// Arduino MCP79412RTC Library

// https://github.com/JChristensen/MCP79412RTC

// Copyright (C) 2018 by Jack Christensen and licensed under

// GNU GPL v3.0, https://www.gnu.org/licenses/gpl.html

//

// Example sketch. Displays the date and time from an MCP79412 RTC

// every second.

//

// Set the date and time by entering the following on the Arduino

// serial monitor:

// Syear,month,day,hour,minute,second,

//

// Where

// year can be two or four digits,

// month is 1-12,

// day is 1-31,

// hour is 0-23, and

// minute and second are 0-59.

//

// Set the calibration register by entering the following:

// Cnnn,

//

// Where nnn can be a positive or negative value, e.g. "c4" or "c-42".

//

// Entering the final comma delimiter (after "second") will avoid a

// one-second timeout and will allow the RTC to be set more accurately.

//

// No validity checking is done, invalid values or incomplete syntax

// in the input will result in an incorrect RTC setting.

//

// Jack Christensen 28Aug2013

#include <MCP79412RTC.h> // https://github.com/JChristensen/MCP79412RTC

#include <Streaming.h> // http://arduiniana.org/libraries/streaming/

MCP79412RTC myRTC;

void setup()

{

Serial.begin(115200);

Serial << F( "\n" __FILE__ "\n" __DATE__ " " __TIME__ "\n" );

myRTC.begin();

// setSyncProvider() causes the Time library to synchronize with the

// external RTC by calling myRTC.get() every five minutes by default.

setSyncProvider([](){return myRTC.get();});

Serial << endl << F("RTC Sync");

if (timeStatus() != timeSet) Serial << F(" FAIL!");

Serial << endl;

uint8_t rtcID[8];

myRTC.idRead(rtcID);

Serial << F("RTC ID = ");

for (int i=0; i<8; ++i) {

if (rtcID[i] < 16) Serial << '0';

Serial << _HEX(rtcID[i]);

}

Serial << endl;

myRTC.getEUI64(rtcID);

Serial << F("EUI-64 = ");

for (int i=0; i<8; ++i) {

if (rtcID[i] < 16) Serial << '0';

Serial << _HEX(rtcID[i]);

}

Serial << endl;

Serial << F("Calibration Register = ") << myRTC.calibRead() << endl;

}

void loop()

{

// check for input, to set rtc time or calibration

if (Serial.available()) setRTC();

// print time and date every second

static time_t tLast;

time_t t { now() };

if (t != tLast) {

tLast = t;

printTime(t);

}

}

void setRTC()

{

// first character is a command, "S" to set date/time, or "C" to set the calibration register

int cmdChar = Serial.read();

switch (cmdChar) {

case 'S':

case 's':

delay(25); // wait for all the input to arrive

// check for input to set the RTC, minimum length is 13, i.e. yy,m,d,h,m,s<nl>

if (Serial.available() < 13) {

while (Serial.available()) Serial.read(); // dump extraneous input

Serial << F("Input error or timeout, try again.\n");

}

else {

// note that the tmElements_t Year member is an offset from 1970,

// but the RTC wants the last two digits of the calendar year.

// use the convenience macros from TimeLib.h to do the conversions.

int y = Serial.parseInt();

if (y >= 100 && y < 1000)

Serial << F("Error: Year must be two digits or four digits!\n");

else {

tmElements_t tm;

if (y >= 1000)

tm.Year = CalendarYrToTm(y);

else //(y < 100)

tm.Year = y2kYearToTm(y);

tm.Month = Serial.parseInt();

tm.Day = Serial.parseInt();

tm.Hour = Serial.parseInt();

tm.Minute = Serial.parseInt();

tm.Second = Serial.parseInt();

if (tm.Month == 0 || tm.Day == 0) {

while (Serial.available()) Serial.read(); // dump extraneous input

Serial << F("Input error or timeout, try again.\n");

}

else {

time_t t = makeTime(tm);

myRTC.set(t); // use the time_t value to ensure correct weekday is set

setTime(t);

Serial << F("RTC set to: ");

printTime(t);

}

}

}

break;

case 'C':

case 'c':

delay(25); // wait for all the input to arrive

if (Serial.available() < 2) { // minimum valid input at this point is 2 chars

while (Serial.available()) Serial.read(); // dump extraneous input

Serial << F("Input error or timeout, try again.\n");

}

else {

int newCal = Serial.parseInt();

int oldCal = myRTC.calibRead();

myRTC.calibWrite(newCal);

Serial << F("Calibration changed from ") << oldCal << F(" to ") << myRTC.calibRead() << endl;

}

break;

default:

Serial << endl << F("Unrecognized command: ") << (char)cmdChar << endl;

break;

}

// dump any extraneous input

while (Serial.available()) Serial.read();

}

// format and print a time_t value

void printTime(const 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);

}