Experimental code to allow timer resyncing after NTP resync

src/WatchFace.cpp

@@ -269,6 +269,7 @@ void WatchFace::MenuNTPSyncSelected()
   ConnectWiFi();
   SyncNTPTime();
   DisconnectWiFi();
+  m_RTC.Resync();
 
 	if (m_inMenu) {
 		m_inMenu = false;

src/WatchyRTC.cpp

@@ -13,10 +13,6 @@ WatchyRTC::WatchyRTC()
 
 void WatchyRTC::Init()
 {
-  tmElements_t tm;
-  Get(tm, 0);
-  rtc_pcf.initClock();
-  Set(tm);
 }
 
 void WatchyRTC::Get(tmElements_t & tm, int offsetInSeconds)
@@ -43,14 +39,7 @@ void WatchyRTC::Set(tmElements_t tm)
 void WatchyRTC::SetTimer()
 {
   if (!m_timerSet) {
-    rtc_pcf.getDateTime();
+    Resync();
-    // Sleep just long enough to get to a multiple of the update interval, makes updates happen on exact turn of the minute
-    int seconds = UPDATE_INTERVAL - (rtc_pcf.getSecond() % UPDATE_INTERVAL);
-
-    // Non repeating
-    rtc_pcf.setTimer(seconds, TMR_1Hz, false);
-    m_timerSet = true;
-    m_initialTimer = true;
   }
 }
 
@@ -133,10 +122,40 @@ bool WatchyRTC::CheckWakeup()
       interval = UPDATE_INTERVAL;
     }
 
+    // Timer doesn't work reliably unless it's cleared first
+    rtc_pcf.clearTimer();
     rtc_pcf.setTimer(interval, frequency, true);
 
     return true;
   }
 
   return true;
+}
+
+void WatchyRTC::Resync()
+{
+  rtc_pcf.getDateTime();
+  // Sleep just long enough to get to a multiple of the update interval, makes updates happen on exact turn of the minute
+  int seconds = UPDATE_INTERVAL - (rtc_pcf.getSecond() % UPDATE_INTERVAL);
+
+  if (seconds < 0) {
+    seconds = 0;
+  }
+
+  // Timer doesn't work reliably unless it's cleared first
+  rtc_pcf.clearTimer();
+
+  if (seconds == 0) {
+    // If there's no time to wait, just call CheckWakeup() immediately and it'll set the repeating timer
+    m_timerSet = true;
+    m_initialTimer = true;
+    CheckWakeup();
+  } else {
+    rtc_pcf.setTimer(seconds, TMR_1Hz, false);
+
+    m_timerSet = true;
+    m_initialTimer = true;
+  }
+
+  seconds = 0;
 }

src/WatchyRTC.h

@@ -20,6 +20,7 @@ public:
   void Set(tmElements_t tm);
   void SetTimer();
   bool CheckWakeup(); // Checks to really wake up or not, also resets the timer after the initial sleep
+  void Resync(); // Resync the timer cycle, both initially and after RTC resync
 
   static void OffsetTime(tmElements_t & tm, int offsetInSeconds);