# DS1307 not detected by i2cdetect **URL:** \ **Category:** balenaFin\ **Created:** [July 16, 2019, 1:17pm UTC](https://forums.balena.io/t/ds1307-not-detected-by-i2cdetect/20123 "2019-07-16T13:17:44Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![scholz](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@scholz](https://forums.balena.io/u/scholz)\ **Post date:** [July 16, 2019, 1:17pm UTC](https://forums.balena.io/t/ds1307-not-detected-by-i2cdetect/20123/1 "2019-07-16T13:17:44Z")
I have the following setup: - BalenaFin v1.1 with CM3+ lite attached - RTC battery (fresh, measured 3.24V) placed in its socket - flashed Raspbian Stretch (using Balena Etcher) - I2C activated in raspi-config -\> Interfacing Options -\> I2C - last line of /boot/config.txt is “dtoverlay=i2c-rtc,ds1307” However, the output of “sudo i2cdetect -y 1” still shows that there is no I2C device. Other I2C devices (for example an ADS1115 a/d-converter) are seen by i2cdetect (after connected to the I2C pins), so I guess the I2C bus itself is working. I also tried flashing the following operating systems and got the same result: Raspbian Jessie Raspbian Buster Raspbian (balena version from [https://www.balena.io/fin/1.1/docs/downloads/](https://www.balena.io/fin/1.1/docs/downloads/)) Am I missing something? Is there any way to tell if the RTC module is working/broken? Any help would be appreciated. // Philipp ---
**Author:** ![thundron](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/thundron/32/1379_2.png) [@thundron](https://forums.balena.io/u/thundron)\ **Post date:** [July 16, 2019, 4:18pm UTC](https://forums.balena.io/t/ds1307-not-detected-by-i2cdetect/20123/5 "2019-07-16T16:18:30Z")
Hi and welcome to the forums! You could try using the `timedatectl` utility: if that shows the RTC output, then RTC is working. More info on that [here](https://www.freedesktop.org/software/systemd/man/timedatectl.html) Tell us if this solves your issue or if you need anything else! ---
**Author:** ![scholz](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@scholz](https://forums.balena.io/u/scholz)\ **Post date:** [July 17, 2019, 5:30am UTC](https://forums.balena.io/t/ds1307-not-detected-by-i2cdetect/20123/7 "2019-07-17T05:30:11Z")
Hi, the ouput of `timedatectl` on Raspbian Stretch says `RTC time: n/a`. If I flash the balena-preconfigured Raspbian, `timedatectl` says `RTC time: Wed 2019-07-17 05:17:47`. The command `i2cdetect -y 1` still indicates that no I2C device is found, but the RTC seems to work. This would mean that some configuration step is missing on Raspbian Stretch apart from these: - I2C activated in raspi-config -\> Interfacing Options -\> I2C - last line of /boot/config.txt is “dtoverlay=i2c-rtc,ds1307” Can anyone give me a hint what I am missing? ---
**Author:** ![scholz](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@scholz](https://forums.balena.io/u/scholz)\ **Post date:** [July 17, 2019, 9:26am UTC](https://forums.balena.io/t/ds1307-not-detected-by-i2cdetect/20123/8 "2019-07-17T09:26:16Z")
Hi, just made it work. Here is my setup now: - BalenaFin v1.1 with CM3+ lite attached - RTC battery (fresh, measured 3.24V) placed in its socket - flashed Raspbian Stretch (using Balena Etcher) - I2C activated in raspi-config -\> Interfacing Options -\> I2C - added to /boot/config.txt: “dtoverlay=balena-fin” - added to /etc/modules: “rtc\_ds1307” Why it didn’t work: - I assumed that the DS1307 was on i2c-1 (as described on [https://learn.adafruit.com/adding-a-real-time-clock-to-raspberry-pi/set-rtc-time](https://learn.adafruit.com/adding-a-real-time-clock-to-raspberry-pi/set-rtc-time)). Instead, the RTC is on i2c-3, which is not available without using “dtoverlay=balena-fin”. - Adding “dtoverlay=i2c-rtc,ds1307” does not load the module “rtc\_ds1307”. Without that, “timedatectl” does not give an RTC output. I had to load the module explicitly in /etc/modules Thanks for the hint with `timedatectl`, that led me on the right track. Greetings // Philipp