I2C communication between PIN on 3V and sensor on 5V?!

[stoyanoff]

Hi! I have a problem with I2C communication between PIC microcontroller (3.3V power supply) and sensor on 5V. Is it possible to be done?
I need to send and recieve data to the sensor. Can you give me and advice how to do it. I know there are level shifters but I don`t think I`ll fine such in the local store. May be something with voltage devider???
Thanks!

 

[FvM]

A voltage divider can't help for an essentially bidirectional bus.

There are two possibilities:
- the sensor can work with 3.3V I2C levels (check the datasheet). It's mainly a question of required high levels
- it can't work, than one of the I2C level converters from NXP or other vendors must be used

P.S.: And a third option. The µP is 5V-tolerant and can work with 5V I2C pull-ups.

 

[Jigar 4 Electronics]

Just try to keep the source same for both (uP & sensor)... I mean you can give 5V to sensor using any regulator say 7805 & can set 3.3 using another - say LM317.
Now you can connect directly the pin of SCL & SDA and others (if any) between them (with pull up resistors)... And as FvM has answered the uP is having 5V tolerant so there is no issue for you.

AGAIN : KEEP THE SOURCE SAME... I MEAN THERE SHOULD BE SINGLE SWITCH TO TURN ON BOTH.