Feature - RTC alarm on every second

src/rp2_common/hardware_rtc/include/hardware/rtc.h

@@ -50,7 +50,7 @@ void rtc_init(void);
  * \param t Pointer to a \ref datetime_t structure contains time to set
  * \return true if set, false if the passed in datetime was invalid.
  */
-bool rtc_set_datetime(datetime_t *t);
+bool rtc_set_datetime(const datetime_t *t);
 
 /*! \brief Get the current time from the RTC
  *  \ingroup hardware_rtc
@@ -71,8 +71,9 @@ bool rtc_running(void);
  *
  *  \param t Pointer to a \ref datetime_t structure containing a time in the future to fire the alarm. Any values set to -1 will not be matched on.
  *  \param user_callback pointer to a \ref rtc_callback_t to call when the alarm fires
+ *  \return false if parameters aren't valid
  */
-void rtc_set_alarm(datetime_t *t, rtc_callback_t user_callback);
+bool rtc_set_alarm(const datetime_t *t, rtc_callback_t user_callback);
 
 /*! \brief Enable the RTC alarm (if inactive)
  *  \ingroup hardware_rtc

src/rp2_common/hardware_rtc/rtc.c

@@ -13,7 +13,14 @@
 
 // Set this when setting an alarm
 static rtc_callback_t _callback = NULL;
-static bool _alarm_repeats = false;
+
+typedef enum {
+    NO_REPEAT                =  0,
+    CONTINUOUS_REPEAT        =  1,
+    CONTINUOUS_REPEAT_ON_SEC =  2,
+} repeat_type;
+
+static repeat_type _alarm_repeats = NO_REPEAT;
 
 bool rtc_running(void) {
     return (rtc_hw->ctrl & RTC_CTRL_RTC_ACTIVE_BITS);
@@ -39,7 +46,7 @@ void rtc_init(void) {
     rtc_hw->clkdiv_m1 = rtc_freq;
 }
 
-static bool valid_datetime(datetime_t *t) {
+static bool valid_datetime(const datetime_t *t) {
     // Valid ranges taken from RTC doc. Note when setting an RTC alarm
     // these values are allowed to be -1 to say "don't match this value"
     if (!(t->year >= 0 && t->year <= 4095)) return false;
@@ -52,7 +59,7 @@ static bool valid_datetime(datetime_t *t) {
     return true;
 }
 
-bool rtc_set_datetime(datetime_t *t) {
+bool rtc_set_datetime(const datetime_t *t) {
     if (!valid_datetime(t)) {
         return false;
     }
@@ -114,6 +121,14 @@ void rtc_enable_alarm(void) {
     }
 }
 
+void rtc_disable_alarm(void) {
+    // Disable matching and wait for it to stop being active
+    hw_clear_bits(&rtc_hw->irq_setup_0, RTC_IRQ_SETUP_0_MATCH_ENA_BITS);
+    while (rtc_hw->irq_setup_0 & RTC_IRQ_SETUP_0_MATCH_ACTIVE_BITS) {
+        tight_loop_contents();
+    }
+}
+
 static void rtc_irq_handler(void) {
     // Always disable the alarm to clear the current IRQ.
     // Even if it is a repeatable alarm, we don't want it to keep firing.
@@ -122,6 +137,11 @@ static void rtc_irq_handler(void) {
 
     if (_alarm_repeats) {
         // If it is a repeatable alarm, re enable the alarm.
+        if(_alarm_repeats == CONTINUOUS_REPEAT_ON_SEC) {
+          datetime_t t;
+          rtc_get_datetime(&t);
+          rtc_hw->irq_setup_1 = RTC_IRQ_SETUP_1_SEC_ENA_BITS | ((((uint)t.sec + 1) % 60) << RTC_IRQ_SETUP_1_SEC_LSB);
+        }
         rtc_enable_alarm();
     }
 
@@ -131,43 +151,46 @@ static void rtc_irq_handler(void) {
     }
 }
 
-static bool rtc_alarm_repeats(datetime_t *t) {
-    // If any value is set to -1 then we don't match on that value
-    // hence the alarm will eventually repeat
-    if (t->year  < 0) return true;
-    if (t->month < 0) return true;
-    if (t->day   < 0) return true;
-    if (t->dotw  < 0) return true;
-    if (t->hour  < 0) return true;
-    if (t->min   < 0) return true;
-    if (t->sec   < 0) return true;
-    return false;
+// return != 0 on repeat, -1 on repeat every second
+static int8_t rtc_alarm_repeats(const datetime_t *t) {
+  // If any value is set to -1 then we don't match on that value
+  // hence the alarm will eventually repeat
+    if((t->year & t->month & t->day & t->dotw & t->hour & t->min & t->sec) < 0) return CONTINUOUS_REPEAT_ON_SEC;
+
+    return (t->year < 0 || t->month < 0 || t->day < 0 || t->dotw < 0
+            || t->hour < 0 || t->min < 0 || t->sec < 0)
+        ? CONTINUOUS_REPEAT : NO_REPEAT;
 }
 
-void rtc_set_alarm(datetime_t *t, rtc_callback_t user_callback) {
+bool rtc_set_alarm(const datetime_t *t, rtc_callback_t user_callback) {
     rtc_disable_alarm();
 
-    // Only add to setup if it isn't -1
-    rtc_hw->irq_setup_0 = ((t->year  < 0) ? 0 : (((uint)t->year)  << RTC_IRQ_SETUP_0_YEAR_LSB )) |
-                          ((t->month < 0) ? 0 : (((uint)t->month) << RTC_IRQ_SETUP_0_MONTH_LSB)) |
-                          ((t->day   < 0) ? 0 : (((uint)t->day)   << RTC_IRQ_SETUP_0_DAY_LSB  ));
-    rtc_hw->irq_setup_1 = ((t->dotw  < 0) ? 0 : (((uint)t->dotw)  << RTC_IRQ_SETUP_1_DOTW_LSB)) |
-                          ((t->hour  < 0) ? 0 : (((uint)t->hour)  << RTC_IRQ_SETUP_1_HOUR_LSB)) |
-                          ((t->min   < 0) ? 0 : (((uint)t->min)   << RTC_IRQ_SETUP_1_MIN_LSB )) |
-                          ((t->sec   < 0) ? 0 : (((uint)t->sec)   << RTC_IRQ_SETUP_1_SEC_LSB ));
-
-    // Set the match enable bits for things we care about
-    if (t->year  >= 0) hw_set_bits(&rtc_hw->irq_setup_0, RTC_IRQ_SETUP_0_YEAR_ENA_BITS);
-    if (t->month >= 0) hw_set_bits(&rtc_hw->irq_setup_0, RTC_IRQ_SETUP_0_MONTH_ENA_BITS);
-    if (t->day   >= 0) hw_set_bits(&rtc_hw->irq_setup_0, RTC_IRQ_SETUP_0_DAY_ENA_BITS);
-    if (t->dotw  >= 0) hw_set_bits(&rtc_hw->irq_setup_1, RTC_IRQ_SETUP_1_DOTW_ENA_BITS);
-    if (t->hour  >= 0) hw_set_bits(&rtc_hw->irq_setup_1, RTC_IRQ_SETUP_1_HOUR_ENA_BITS);
-    if (t->min   >= 0) hw_set_bits(&rtc_hw->irq_setup_1, RTC_IRQ_SETUP_1_MIN_ENA_BITS);
-    if (t->sec   >= 0) hw_set_bits(&rtc_hw->irq_setup_1, RTC_IRQ_SETUP_1_SEC_ENA_BITS);
+    uint32_t s0 = 0, s1 = 0;
 
     // Does it repeat? I.e. do we not match on any of the bits
     _alarm_repeats = rtc_alarm_repeats(t);
 
+    if( (!valid_datetime(t) && !_alarm_repeats) || !user_callback)	// none of the parameters is valid
+        return false;
+
+    // Set the match enable bits for things we care about
+    if (t->year  >= 0) s0 |= RTC_IRQ_SETUP_0_YEAR_ENA_BITS  | (((uint)t->year)  << RTC_IRQ_SETUP_0_YEAR_LSB );
+    if (t->month >= 1) s0 |= RTC_IRQ_SETUP_0_MONTH_ENA_BITS | (((uint)t->month) << RTC_IRQ_SETUP_0_MONTH_LSB);
+    if (t->day   >= 1) s0 |= RTC_IRQ_SETUP_0_DAY_ENA_BITS   | (((uint)t->day)   << RTC_IRQ_SETUP_0_DAY_LSB  );
+    if (t->dotw  >= 0) s1 |= RTC_IRQ_SETUP_1_DOTW_ENA_BITS  | (((uint)t->dotw)  << RTC_IRQ_SETUP_1_DOTW_LSB);
+    if (t->hour  >= 0) s1 |= RTC_IRQ_SETUP_1_HOUR_ENA_BITS  | (((uint)t->hour)  << RTC_IRQ_SETUP_1_HOUR_LSB);
+    if (t->min   >= 0) s1 |= RTC_IRQ_SETUP_1_MIN_ENA_BITS   | (((uint)t->min)   << RTC_IRQ_SETUP_1_MIN_LSB);
+    if (t->sec   >= 0) s1 |= RTC_IRQ_SETUP_1_SEC_ENA_BITS   | (((uint)t->sec)   << RTC_IRQ_SETUP_1_SEC_LSB);
+    else if (_alarm_repeats == CONTINUOUS_REPEAT_ON_SEC) {
+        // repeatable every second! All entries are -1
+        datetime_t new_dt;
+        rtc_get_datetime(&new_dt);
+        s1 = RTC_IRQ_SETUP_1_SEC_ENA_BITS | ((((uint)new_dt.sec + 1) % 60) << RTC_IRQ_SETUP_1_SEC_LSB);
+    }
+
+    rtc_hw->irq_setup_0 = s0;
+    rtc_hw->irq_setup_1 = s1;
+
     // Store function pointer we can call later
     _callback = user_callback;
 
@@ -180,12 +203,5 @@ void rtc_set_alarm(datetime_t *t, rtc_callback_t user_callback) {
     irq_set_enabled(RTC_IRQ, true);
 
     rtc_enable_alarm();
-}
-
-void rtc_disable_alarm(void) {
-    // Disable matching and wait for it to stop being active
-    hw_clear_bits(&rtc_hw->irq_setup_0, RTC_IRQ_SETUP_0_MATCH_ENA_BITS);
-    while(rtc_hw->irq_setup_0 & RTC_IRQ_SETUP_0_MATCH_ACTIVE_BITS) {
-        tight_loop_contents();
-    }
+    return true;
 }