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prachi
prachi
Visitor II
March 1, 2017
Question

Interpretation of output of LSM6DS33

  • March 1, 2017
  • 1 reply
  • 767 views
Posted on March 01, 2017 at 08:30

Hi,

In the 'Examples of output data' section of the LSM6DS33 application note AN4682, there are tables showing examples of the output register values and the corresponding acceleration and angular rate values for a given scale. Can you please elaborate how the values are calculated?

Regards,

Prachi 

#lsm6ds33 #accelerometer #gyroscope
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1 reply

M
Miroslav BATEK
ST Employee
March 2, 2017
Posted on March 02, 2017 at 10:04

First of all it is necessary to be familiar with terms Big Endian, Little Endian (check chapter 4.5.1 in AN4682 or

https://en.wikipedia.org/wiki/Endianness

) and

https://en.wikipedia.org/wiki/Two's_complement

.

Than what you need to do is convert two bytes from output registers into one number and multiply this number by sensitivity.

0690X00000606StQAI.png

Example 1 (2nd line of the table):

16h = +22, 69h = 105 ... MSB is 0 -> it is possitive value

22*256+105 = 5737 ... 5737 * 0.061 LSB/mg (sensitivity for FS=2g from Table 3 in datasheet) = 350mg

Example 2 (4th line of the table):

E9h = -105, 97h = 151 ... MSB is 1 -> it is negative value

-(105*256 + 151) + 32768 = -5737 ... -5737 * 0.061 LSB/mg (sensitivity

for FS=2g 

from Table 3 in datasheet) = -350mg
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