# RTC Pi not detected on i2C grid
**URL:** https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254
**Category:** Uncategorized
**Created:** [24 May 2021 07:07 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254 "2021-05-24T07:07:52Z")
**Posts on this page:** 13
**Page:** 1
### Author:  [@Samuil155885](https://forum.core-electronics.com.au/u/Samuil155885)
#### Post date: [24 May 2021 07:07 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/1 "2021-05-24T07:07:52Z")
Hi,
I recently purchased the RTC Pi from Core Electronics: [RTC Pi - Raspberry Pi Realtime Clock module](https://www.abelectronics.co.uk/p/70/rtc-pi)
Current set up:
1. Raspberry Pi 4 B+
2. RTC Hat connected onto RTC directly ontop of GPIO pins with the CR battery placed
3. I confirmed my CR2032 battery isn’t dead as it’s new and measured a voltage of 3.22V.
I have ensured the CR battery is connected the entire time when on the PI 4. I have enabled i2C In the Pi configuration settings and sudo rebooted.
I am not receiving any devices on the i2C grid when using sudo i2cdetect -y 1
Your help would be much appreciated.
Edit: I have already installed IC2 Tools: sudo apt-get install i2c-tools
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### Author:  [@Oliver33](https://forum.core-electronics.com.au/u/Oliver33)
#### Post date: [24 May 2021 08:49 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/2 "2021-05-24T08:49:18Z")
Hi Samuil,
That link is to a different website, but I presume it’s still a DS1307 RTC?
Adafruit have a really good tutorial on this, whichever model of RTC you’re using:
> **[Adding a Real Time Clock to Raspberry Pi](https://learn.adafruit.com/adding-a-real-time-clock-to-raspberry-pi/overview)**
>
> To keep costs low, the Raspberry Pi does not include a Real Time Clock module. Instead, users are expected to have it always connected to WiFi or Ethernet and keep time by checking the network. Since we want to include an external module, we'll have...
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### Author:  [@brian86770](https://forum.core-electronics.com.au/u/brian86770)
#### Post date: [24 May 2021 19:53 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/3 "2021-05-24T19:53:50Z")
**sudo apt-get install python-smbus i2c-tools**
i would code the above and reboot the rpi then run detect again
depending on which way you go about things…
most common issue is reversed scl/sca lines …or data lines check these are correctly matching…
when building home brew units…
also this is the device you gave a link to…is setup page
> **[RTC Pi on a Raspberry Pi with Raspberry Pi OS](https://www.abelectronics.co.uk/kb/article/30/rtc-pi-setup-on-raspberry-pi-os)**
>
> A tutorial showing how to use the RTC Pi on a Raspberry Pi in the AB Electronics UK Knowledge Base
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### Author:  [@Samuil155885](https://forum.core-electronics.com.au/u/Samuil155885)
#### Post date: [24 May 2021 22:03 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/4 "2021-05-24T22:03:21Z")
Hi Brian,
Thanks for your response, I will try code the above shortly. This is the product link sorry I posted the original manufacturers product link in the OP, [https://core-electronics.com.au/rtc-pi.html](https://core-electronics.com.au/rtc-pi.html)
With regards to the lines, I have not taken this into account really because I just put the hat ontop of the Pi 4 the same way shown in the product page:
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### Author:  [@Samuil155885](https://forum.core-electronics.com.au/u/Samuil155885)
#### Post date: [24 May 2021 22:04 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/5 "2021-05-24T22:04:09Z")
Hi Oliver,
Product link correction: [https://core-electronics.com.au/rtc-pi.html](https://core-electronics.com.au/rtc-pi.html)
Was hoping to get the one I purchased working instead.
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### Author:  [@James](https://forum.core-electronics.com.au/u/James)
#### Post date: [25 May 2021 00:00 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/6 "2021-05-25T00:00:42Z")
Hi Samuil,
Just to confirm since I’m getting myself up to speed on this problem, could you send through a photo of your hat on your Pi?
I’ve used a very similar board for my RTC on a project and had no issues getting it seen over i2c.
Keen to get to the bottom of this!
-James
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### Author:  [@Samuil155885](https://forum.core-electronics.com.au/u/Samuil155885)
#### Post date: [25 May 2021 00:53 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/7 "2021-05-25T00:53:12Z")
Hi James,
Your help would be much appreciated.
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### Author:  [@James](https://forum.core-electronics.com.au/u/James)
#### Post date: [25 May 2021 00:59 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/8 "2021-05-25T00:59:08Z")
Hi Samuil,
Apologies if this wasn’t clear in the product documentation, but you’ll need to solder the stacking headers onto your RTC board in order to get good continuity.
Once you’ve done this, let us know whether if you’re still having the same problems
-James
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### Author:  [@Samuil155885](https://forum.core-electronics.com.au/u/Samuil155885)
#### Post date: [25 May 2021 01:04 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/9 "2021-05-25T01:04:07Z")
Hi James,
Thank you for clarifying that I will take care of this later today when I return home.
While I have you, is it possible to trigger the RTC to turn on the Pi from ‘sleep’ or ‘hibernation’ ?
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### Author:  [@James](https://forum.core-electronics.com.au/u/James)
#### Post date: [25 May 2021 01:17 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/10 "2021-05-25T01:17:12Z")
Hi Samuil,
The functionality you’re looking for would be pretty hard for a simple RTC to do, you’d need some kind of microcontroller looking at the RTC and bridging a pin on the Pi to turn it on. By the way, the Pi has no true low-power state, the shutdown is actually a reboot that stops very early on in the boot process, and waits for a pin to continue.
While I believe the wake-on-pin functionality varies based on the Pi model, I’ve gotten it to work on a zero and I’ll check which pin it was when I get home.
-James
EDIT: 90% sure it was pins 5 and 6
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### Author:  [@Samuil155885](https://forum.core-electronics.com.au/u/Samuil155885)
#### Post date: [25 May 2021 01:23 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/11 "2021-05-25T01:23:29Z")
Thanks James much appreciated!
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### Author:  [@brian86770](https://forum.core-electronics.com.au/u/brian86770)
#### Post date: [25 May 2021 14:18 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/12 "2021-05-25T14:18:59Z")
if your worried i`d solder one of these to the rtc module pushing the pins right through as far as they can and solder the appropriate terminals then it becomes a proper stack-able unit…just straight out soldering to the rpi is not a good idea…seems to me what if you required it for another purpose …
this part.
> **[GPIO Stacking Header for Pi A+/B+/Pi 2/Pi 3 - Extra-long 2x20 Pins](https://core-electronics.com.au/gpio-header-for-raspberry-pi-b-extra-long-2x20-female-header.html)**
>
> Connect your own PCB to a Raspberry Pi B+ and stack on top with this normal-height female header with extra long pins. The female header part is about 8.5mm tall, .. read more
i see it comes with the header yes solder it to the board it should be fine after that…i did not see its accessories til now…sozz…
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### Author:  [@Oliver33](https://forum.core-electronics.com.au/u/Oliver33)
#### Post date: [27 May 2021 00:57 UTC](https://forum.core-electronics.com.au/t/rtc-pi-not-detected-on-i2c-grid/10254/13 "2021-05-27T00:57:18Z")
Good tip James 🙂