FXLS8471Q Datasheet, PDF (58/75 Pages) Freescale Semiconductor, Inc – Linear Accelerometer

Table 106. A_VECM_INITZ_MSB bit description
Field
a_vecm_initz[13:8]
Description
Most significant 6 bits of the signed 14-bit initial Z-axis value to be used as ref_z when A_VECM_CFG[a_vecm_initm]
= 1. The resolution is determined by the settings made in XYZ_DATA_CFG[fs], and is equal to the accelerometer
resolution.
10.9.10 A_VECM_INITZ_LSB (0x68) register
Table 107. A_VECM_INITZ_LSB register
a_vecm_initz[7:0]
8’b00000000
Table 108. A_VECM_INITZ_LSB bit description
Field
a_vecm_initz[7:0]
Description
LSB of the signed 14-bit initial Z-axis value to be used as ref_z when A_VECM_CFG[a_vecm_initm] = 1. The
resolution is determined by the settings made in XYZ_DATA_CFG[fs], and is equal to the accelerometer resolution.
10.10 Transient (AC) acceleration detection
The transient detection function is similar to the freefall/motion detection function with the exception that a high-pass filter can be
used to eliminate the DC offset from the acceleration data. There is an option to disable the high-pass filter, which causes the
transient detection function to work in a similar manner to the motion detection function.
The transient detection function can be configured to signal an interrupt when the high-pass filtered acceleration delta values for
any of the enabled axes exceeds the threshold programmed in TRANSIENT_THS for the debounce time programmed in
TRANSIENT_COUNT. For more information on how to use and configure the transient detection function please refer to
Freescale application note AN4461.
10.10.1 TRANSIENT_CFG (0x1D) register
Table 109. TRANSIENT_ CFG register
—
—
—
0
0
0
tran_ele
0
tran_zefe
0
tran_yefe
0
tran_xefe
0
tran_hpf_byp
0
Table 110. TRANSIENT_ CFG bit descriptions
Field
tran_ele
tran_zefe
tran_yefe
tran_xefe
tran_hpf_byp
Description
Transient event flag latch enable. Default value: 0
0: Event flag latch disabled: the transient interrupt flag reflects the real-time status of the function.
1: Event flag latch enabled: the transient interrupt event flag is latched and a read of the TRANSIENT_SRC register is
required to clear the event flag.
Z-axis transient event flag enable. Default value: 0
0: Z-axis event detection disabled
1: Z-axis event detection enabled. Raise event flag on Z-axis acceleration value greater than threshold.
Y-axis transient event flag enable. Default value: 0
0: Y-axis event detection disabled
1: Y-axis event detection enabled. Raise event flag on Y-axis acceleration value greater than threshold.
X-axis transient event flag enable. Default value: 0
0: X-axis event detection disabled
1: X-axis event detection enabled. Raise event flag on X-axis acceleration value greater than threshold.
Transient function high-pass filter bypass. Default value: 0
0: High-pass filter is applied to accelerometer data input to the transient function.
1: High-pass filter is not applied to accelerometer data input to the transient function.
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