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Can I connect like this ?

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pic.programmer

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I want to use I2C LCD with Arduino Mini Pro 3.3V. Arduino runs at 3.3V and LCd is powered from 5V but I am using readily available I2C LCD modules which have pullups on I2C lines connected to 5V. So, Can I connect 5V pulled I2C lines to 3.3V I2C lines of Arduino ?
 

Hi,

Simple answer: read the arduino's microcontroller datasheet.
(If you ask me for a yes/no answer, I need to do the same)

Check what's the max signal input voltage for the I2C pins, when supply voltage is 3V3.

Often with microcontrollers the max inout voltage is VCC + 0.5V or so...

With dedicated I2C chips it is often 5.5V (independent of supply voltage).
I2C input threshold is similar to TTL levels (0.7V, 2.0V).
With this the I2C chips are compatible, they can be mixed woth 2.5V, 3.3V and 5V supplies and the pullups can also be connected to 2.5V, 3.3V and 5.0V.

Klaus
 

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