WIP: refactor RTC to use clock mode directly

watch-library/watch/watch_rtc.h

@@ -35,24 +35,84 @@
   *          to wake from STANDBY mode.
   */
 /// @{
+
+#define WATCH_RTC_REFERENCE_YEAR (2020)
+
+typedef struct watch_date_time {
+    uint16_t year;
+    uint8_t month;
+    uint8_t day;
+    uint8_t hour;
+    uint8_t minute;
+    uint8_t second;
+} watch_date_time;
+
+typedef enum watch_rtc_alarm_match {
+    ALARM_MATCH_DISABLED = 0,
+    ALARM_MATCH_SS,
+    ALARM_MATCH_MMSS,
+    ALARM_MATCH_HHMMSS,
+} watch_rtc_alarm_match;
+
 /** @brief Called by main.c to check if the RTC is enabled.
-  * You may call this function, but outside of app_init, it sbould always return true.
+  * You may call this function, but outside of app_init, it should always return true.
   */
 bool _watch_rtc_is_enabled();
 
+/** @brief Sets the date and time.
+  * @param date_time The time you wish to set.
+  * @note Internally, the SAM L22 stores the year as six bits representing a value from 0 to 63. It treats this
+  *       as a year offset from a reference year, which must be a leap year. For now, this library uses 2020 as
+  *       the reference year, so the range of valid values is 2020 to 2083.
+  */
+void watch_rtc_set_date_time(watch_date_time date_time);
+
+/** @brief Returns the system date and time in the provided struct.
+  * @return A watch_date_time with the current date and time.
+  */
+watch_date_time watch_rtc_get_date_time();
+
+/** @brief Registers an alarm callback that will be called when the RTC time matches the target time, as masked
+  *        by the provided mask.
+  * @param callback The function you wish to have called when the alarm fires. If this value is NULL, the alarm
+  *                 interrupt will still be enabled, but no callback function will be called.
+  * @param alarm_time The time that you wish to match. The date is currently ignored.
+  * @param mask One of the values in watch_rtc_alarm_match indicating which values to check.
+  * @details The alarm interrupt is a versatile tool for scheduling events in the future, especially since it can
+  *          wake the device from both shallow and deep sleep modes. The key to its versatility is the mask
+  *          parameter. Suppose we set an alarm for midnight, 00:00:00.
+  *           * if mask is ALARM_MATCH_SS, the alarm will fire every minute when the clock ticks to seconds == 0.
+  *           * with ALARM_MATCH_MMSS, the alarm will once an hour, at the top of each hour.
+  *           * with ALARM_MATCH_HHMMSS, the alarm will fire at midnight every day.
+  *          In theory the SAM L22's alarm function can match on days, months and even years, but I have not had
+  *          success with this yet; as such, I am omitting these options for now.
+  */
+void watch_rtc_register_alarm_callback(ext_irq_cb_t callback, watch_date_time alarm_time, watch_rtc_alarm_match mask);
+
+/** @brief Disables the alarm callback.
+  */
+void watch_rtc_disable_alarm_callback();
+
+/** @brief Registers a "tick" callback that will be called once per second.
+  * @param callback The function you wish to have called when the clock ticks. If you pass in NULL, the tick
+  *                 interrupt will still be enabled, but no callback function will be called.
+  */
+void watch_register_tick_callback(ext_irq_cb_t callback);
+
+/** @brief Disables the tick callback.
+  */
+void watch_disable_tick_callback();
+
 /** @brief Sets the system date and time.
   * @param date_time A struct representing the date and time you wish to set.
   */
+__attribute__((deprecated("Use watch_rtc_set_date_time function instead")))
 void watch_set_date_time(struct calendar_date_time date_time);
 
 /** @brief Returns the system date and time in the provided struct.
-  * @param date_time A pointer to a calendar_date_time struct.
-                     It will be populated with the correct date and time on return.
+  * @param date_time A pointer to a calendar_date_time struct. It will have with the correct date and time on return.
   */
+__attribute__((deprecated("Use the watch_rtc_get_date_time function instead")))
 void watch_get_date_time(struct calendar_date_time *date_time);
 
-/** @brief Registers a "tick" callback that will be called once per second.
-  * @param callback The function you wish to have called when the clock ticks.
-  */
-void watch_register_tick_callback(ext_irq_cb_t callback);
 /// @}