From c2b89e077ba84a076fc3bcb88858601ff365e563 Mon Sep 17 00:00:00 2001
From: Justin Newitter <justin@newitter.com>
Date: Tue, 20 Dec 2022 23:07:18 -0500
Subject: [PATCH] DS3231: Add support for fetching alarm enabled status

This commit introduces one new method for DS3231 devices:
  - bool alarmEnabled(uint8_t alarm_num);

Updated the DS3231_alarm example to fetch the alarm1
enabled status. Locally validated that this correctly
fetches the enabled/disabled status for alarm2 as well.
---
 examples/DS3231_alarm/DS3231_alarm.ino |  8 ++++++--
 src/RTC_DS3231.cpp                     | 15 +++++++++++++--
 src/RTClib.h                           |  1 +
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/examples/DS3231_alarm/DS3231_alarm.ino b/examples/DS3231_alarm/DS3231_alarm.ino
index f1d8b1ea..86ba39f8 100644
--- a/examples/DS3231_alarm/DS3231_alarm.ino
+++ b/examples/DS3231_alarm/DS3231_alarm.ino
@@ -87,8 +87,12 @@ void loop() {
     Serial.print("] SQW: ");
     Serial.print(digitalRead(CLOCK_INTERRUPT_PIN));
 
-    // whether a alarm fired
-    Serial.print(" Fired: ");
+    // indicates if alarm 1 is enabled
+    Serial.print(", Enabled: ");
+    Serial.print(rtc.alarmEnabled(1));
+
+    // whether alarm 1 fired
+    Serial.print(", Fired: ");
     Serial.print(rtc.alarmFired(1));
 
     // Serial.print(" Alarm2: ");
diff --git a/src/RTC_DS3231.cpp b/src/RTC_DS3231.cpp
index c24a65a2..26ce0096 100644
--- a/src/RTC_DS3231.cpp
+++ b/src/RTC_DS3231.cpp
@@ -340,8 +340,19 @@ void RTC_DS3231::clearAlarm(uint8_t alarm_num) {
 
 /**************************************************************************/
 /*!
-    @brief  Get status of alarm
-        @param 	alarm_num Alarm number to check status of
+    @brief  Get enabled status of alarm
+        @param 	alarm_num Alarm number to check enabled status of
+        @return True if alarm is enabled otherwise false
+*/
+/**************************************************************************/
+bool RTC_DS3231::alarmEnabled(uint8_t alarm_num) {
+  return (read_register(DS3231_CONTROL) >> (alarm_num - 1)) & 0x1;
+}
+
+/**************************************************************************/
+/*!
+    @brief  Get fired status of alarm
+        @param 	alarm_num Alarm number to check fired status of
         @return True if alarm has been fired otherwise false
 */
 /**************************************************************************/
diff --git a/src/RTClib.h b/src/RTClib.h
index 879bb3fa..79dae57e 100644
--- a/src/RTClib.h
+++ b/src/RTClib.h
@@ -383,6 +383,7 @@ class RTC_DS3231 : RTC_I2C {
   Ds3231Alarm2Mode getAlarm2Mode();
   void disableAlarm(uint8_t alarm_num);
   void clearAlarm(uint8_t alarm_num);
+  bool alarmEnabled(uint8_t alarm_num);
   bool alarmFired(uint8_t alarm_num);
   void enable32K(void);
   void disable32K(void);