M5 Stack에 날짜 및 시간 표시

#include <M5Stack.h>
#include <WiFi.h>
#include "time.h"

const char* ssid       = "XXXXXXXXXXXXX";
const char* password   = "XXXXXXXXXXXXX";

const char* ntpServer = "ntp.nict.jp";
const long  gmtOffset_sec = 3600 * 9;
const int   daylightOffset_sec = 0;

void printLocalTime()
{
  struct tm timeinfo;

  if(!getLocalTime(&timeinfo)){
    M5.Lcd.println("Failed to obtain time");
    return;
  }
  // テキストサイズ指定
  M5.Lcd.setTextSize(2);
  // カーソル位置を設定
  M5.Lcd.setCursor(40,100);
  M5.Lcd.printf("%04d-%02d-%02d %02d:%02d:%02d" 
                ,timeinfo.tm_year + 1900
                ,timeinfo.tm_mon + 1
                ,timeinfo.tm_mday
                ,timeinfo.tm_hour
                ,timeinfo.tm_min
                ,timeinfo.tm_sec
                );
}

void setup()
{
  M5.begin();

  //connect to WiFi
  int cnt=0;
  M5.Lcd.print("Connecting to YOUR_SSID ");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    cnt++;
    delay(500);
    M5.Lcd.print(".");
  }
  M5.Lcd.println(" CONNECTED");

  //init and get the time
  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);
  printLocalTime();

  //disconnect WiFi as it's no longer needed
  WiFi.disconnect(true);
  WiFi.mode(WIFI_OFF);
}

void loop()
{
  delay(1000);
  printLocalTime();
}