Using LIS3DH with VDD only and using VDD_IO for setup only.

[GLuts.1]

Question is if I can use LIS3DH with VDD only (3.3v) , and VDD_IO (1.8v) supply only during configuration ?

And in this case, what power use INT1 and INT2 pins ? If possible to run on VDD only with having them working (at least as OD ?).

Datasheet is not clear about that....

[Eleon BORLINI]

Hi @GLuts.1​ ,

Vdd 3.3V and Vdd_IO 1.8V (and, in general, Vdd > VddIO) is a safe condition on LIS3DH device.

All the digital features (I2C and SPI communications and interrupts) are regulated by the VddIO, so the high voltage level will be this.

I however don't understand well your question here:

>> If possible to run on VDD only with having them working (at least as OD ?)

Can you please explain a little more the point?

-Eleon

[GLuts.1]

Hi @Eleon BORLINI​ ,

Idea is bit tricky, so guess I have to give more information...

Device implements MCU (STM8) and cellular modem. MCU is powered from 3.3 but modem has IO @ 1.8 v and has also output power. Idea is that modem is off most time and MCU works as timer to power it on. Beside that need to have some motion detection. And what I want in terms of saving device cost (project is very price aggressive) , so I thought if is that possible that interrupt from LIS3DH will used to wakeup MCU, and LIS3DH shall be powered from same 3.3 . But configuration of accelerometer to be made via modem (as it has internal program running), so in that case IO part of LIS3DH would be powered from modem, after configuring it will be off and only 3.3 v will stay on VDD and in perfect condition if LIS3DH can work this way with only VDD supplied and generate interrupts ?