p && *p <='9')    v = *p -'0';return10 * v + *++p -'0';}// sample input: date = "Dec 26 2009", time = "12:34:56"voidinitDateTime (void) {  year =conv2d(mydate +9);// Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Decswitch (mydate[0]) {case'J': month = (mydate[1] =='a') ?1 : ((mydate[2] =='n') ?6 :7);break;case'F': month =2;break;case'A': month = mydate[2] =='r' ?4 :8;break;case'M': month = mydate[2] =='r' ?3 :5;break;case'S': month =9;break;case'O': month =10;break;case'N': month =11;break;case'D': month =12;break;  }  day =conv2d(mydate +4);  hours =conv2d(mytime);if (hourFormat == rtc.HOUR_12) {    period = hours >=12 ? rtc.PM : rtc.AM;    hours = hours >=13 ? hours -12 : (hours <1 ? hours +12 : hours);  }  minutes =conv2d(mytime +3);  seconds =conv2d(mytime +6);}voidsetup(){  Serial.begin(9600);while (!Serial);initDateTime();// Select RTC clock source: LSI_CLOCK, LSE_CLOCK or HSE_CLOCK.// By default the LSI is selected as source.  rtc.setClockSource(STM32RTC::LSE_CLOCK);  rtc.begin();// initialize RTC 24H formatif (!rtc.isTimeSet()) {    Serial.printf("RTC time not set\n Set it!\n");// Set the time    rtc.setTime(hours, minutes, seconds);    rtc.setDate(weekDay, day, month, year);  }else {    Serial.printf("RTC time already set\n");  }}voidloop(){  rtc.getTime(&hours, &minutes, &seconds, &subSeconds, &period);// Print date time  Serial.printf("%02d/%02d/%02d %02d:%02d:%02d.%03d\n", rtc.getDay(), rtc.getMonth(), rtc.getYear(), hours, minutes, seconds, subSeconds);delay(1000);}