Added support for Mode 0 and Mode 1

Adds support for Mode 0 (32-bit counter) and Mode 1 (16-bit periodic counter).  Mode 1 can operate with one or two compare values and optionally a set period.  Adds options to reset on match and interrupt on overflow as well as a helper function to get the source of RTC interrupts and enums for prescale values and interrupt sources.  Includes examples for Mode 0 with reset on match, Mode 1 with two compares and a set period and Mode 1 with interrupt on overflow enabled (along with two compares).

Author: amcmahon01

examples/Mode0_32-bit_Counter/Mode0_32-bit_Counter.ino

@@ -0,0 +1,41 @@
+/*
+  RTC counter for SAMD21 controllers (Arduino Zero, MKR1000, Adafruit Feather M0)
+
+  Demonstrates the use of the RTC library Mode 0 (32-bit counter) for SAMD21 controllers
+  This example starts a counter that interrupts and resets after 10 seconds* since
+  "reset on match" is set to true.
+  
+  (*seconds, based on GCLK_RTC = 1.024khz and default 1/1024 prescaler)
+
+  This example code is in the public domain
+
+  created by A. McMahon
+  20 Feb 2020
+*/
+
+#include <RTCZero.h>
+
+/* Create an rtc object */
+RTCZero rtc;
+
+void countDone(void);
+
+void setup()
+{
+  Serial.begin(9600);
+
+  rtc.begin(true, 0, true);                     // initialize RTC: reset starting value, Mode 0 (32-bit counter), reset on match
+  rtc.enableCounter(10);                        // set counter compare value
+  rtc.attachInterrupt(countDone);               // attach interrupt
+}
+
+void loop()
+{
+  Serial.println(rtc.getCount());               // print the current count
+  delay(1000);
+}
+
+void countDone()                                // interrupt when compare value is reached
+{                              
+  Serial.println("Reset!");
+}

examples/Mode1_16-bit_Periodic_Counter/Mode1_16-bit_Periodic_Counter.ino

@@ -0,0 +1,46 @@
+/*
+  RTC counter for SAMD21 controllers (Arduino Zero, MKR1000, Adafruit Feather M0)
+
+  Demonstrates the use of the RTC library Mode 1 (16-bit periodic counter) for SAMD21 controllers
+  This example starts a counter that interrupts at 10 and 30 seconds* (for the compare values).
+  The count is then reset after 60 since that is the set counter period. 
+
+  (*seconds, based on GCLK_RTC = 1.024khz and default 1/1024 prescaler)
+
+  This example code is in the public domain
+
+  created by A. McMahon
+  20 Feb 2020
+*/
+
+#include "RTCZero.h"
+
+/* Create an rtc object */
+RTCZero rtc;
+
+void countInt(void);
+
+void setup()
+{
+  Serial.begin(9600);
+
+  rtc.begin(true, 1);                           // initialize RTC: reset starting value, Mode 1 (16-bit counter)
+  rtc.enableCounter(10, 30);                    // set counter compare values (interrupt at 10 and 30)
+  rtc.setPeriod(60);                            // set counter period
+  rtc.attachInterrupt(countInt);                // attach interrupt
+}
+
+void loop()
+{
+  Serial.println(rtc.getCount());               // print the current count
+  delay(1000);
+}
+
+void countInt()                                 // interrupt when compare value is reached
+{
+  uint8_t source;
+  source = rtc.getIntSource();                  // check what caused the interrupt
+
+  if (source == rtc.INT_COMP0) Serial.println("Count = Compare 0!");
+  if (source == rtc.INT_COMP1) Serial.println("Count = Compare 1!");
+} 

examples/Mode1_16-bit_Periodic_Counter_Overflow/Mode1_16-bit_Periodic_Counter_Overflow.ino

@@ -0,0 +1,49 @@
+/*
+  RTC counter for SAMD21 controllers (Arduino Zero, MKR1000, Adafruit Feather M0)
+
+  Demonstrates the use of the RTC library Mode 1 (16-bit periodic counter) for SAMD21 controllers
+  This example starts a counter that interrupts at 10 and 30 seconds* (for the compare values) 
+  and at 60 (since the overflow interrupt is also enabled).  The count is then reset after 60
+  since that is the set counter period. 
+
+  (*seconds, based on GCLK_RTC = 1.024khz and default 1/1024 prescaler)
+
+  This example code is in the public domain
+
+  created by A. McMahon
+  20 Feb 2020
+*/
+
+#include "RTCZero.h"
+
+/* Create an rtc object */
+RTCZero rtc;
+
+void countInt(void);
+
+void setup()
+{
+  Serial.begin(9600);
+
+  rtc.begin(true, 1);                           // initialize RTC: reset starting value, Mode 1 (16-bit counter)
+  rtc.enableCounter(10, 30);                    // set counter compare values (interrupt at 10 and 30)
+  rtc.setPeriod(60);                            // set counter period
+  rtc.enableOverflow();                         // enable interrupt on overflow
+  rtc.attachInterrupt(countInt);                // attach interrupt
+}
+
+void loop()
+{
+  Serial.println(rtc.getCount());               // print the current count
+  delay(1000);
+}
+
+void countInt()                                 // interrupt when compare value is reached
+{
+  uint8_t source;
+  source = rtc.getIntSource();                  // check what caused the interrupt
+
+  if (source == rtc.INT_COMP0) Serial.println("Count = Compare 0!");
+  if (source == rtc.INT_COMP1) Serial.println("Count = Compare 1!");
+  if (source == rtc.INT_OVERFLOW) Serial.println("Overflow!");
+} 

keywords.txt

@@ -52,6 +52,19 @@ setAlarmTime	KEYWORD2
 enableAlarm	KEYWORD2
 disableAlarm	KEYWORD2
 
+enableCounter   KEYWORD2
+disableCounter  KEYWORD2
+
+enableOverflow  KEYWORD2
+disableOverflow KEYWORD2
+
+getIntSource    KEYWORD2
+getCount    KEYWORD2
+getCompare  KEYWORD2
+
+setCount    KEYWORD2
+setPeriod   KEYWORD2
+
 standbyMode	KEYWORD2
 
 #######################################

library.properties

@@ -1,5 +1,5 @@
 name=RTCZero
-version=1.6.0
+version=2.0.0
 author=Arduino
 maintainer=Arduino <info@arduino.cc>
 sentence=Allows to use the RTC functionalities. For Arduino Zero, MKRZero and MKR1000 only.