Added Epoch Support

src/RTCZero.cpp

@@ -19,6 +19,10 @@
 
 #include "RTCZero.h"
 
+#define EPOCH_TIME_OFF 946684800  // This is 1st January 2000, 00:00:00 in epoch time
+
+static const uint8_t daysInMonth[12] = { 31,28,31,30,31,30,31,31,30,31,30,31 };
+
 voidFuncPtr RTC_callBack = NULL;
 
 void RTCZero::begin() 
@@ -46,7 +50,9 @@ void RTCZero::begin()
   tmp_reg |= RTC_MODE2_CTRL_MODE_CLOCK; // set clock operating mode
   tmp_reg |= RTC_MODE2_CTRL_PRESCALER_DIV1024; // set prescaler to 1024 for MODE2
   tmp_reg &= ~RTC_MODE2_CTRL_MATCHCLR; // disable clear on match
-  tmp_reg |= RTC_MODE2_CTRL_CLKREP; // 24h time representation
+
+  //According to the datasheet RTC_MODE2_CTRL_CLKREP = 0 for 24h
+  tmp_reg &= ~RTC_MODE2_CTRL_CLKREP; // 24h time representation
 
   RTC->MODE2.READREQ.reg &= ~RTC_READREQ_RCONT; // disable continuously mode
 
@@ -102,7 +108,9 @@ void RTCZero::detachInterrupt()
 
 void RTCZero::standbyMode()
 {
-	SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
+  // Entering standby mode when connected
+  // via the native USB port causes issues.
+  SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
   __WFI();
 }
 
@@ -286,6 +294,82 @@ void RTCZero::setAlarmDate(uint8_t day, uint8_t month, uint8_t year)
   setAlarmYear(year);
 }
 
+uint32_t RTCZero::getEpoch()
+{
+  return getY2kEpoch() + EPOCH_TIME_OFF;
+}
+
+uint32_t RTCZero::getY2kEpoch()
+{
+  uint16_t days = RTC->MODE2.CLOCK.bit.DAY;
+  days = days > 0 ? days : 1;
+  uint8_t months = RTC->MODE2.CLOCK.bit.MONTH;
+  uint16_t years = RTC->MODE2.CLOCK.bit.YEAR;
+
+  for (uint8_t i = 1; i < months; ++i) {
+    days += daysInMonth[i - 1];
+  }
+
+  if ((months > 2) && (years % 4 == 0)) {
+    ++days;
+  }
+  days += 365 * years + (years + 3) / 4 - 1;
+
+  uint8_t hours = RTC->MODE2.CLOCK.bit.HOUR;
+
+  return ((days * 24 + hours) * 60 +
+    RTC->MODE2.CLOCK.bit.MINUTE) * 60 + RTC->MODE2.CLOCK.bit.SECOND;
+}
+
+void RTCZero::setEpoch(uint32_t ts)
+{
+  if (ts < EPOCH_TIME_OFF) {
+    setY2kEpoch(0);
+  }
+  else {
+    setY2kEpoch(ts - EPOCH_TIME_OFF);
+  }
+}
+
+void RTCZero::setY2kEpoch(uint32_t ts)
+{
+  RTC->MODE2.CLOCK.bit.SECOND = ts % 60;
+  ts /= 60;
+  RTC->MODE2.CLOCK.bit.MINUTE = ts % 60;
+  ts /= 60;
+  RTC->MODE2.CLOCK.bit.HOUR = ts % 24;
+
+  uint16_t days = ts / 24;
+  uint8_t months;
+  uint8_t years;
+
+  uint8_t leap;
+
+  // Calculate years
+  for (years = 0; ; ++years) {
+    leap = years % 4 == 0;
+    if (days < 365 + leap)
+      break;
+    days -= 365 + leap;
+  }
+
+  // Calculate months
+  for (months = 1; ; ++months) {
+    uint8_t daysPerMonth = daysInMonth[months - 1];
+    if (leap && months == 2)
+      ++daysPerMonth;
+    if (days < daysPerMonth)
+      break;
+    days -= daysPerMonth;
+  }
+
+  RTC->MODE2.CLOCK.bit.YEAR = years;
+  RTC->MODE2.CLOCK.bit.MONTH = months;
+  RTC->MODE2.CLOCK.bit.DAY = days + 1;
+  while (RTCisSyncing())
+    ;
+}
+
 /*
  * Private Utility Functions
  */

src/RTCZero.h

@@ -17,10 +17,8 @@
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */
 
-#pragma once
-
-#define H24 1
-#define H12 0
+#ifndef RTC_ZERO_H
+#define RTC_ZERO_H
 
 #include "Arduino.h"
 
@@ -31,13 +29,13 @@ class RTCZero {
 
   enum Alarm_Match: uint8_t // Should we have this enum or just use the identifiers from /component/rtc.h ?
   {
-    MATCH_OFF          = RTC_MODE2_MASK_SEL_OFF_Val,
-    MATCH_SS           = RTC_MODE2_MASK_SEL_SS_Val,
-    MATCH_MMSS         = RTC_MODE2_MASK_SEL_MMSS_Val,
-    MATCH_HHMMSS       = RTC_MODE2_MASK_SEL_HHMMSS_Val,
-    MATCH_DHHMMSS      = RTC_MODE2_MASK_SEL_DDHHMMSS_Val,
-    MATCH_MMDDHHMMSS   = RTC_MODE2_MASK_SEL_MMDDHHMMSS_Val,
-    MATCH_YYMMDDHHMMSS = RTC_MODE2_MASK_SEL_YYMMDDHHMMSS_Val
+    MATCH_OFF          = RTC_MODE2_MASK_SEL_OFF_Val,          // Never
+    MATCH_SS           = RTC_MODE2_MASK_SEL_SS_Val,           // Every Minute
+    MATCH_MMSS         = RTC_MODE2_MASK_SEL_MMSS_Val,         // Every Hour
+    MATCH_HHMMSS       = RTC_MODE2_MASK_SEL_HHMMSS_Val,       // Every Day
+    MATCH_DHHMMSS      = RTC_MODE2_MASK_SEL_DDHHMMSS_Val,     // Every Month
+    MATCH_MMDDHHMMSS   = RTC_MODE2_MASK_SEL_MMDDHHMMSS_Val,   // Every Year
+    MATCH_YYMMDDHHMMSS = RTC_MODE2_MASK_SEL_YYMMDDHHMMSS_Val  // Once, on a specific date and a specific time
   };
 
   RTCZero() {};
@@ -56,14 +54,16 @@ class RTCZero {
   uint8_t getSeconds();
   uint8_t getMinutes();
   uint8_t getHours();
+  uint8_t getAM_PM();
 
   uint8_t getDay();
   uint8_t getMonth();
   uint8_t getYear();
-
+  
   uint8_t getAlarmSeconds();
   uint8_t getAlarmMinutes();
   uint8_t getAlarmHours();
+  uint8_t getAlarmAM_PM();
 
   uint8_t getAlarmDay();
   uint8_t getAlarmMonth();
@@ -91,6 +91,13 @@ class RTCZero {
   void setAlarmYear(uint8_t year);
   void setAlarmDate(uint8_t day, uint8_t month, uint8_t year);
 
+  /* Epoch Functions */
+
+  uint32_t getEpoch();
+  uint32_t getY2kEpoch();
+  void setEpoch(uint32_t ts);
+  void setY2kEpoch(uint32_t ts);
+
 private:
   void config32kOSC(void);
   bool RTCisSyncing(void);
@@ -99,3 +106,5 @@ class RTCZero {
   void RTCreset();
   void RTCresetRemove();
 };
+
+#endif // RTC_ZERO_H