MCP7940 how to set alarm to Day-of-the-week(1-7) about mcp7940 HOT 8 CLOSED

Setting the Alarm to a day of the week works. You specified the mask as 3 in your example above, which denotes "day of week", but then you used the construct "DateTime(0,0,3,0,0,0)" I think you did something you didn't expect

  DateTime xxx(0, 0, 3, 0, 0, 0);
  Serial.print("Day of Week ");
  Serial.println(xxx.dayOfTheWeek());

returns day "1" Which I believe you probably didn't want. You should enter a valid date as input for the DateTime() function and the the MCP7940.setAlarm() will take the DOW from that date and set the alarm accordingly.

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That means if you call MCP7940.setAlarm(0,3,2019,02,01,0,0,0)); then it will set alarm 0 to trigger on a Friday.

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Hello, SV-Zanshin,

Your solution works!!! thank you very much!!

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No worries, glad you are having some success with the library!

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Hello Zanshin,

Is it also possible to do a wake up after 10 or 30 seconds? How can i program that?

Kind regards,

Wim

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Hello Zanshin,

is it possible to use the MCP7940 to interrupt the arduino mega by interrupt? and so yes, what am i doing wrong in the code below?
Kind regards,
Wim

#include <MCP7940.h> // Include the MCP7940 RTC library
/***************************************************************************************************
** Declare all program constants and enumerated types **
/
const uint32_t SERIAL_SPEED{9600}; ///< Set the baud rate for Serial I/O
const uint8_t LED_PIN{13}; ///< Arduino built-in LED pin number
const uint8_t SPRINTF_BUFFER_SIZE{32}; ///< Buffer size for sprintf()
const uint8_t ALARM1_INTERVAL{15}; ///< Interval seconds for alarm
const byte interruptPin = 82;
boolean mfpPinTriggered = false;
/! ///< Enumeration of MCP7940 alarm types /
enum alarmTypes {
matchSeconds,
matchMinutes,
matchHours,
matchDayOfWeek,
matchDayOfMonth,
Unused1,
Unused2,
matchAll,
Unknown
};
/
** Declare global variables and instantiate classes **
***************************************************************************************************/
MCP7940_Class MCP7940; ///< Create instance of the MCP7940M
char inputBuffer[SPRINTF_BUFFER_SIZE]; ///< Buffer for sprintf() / sscanf()

void rtcMFP()
{
mfpPinTriggered = true;
Serial.println(F(" #INTRTC#"));//delay(50);
}

void setup() {
attachInterrupt(digitalPinToInterrupt(2), rtcMFP, RISING);// (recommended)
//attachInterrupt(82, rtcMFP, RISING);//interrupt for rtc Alarm
/*!
@brief Arduino method called once upon start or restart.
*/
Serial.begin(SERIAL_SPEED); // Start serial port at specified Baud rate
#ifdef AVR_ATmega32U4 // If this is a 32U4 processor, then wait 3 seconds for the serial
// interface to initialize
delay(3000);
#endif
Serial.print(F("\nStarting SetAlarms program\n"));
Serial.print(F("- Compiled with c++ version "));
Serial.print(F(VERSION)); // Show compiler information
Serial.print(F("\n- On "));
Serial.print(F(DATE));
Serial.print(F(" at "));
Serial.print(F(TIME));
Serial.print(F("\n"));
while (!MCP7940.begin()) // Loop until the RTC communications are established
{
Serial.println(F("Unable to find MCP7940. Checking again in 3s."));
delay(3000);
} // of loop until device is located
Serial.println(F("MCP7940 initialized."));
while (!MCP7940.deviceStatus()) // Turn oscillator on if necessary
{
Serial.println(F("Oscillator is off, turning it on."));
bool deviceStatus = MCP7940.deviceStart(); // Start oscillator and return state
if (!deviceStatus) // If it didn't start
{
Serial.println(F("Oscillator did not start, trying again."));
delay(1000);
} // of if-then oscillator didn't start
} // of while the oscillator is of

Serial.println("Setting MCP7940M to date/time of library compile");
MCP7940.adjust(); // Use compile date/time to set clock
Serial.print("Date/Time set to ");
DateTime now = MCP7940.now(); // get the current time
// Use sprintf() to pretty print date/time with leading zeroes
sprintf(inputBuffer, "%04d-%02d-%02d %02d:%02d:%02d", now.year(), now.month(), now.day(),
now.hour(), now.minute(), now.second());
Serial.println(inputBuffer);
Serial.println("Setting alarm 0 for every minute at 0 seconds.");
MCP7940.setAlarm(0, matchSeconds, now - TimeSpan(0, 0, 0, now.second()),
true); // Match once a minute at 0 seconds
Serial.print("Setting alarm 1 to go off at ");
now = now + TimeSpan(0, 0, 0, ALARM1_INTERVAL); // Add interval to current time
sprintf(inputBuffer, "%04d-%02d-%02d %02d:%02d:%02d", now.year(), now.month(), now.day(),
now.hour(), now.minute(), now.second());
Serial.println(inputBuffer);
MCP7940.setAlarm(1, matchAll, now, true); // Set alarm to go off then
pinMode(LED_PIN, OUTPUT); // Declare built-in LED as output
} // of method setup()

void loop() {
/*!
@brief Arduino method called after setup() which loops forever
*/
static uint8_t secs;
DateTime now = MCP7940.now(); // get the current time
if (secs != now.second()) // Output if seconds have changed
{
sprintf(inputBuffer, "%04d-%02d-%02d %02d:%02d:%02d", now.year(), now.month(), now.day(),
now.hour(), now.minute(), now.second());
//Serial.print(inputBuffer);
secs = now.second(); // Set the counter for later comparision
if (MCP7940.isAlarm(0)) // When alarm 0 is triggered
{
Serial.print(" Alarm0");Serial.println(inputBuffer);
MCP7940.clearAlarm(0);
} // of if Alarm 0 has been triggered
if (MCP7940.isAlarm(1)) // When alarm 0 is triggered
{
Serial.print(" Alarm1 resetting to go off next at ");
now = now + TimeSpan(0, 0, 0, ALARM1_INTERVAL); // Add interval to current time
sprintf(inputBuffer, "%04d-%02d-%02d %02d:%02d:%02d", now.year(), now.month(), now.day(),
now.hour(), now.minute(), now.second());
Serial.println(inputBuffer);
MCP7940.setAlarm(1, matchAll, now, true); // Set alarm to go off in 10s again
} // of if Alarm 0 has been triggered
//Serial.println();
} // of if the seconds have changed
} // of method loop()

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@wimvanderneut - yes, you can use the MCP7940 for interrupts. Check out the example example, Square Wave, to see see how a simple interrupt is used there. That can be adapted as you want.

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