Get time as 24 hour format from RTC

Question

I have a DS3231 RTC module.

I would like to get the time from the RTC as 24 hour format not 12 hour. The library that I'm using requires that I pass in 2 Boolean values into Clock.getHour(), however changing these values does not change the returned time format.

Code;

/*
DS3231_test.pde
Eric Ayars
4/11
Test/demo of read routines for a DS3231 RTC.
Turn on the serial monitor after loading this to check if things are
working as they should.
*/
#include <DS3231.h>
#include <Wire.h>
DS3231 clock;
bool century = false;
bool h12Flag;
bool pmFlag;
byte alarmDay, alarmHour, alarmMinute, alarmSecond, alarmBits;
bool alarmDy, alarmH12Flag, alarmPmFlag;
void setup() {
 // Start the I2C interface
 Wire.begin();
 
 // Start the serial interface
 Serial.begin(57600);
}
void loop() {
 // send what's going on to the serial monitor.
 
 // Start with the year
 Serial.print("2");
 if (century) { // Won't need this for 89 years.
 Serial.print("1");
 } else {
 Serial.print("0");
 }
 Serial.print(clock.getYear(), DEC);
 Serial.print(' ');
 
 // then the month
 Serial.print(clock.getMonth(century), DEC);
 Serial.print(" ");
 
 // then the date
 Serial.print(clock.getDate(), DEC);
 Serial.print(" ");
 
 // and the day of the week
 Serial.print(clock.getDoW(), DEC);
 Serial.print(" ");
 
 // Finally the hour, minute, and second
 Serial.print(clock.getHour(h12Flag, pmFlag), DEC);
 Serial.print(" ");
 Serial.print(clock.getMinute(), DEC);
 Serial.print(" ");
 Serial.print(clock.getSecond(), DEC);
 
 // Add AM/PM indicator
 if (h12Flag) {
 if (pmFlag) {
 Serial.print(" PM ");
 } else {
 Serial.print(" AM ");
 }
 } else {
 Serial.print(" 24h ");
 }
 
 // Display the temperature
 Serial.print("T=");
 Serial.print(clock.getTemperature(), 2);
 
 // Tell whether the time is (likely to be) valid
 if (clock.oscillatorCheck()) {
 Serial.print(" O+");
 } else {
 Serial.print(" O-");
 }
 
 // Indicate whether an alarm went off
 if (clock.checkIfAlarm(1)) {
 Serial.print(" A1!");
 }
 
 if (clock.checkIfAlarm(2)) {
 Serial.print(" A2!");
 }
 
 // New line on display
 Serial.println();
 
 // Display Alarm 1 information
 Serial.print("Alarm 1: ");
 clock.getA1Time(alarmDay, alarmHour, alarmMinute, alarmSecond, alarmBits, alarmDy, alarmH12Flag, alarmPmFlag);
 Serial.print(alarmDay, DEC);
 if (alarmDy) {
 Serial.print(" DoW");
 } else {
 Serial.print(" Date");
 }
 Serial.print(' ');
 Serial.print(alarmHour, DEC);
 Serial.print(' ');
 Serial.print(alarmMinute, DEC);
 Serial.print(' ');
 Serial.print(alarmSecond, DEC);
 Serial.print(' ');
 if (alarmH12Flag) {
 if (alarmPmFlag) {
 Serial.print("pm ");
 } else {
 Serial.print("am ");
 }
 }
 if (clock.checkAlarmEnabled(1)) {
 Serial.print("enabled");
 }
 Serial.println();
 
 // Display Alarm 2 information
 Serial.print("Alarm 2: ");
 clock.getA2Time(alarmDay, alarmHour, alarmMinute, alarmBits, alarmDy, alarmH12Flag, alarmPmFlag);
 Serial.print(alarmDay, DEC);
 if (alarmDy) {
 Serial.print(" DoW");
 } else {
 Serial.print(" Date");
 }
 Serial.print(" ");
 Serial.print(alarmHour, DEC);
 Serial.print(" ");
 Serial.print(alarmMinute, DEC);
 Serial.print(" ");
 if (alarmH12Flag) {
 if (alarmPmFlag) {
 Serial.print("pm");
 } else {
 Serial.print("am");
 }
 }
 if (clock.checkAlarmEnabled(2)) {
 Serial.print("enabled");
 }
 
 // display alarm bits
 Serial.println();
 Serial.print("Alarm bits: ");
 Serial.println(alarmBits, BIN);
 Serial.println();
 delay(1000);
}

How do I make this happen?

Answer 1

The library that I'm using requires that I pass in 2 Boolean values into Clock.getHour(), however changing these values does not change the returned time format.

You appear to be talking about the parameters here, which the second is for getting the current state of the AM/PM flag and configuration and not altering the kind of value you get in the return.

There's a setClockMode function you can call which will configure the chip to report in 24-hour mode. If you call that passing in false, getHour should begin returning 24-hour time.