displaySecond.ino

#include <M5Atom.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <WiFi.h>
#include "time.h"

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET     4 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Wi-Fi SSID
char *ssid = "[WIFI SSID]";
// Wi-Fi Password
char *password = "[WIFI PASSWORD]";

#define JST 3600* 9

void setup() {
  Wire.begin(21,25);

  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  delay(1000);
  display.clearDisplay();
  display.setRotation(2);
  
  display.setTextSize(3);
  display.setTextColor(SSD1306_WHITE);

  WiFi.disconnect( true, true ); 
  delay(500);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED){
    delay(500);
    display.print(".");
    display.display();
  }

  //configTime(JST, 0, "ntp.nict.jp", "time.google.com", "ntp.jst.mfeed.ad.jp");
  configTime(JST, 0, "time.windows.com");

  //Wi-Fi接続したままで一度 getLocalTime しておく必要があるらしい。
  struct tm timeInfo;
  getLocalTime(&timeInfo);
  
  WiFi.disconnect(true);
  WiFi.mode(WIFI_OFF);
  display.clearDisplay();
  display.display();
}

int preSecond = 0;
unsigned long ss = 0;
unsigned long ssCount = 0;

void loop(){
  ss = millis() / 10;
  while(true){
    int newSS = millis() / 10;
    if(newSS != ss){
      ssCount = ssCount + (newSS - ss);
      if(ssCount > 99){
        ssCount = 99; //ごまかし
      }
      ss = newSS;
      struct tm timeinfo;
      if(!getLocalTime(&timeinfo)){
        display.println("Error!");
        display.display();
      }else{
         display.clearDisplay();
         display.setCursor(0,20);
         display.printf(":%02d.%02d",timeinfo.tm_sec,ssCount);
         display.display();
         if(timeinfo.tm_sec != preSecond){
            ssCount = 0;
            preSecond = timeinfo.tm_sec;
            
         }
      }
    }
    delay(1);
  }  
}