WHO_AM_I register value read as 0xFF

AB.4 · ‎2021-01-28

Hello ST Community,

I have some hardware samples with LIS2DH12 accelerometer. For all the samples except one, the value of WHO_AM_I register is read as 0x33 (which is expected). However, for one of the samples, it is read as 0xFF. What could be the possible reason for this? Note that this behavior was observed after being in use for a few months. Could physical damage or such incidents cause this?

Regards,

Anusha

Uwe Bonnes · ‎2021-01-28

Do other registers read non 0xff values. If not, double check wiring, the error is on your side!Check with a scope if there is nothing obvious.!

AB.4 · ‎2021-01-30

Hi Uwe,

Thanks for your response. I checked other registers' default values such as Control 1 register and control 2 register. These values are also 0xff.

Regards,

Anusha

Eleon BORLINI · ‎2021-02-03

Hi Anusha,

so on some samples all the registers read values are 0xFF, after being working for months, right?

Besides Uwe suggestion of checking the communication with a scope, are all the device pins in the datasheet p.9 conditions?

-Eleon

AB.4 · ‎2021-02-04

Hi Eleon,

Thanks for your response. I haven't been able to check this but I do notice some rust on the PCB. Maybe this could be the reason?

Regards,

Anusha

Eleon BORLINI · ‎2021-02-04

Hi Anusha,

well, it could be that some tracks corrupted by the rust make the device communication problematic... you should check an apparently good board and see what happens.

-Eleon