Hello everyone!
I’m reaching out cause i can’t quite understand what’s wrong here.
For context, i am making a device that should wake up every day and then go to sleep until the next day
For this i am using a DS3231 RTC, as it supports alarms.
I am using this library which has an example code to do just that, problem is it uses #include <avr/sleep.h> as its low power library, which is not compatible with the SAMD21, so i replaced it with the library that works (ArduinoLowPower), but am unable to get my xiao to wake up when the alarm should trigger. Here is the modified code:
// Arduino DS3232RTC Library
// https://github.com/JChristensen/DS3232RTC
// Copyright (C) 2022 by Jack Christensen and licensed under
// GNU GPL v3.0, https://www.gnu.org/licenses/gpl.html
//
// DS3231/DS3232 Alarm Example Sketch #10
//
// Wakes the MCU at regular intervals with an interrupt generated by
// an RTC alarm. After waking, the built-in LED is turned on for several
// seconds, then the MCU sleeps until the next alarm.
// Assumes that the RTC time was previously set and that the RTC is running.
//
// The "wakeInterval" variable sets the alarm interval, in minutes.
// The "ledInterval" variable sets the LED on-time, in seconds.
//
// Power to the RTC is supplied from an MCU pin, which is turned off while
// sleeping to minimize power consumption.
// Supply current while sleeping should be less than 1μA.
//
// Hardware:
// Arduino Uno, DS3231/2 RTC.
// Connect RTC SDA to Arduino pin A4.
// Connect RTC SCL to Arduino pin A5.
// Connect RTC INT/SQW to Arduino pin 2 or 3.
// Connect RTC Vcc to Arduino pin 5.
//
// Jack Christensen 17Jan2022
#include "ArduinoLowPower.h"
#include <DS3232RTC.h> // https://github.com/JChristensen/DS3232RTC
#include <Streaming.h> // https://github.com/janelia-arduino/Streaming
#include <TimeLib.h> // https://github.com/PaulStoffregen/Time
#include <Wire.h> // https://arduino.cc/en/Reference/Wire
// globals
constexpr uint32_t wakeInterval {5}; // wake interval in minutes
constexpr uint32_t ledInterval {30}; // seconds to leave the LED on after an alarm
static_assert(ledInterval < wakeInterval*60, "ledInterval must be less than wakeInterval!");
constexpr uint8_t rtcIntPin {3}; // RTC interrupt. Pin 2 for INT0, Pin 3 for INT1.
constexpr uint8_t rtcPower {8}; // RTC power is supplied by the MCU
volatile bool rtcAlarm {false}; // ISR flag
DS3232RTC myRTC;
void setup()
{
Serial.begin(115200);
while(!Serial){
;
}
Serial << F( "\n" __FILE__ "\n" __DATE__ " " __TIME__ "\n" );
myRTC.begin();
pinMode(LED_BUILTIN, OUTPUT);
pinMode(rtcPower, OUTPUT);
digitalWrite(rtcPower, HIGH);
// enable pullup on interrupt pin (RTC SQW pin is open drain)
pinMode(rtcIntPin, INPUT_PULLUP);
// set up the interrupt handler
attachInterrupt(digitalPinToInterrupt(rtcIntPin), rtcInterrupt, FALLING);
LowPower.attachInterruptWakeup(3, rtcInterrupt, FALLING);
myRTC.begin();
Serial << F("Sketch start "); printTime(myRTC.get());
Serial << F("Wake interval: ") << wakeInterval << F(" minutes.\n");
Serial << F("Using interrupt INT") << digitalPinToInterrupt(rtcIntPin) << endl;
Serial << F("RTC interrupt pin: ") << rtcIntPin << endl;
Serial << F("RTC power pin: ") << rtcPower << endl;
// initialize the alarms to known values, clear the alarm flags, clear the alarm interrupt flags
myRTC.setAlarm(DS3232RTC::ALM1_MATCH_DATE, 0, 0, 0, 1);
myRTC.setAlarm(DS3232RTC::ALM2_MATCH_DATE, 0, 0, 0, 1);
myRTC.alarm(DS3232RTC::ALARM_1);
myRTC.alarm(DS3232RTC::ALARM_2);
myRTC.alarmInterrupt(DS3232RTC::ALARM_1, false);
myRTC.alarmInterrupt(DS3232RTC::ALARM_2, false);
myRTC.squareWave(DS3232RTC::SQWAVE_NONE); // assert INT/SQW pin on alarm
}
void loop()
{
enum states_t { wait, alarm, ledOn, setAlarm };
static states_t state { setAlarm };
static uint32_t msLED;
switch (state)
{
case wait:
Serial << F("Going to sleep at "); printTime(myRTC.get()); Serial.flush();
digitalWrite(rtcPower, LOW);
pinMode(rtcPower, INPUT); // high-z, turn off power to the rtc
pinMode(SDA, INPUT); // high-z for the i2c bus
pinMode(SCL, INPUT);
goToSleep();
pinMode(rtcPower, OUTPUT);
digitalWrite(rtcPower, HIGH);
delay(20); // a little wake-up time for the rtc & i2c
if (rtcAlarm) { state = alarm; }
break;
case alarm:
state = ledOn;
Serial << F("Alarm at "); printTime(myRTC.get());
myRTC.alarm(DS3232RTC::ALARM_1); // clear alarm flag
myRTC.alarmInterrupt(DS3232RTC::ALARM_1, false);
noInterrupts();
rtcAlarm = false;
interrupts();
msLED = millis();
digitalWrite(LED_BUILTIN, HIGH);
break;
case ledOn:
if (millis() - msLED >= ledInterval * 1000) {
state = setAlarm;
digitalWrite(LED_BUILTIN, LOW);
}
break;
case setAlarm:
state = wait;
time_t utc = myRTC.get();
time_t wake = wakeInterval * 60;
time_t alm = utc - utc % wake + wake;
Serial << F("Setting alarm for "); printTime(alm);
myRTC.setAlarm(DS3232RTC::ALM1_MATCH_DATE, second(alm), minute(alm), hour(alm), day(alm));
myRTC.alarmInterrupt(DS3232RTC::ALARM_1, true);
break;
}
}
// RTC interrupt handler
void rtcInterrupt()
{
rtcAlarm = true;
}
// format and print a time_t value
void printTime(time_t t)
{
char buf[25];
char m[4]; // temporary storage for month string (DateStrings.cpp uses shared buffer)
strcpy(m, monthShortStr(month(t)));
sprintf(buf, "%.2d:%.2d:%.2d %s %.2d %s %d",
hour(t), minute(t), second(t), dayShortStr(weekday(t)), day(t), m, year(t));
Serial.println(buf);
}
void goToSleep()
{ // disable the ADC
// ensure interrupts enabled so we can wake up again
LowPower.deepSleep(); // go to sleep
// wake up here // restore ADCSRA
}
could anyone point me to what im doing wrong?
thanks in advance
PJ
