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Associate
February 19, 2025
Solved

lsm6dsl FIFO DATA misaligned.

  • February 19, 2025
  • 2 replies
  • 956 views

hi,

     we use one LSM6DSL sensor to read 3 axis acc FIFO data each second, but after some times, the FIFO out data become misaligned. 

the sensor setting is below:

  • XL_ODR_26HZ
  • Gyro disabled.
  • FIFO ODR = 26Hz
  • FIFO threshold (water mark) = 128
  • No decimation
  • BDU Block Update enabled
  • FIFO Is in continuous modewe have a timer to trigger to read FIFO data by Zephyr I2C(frequency: 100000bits/s) each second, before data reading, we check the numbers of FIFO by checking FIFO_STATUS1 and FIFO_STATUS2 register, then we read a multiple of 3 axis sets each time, for example if the FIFO data number has 78, we will read all FIFO data one time, if the number is 76 or 77, we only read 75 data one time. it can make sure reading data is complete 3-axis data. firstly, the reading data is the right like as (X_ACC, Y_ACC, Z_ACC). but after some time (the time is not fixed) the data will become (Y_ACC, Z_ACC, X_ACC). we don't know how to fix this issue. please help us.
Best answer by Federica Bossi

Hi @cdong ,

It happens when you miss some word fifo.
I suggest you always check the TAG position, after the tag there are 2 bytes per axis: X Y Z.

2 replies

Federica Bossi
Federica BossiBest answer
Technical Moderator
February 20, 2025

Hi @cdong ,

It happens when you miss some word fifo.
I suggest you always check the TAG position, after the tag there are 2 bytes per axis: X Y Z.

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cdongAuthor
Associate
February 21, 2025

what is the TAG position? do you mean we need to check pattern(FIFO_STATUS3 & FIFO_STATUS4) before reading FIFO?

Federica Bossi
Technical Moderator
February 21, 2025

Hi @cdong ,

For this product it is called FIFO_PATTERN, you can refer to par 8.4 of AN5040

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.
ST Employee
February 20, 2025

Hi All,

 

This post has been escalated to the ST Online Support Team for additional assistance. We'll contact you directly.

 

Regards,
Jake

ST Support