Example application circuit for combining LSM6SD0X with LIS3MDL in "Mode 2"?

[AVeze.1]

Hi, I am following the datasheets to combine a LSM6SD0X with a LIS3MDL on the same board, with the LSM6SD0X in "Mode 2." My understanding is that this mode permits fusion of the magnetometer to the other data. However, does this really fuse the data in a meaningful way? I'm already planning to use an ARM chip for sensor fusion... so is there an advantage of using the "Sensor Hub" mode (aka Mode 2)? Or, should I just operate it in mode 1 and stop confusing the matter?

Also, could I please get a more clear example/schematic of how to hook these two chips up in this mode? I was planning to connect SDA (pin 11) and SCL (pin 1) from LIS3MDL to MSDA (pin 2) and MSCL (pin 3) on LSM6SDS0X. Is this correct? What should I do with MDRDY on LSM6SDS0X? What should I do with DRDY on LIS3MDL? Should these pins be connected to each other?

Presumably I should use pull-up resistors on the master I2C?

Thanks!

[Eleon BORLINI]

Hi @AVeze.1​ , to answer your central question "is there an advantage of using the "Sensor Hub" mode (aka Mode 2)?", yes, there is the advantage that you can well synchronize all the sensor acquisition, trigger the magnetometer ("sensor hub trigger signal can be synchronized with the accelerometer/gyroscope data-ready signal") and store all the sensor data in the same FIFO stack of the LSM6DSOX. Synchronization is extremely important to have a good sensor fusion among the sensors (for a description of the motion sensor fusion, please check the user manual on MotionFX firmware library).

Regarding your other request "could I please get a more clear example/schematic of how to hook these two chips up in this mode?", you can find the description in the AN5272 app note, p. 65. External pull-ups are optional, but I would suggest you to add them to your circuit.

Regards