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Sparse LIS331 Datasheet(s)

Question asked by Jan Belohoubek on Jul 12, 2018

Dear all - especially STM developers,

I recently integrated an LIS331HH sensor. It seams to be very nice sensor! But anyway while reading LIS331 Datasheet, I found that information required for proper MCU driver implementation (especially interrupt-related information) missing.

 

Even though some information become clear during repeated reading of Datasheet, something remains unclear. Even though I was able to find proper settings experimentally, it took some time...

 

Some points:

  • The two's complement output (OUT_X_L, OUT_X_H, ...) range is not explicitely given (it is clear after repeated Datasheet reading, but implicitly hidden) - is it full range (16bit two's complement used? or there are limits? e.g. -4096 to 4096?) - I found, that full range is used for LIS331HH, but other family members are be different (I have no experience, but I saw code here: LIS331/LIS331.cpp at master · szotsaki/LIS331 · GitHub ) - missing explicite range declaration in Datasheet causes confusion
  • meaning of threshold and other interrupt-related settings is foggy:
    • it is unclear how to set-up threshold value (INT1_THS/INT2_THS) - depends on range ...
    • for XLIE interrupt: "value lower than preset threshold" is ambiguous (same for other interrupts): means "abs(INT1_THS) > abs(accel)" or "- INT1_THS > accel", thus signaling "crossing threshold back to defined range" or "crossing threshold out of range"
  • self-test function is described poorly (missing use-case?)

 

Please, could you clarify here or extend the datasheet?

 

Thank you!

Jan

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