// Reference for connecting SPI see https://www.arduino.cc/en/Reference/SPI
// CONNECTIONS:
// DS3234 MISO --> MISO
// DS3234 MOSI --> MOSI
// DS3234 CLK --> CLK (SCK)
// DS3234 CS (SS) --> 5 (pin used to select the DS3234 on the SPI)
// DS3234 VCC --> 3.3v or 5v
// DS3234 GND --> GND
// SQW ---> (Pin19) Don't forget to pullup (4.7k to 10k to VCC)
#include <RtcDS3234.h>
#include <Arduino.h>
#include <SPI.h>
// Interrupt Pin Lookup Table
// (copied from Arduino Docs)
//
// CAUTION: The interrupts are Arduino numbers NOT Atmel numbers
// and may not match (example, Mega2560 int.4 is actually Atmel Int2)
// this is only an issue if you plan to use the lower level interupt features
//
// Board int.0 int.1 int.2 int.3 int.4 int.5
// ---------------------------------------------------------------
// Uno, Ethernet 2 3
// Mega2560 2 3 21 20 [19] 18
// Leonardo 3 2 0 1 7
// esp8266 (pin and interrupt should be the same thing)
// esp32 (pin and interrupt should be the same thing)
const uint8_t DS3234_CS_PIN = 5;
RtcDS3234<SPIClass> Rtc(SPI, DS3234_CS_PIN);
#define RtcSquareWavePin 19 // Mega2560
#define RtcSquareWaveInterrupt 4 // Mega2560
// marked volatile so interrupt can safely modify them and
// other code can safely read and modify them
volatile uint16_t interuptCount = 0;
volatile bool interuptFlag = false;
bool Alarmed()
{
bool wasAlarmed = false;
if (interuptFlag) // check our flag that gets sets in the interupt
{
wasAlarmed = true;
interuptFlag = false; // reset the flag
// this gives us which alarms triggered and
// then allows for others to trigger again
DS3234AlarmFlag flag = Rtc.LatchAlarmsTriggeredFlags();
if (flag & DS3234AlarmFlag_Alarm1)
{
Serial.println("alarm one triggered");
}
if (flag & DS3234AlarmFlag_Alarm2)
{
Serial.println("alarm two triggered");
}
}
return wasAlarmed;
}
#define countof(a) (sizeof(a) / sizeof(a[0]))
void printDateTime(const RtcDateTime& dt)
{
char datestring[20];
Serial.println(String(dt.Day()) + String("/") +
String(dt.Month()) + String("/") +
String(dt.Year()) + String(" : ") +
String(dt.Hour()) + String(":") +
String(dt.Minute()) + String(":") +
String(dt.Second()));
/*snprintf_P(datestring,
countof(datestring),
PSTR("%02u/%02u/%04u %02u:%02u:%02u"),
dt.Month(),
dt.Day(),
dt.Year(),
dt.Hour(),
dt.Minute(),
dt.Second() );*/
// Serial.print(datestring);
}
void ISR_ATTR InteruptServiceRoutine()
{
// since this interupted any other running code,
// don't do anything that takes long and especially avoid
// any communications calls within this routine
interuptCount++;
interuptFlag = true;
}
void setup ()
{
Serial.begin(9600);
while (!Serial);
// set the interrupt pin to input mode
pinMode(RtcSquareWavePin, INPUT_PULLUP); // external pullup maybe required still
SPI.begin();
Rtc.Begin();
RtcDateTime compiled = RtcDateTime(__DATE__, __TIME__);
if (!Rtc.GetIsRunning())
{
Serial.println("RTC was not actively running, starting now");
Rtc.SetIsRunning(true);
}
if (!Rtc.IsDateTimeValid())
{
Serial.println("RTC lost confidence in the DateTime!");
Rtc.SetDateTime(compiled);
}
RtcDateTime now = Rtc.GetDateTime();
if (now < compiled)
{
Serial.println("RTC is older than compile time! (Updating DateTime)");
printDateTime(compiled);
Rtc.SetDateTime(compiled);
}
RtcDateTime curr_time = Rtc.GetDateTime();
printDateTime(curr_time);
Serial.println();
Rtc.Enable32kHzPin(false);
Rtc.SetSquareWavePin(DS3234SquareWavePin_ModeAlarmBoth);
// Alarm 1 set to trigger every day when
// the hours, minutes, and seconds match
RtcDateTime alarmTime = now + 88; // into the future
DS3234AlarmOne alarm1(
alarmTime.Day(),
alarmTime.Hour(),
alarmTime.Minute(),
alarmTime.Second(),
DS3234AlarmOneControl_HoursMinutesSecondsMatch);
Rtc.SetAlarmOne(alarm1);
// Alarm 2 set to trigger at the top of the minute
DS3234AlarmTwo alarm2(0,0,0,
DS3234AlarmTwoControl_OncePerMinute);
Rtc.SetAlarmTwo(alarm2);
// throw away any old alarm state before we ran
Rtc.LatchAlarmsTriggeredFlags();
// setup external interupt
attachInterrupt(RtcSquareWaveInterrupt, InteruptServiceRoutine, FALLING);
}
void loop ()
{
if (!Rtc.IsDateTimeValid()){
Serial.println("RTC lost confidence in the DateTime!");
}
RtcDateTime now = Rtc.GetDateTime();
printDateTime(now);
Serial.println();
// we only want to show time every 10 seconds
// but we want to show response to the interrupt firing
for (int timeCount = 0; timeCount < 20; timeCount++)
{
if (Alarmed())
{
Serial.print(">>Interrupt Count: ");
Serial.print(interuptCount);
Serial.println("<<");
}
delay(500);
}
}