Posts: 50
Joined: Wed Sep 18, 2013 7:57 am
Location: European Union
Contact: Website

DS1307 RTC I2C 5V

Wed Oct 16, 2013 9:07 am

I have Real Time Clock module with DS1307. The problem is that SCL and SDA are connected to 5V via 4,7k resistors. So voltage are to high to connect to Rasbpberry Pi DSA and SCL.

I need help with this.
Can i connect Raspberry Pi to RTC via 400k resistors to reduce 5V to 3.2V on I2C? Will it work?
Or connect rather user I2C Level Shifter ... i2c-bridge

5V take from Raspberry pins nr 1 or take external PSU?

datasheet : ... 281d7418b5
picture Image
board Image
Tomas Freeman

Posts: 1512
Joined: Sat Jul 14, 2012 6:40 pm
Location: Reading, UK
Contact: Website

Re: DS1307 RTC I2C 5V

Wed Oct 16, 2013 6:41 pm

Either use any level shifter or remove the pull-up resistors on the RTC baord and it will work.

Alternatively use a different RTC board or make your own
Just another techie on the net - For GPIO boards see http:///

Return to “Interfacing (DSI, CSI, I2C, etc.)”