x OBでPA2をGPIOがわかる人むけ
目的
簡易な時間づくり
leafonyさんのページより引用
参考
STM32 MCU の Arduino IDE 設定
SER_time_test2_031_1



#include <Arduino.h>
#include <time.h>

#define LOOP_INTERVAL 1000000
#define BOARD_LED_PIN PA11

HardwareTimer *timer2 = new HardwareTimer (TIM2);

//time_t seconds = 0 + (60 * 60 * 9); // JST
time_t seconds = (60*60*24*365) - (60 * 60 * 9) ; // JST

//二桁の変換
#define DIV10(n) ((n*205)>>11)
char data1[16];
char *itoa99(int n) {


  data1[0] = '0' + DIV10(n);                        // n / 10
  data1[1] = '0' + (  n - ((data1[0] - '0') * 10) ); // n % 10
  data1[2] =  0;

  return (data1);

}//itoa99

void setup() {

  delay(3000); //not delete

  //シリアルの初期化
  Serial.setTx(PA2_ALT1);
  Serial.setHalfDuplex();
  Serial.begin(9600);

  pinMode(BOARD_LED_PIN, OUTPUT);

  timer2->setOverflow(LOOP_INTERVAL, MICROSEC_FORMAT);       // 125ms
  timer2->attachInterrupt(intTimer);
  timer2->resume();

}

struct tm *t;
struct tm tm;

void loop() {

  //t = localtime(&seconds);

  int tj = seconds;

  tm.tm_hour = ( (tj / 3600 + 9) % 24);
  tm.tm_min =  (tj / 60 % 60);
  tm.tm_sec =  (tj % 60);

  t = &tm;

  //    Serial.print(         t->tm_year + 1900 );
  //    Serial.print( itoa99( t->tm_mon + 1 ) );
  //    Serial.print( itoa99( t->tm_mday    ) );
  //    Serial.print( ' ' );
  Serial.print( itoa99( t->tm_hour    ) ); Serial.print( ':' );
  Serial.print( itoa99( t->tm_min     ) ); Serial.print( ':' );
  Serial.print( itoa99( t->tm_sec     ) );

  Serial.printf("\r\n");

  delay(1000);

}

void intTimer(void) {

  static int LEDstate = 0;
  digitalWrite( BOARD_LED_PIN, LEDstate);
  if ( 0 < LEDstate )
  {
    LEDstate = 0;
  } else {
    LEDstate = 1;
  }

  seconds++;

}