SOLVED-DDS 1307 RTC not working on coin celland external power, works only on 5v

hi everyone
i’m new to arduino and im learning , i connected a DS1307RTC to arduino pro mini and ran the example timeset program when ever i add the coin cell to the RTC its not working , its works fine when it is powered by 5v from arduino alone i tried replacing pullup resistors to 4.7k and 10k and also replace the DS 1307 with new one nothing worked. the battery im using is CR 2025 coin cell. my RTC board also has a 24C16 eeprom on it can anyone help me on this. thanks in advance.

You'll need to explain what you mean by "not working".

My understanding is that with the coin cell the RTC is not supposed to "work" in the sense of being interrogated for the time. The coin cell's purpose is (afaik) to keep the clock operating so that it keeps the time, then when you next hook it up to 5V and interrogate it, it knows and shows the right time.

I for example have had my 1307 module disconnected from a project for some time, but with the coin cell in for some weeks, and then when I hook it back up to the project with 5V connected, the time's still correct.

Are you saying you hoped to have the RTC fully operational with the coin cell as its power?- if so I don't think that's what it's supposed to do.

But I might be misinterpreting your question.....

JimboZA: But I might be misinterpreting your question.....

You may be right, but another common newbie mistake that occurs is that they leave the part in the setup() function that sets the current time to the time of compilation. Since it executes this every time they boot up, it appears that the RTC "isn't working".

Yes Ken I wondered about that too, but going off what OP says about it working correctly with 5V, I more-or-less discounted that.

senthilkumar: hi everyone i'm new to arduino and im learning , i connected a DS1307RTC to arduino pro mini and ran the example timeset program when ever i add the coin cell to the RTC its not working , its works fine when it is powered by 5v from arduino alone i tried replacing pullup resistors to 4.7k and 10k and also replace the DS 1307 with new one nothing worked. the battery im using is CR 2025 coin cell. my RTC board also has a 24C16 eeprom on it can anyone help me on this. thanks in advance.

The DS1307 requires a supply greater than the back up battery voltage to power up.

The DS1338-33 is a compatible device that will work with Vcc = 3.3V. DS1307 is designed for 5V

JimboZA: You'll need to explain what you mean by "not working".

My understanding is that with the coin cell the RTC is not supposed to "work" in the sense of being interrogated for the time. The coin cell's purpose is (afaik) to keep the clock operating so that it keeps the time, then when you next hook it up to 5V and interrogate it, it knows and shows the right time.

I for example have had my 1307 module disconnected from a project for some time, but with the coin cell in for some weeks, and then when I hook it back up to the project with 5V connected, the time's still correct.

Are you saying you hoped to have the RTC fully operational with the coin cell as its power?- if so I don't think that's what it's supposed to do.

But I might be misinterpreting your question.....

thanks jimboza for your reply.

i'm able to set time using the example program. and read the time using readtime example program DS 1307 is performing normal only with 5v power source but when i place the coin cell connected to DS1307 im unable to set time or read it. everything is fine untill i power ds1307 by both 5v and coin cell. i hope you understand my problem better now.

KenF: You may be right, but another common newbie mistake that occurs is that they leave the part in the setup() function that sets the current time to the time of compilation. Since it executes this every time they boot up, it appears that the RTC "isn't working".

thanks KenF for your time

i'm setting time and reading it using example program, clock works fine. but im unble to set time and read it when DS1307 is powered by both 5v and coin cell

MarkT: The DS1307 requires a supply greater than the back up battery voltage to power up.

The DS1338-33 is a compatible device that will work with Vcc = 3.3V. DS1307 is designed for 5V

thanks MarkT

i will look in to this , and see weather the problem is resolved. thanks again

everything is fine untill i power ds1307 by both 5v and coin cell

I have a vague memory of reading somewhere in the forum, that one of the modules gets a short-circuit when the coin-cell battery is installed. Sorry I'm vague on the details: check that when the coin-cell is in, that the connections aren't shorted: check the battery body.

I wonder if you’re putting the battery in upside down.

thanks guys for your time ,

the problem got solved the external voltage was only 3V , so then DS 1307 failed to work on battery.as i increased then supply voltage to 5volts its now works fine.

thanks markT.

T

MarkT: The DS1307 requires a supply greater than the back up battery voltage to power up.

The DS1338-33 is a compatible device that will work with Vcc = 3.3V. DS1307 is designed for 5V

Great.

It's a good idea to go back to the top post, choose More > Modify, and add "solved" to the title. (Must be in the title of the top post: that's the one that appears in the index.)