Change the example to configure RTC alarm in MIX mode

In this sketch the RTC is configured in BCD or MIX mode
(for the stm32 devices that supports it)
An Alarm A is set to wakeup the system from low power
deep sleep.

Signed-off-by: Francois Ramu <francois.ramu@st.com>

examples/AlarmTimedWakeup/AlarmTimedWakeup.ino

@@ -1,9 +1,10 @@
 /*
-  AdvancedTimedWakeup
+  AlarmTimedWakeup
 
   This sketch demonstrates the usage of Internal Interrupts to wakeup a chip in deep sleep mode.
 
   In this sketch:
+  - RTC is configured in BCD (default) or MIX mode (BCD and BINARY)
   - RTC date and time are configured.
   - Alarm is set to wake up the processor each 'atime' and called a custom alarm callback
   which increment a value and reload alarm with 'atime' offset.
@@ -19,7 +20,7 @@ STM32RTC& rtc = STM32RTC::getInstance();
 
 /* Change this value to set alarm match offset in millisecond */
 /* Note that STM32F1xx does not manage subsecond only second */
-static uint32_t atime = 567;
+static uint32_t atime = 600;
 
 // Declare it volatile since it's incremented inside an interrupt
 volatile int alarmMatch_counter = 0;
@@ -35,21 +36,30 @@ static byte month = 1;
 static byte year = 18;
 
 void setup() {
+#if defined(RTC_BINARY_NONE)
+  // Select RTC clock source: LSI_CLOCK, LSE_CLOCK or HSE_CLOCK.
+  rtc.setClockSource(STM32RTC::LSE_CLOCK);
+  // Select the STM32RTC::MODE_BCD or STM32RTC::MODE_MIX
+  rtc.setBinaryMode(STM32RTC::MODE_BCD);
+  rtc.begin(true); /* reset the RTC else the binary mode is not changed */
+#else
   rtc.begin();
+#endif /* RTC_BINARY_NONE */
   rtc.setTime(hours, minutes, seconds);
   rtc.setDate(weekDay, day, month, year);
 
   pinMode(LED_BUILTIN, OUTPUT);
 
-  Serial.begin(9600);
+  Serial.begin(115200);
   while (!Serial) {}
+  Serial.println(" Start !");
 
   // Configure low power
   LowPower.begin();
   LowPower.enableWakeupFrom(&rtc, alarmMatch, &atime);
 
   // Configure first alarm in 2 second then it will be done in the rtc callback
-  rtc.setAlarmEpoch( rtc.getEpoch() + 2);
+  rtc.setAlarmEpoch(rtc.getEpoch() + 2);
 }
 
 void loop() {