LIS3DH SA0 PIN CONNECTION

[Arna Lee]

Posted on March 07, 2018 at 13:10

Hi Sir,

I am using ST accelerometer Sensor  LIS3DH (adapter board STEVAL-MKI105V1).

From the data sheet 'DS6839_MEMS digital output motion sensor_ultra-low-power high-performance 3-axis “nanoâ€� accelerometer', 

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6.1.1 I2C operation

'The Slave ADdress (SAD) associated to the LIS3DH is 001100xb. The SDO/SA0 pad can be used to modify the less significant bit of the device address. If the SA0 pad is connected to the voltage supply, LSb is ‘1’ (address 0011001b) else if SA0 pad is connected to ground, the LSb value is ‘0’ (address 0011000b). This solution permits to connect and address two different accelerometers to the same I2C lines. '

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My question:

For SA0 PIN, can we let it free? That is, SA0 PIN is NEITHER connected to the voltage supply, NOR connected to ground.I tested the SA0 PIN with multimeter and it has voltage when it is floating.

Thanks,

Arna Lee

[Miroslav BATEK]

Posted on March 07, 2018 at 14:43

There is internal week pull-up resistor on SA0 pit so you can let it floating, but it is not recommended. 

It is better to connect it to ground or VDDIO to make strong voltage potential on the pin.