feat: add second alarm (B) support

Fixes #74

Signed-off-by: Frederic Pillon <frederic.pillon@st.com>
Co-authored-by: hariton_batkov <yanker90@gmail.com>

Author: fpistm

README.md

@@ -72,7 +72,7 @@ _SubSeconds alarm management_
     * **`void setAlarmTime(uint8_t hours, uint8_t minutes, uint8_t seconds, uint32_t subSeconds = 0, AM_PM period = AM)`**
     * **`uint32_t getEpoch(uint32_t *subSeconds = nullptr)`**
     * **`void setEpoch(uint32_t ts, uint32_t subSeconds = 0)`**
-    * **`void setAlarmEpoch(uint32_t ts, Alarm_Match match = MATCH_DHHMMSS, uint32_t subSeconds = 0)`** 
+    * **`void setAlarmEpoch(uint32_t ts, Alarm_Match match = MATCH_DHHMMSS, uint32_t subSeconds = 0)`**
 
 _Library version management_
 
@@ -105,7 +105,7 @@ _Library version management_
 _One-Second interrupt_
 
   STM32 RTC includes a one-second interrupt for generating a periodic interrupt signal.
-  - This feature is native on the stm32F1xx and mapped on the existing WakeUp interrupt on other stm32 mcus. 
+  - This feature is native on the stm32F1xx and mapped on the existing WakeUp interrupt on other stm32 mcus.
   - It is not available on some stm32F0 devices.
 
   * **new API:**
@@ -138,6 +138,21 @@ To know if a time has already been set use:
   }
 ```
 
+### Since STM32RTC version higher than 1.3.4
+_Second alarm (Alarm B)_
+
+Some STM32 RTC have a second alarm named `RTC_ALARM_B`.
+It is possible to use it thanks all alarm API with an extra argument:
+  - `STM32RTC::ALARM_A`
+  - `STM32RTC::ALARM_B`
+
+```C++
+    rtc.attachInterrupt(myCallback, &myCallbackdata, STM32RTC::ALARM_B);
+    rtc.setAlarmDay(day, STM32RTC::ALARM_B);
+    rtc.setAlarmTime(hours, minutes, seconds + 5, 567, STM32RTC::ALARM_B);
+    rtc.enableAlarm(rtc.MATCH_DHHMMSS, STM32RTC::ALARM_B);
+```
+
 Refer to the Arduino RTC documentation for the other functions
 http://arduino.cc/en/Reference/RTC
 

examples/advancedRTCAlarm/advancedRTCAlarm.ino

@@ -5,6 +5,9 @@
   It uses the optional 'data' alarm callback parameters to
   reload alarm with 'atime' offset indefinitely.
 
+  If a second alarm (B) is available, it is configured
+  to trigger each second.
+
   Creation 25 May 2018
   by Frederic Pillon for STMicroelectronics
   Modified 03 Jul 2020
@@ -22,6 +25,9 @@ STM32RTC& rtc = STM32RTC::getInstance();
 
 /* Declare it volatile since it's incremented inside an interrupt */
 volatile int alarmMatch_counter = 0;
+#ifdef RTC_ALARM_B
+volatile int alarmBMatch_counter = 0;
+#endif
 
 /* Change this value to set alarm match offset in millisecond */
 /* Note that STM32F1xx does not manage subsecond only second */
@@ -54,6 +60,13 @@ void setup()
   rtc.setAlarmDay(day);
   rtc.setAlarmTime(16, 0, 10, 567);
   rtc.enableAlarm(rtc.MATCH_DHHMMSS);
+
+#ifdef RTC_ALARM_B
+  rtc.attachInterrupt(alarmBMatch, STM32RTC::ALARM_B);
+  rtc.setAlarmDay(day, STM32RTC::ALARM_B);
+  rtc.setAlarmTime(16, 0, 11, 567, STM32RTC::ALARM_B);
+  rtc.enableAlarm(rtc.MATCH_DHHMMSS, STM32RTC::ALARM_B);
+#endif
 }
 
 void loop()
@@ -97,3 +110,12 @@ void alarmMatch(void *data)
   Serial.printf("Alarm Match %i\n", ++alarmMatch_counter);
   rtc.setAlarmEpoch(epoc + sec, STM32RTC::MATCH_SS, epoc_ms);
 }
+
+#ifdef RTC_ALARM_B
+void alarmBMatch(void *data)
+{
+  (void)data;
+  Serial.printf("Alarm B Match %i\n", ++alarmBMatch_counter);
+  rtc.setAlarmEpoch(rtc.getEpoch() + 2, STM32RTC::MATCH_SS, STM32RTC::ALARM_B);
+}
+#endif

keywords.txt

@@ -97,3 +97,5 @@ PM	LITERAL1
 LSE_CLOCK	LITERAL1
 LSI_CLOCK	LITERAL1
 HSE_CLOCK	LITERAL1
+ALARM_A	LITERAL1
+ALARM_B	LITERAL1