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Fahad Mirza
Visitor II
November 9, 2017
Solved

LIS2DE12 Accelerometer data bytes

  • November 9, 2017
  • 1 reply
  • 972 views
Posted on November 09, 2017 at 22:50

http://www.st.com/content/ccc/resource/technical/document/datasheet/group0/72/cb/80/a7/5e/fe/46/9d/DM00153214/files/DM00153214.pdf/jcr:content/translations/en.DM00153214.pdf

says it provides 8-bit accelerometer value. But then again it says ''

The LIS2DE12 contains a 10-bit, 32-level FIFO''. Why?


_legacyfs_online_stmicro_images_0690X0000060MvBQAU.png

I am assuming it is 8bit, but then why do I need to read two bytes (for example, to get X-axis value from

OUT_X_H [29h] 

) ? Isn't it supposed to be 1 byte for a single axis, 3 bytes for a single FIFO and 96 bytes for whole FIFO as opposed to 2bytes, 6bytes and 192 bytes?
_legacyfs_online_stmicro_images_0690X0000060MvGQAU.png

#accelerometer #mems
    This topic has been closed for replies.
    Best answer by Miroslav BATEK
    Posted on November 10, 2017 at 10:52

    The LIS2DE12 reused a FIFO block from other device, that is why the FIFO store 10 bits, even if the accelerometer provides only 8bits.

    When reading data from FIFO, it is possible to do three single byte read operations (OUT_X_H, 

    OUT_Y_H, OUT_Z_H) but it is faster to perform one 6 bytes read operation and discard the unused bytes.

    1 reply

    M
    Miroslav BATEKAnswer
    ST Employee
    November 10, 2017
    Posted on November 10, 2017 at 10:52

    The LIS2DE12 reused a FIFO block from other device, that is why the FIFO store 10 bits, even if the accelerometer provides only 8bits.

    When reading data from FIFO, it is possible to do three single byte read operations (OUT_X_H, 

    OUT_Y_H, OUT_Z_H) but it is faster to perform one 6 bytes read operation and discard the unused bytes.

    F
    Fahad MirzaAuthor
    Visitor II
    November 10, 2017
    Posted on November 10, 2017 at 17:31

    Thanks, Miroslav.

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