LSM6DSV320X sensor not responding

[yaxsomo]

Hello everyone. 

I would really appreciate if someone could help me sort out a really annoying issue i have with a new STM32WB5MMGH6 based board i made.

On this board i have two sensors connected to the same SPI interface (hspi2) with different CS pins to address the sensors. Here's the schematic sections of the two sensors : 

MS5607 : 

LSM6DSV320XTR with an auxiliary IIS2MDCTR tied directly to it (for the test board, the magnetometer is not soldered yet):

I'm currently on test phase, and the MS5607 is responding correctly. But the LSM6DSV320XTR does not respond at all. i'm not even getting the whoami ID (i get a 0).

For the SPI configuration i have this : 

For the 2 Chip Select pins i have this config : 

 

I don't understand where the problem comes from. Could someone help me asap ? I'm losing hope :(

[Federica Bossi]

Hi @yaxsomo ,

Using MKI109D motherboard with STEVAL-MKI251A, the sensor communicate correctly using your SPI configuration (Baud Rate: 4MBits/s, CPOL: High, CPHA: 2Edge) and assuming IMU_CS configuration same of BARO_CS that you posted.

Debug tips:

Are you sure that SPI2 lines are connected to LSM6DSV320X? Do they move on its side when communicate with the other sensor (oscilloscope probing)?

Did you check on IMU_CS behavior (oscilloscope probing)?

In your main FW when LSM6DSV320X communication takes place? Did you try to communicate only with it?

[yaxsomo]

Hello @Federica Bossi , sorry for the late response, i'm trying to debug this thing.
I'm starting to think it's a soldering issue, because when communicating with the barometer, there's no issue.

And the LSM6DSV320X is soldered with a hot air gun. 

I tried to communicate only with the IMU on main.c and i get zeroed values, which is not good at all.

Is it an issue if the sensor is powered (both VDD and VDDIO) with 3.3V ? 

[yaxsomo · Accepted solution]

Hello @Federica Bossi , I finally found the issue. It was a solder joint issue, and i blamed the software for nothing. One tip for other users that may encounter similar issues : When hand soldering a sensor like this one with a hot air gun, first apply solder on the PCB pads, then apply solder ALSO on the sensor. I applied solder on PCB pads but not on the sensor, resulting in really poor connection and therefore, a unusable IC. 

Thank you for helping, I'm closing the thread