Freescale Semiconductor FRDM-FXS-MULTI Datenbogen
FXOS8700CQ
Sensors
86
Freescale Semiconductor, Inc.
10.18
Magnetometer vector-magnitude function
The magnetometer vector-magnitude function will generate an interrupt when
> M_VECM_THS value and t > M_VECM_CNT
value. Where m_x_out, m_y_out, and m_z_out are the current decimated magnetometer output values, and m_x_ref, m_y_ref,
and m_z_ref are the internally latched reference values. The user may program the M_VECM_THS and M_VECM_CNT registers
to establish the conditions needed to detect a magnetic vector-magnitude change event. Depending on the values chosen for the
reference values, this function may be configured to detect a magnetic field magnitude that is above a preset threshold (with
reference values = 0), or a change in magnitude between two magnetic vectors greater than the preset threshold (with reference
values non-zero). Please note x_ref, y_ref, z_ref are stored internally and are not observable by the user through the register
interface. Please refer to Freescale application note AN4458.
and m_z_ref are the internally latched reference values. The user may program the M_VECM_THS and M_VECM_CNT registers
to establish the conditions needed to detect a magnetic vector-magnitude change event. Depending on the values chosen for the
reference values, this function may be configured to detect a magnetic field magnitude that is above a preset threshold (with
reference values = 0), or a change in magnitude between two magnetic vectors greater than the preset threshold (with reference
values non-zero). Please note x_ref, y_ref, z_ref are stored internally and are not observable by the user through the register
interface. Please refer to Freescale application note AN4458.
10.18.1 M_VECM_CFG (0x69) register
Table 204. M_VECM_CFG register
—
m_vecm_ele
m_vecm_initm
m_vecm_updm
m_vecm_en
m_vecm_wake_en
m_vecm_init_en m_vecm_init_cfg
0
0
0
0
0
0
0
0
Table 205. M_VECM_CFG bit descriptions
Field
Description
m_vecm_ele
Magnetic vector-magnitude event latch enable:
0: Event latch disabled
1: Event latch enabled
With event latching enabled, the src_m_vecm interrupt flag may only be cleared by reading the M_INT_SRC register.
With event latching disabled, the src_m_vecm interrupt flag is updated in real time and may be cleared by the ASIC prior
to the user reading the flag.
0: Event latch disabled
1: Event latch enabled
With event latching enabled, the src_m_vecm interrupt flag may only be cleared by reading the M_INT_SRC register.
With event latching disabled, the src_m_vecm interrupt flag is updated in real time and may be cleared by the ASIC prior
to the user reading the flag.
m_vecm_initm
Magnetic vector-magnitude initialization mode:
0: The ASIC uses the current magnetic output data as the initial reference values at the time the m_vecm_en bit is set.
1: The ASIC uses the data stored in the M_VECM_X/Y/Z_INIT registers as the initial reference values at the time the
m_vecm_en bit is set.
0: The ASIC uses the current magnetic output data as the initial reference values at the time the m_vecm_en bit is set.
1: The ASIC uses the data stored in the M_VECM_X/Y/Z_INIT registers as the initial reference values at the time the
m_vecm_en bit is set.
m_vecm_updm
Magnetic vector-magnitude reference value update mode:
0: The function updates the reference values with the current X/Y/Z magnetic data when the event is triggered.
1: The function does not update the reference values when the event is triggered.
Setting m_vecm_initm = 1 and m_vecm_updm = 1 allows the user to manually update the reference values using the
M_VECM_INIT_X/Y/Z registers in real time when the function is enabled.
0: The function updates the reference values with the current X/Y/Z magnetic data when the event is triggered.
1: The function does not update the reference values when the event is triggered.
Setting m_vecm_initm = 1 and m_vecm_updm = 1 allows the user to manually update the reference values using the
M_VECM_INIT_X/Y/Z registers in real time when the function is enabled.
m_vecm_en
Magnetic vector-magnitude function enable:
0: Function is disabled.
1: Function is enabled, the ASIC will update the internal m_x/y/z_ref registers with either the current magnetic output
data or the values stored in the M_VECM_INIT_X/Y/Z registers depending on the state of m_vecm_initm.
Note: The magnetic vector-magnitude function will only function correctly up to a maximum ODR of 400 Hz.
0: Function is disabled.
1: Function is enabled, the ASIC will update the internal m_x/y/z_ref registers with either the current magnetic output
data or the values stored in the M_VECM_INIT_X/Y/Z registers depending on the state of m_vecm_initm.
Note: The magnetic vector-magnitude function will only function correctly up to a maximum ODR of 400 Hz.
m_vecm_wake_en
Magnetic vector-magnitude wake enable:
0: The system excludes the src_m_vecm event flag when evaluating the Auto-Sleep function.
1: The system includes the src_m_vecm event flag when evaluating the Auto-Sleep function.
0: The system excludes the src_m_vecm event flag when evaluating the Auto-Sleep function.
1: The system includes the src_m_vecm event flag when evaluating the Auto-Sleep function.
m_vecm_int_en
Magnetic vector-magnitude interrupt enable:
0: Magnetic vector-magnitude interrupt is disabled.
1: Magnetic vector-magnitude interrupt is enabled.
0: Magnetic vector-magnitude interrupt is disabled.
1: Magnetic vector-magnitude interrupt is enabled.
m_vecm_init_cfg
Magnetic vector-magnitude interrupt configuration:
0: Magnetic vector-magnitude interrupt is output on INT2 pin.
1: Magnetic vector-magnitude interrupt is output on INT1 pin.
0: Magnetic vector-magnitude interrupt is output on INT2 pin.
1: Magnetic vector-magnitude interrupt is output on INT1 pin.
m_x_out
m_x_ref
–
(
)
2
m_y_out
m_y_ref
–
(
)
2
m_z_out
m_z_ref
–
(
)
2
+
+