I2C SCL SDA communication problem

Hi,I'm doing a project using Raspberry & ATMega328P by having I2C Comm. to turn ON/OFF LEDs.
The problem I'm getting is that when I send any Data to ATMega then SCL is driving to 0V before that its being 4V.
So I kept pull-up at SCL and it wasn't driving to 0V but now SDA was driving to 0V when I sent some data
What would be the reasons for this ?
(I tried by directly using UNO Board having SDA SCL Jumpers )to my board and then it worked

Just post schematics and RPI and AVR code so we can help...

The Arduino core enables a weak pull up for I2C, so that means the AVR will try to pull the Pi pin to 5V through a 60k Ohm resistor. The Pi works at 3.3V but it has an ESD protection diode that will start to conduct at about .65V above 3.3V so that is likely why you see almost 4V on the I2C pin. I'm not sure there is a risk to the Pi but I don't like seeing that much voltage on its pin.

Update: The Pi has 1.8k Ohm pullups to 3.3V on its I2C pins so you may be using the wrong pins.

ishtiaqshaheer:
Hi,I'm doing a project using Raspberry & ATMega328P by having I2C Comm. to turn ON/OFF LEDs.
The problem I'm getting is that when I send any Data to ATMega then SCL is driving to 0V before that its being 4V.
So I kept pull-up at SCL and it wasn't driving to 0V but now SDA was driving to 0V when I sent some data
What would be the reasons for this ?
(I tried by directly using UNO Board having SDA SCL Jumpers )to my board and then it worked

Raspberry Pi is strictly 3.3V only, no exceptions.