Can I2c have external pull-up resistors on 3 voltage,when I using 1.8 voltage VDDIO

[Shuyu Ma]

Posted on May 19, 2017 at 10:57

The MCU use 3 volt power supply in my design. And

LIS2DH

’s VDDIO is 1.8 voltage. And I saw the sentence�

There are two signals associated with the I

2

C bus: the serial clock line (SCL) and the serial data line (SDA). The latter is a bidirectional line used for sending and receiving data to/from the interface. Both the lines must be connected to Vdd_IO through an external pull-up resistor. When the bus is free, both the lines are high.

� in your document. So I wonder can I use 3 voltage on

external pull-up resistors of I2c.

[Shuyu Ma]

Posted on May 23, 2017 at 11:06

I modified the circuit, use 3 volt as VDDIO input voltage. Then I2C is OK. It is not right that LIS2DH12’s VDDIO use 3 volt and another device’s VDD use 1.8 volt when I2C communication was used.