Do the LIS3MDL Reserved Pins need to be connected?

[JRule]

Hi, we have a board with several I2C based sensors on it, including the LIS3MDL and LIS3DH.

The 3DH works like a treat, but I cant get any communication from the 3MDL. The only thing I can see that would cause this is a discrepancy with our board design and the data sheet. I was hoping someone can confirm whether the reserved pins (2 and 12) are essential for operation and need to be connected to ground to work or if its ok for them to remain Not Connected. Thanks.

[AvaTar]

Didn't the LIS3 have the combo interface, at least the LIS3MDL ?

The interface mode (I2C or SPI) is defined by an input pin. I guess you tried the "wrong" mode.

Check the schematics, and either change the hardware to get your preferred bus mode, or switch the interface.

[videojames]

Hi, yes I am pulling CS mode high to enable I2C.

[Miroslav BATEK]

I would need to check with sensor specialist if it is mandatory to connect reserved pins to ground, personally I think it should work even if they are not connected.

Can you double check if you have correct I2C address?

Can you check the I2C signals with logic analyzer?

[videojames]

Hi, I have a functioning I2C on the MSP430 which is working with TMP75 and LIS3DH. I have tried all available I2C addresses. I have used the Saelae to confirm that I get NAK when I try to communicate with the LIS3MDL.

It would be great if a sensor specialist can confirm whether or not these need to be connected. Thanks,

[Miroslav BATEK]

I have got the answer from sensor specialist and connections between pins 2, 12 to GND, are mandatory.