LSM320HAY30 Datasheet, PDF (30/42 Pages) STMicroelectronics – MEMS motion sensor module: 3D digital accelerometer and 2D pitch and yaw analog gyroscope

Register description
LSM320HAY30
Table 21.
HPen1
HPCF1,
HPCF0
LA_CTRL_REG2 description (continued)
High-pass filter enabled for Interrupt 1 source. Default value: 0
(0: filter bypassed; 1: filter enabled)
High-pass filter cut-off frequency configuration. Default value: 00
(00: HPc=8; 01: HPc=16; 10: HPc=32; 11: HPc=64)
The BOOT bit is used to refresh the content of the internal registers stored in the Flash
memory block. At device power-up, the content of the Flash memory block is transferred to
the internal registers related to trimming functions to permit good device behavior. If, for any
reason, the content of the trimming registers was changed, it is sufficient to use this bit to
restore the correct values. When the BOOT bit is set to ‘1’, the content of internal Flash is
copied to the corresponding internal registers and is used to calibrate the device. These
values are factory-trimmed and are different for every accelerometer. They permit good
device behavior and normally do not have to be modified. At the end of the boot process, the
BOOT bit is again set to ‘0’.
Table 22. High-pass filter mode configuration
HPM1
HPM0
High-pass filter mode
0
0
Normal mode (reset reading HP_RESET_FILTER)
0
1
Reference signal for filtering
1
0
Normal mode (reset reading HP_RESET_FILTER)
HPCF[1:0]. These bits are used to configure the high-pass filter cut-off frequency f_t which is
given by:
f_t =
ln _⎝⎛1 – _H-----^1P-----_c-_⎠⎞ ⋅
--^f--^s--
2π
The equation can be simplified to the following approximated equation:
f_t
=
----------^f--^s----------
6 ⋅ HPc
Table 23. High-pass filter cut-off frequency configuration
HPcoeff2,1
f_t [Hz]
f_t [Hz]
f_t [Hz]
f_t [Hz]
Data rate = 50 Hz Data rate = 100 Hz Data rate = 400 Hz Data rate = 1000 Hz
00
1
2
8
20
01
0.5
1
4
10
10
0.25
0.5
2
5
11
0.125
0.25
1
2.5
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Doc ID 16917 Rev 1