Add new example using alarm data callback

Add advancedRTCAlarm example using data callback to reload
alarm. So, alarm will match indefinitely.

Fix also warning in simpleRTCAlarm.

Signed-off-by: Frederic.Pillon <[email protected]>

Author: fpistm

examples/advancedRTCAlarm/advancedRTCAlarm.ino

@@ -0,0 +1,73 @@
+/*
+  advancedRTCAlarm
+
+  This sketch is an extension of simpleRTCAlarm.
+  It uses the optional 'data' alarm callback parameters to
+  reload alarm with 'atime' offset indefinitely.
+
+
+  Creation 25 May 2018
+  by Frederic Pillon for STMicroelectronics
+
+  This example code is in the public domain.
+
+  https://github.com/stm32duino/STM32RTC
+
+*/
+
+#include <STM32RTC.h>
+
+/* Get the rtc object */
+STM32RTC& rtc = STM32RTC::getInstance();
+
+/* Declare it volatile since it's incremented inside an interrupt */
+volatile int alarmMatch_counter = 0;
+
+/* Change this value to set alarm match offset */
+static uint32_t atime = 5;
+
+/* Change these values to set the current initial time */
+const byte seconds = 0;
+const byte minutes = 0;
+const byte hours = 16;
+
+/* Change these values to set the current initial date */
+const byte day = 25;
+const byte month = 9;
+const byte year = 15;
+
+void setup()
+{
+  Serial.begin(9600);
+
+  rtc.begin(); // initialize RTC 24H format
+
+  rtc.setTime(hours, minutes, seconds);
+  rtc.setDate(day, month, year);
+
+  rtc.attachInterrupt(alarmMatch, &atime);
+  rtc.setAlarmDay(day);
+  rtc.setAlarmTime(16, 0, 10);
+  rtc.enableAlarm(rtc.MATCH_DHHMMSS);
+}
+
+void loop()
+{
+
+}
+
+void alarmMatch(void *data)
+{
+  uint32_t sec = 1;
+  if(data != NULL) {
+    sec = *(uint32_t*)data;
+    // Minimum is 1 second
+    if (sec == 0){
+      sec = 1;
+    }
+  }
+  alarmMatch_counter++;
+  Serial.print("Alarm Match ");
+  Serial.println(alarmMatch_counter);
+  rtc.setAlarmEpoch( rtc.getEpoch() + sec);
+}

examples/simpleRTCAlarm/simpleRTCAlarm.ino

@@ -73,5 +73,6 @@ void loop()
 
 void alarmMatch(void *data)
 {
+  UNUSED(data);
   Serial.println("Alarm Match!");
 }