MPL3115A2?

[jubeira]

Hi all,

I bought a sensor marked as "m3pr yw0f" thinking it was a MPL3115A2. The I2C address is correct, but when I read WHO I AM, the result is 0x0E instead of 0xC4. Also, after following the quick start steps, the sensor doesn't seem to recognize changes in altitude of more than 1m, even though it should show significant changes in 0.3m. And finally, the lower 4 bits of the LSB of the pressure measurement are not 0 when I read them as the datasheet says (they keep changing randomly even if the sensor is not moving).

Is there any chance that the sensor I bought is NOT MPL3115A2? What does that marking mean? Any help is very much appreciated.

[TomasVaverka]

Hi,

First, M3PR is a correct part marking for the MPL3115A2.

Do you have a logic analyzer or an oscilloscope to know what is going on on the I2C bus when you read the WHO_AM_I register (0x0C)? It might also be helpful to see your source code (at least the initialization and data processing routines).

To achieve 30cm resolution, it is necessary to set max oversampling (OS[2:0] = 0x07).

Take a look at my example project for the MPL3115A2 and KL25Z, you might find it useful.

I hope it helps.

Regards,

Tomas

PS: If my answer helps to solve your question, please mark it as "Correct" or “Helpful”. Thank you.