Grove RTC (1307) and Arduino Nano IOT33

Products & Technology Grove
#1

Hi folks – grateful for any assistance on this.

So with an Arduino Nano IOT33, on a Grove Shield, hooked up to the I2C port, the output is not at all what it’s supposed to be.

I’m running the bare bones basic example:

#include <Wire.h>
#include "DS1307.h"

DS1307 clock;//define a object of DS1307 class
void setup()
{
	Serial.begin(9600);
	clock.begin();
	clock.fillByYMD(2013,1,19);//Jan 19,2013
	clock.fillByHMS(15,28,30);//15:28 30"
	clock.fillDayOfWeek(SAT);//Saturday
	clock.setTime();//write time to the RTC chip
}
void loop()
{
	printTime();
}
/*Function: Display time on the serial monitor*/
void printTime()
{
	clock.getTime();
	Serial.print(clock.hour, DEC);
	Serial.print(":");
	Serial.print(clock.minute, DEC);
	Serial.print(":");
	Serial.print(clock.second, DEC);
	Serial.print("	");
	Serial.print(clock.month, DEC);
	Serial.print("/");
	Serial.print(clock.dayOfMonth, DEC);
	Serial.print("/");
	Serial.print(clock.year+2000, DEC);
	Serial.print(" ");
	Serial.print(clock.dayOfMonth);
	Serial.print("*");
	switch (clock.dayOfWeek)// Friendly printout the weekday
	{
		case MON:
		  Serial.print("MON");
		  break;
		case TUE:
		  Serial.print("TUE");
		  break;
		case WED:
		  Serial.print("WED");
		  break;
		case THU:
		  Serial.print("THU");
		  break;
		case FRI:
		  Serial.print("FRI");
		  break;
		case SAT:
		  Serial.print("SAT");
		  break;
		case SUN:
		  Serial.print("SUN");
		  break;
	}
	Serial.println(" ");
}

But the output I get is:

45:165:85 165/165/2165 165*
45:165:85 165/165/2165 165*
45:165:85 165/165/2165 165*
45:165:85 165/165/2165 165*
45:165:85 165/165/2165 165*
45:165:85 165/165/2165 165*

This output doesn’t make sense, of course, and the code is exactly the example.

#2

So … am I looking at bad hardware? Incompatibility with the Arduino Nano? Other?

#3

Try to set the date of the RTC and then run. Sometimes we need to set these RTCs before the first use.

#4

But…the code literally does that:

clock.begin();
clock.fillByYMD(2013,1,19);//Jan 19,2013
clock.fillByHMS(15,28,30);//15:28 30"
clock.fillDayOfWeek(SAT);//Saturday
clock.setTime();//write time to the RTC chip
#5

Oh I see. Sometimes the coin cell battery voltage drop creates problems. Do you have a multimeter? If yes, plz measure if the coin cell battery has 3V.

#6

So it turns out the problem is that I’m an idiot.

IF you put the coin cell in upside down, you will see the same behavior I observed above!

When I turned the coin cell right side up…the problem disappeared.