Freescale Semiconductor FRDM-FXS-MULTI 데이터 시트
MMA8652FC
Sensors
Freescale Semiconductor, Inc.
Freescale Semiconductor, Inc.
37
6.8.2
0x15: FF_MT_CFG Freefall/Motion Configuration register
This is the Freefall/Motion configuration register for setting up the conditions of the freefall or motion function.
Figure 14. FF_MT_CFG high-g and low-g threshold
Table 49. 0x15 FF_MT_CFG register (Read/Write)
Back to Register Address Map
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
ELE
OAE
ZEFE
YEFE
XEFE
—
—
—
Table 50. FF_MT_CFG register
Bit(s)
Field
Description
7
ELE
Event Latch Enable: Event flags are latched into FF_MT_SRC register.
ELE denotes whether the enabled event flag will to be latched into the FF_MT_SRC register or whether the event flag
status in the FF_MT_SRC will indicate the real-time status of the event.
• If ELE bit is set to 1, then the event flags are frozen when the EA bit gets set, and the event flags are cleared by
ELE denotes whether the enabled event flag will to be latched into the FF_MT_SRC register or whether the event flag
status in the FF_MT_SRC will indicate the real-time status of the event.
• If ELE bit is set to 1, then the event flags are frozen when the EA bit gets set, and the event flags are cleared by
reading the FF_MT_SRC source register.
• Reading the FF_MT_SRC register clears the event flag EA and all FF_MT_SRC bits.
0 Event flag latch disabled (default)
1 Event flag latch enabled
0 Event flag latch disabled (default)
1 Event flag latch enabled
6
OAE
Motion detect / Freefall detect flag selection
Selects between Motion (logical OR combination) and Freefall (logical AND combination) detection.
0 Freefall flag (Logical AND combination) (default)
1 Motion flag (Logical OR combination)
Selects between Motion (logical OR combination) and Freefall (logical AND combination) detection.
0 Freefall flag (Logical AND combination) (default)
1 Motion flag (Logical OR combination)
5
ZEFE
Event flag enable on Z
ZHFE enables the detection of a motion or freefall event when the measured acceleration data on Z channel is beyond
the threshold set in FF_MT_THS register.
• If ELE bit (FF_MT_CFG register) is set to 1, then new event flags are blocked from updating the FF_MT_SRC
ZHFE enables the detection of a motion or freefall event when the measured acceleration data on Z channel is beyond
the threshold set in FF_MT_THS register.
• If ELE bit (FF_MT_CFG register) is set to 1, then new event flags are blocked from updating the FF_MT_SRC
register.
0 Event detection disabled (default)
1 Raise event flag on measured acceleration value beyond preset threshold
1 Raise event flag on measured acceleration value beyond preset threshold
4
YEFE
Event flag enable on Y event
YEFE enables the detection of a motion or freefall event when the measured acceleration data on Y channel is beyond
the threshold set in FF_MT_THS register.
• If ELE bit (FF_MT_CFG register) is set to 1, then new event flags are blocked from updating the FF_MT_SRC
YEFE enables the detection of a motion or freefall event when the measured acceleration data on Y channel is beyond
the threshold set in FF_MT_THS register.
• If ELE bit (FF_MT_CFG register) is set to 1, then new event flags are blocked from updating the FF_MT_SRC
register.
0 Event detection disabled (default)
1 Raise event flag on measured acceleration value beyond preset threshold
1 Raise event flag on measured acceleration value beyond preset threshold
3
XEFE
Event flag enable on X event
XEFE enables the detection of a motion or freefall event when the measured acceleration data on X channel is beyond
the threshold set in FF_MT_THS register.
• If ELE bit (FF_MT_CFG register) is set to 1, then new event flags are blocked from updating the FF_MT_SRC
XEFE enables the detection of a motion or freefall event when the measured acceleration data on X channel is beyond
the threshold set in FF_MT_THS register.
• If ELE bit (FF_MT_CFG register) is set to 1, then new event flags are blocked from updating the FF_MT_SRC
register.
0 Event detection disabled (default)
1 Raise event flag on measured acceleration value beyond preset threshold
1 Raise event flag on measured acceleration value beyond preset threshold
2–0
—
+8 g
High-g + Threshold (Motion)
Low-g Threshold (Freefall)
High-g – Threshold (Motion)
–8 g
X, Y, or Z High-g Region
X, Y, or Z High-g Region
X, Y, or Z Low-g Region
Negative
Positive
Acceleration
Acceleration